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Sample records for satellite control centre

  1. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...

  2. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...

  3. Council celebrates CERN Control Centre

    CERN Multimedia

    2006-01-01

    With the unveiling of its new sign, the CERN Control Centre was officially inaugurated on Thursday 16 March. To celebrate its startup, CERN Council members visited the sleek centre, a futuristic-looking room filled with a multitude of monitoring screens.

  4. The new AMS control centre

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    Construction work for the future AMS control room began in November 2010 and should be finished this June. The new building, which will have been completed in record time thanks to the professionalism of the project team, will soon be ready to receive the initial data from the AMS experiment.     Luigi Scibile and Michael Poehler, from the GS department, at the AMS control centre construction site.   The Alpha Magnetic Spectrometer (AMS) is due to wing its way towards the International Space Station (ISS) on board the shuttle Discovery in April. Mainly intended for research on antimatter and dark matter, the data collected by AMS will be sent to Houston in the United States and then directly to CERN’s new Building 946. Construction work for the AMS control centre building on the Route Gentner at CERN’s Prévessin site started in November 2010 and must be completed in time to receive the first data from the spectrometer in June. “It normall...

  5. Satellite Attitude Control System Simulator

    Directory of Open Access Journals (Sweden)

    G.T. Conti

    2008-01-01

    Full Text Available Future space missions will involve satellites with great autonomy and stringent pointing precision, requiring of the Attitude Control Systems (ACS with better performance than before, which is function of the control algorithms implemented on board computers. The difficulties for developing experimental ACS test is to obtain zero gravity and torque free conditions similar to the SCA operate in space. However, prototypes for control algorithms experimental verification are fundamental for space mission success. This paper presents the parameters estimation such as inertia matrix and position of mass centre of a Satellite Attitude Control System Simulator (SACSS, using algorithms based on least square regression and least square recursive methods. Simulations have shown that both methods have estimated the system parameters with small error. However, the least square recursive methods have performance more adequate for the SACSS objectives. The SACSS platform model will be used to do experimental verification of fundamental aspects of the satellite attitude dynamics and design of different attitude control algorithm.

  6. European Centre for Disease Prevention and Control.

    Science.gov (United States)

    Evans, Roger

    2014-11-04

    The European Centre for Disease Prevention and Control was set up in 2005 to strengthen Europe's defences against infectious diseases. The centre is an independent agency of the European Union and is based in Stockholm, Sweden.

  7. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...... can be implemented in the laboratory, e.g. three-axis attitude control, slew manoeuvres, spins stabilization using magnetic actuation and/or reaction wheels. The spacecraft attitude can be determined applying magnetometer measurements...

  8. A day in the CERN Control Centre

    CERN Multimedia

    Rosaria Marraffino

    2015-01-01

    The CERN Control Centre (CCC) is the nerve centre of the CERN beam systems. From this room, the experts prepare, monitor, adjust, and control the particle beams that circulate throughout the accelerator complex while ensuring that the services and the technical infrastructure work flawlessly. Buttons, screens, telephones, lights (but no sound): in the CCC, everything is ready to make it possible for the LHC to reach the unprecedented energies expected at Run 2.   Seen from above, the CERN Control Centre resembles the shape of a quadrupole magnet. The consoles are distributed in four circles, called “islands”, dedicated to the LHC, the SPS, the PS Complex and the Technical Infrastructure (TI) respectively. Spread between TI and LHC are the Cryogenics consoles. Being in the same room allows the 24h-manned islands to be constantly in touch with one another, thus ensuring the best performance of the machines. At the LHC island, operators are currently busy training the magnet...

  9. Enhancing Safety at Airline Operations Control Centre

    Directory of Open Access Journals (Sweden)

    Lukáš Řasa

    2015-04-01

    Full Text Available In recent years a new term of Safety Management System (SMS has been introduced into aviation legislation. This system is being adopted by airline operators. One of the groundbased actors of everyday operations is Operations Control Centre (OCC. The goal of this article has been to identify and assess risks and dangers which occur at OCC and create a template for OCC implementation into SMS.

  10. Satellite Infall and Mass Deposition on the Galactic Centre

    CERN Document Server

    Gallego, Sofia G

    2016-01-01

    We model the infall of a 2e5 Msun satellite galaxy on to the inner 200 parsec of our Galaxy, to test whether the satellite could perturb the gas previously on stable orbits in the central molecular zone (CMZ), as proposed by Lang et al. (2013). This process would have driven a large gas inflow around 10 Myr ago, necessary to explain the past high accretion rate onto the super-massive black hole, and the presence of young stars in the inner parsecs of the Galaxy. Our hydrodynamical simulations show a much smaller inflow of gas, not sufficient to produce the aforementioned effects.

  11. Satellite Attitude Control System Design considering the Fuel Slosh Dynamics

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Gadelha de Souza

    2014-01-01

    Full Text Available The design of the satellite attitude control system (ACS becomes more complex when the satellite structure has different type of components like, flexible solar panels, antennas, mechanical manipulators, and tanks with fuel. A crucial interaction can occur between the fuel slosh motion and the satellite rigid motion during translational and/or rotational manoeuvre since these interactions can change the satellite centre of mass position damaging the ACS pointing accuracy. Although, a well-designed controller can suppress such disturbances quickly, the controller error pointing may be limited by the minimum time necessary to suppress such disturbances thus affecting the satellite attitude acquisition. As a result, the design of the satellite controller needs to explore the limits between the conflicting requirements of performance and robustness. This paper investigates the effects of the interaction between the liquid motion (slosh and the satellite dynamics in order to predict what the damage to the controller performance and robustness is. The fuel slosh dynamics is modelled by a pendulum which parameters are identified using the Kalman filter technique. This information is used to design the satellite controller by the linear quadratic regulator (LQR and linear quadratic Gaussian (LQG methods to perform a planar manoeuvre assuming thrusters are actuators.

  12. The CERN Control Centre is up and running!

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    The CERN Control Centre (CCC) that combines all the control rooms for the accelerators, the cryogenic system and the technical infrastructure came into operation on 1st February. On 1st February, at 2.00 p.m., Patrick Villeton Pachot started the first Technical Infrastructure shift at the brand new CERN Control Centre.

  13. Situational Analysis on Infection Control Practices in DOTS Centres ...

    African Journals Online (AJOL)

    Situational Analysis on Infection Control Practices in DOTS Centres in 7 Local Government Areas in Abia State. ... Open Access DOWNLOAD FULL TEXT ... Instruments used for data collection were the infection control checklist (modified with ...

  14. "SeismoSAT" project results in connecting seismic data centres via satellite

    Science.gov (United States)

    Pesaresi, Damiano; Lenhardt, Wolfgang; Rauch, Markus; Živčić, Mladen; Steiner, Rudolf; Bertoni, Michele; Delazer, Heimo

    2016-04-01

    Since 2002 the OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Udine (Italy), the Zentralanstalt für Meteorologie und Geodynamik (ZAMG) in Vienna (Austria), and the Agencija Republike Slovenije za Okolje (ARSO) in Ljubljana (Slovenia) are collecting, analysing, archiving and exchanging seismic data in real time. Up to now the data exchange between the seismic data centres relied on internet: this however was not an ideal condition for civil protection purposes, since internet reliability is poor. For this reason, in 2012 the Protezione Civile della Provincia Autonoma di Bolzano in Bolzano (Italy) joined OGS, ZAMG and ARSO in the Interreg IV Italia-Austria project "SeismoSAT" (Progetto SeismoSAT, 2014) aimed in connecting the seismic data centres in real time via satellite. As already presented in the past, the general technical schema of the project has been outlined, data bandwidths and monthly volumes required have been quantified, the common satellite provider has been selected and the hardware has been purchased and installed. Right before the end of its financial period, the SeismoSAT project proved to be successful guaranteeing data connection stability between the involved data centres during an internet outage.

  15. Satellite-based climate information within the WMO RA VI Regional Climate Centre on Climate Monitoring

    Science.gov (United States)

    Obregón, A.; Nitsche, H.; Körber, M.; Kreis, A.; Bissolli, P.; Friedrich, K.; Rösner, S.

    2014-05-01

    The World Meteorological Organization (WMO) established Regional Climate Centres (RCCs) around the world to create science-based climate information on a regional scale within the Global Framework for Climate Services (GFCS). The paper introduces the satellite component of the WMO Regional Climate Centre on Climate Monitoring (RCC-CM) for Europe and the Middle East. The RCC-CM product portfolio is based on essential climate variables (ECVs) as defined by the Global Climate Observing System (GCOS), spanning the atmospheric (radiation, clouds, water vapour) and terrestrial domains (snow cover, soil moisture). In the first part, the input data sets are briefly described, which are provided by the EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) Satellite Application Facilities (SAF), in particular CM SAF, and by the ESA (European Space Agency) Climate Change Initiative (CCI). In the second part, the derived RCC-CM products are presented, which are divided into two groups: (i) operational monitoring products (e.g. monthly means and anomalies) based on near-real-time environmental data records (EDRs) and (ii) climate information records (e.g. climatologies, time series, trend maps) based on long-term thematic climate data records (TCDRs) with adequate stability, accuracy and homogeneity. The products are provided as maps, statistical plots and gridded data, which are made available through the RCC-CM website (www.dwd.de/rcc-cm).

  16. Satellite Attitude Control Using Only Electromagnetic Actuation

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    The primary purpose of this work was to develop control laws for three axis stabilization of a magnetic actuated satellite. This was achieved by a combination of linear and nonlinear system theory. In order to reach this goal new theoretical results were produced in both fields. The focus...... was that interaction between the Earth's magnetic field and a magnetic field generated by a set of coils in the satellite can be used for actuation. Magnetic torquing was found attractive for generation of control torques on small satellites, since magnetic control systems are relatively lightweight, require low power...... was stated as a continuous function of the state. A control law for magnetic actuated satellite was proposed. Complete comprehension of the nature of the satellite control problem required a new approach merging the nonlinear control theory with physics of the rigid body motion and an extension of earlier...

  17. The CERN Control Centre is up and running!

    CERN Multimedia

    2006-01-01

    The CERN Control Centre (CCC) that combines all the control rooms for the accelerators, the cryogenic system and the technical infrastructure came into operation on 1st February. This is not a mock-up but the real thing! The CERN Control Centre has been built and put into operation in only 15 months.On 1st February, at 2.00 p.m., Patrick Villeton Pachot started the first Technical Infrastructure shift at the brand new CERN Control Centre. From now on, when you dial 72201 to report a leak or an electrical fault, your call will ring out in the brand new CERN Control Centre. The much anticipated CCC came on line on 1st February, exactly as planned. The 2.00 p.m. shift by the operators of the former Technical Control Room (TCR), now renamed TI for Technical Infrastructure, marked the start of operations at the Centre. The PCR, MCR, TCR and QCR are no more, and all the individual control rooms have been merged into one. And what a control room it is! True to the streamlined image announced when the project was f...

  18. Lorentz Force Based Satellite Attitude Control

    Science.gov (United States)

    Giri, Dipak Kumar; Sinha, Manoranjan

    2016-07-01

    Since the inception of attitude control of a satellite, various active and passive control strategies have been developed. These include using thrusters, momentum wheels, control moment gyros and magnetic torquers. In this present work, a new technique named Lorentz force based Coulombic actuators for the active control is proposed. This method uses electrostatic charged shells, which interact with the time varying earth's magnetic field to establish a full three axes control of the satellite. It is shown that the proposed actuation mechanism is similar to a satellite actuated by magnetic coils except that the resultant magnetic moment vanishes under two different conditions. The equation for the required charges on the the Coulomb shells attached to the satellite body axes is derived, which is in turn used to find the available control torque for actuating the satellite along the orbit. Stability of the proposed system for very high initial angular velocity and exponential stability about the origin are proved for a proportional-differential control input. Simulations are carried out to show the efficacy of the proposed system for the attitude control of the earth-pointing satellite.

  19. Adaptive Fuzzy Attitude Control of Flexible Satellite

    Institute of Scientific and Technical Information of China (English)

    GUAN Ping; LIU Xiang-dong; CHEN Jia-bin

    2005-01-01

    The adaptive fuzzy control is applied in the attitude stabilization of flexible satellite. The detailed design procedure of the adaptive fuzzy control system is presented. Two T-S models are used as both controller and identifier. The parameters of the controller could be modified according to the information of the identifier. Simulation results show that the method can effectively cope with the uncertainty of flexible satellite by on-line learning and thus posses the good robustness. With the proposed method, the precise attitude control is accomplished.

  20. An active attitude control system for a drag sail satellite

    Science.gov (United States)

    Steyn, Willem Herman; Jordaan, Hendrik Willem

    2016-11-01

    The paper describes the development and simulation results of a full ADCS subsystem for the deOrbitSail drag sail mission. The deOrbitSail satellite was developed as part of an European FP7 collaboration research project. The satellite was launched and commissioning started on 10th July 2015. Various new actuators and sensors designed for this mission will be presented. The deOrbitSail satellite is a 3U CubeSat to deploy a 4 by 4 m drag sail from an initial 650 km circular polar low earth orbit. With an active attitude control system it will be shown that by maximising the drag force, the expected de-orbiting period from the initial altitude will be less than 50 days. A future application of this technology will be the use of small drag sails as low-cost devices to de-orbit LEO satellites, when they have reached their end of life, without having to use expensive propulsion systems. Simulation and Hardware-in-Loop experiments proved the feasibility of the proposed attitude control system. A magnetic-only control approach using a Y-Thomson spin, is used to detumble the 3U Cubesat with stowed sail and subsequently to 3-axis stabilise the satellite to be ready for the final deployment phase. Minituarised torquer rods, a nano-sized momentum wheel, attitude sensor hardware (magnetometer, sun, earth) developed for this phase will be presented. The final phase will be to deploy and 3-axis stabilise the drag sail normal to the satellite's velocity vector, using a combined Y-momentum wheel and magnetic controller. The design and performance improvements when using a 2-axis translation stage to adjust the sail centre-of-pressure to satellite centre-of-mass offset, will also be discussed, although for launch risk reasons this stage was not included in the final flight configuration. To accurately determine the drag sail's attitude during the sunlit part of the orbit, an accurate wide field of view dual sensor to measure both the sun and nadir vector direction was developed for

  1. Digital frequency control of satellite frequency standards. [Defense Navigation Satellites

    Science.gov (United States)

    Nichols, S. A.

    1973-01-01

    In the Frequency and Time Standard Development Program of the TIMATION System, a new miniaturized rubidium vapor frequency standard has been tested and analyzed for possible use on the TIMATION 3A launch, as part of the Defense Navigation Satellite Development Program. The design and construction of a digital frequency control was required to remotely control this rubidium vapor frequency standard as well as the quartz oscillator in current use. This control must be capable of accepting commands from a satellite telemetry system, verify that the correct commands have been sent and control the frequency to the requirements of the system. Several modifications must be performed to the rubidium vapor frequency standard to allow it to be compatible with the digital frequency control. These include the addition of a varactor to voltage tune the coarse range of the flywheel oscillator, and a modification to supply the C field current externally. The digital frequency control for the rubidium vapor frequency standard has been successfully tested in prototype form.

  2. Adaptive Control of Rigid Body Satellite

    Institute of Scientific and Technical Information of China (English)

    Thawar T. Arif

    2008-01-01

    The minimal controller synthesis (MCS) is an extension of the hyperstable model reference adaptive control algorithm. The aim of minimal controller synthesis is to achieve excellent closed-loop control despite the presence of plant parameter variations, external disturbances, dynamic coupling within the plant and plant nonlinearities. The minimal controller synthesis algorithm was successfully applied to the problem of decentralized adaptive schemes. The decentralized minimal controller synthesis adaptive control strategy for controlling the attitude of a rigid body satellite is adopted in this paper. A model reference adaptive control strategy which uses one single three-axis slew is proposed for the purpose of controlling the attitude of a rigid body satellite. The simulation results are excellent and show that the controlled system is robust against disturbances.

  3. A centre for accommodative vergence motor control

    Science.gov (United States)

    Wilson, D.

    1973-01-01

    Latencies in accommodation, accommodative-vergence, and pupil-diameter responses to changing accommodation stimuli, as well as latencies in pupil response to light-intensity changes were measured. From the information obtained, a block diagram has been derived that uses the least number of blocks for representing the accommodation, accommodative-vergence, and pupil systems. The signal transmission delays over the various circuits of the model have been determined and compared to known experimental physiological-delay data. The results suggest the existence of a motor center that controls the accommodative vergence and is completely independent of the accommodation system.

  4. A computer simulation of the new Control Centre (CCC)

    CERN Multimedia

    2004-01-01

    In a development crucial for the success of the LHC, CERN will build a Control Centre (CCC) for the operation of all its beams and accelerators. The CCC will be an extension of the existing PCR building at Prévessin and is due to be operational by 1 February 2006.

  5. RIVM Centre for Infectious Disease Control : Strategy 2016-2021

    NARCIS (Netherlands)

    Riesmeijer RM; van Dissel JT; I&V

    2017-01-01

    This strategy describes the ambitions of the Centre for Infectious Disease Control (CIb) for the coming years. It concerns the changes that the CIb considers to be necessary, rather than a summary of activities.

    Thanks to the efforts made by prevention and vaccination programmes, in the

  6. Chaotic satellite attitude control by adaptive approach

    Science.gov (United States)

    Wei, Wei; Wang, Jing; Zuo, Min; Liu, Zaiwen; Du, Junping

    2014-06-01

    In this article, chaos control of satellite attitude motion is considered. Adaptive control based on dynamic compensation is utilised to suppress the chaotic behaviour. Control approaches with three control inputs and with only one control input are proposed. Since the adaptive control employed is based on dynamic compensation, faithful model of the system is of no necessity. Sinusoidal disturbance and parameter uncertainties are considered to evaluate the robustness of the closed-loop system. Both of the approaches are confirmed by theoretical and numerical results.

  7. The MyOcean Thematic Assembly Centres: Satellite and In-situ Observation Services in Review

    Science.gov (United States)

    Hackett, Bruce; Breivik, Lars-Anders; Larnicol, Gilles; Pouliquen, Sylvie; Santoleri, Rosalia; Roquet, Hervé; Stoffelen, Ad

    2015-04-01

    The MyOcean (2009-2012), MyOcean2 (2012-2014) and MyOcean Follow-On (October 2014 - March 2015) projects, respectively funded by the EU's 7th Framework Programme for Research (FP7 2007-2013) and HORIZON 2020 (EU Research and Innovation programme 2014-2020), have been designed to prepare and to lead the demonstration phases of the nascent European Copernicus Marine Environment Monitoring Service (CMS). The observational component of the MyOcean services is embodied in four Thematic Assembly Centres (TACs): Three provide satellite-based products for sea level (SL-TAC), for ocean colour (OC-TAC) and for surface temperature, winds and sea ice (OSI-TAC), while the fourth provides in-situ observations (INS-TAC). All the TAC production is developed from existing capabilities and there is close collaboration with related national and European data providers. Data products include near-real-time data and multi-year reprocessed datasets. Data formatting, dissemination methods and documentation follow uniform MyOcean standards for ease of use. The presentation will track the evolution of the TAC services through the MyOcean projects up to the opening of the CMS.

  8. Determination of the centre of mass kinematics in alpine skiing using differential global navigation satellite systems.

    Science.gov (United States)

    Gilgien, Matthias; Spörri, Jörg; Chardonnens, Julien; Kröll, Josef; Limpach, Philippe; Müller, Erich

    2015-01-01

    In the sport of alpine skiing, knowledge about the centre of mass (CoM) kinematics (i.e. position, velocity and acceleration) is essential to better understand both performance and injury. This study proposes a global navigation satellite system (GNSS)-based method to measure CoM kinematics without restriction of capture volume and with reasonable set-up and processing requirements. It combines the GNSS antenna position, terrain data and the accelerations acting on the skier in order to approximate the CoM location, velocity and acceleration. The validity of the method was assessed against a reference system (video-based 3D kinematics) over 12 turn cycles on a giant slalom skiing course. The mean (± s) position, velocity and acceleration differences between the CoM obtained from the GNSS and the reference system were 9 ± 12 cm, 0.08 ± 0.19 m · s(-1) and 0.22 ± 1.28 m · s(-2), respectively. The velocity and acceleration differences obtained were smaller than typical differences between the measures of several skiers on the same course observed in the literature, while the position differences were slightly larger than its discriminative meaningful change. The proposed method can therefore be interpreted to be technically valid and adequate for a variety of biomechanical research questions in the field of alpine skiing with certain limitations regarding position.

  9. Congestion control and routing over satellite networks

    Science.gov (United States)

    Cao, Jinhua

    Satellite networks and transmissions find their application in fields of computer communications, telephone communications, television broadcasting, transportation, space situational awareness systems and so on. This thesis mainly focuses on two networking issues affecting satellite networking: network congestion control and network routing optimization. Congestion, which leads to long queueing delays, packet losses or both, is a networking problem that has drawn the attention of many researchers. The goal of congestion control mechanisms is to ensure high bandwidth utilization while avoiding network congestion by regulating the rate at which traffic sources inject packets into a network. In this thesis, we propose a stable congestion controller using data-driven, safe switching control theory to improve the dynamic performance of satellite Transmission Control Protocol/Active Queue Management (TCP/AQM) networks. First, the stable region of the Proportional-Integral (PI) parameters for a nominal model is explored. Then, a PI controller, whose parameters are adaptively tuned by switching among members of a given candidate set, using observed plant data, is presented and compared with some classical AQM policy examples, such as Random Early Detection (RED) and fixed PI control. A new cost detectable switching law with an interval cost function switching algorithm, which improves the performance and also saves the computational cost, is developed and compared with a law commonly used in the switching control literature. Finite-gain stability of the system is proved. A fuzzy logic PI controller is incorporated as a special candidate to achieve good performance at all nominal points with the available set of candidate controllers. Simulations are presented to validate the theory. An effocient routing algorithm plays a key role in optimizing network resources. In this thesis, we briefly analyze Low Earth Orbit (LEO) satellite networks, review the Cross Entropy (CE

  10. Satellite Formation Control Using Atmospheric Drag

    Science.gov (United States)

    2007-03-01

    all cases tested, and the eccentricity-minimizing control law was able to maintain the position within 4.17 feet. More recently, Wedekind considered...three different formations, in-plane, in-track, and circular, was considered. Wedekind achieved favorable results for these three formations when the...and Kluwer Academic Publishers, 2004. 23. Wedekind , James T. Characterizing and Controlling the Effects of Differential Drag on Satellite Formations

  11. Small Satellite Passive Magnetic Attitude Control

    Science.gov (United States)

    Gerhardt, David T.

    Passive Magnetic Attitude Control (PMAC) is capable of aligning a satellite within 5 degrees of the local magnetic field at low resource cost, making it ideal for a small satellite. However, simulation attempts to date have not been able to predict the attitude dynamics at a level sufficient for mission design. Also, some satellites have suffered from degraded performance due to an incomplete understanding of PMAC system design. This dissertation alleviates these issues by discussing the design, inputs, and validation of PMAC systems for small satellites. Design rules for a PMAC system are defined using the Colorado Student Space Weather Experiment (CSSWE) CubeSat as an example. A Multiplicative Extended Kalman Filter (MEKF) is defined for the attitude determination of a PMAC satellite without a rate gyro. After on-orbit calibration of the off-the-shelf magnetometer and photodiodes and an on-orbit fit to the satellite magnetic moment, the MEKF regularly achieves a three sigma attitude uncertainty of 4 degrees or less. CSSWE is found to settle to the magnetic field in seven days, verifying its attitude design requirement. A Helmholtz cage is constructed and used to characterize the CSSWE bar magnet and hysteresis rods both individually and in the flight configuration. Fitted parameters which govern the magnetic material behavior are used as input to a PMAC dynamics simulation. All components of this simulation are described and defined. Simulation-based dynamics analysis shows that certain initial conditions result in abnormally decreased settling times; these cases may be identified by their dynamic response. The simulation output is compared to the MEKF output; the true dynamics are well modeled and the predicted settling time is found to possess a 20 percent error, a significant improvement over prior simulation.

  12. Satellite Attitude Control Using Atmospheric Drag

    Science.gov (United States)

    2007-03-01

    Astronautics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command In...yaw axes and provide magnetic damping on both the pitch and yaw axes. The satellite resem- bles a shuttlecock used in badminton (see Figure 2.2). The...Control Using Atmospheric Drag Guettler, David B., Captain, USAF Air Force Institute of Technology Graduate School of Engineering and Management (AFIT

  13. Integrated solution for the complete remote sensing process - Earth Observation Mission Control Centre (EOMC2)

    Science.gov (United States)

    Czapski, Paweł

    2016-07-01

    We are going to show the latest achievements of the Remote Sensing Division of the Institute of Aviation in the area of remote sensing, i.e. the project of the integrated solution for the whole remote sensing process ranging from acquiring to providing the end user with required information. Currently, these tasks are partially performed by several centers in Poland, however there is no leader providing an integrated solution. Motivated by this fact, the Earth Observation Mission Control Centre (EOMC2) was established in the Remote Sensing Division of the Institute of Aviation that will provide such a comprehensive approach. Establishing of EOMC2 can be compared with creating Data Center Aerial and Satellite Data Centre (OPOLIS) in the Institute of Geodesy and Cartography in the mid-70s in Poland. OPOLIS was responsible for broadly defined data processing, it was a breakthrough innovation that initiated the use of aerial image analysis in Poland. Operation center is a part of the project that will be created, which in comparison with the competitors will provide better solutions, i.e.: • Centralization of the acquiring, processing, publishing and archiving of data, • Implementing elements of the INSPIRE directive recommendations on spatial data management, • Providing the end-user with information in the near real-time, • Ability of supplying the system with images of various origin (aerial, satellite, e.g. EUMETCast, Sentinel, Landsat) and diversity of telemetry data, data aggregation and using the same algorithms to images obtained from different sources, • System reconfiguration and batch processing of large data sets at any time, • A wide range of potential applications: precision agriculture, environmental protection, crisis management and national security, aerial, small satellite and sounding rocket missions monitoring.

  14. Profit Centres and Internal Controls as Drivers of Business Efficiency

    Directory of Open Access Journals (Sweden)

    Ivana Drožđek

    2013-07-01

    Full Text Available Understanding the current and future needs of the market, and knowing how to fulfil them, is the task of any successful economy. Companies wanting to be in step with the development of modern economy are trying to reorient their business regarding its organization, technology and information processes in order to increase their business efficiency. Thus, an adequately established and organized system of internal control, as well as a properly designed and highly efficient organizational structure also represents one of the challenges of a modern enterprise. Therefore, the combination of the internal control system and profit centres is the system which reduces the probability of errors and possible fraud to a minimum and is a prerequisite of efficient business.

  15. Satellite Laser Ranging Photon-Budget Calculations for a Single Satellite Cornercube Retroreflector: Attitude Control Tolerance

    Science.gov (United States)

    2015-11-01

    UNCLASSIFIED Satellite Laser Ranging Photon-Budget Calculations for a Single Satellite Cornercube Retroreflector: Attitude Control Tolerance Philip C...the SLR station, and the direction of the satellite from the SLR station. The required attitude control tolerance is to within 17◦ of the optimal... attitude control strategy determined in the present work. A pre-launch measurement of the re- flectance (diffraction) pattern of each retroreflector is

  16. Observer-based Satellite Attitude Control and Simulation Researches

    Institute of Scientific and Technical Information of China (English)

    王子才; 马克茂

    2002-01-01

    Observer design method is applied to the realization of satellite attitude control law baaed on simplified control model. Exact mathematical model of the satellite attitude control system is also constructed, together with the observer-based control law, to conduct simulation research. The simulation results justify the effectiveness andfeasibility of the observer-based control method.

  17. {\\pi}-Control: A Personal Cloud Control Centre

    CERN Document Server

    Spillner, Josef

    2012-01-01

    Consumption of online services and cloud computing offerings is on the rise, largely due to compelling advantages over traditional local applications. From a user perspective, these include zero-maintenance of software, the always-on nature of such services, mashups of different applications and the networking effect with other users. Associated disadvantages are known, but effective means and tools to limit their effect are not yet well-established and not yet generally available to service users. We propose (1) a user-centric model of cloud elements beyond the conventional aaS layers, including activities across trust zones, and (2) a personal control console for all individual and collaborative user activities in the cloud.

  18. Flexible Satellite Attitude Control via Adaptive Fuzzy Linearization

    Institute of Scientific and Technical Information of China (English)

    GUAN Ping; LIU Xiang-dong; CHEN Jia-bin; LIU Xiao-he

    2005-01-01

    The adaptive fuzzy control is combined with input-output linearization control to constitute the hybrid controller. The control method is then applied to the attitude maneuver control of the flexible satellite.The basic control structure is given. The rules of the controller parameter selection, which guarantee the attitude stabilization of the satellite with parameter uncertainties, have been analyzed. Simulation results show that the precise attitude control is accomplished in spite of the uncertainty in the system.

  19. Optimal Release Control of Companion Satellite System Using Electromagnetic Forces

    Institute of Scientific and Technical Information of China (English)

    Zengwen Xu,Peng Shi; Yushan Zhao∗

    2015-01-01

    Electromagnetic forces generated by the inter⁃action of component satellites can be used to release companion satellites. Optimal release trajectories for companion satellite system using inter⁃electromagnetic forces were investigated. Firstly, nonlinear relative motion dynamic equations of a two⁃craft electromagnetic companion satellite system were derived in spatial polar coordinates. Then principles of electromagnetic satellite formation flying were introduced. Secondly, the characteristics of the electromagnetic companion satellites release were analyzed and optimal release trajectories of companion satellites using electromagnetic forces were obtained using Gauss pseudospectral method. Three performance criteria were chosen as minimum time, minimum acceleration of the separation distance and minimum control acceleration. Finally, three release examples including expansion along separation distance, rotation in orbital plane and stable formation reconfiguration were given to demonstrate the feasibility of this method. Results indicated that the release trajectories can converge to optimal solutions effectively and the concept of release companion satellites using electromagnetic forces is practicable.

  20. Interface control procedures for university satellite programmes

    NARCIS (Netherlands)

    Perez Lebbink, L.; Hamann, R.J.; Bouwmeester, J.; Brouwer, G.F.

    2009-01-01

    Now that more and more universities have joined the CubeSat community and have their own satellite in Earth orbit, it is expected that the planned successors will be of higher complexity. These successors within a university satellite programme will often house more technically ad-vanced subsystems

  1. Interface control procedures for university satellite programmes

    NARCIS (Netherlands)

    Perez Lebbink, L.; Hamann, R.J.; Bouwmeester, J.; Brouwer, G.F.

    2009-01-01

    Now that more and more universities have joined the CubeSat community and have their own satellite in Earth orbit, it is expected that the planned successors will be of higher complexity. These successors within a university satellite programme will often house more technically ad-vanced subsystems

  2. High Precision Control of Ship-Mounted Satellite Tracking Antenna

    DEFF Research Database (Denmark)

    Mohsen, Soltani; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

    2007-01-01

    The telecommunication on a modern merchandise ship is maintained by means of satellite communication. The task of the tracking system is to position the on-board antenna toward a chosen satellite. The control system is capable of rejecting the external disturbances which affect on the under......-actuated antenna and ensures that it remains locked on the satellite. In this paper, a nonlinear internal model controller (NIMC), which achieves asymptotic tracking for the nonlinear antenna system with nonlinear exogenous dynamics, is proposed. Computer simulations as well as practical tests verify...... the effectiveness of this method to cope with the external disturbances that are imposed to the satellite tracking antenna (STA)....

  3. High Precision Control of Ship-Mounted Satellite Tracking Antenna

    DEFF Research Database (Denmark)

    Mohsen, Soltani; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

    2007-01-01

    The telecommunication on a modern merchandise ship is maintained by means of satellite communication. The task of the tracking system is to position the on-board antenna toward a chosen satellite. The control system is capable of rejecting the external disturbances which affect on the under......-actuated antenna and ensures that it remains locked on the satellite. In this paper, a nonlinear internal model controller (NIMC), which achieves asymptotic tracking for the nonlinear antenna system with nonlinear exogenous dynamics, is proposed. Computer simulations as well as practical tests verify...... the effectiveness of this method to cope with the external disturbances that are imposed to the satellite tracking antenna (STA)....

  4. A Robust Controller Structure for Pico-Satellite Applications

    DEFF Research Database (Denmark)

    Kragelund, Martin Nygaard; Green, Martin; Kristensen, Mads

    This paper describes the development of a robust controller structure for use in pico-satellite missions. The structure relies on unknown disturbance estimation and use of robust control theory to implement a system that is robust to both unmodeled disturbances and parameter uncertainties. As one...... possible application, a satellite mission with the purpose of monitoring shipping routes for oil spills has been considered. However, it is the aim of the control structure to be widely applicable and adaptable for a vide variety of pico-satellite missions. The robust control structure has been evaluated...

  5. Sliding Mode Attitude Control for Magnetic Actuated Satellite

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1998-01-01

    Magnetic torquing is attractive as a control principle on small satellites. The actuation principle is to use the interaction between the earth's magnetic field and magnetic field generated by a coil set in the satellite. This control principle is inherently nonlinear, and difficult to use becaus...... the spacecraft attitude using only magnetic torquing is realized in the form of the sliding mode control. A three dimensional sliding manifold is proposed, and it is shown that the satellite motion on the sliding manifold is asymptotically stable......Magnetic torquing is attractive as a control principle on small satellites. The actuation principle is to use the interaction between the earth's magnetic field and magnetic field generated by a coil set in the satellite. This control principle is inherently nonlinear, and difficult to use because...... control torques can only be generated perpendicular to the local geomagnetic field vector. This has been a serious obstacle for using magnetorquer based control for three-axis attitude control. This paper deals with three-axis stabilization of a low earth orbit satellite. The problem of controlling...

  6. Guidance and Control System for a Satellite Constellation

    Science.gov (United States)

    Bryson, Jonathan Lamar; Cox, James; Mays, Paul Richard; Neidhoefer, James Christian; Ephrain, Richard

    2010-01-01

    A distributed guidance and control algorithm was developed for a constellation of satellites. The system repositions satellites as required, regulates satellites to desired orbits, and prevents collisions. 1. Optimal methods are used to compute nominal transfers from orbit to orbit. 2. Satellites are regulated to maintain the desired orbits once the transfers are complete. 3. A simulator is used to predict potential collisions or near-misses. 4. Each satellite computes perturbations to its controls so as to increase any unacceptable distances of nearest approach to other objects. a. The avoidance problem is recast in a distributed and locally-linear form to arrive at a tractable solution. b. Plant matrix values are approximated via simulation at each time step. c. The Linear Quadratic Gaussian (LQG) method is used to compute perturbations to the controls that will result in increased miss distances. 5. Once all danger is passed, the satellites return to their original orbits, all the while avoiding each other as above. 6. The delta-Vs are reasonable. The controller begins maneuvers as soon as practical to minimize delta-V. 7. Despite the inclusion of trajectory simulations within the control loop, the algorithm is sufficiently fast for available satellite computer hardware. 8. The required measurement accuracies are within the capabilities of modern inertial measurement devices and modern positioning devices.

  7. Orbit control of a stratospheric satellite with parameter uncertainties

    Science.gov (United States)

    Xu, Ming; Huo, Wei

    2016-12-01

    When a stratospheric satellite travels by prevailing winds in the stratosphere, its cross-track displacement needs to be controlled to keep a constant latitude orbital flight. To design the orbit control system, a 6 degree-of-freedom (DOF) model of the satellite is established based on the second Lagrangian formulation, it is proven that the input/output feedback linearization theory cannot be directly implemented for the orbit control with this model, thus three subsystem models are deduced from the 6-DOF model to develop a sequential nonlinear control strategy. The control strategy includes an adaptive controller for the balloon-tether subsystem with uncertain balloon parameters, a PD controller based on feedback linearization for the tether-sail subsystem, and a sliding mode controller for the sail-rudder subsystem with uncertain sail parameters. Simulation studies demonstrate that the proposed control strategy is robust to uncertainties and satisfies high precision requirements for the orbit flight of the satellite.

  8. Statistical Design Model (SDM) of satellite thermal control subsystem

    Science.gov (United States)

    Mirshams, Mehran; Zabihian, Ehsan; Aarabi Chamalishahi, Mahdi

    2016-07-01

    Satellites thermal control, is a satellite subsystem that its main task is keeping the satellite components at its own survival and activity temperatures. Ability of satellite thermal control plays a key role in satisfying satellite's operational requirements and designing this subsystem is a part of satellite design. In the other hand due to the lack of information provided by companies and designers still doesn't have a specific design process while it is one of the fundamental subsystems. The aim of this paper, is to identify and extract statistical design models of spacecraft thermal control subsystem by using SDM design method. This method analyses statistical data with a particular procedure. To implement SDM method, a complete database is required. Therefore, we first collect spacecraft data and create a database, and then we extract statistical graphs using Microsoft Excel, from which we further extract mathematical models. Inputs parameters of the method are mass, mission, and life time of the satellite. For this purpose at first thermal control subsystem has been introduced and hardware using in the this subsystem and its variants has been investigated. In the next part different statistical models has been mentioned and a brief compare will be between them. Finally, this paper particular statistical model is extracted from collected statistical data. Process of testing the accuracy and verifying the method use a case study. Which by the comparisons between the specifications of thermal control subsystem of a fabricated satellite and the analyses results, the methodology in this paper was proved to be effective. Key Words: Thermal control subsystem design, Statistical design model (SDM), Satellite conceptual design, Thermal hardware

  9. Control of satellite clusters in elliptic orbit with limited communication.

    Science.gov (United States)

    Chichka, David F; Belanger, Gene; Speyer, Jason L

    2004-05-01

    The cooperative control of satellite clusters in elliptical, low-Earth orbit is studied, with the goal of minimizing the necessary information passed among the individual satellites in the cluster. We investigate two possible control paradigms in this paper. The system is described using linearized equations of motion, allowing it to be expressed as a time-varying linear system. The control objective is to attain a required formation at a specified point along the orbit. A decentralized controller is used, in which each satellite maintains a local estimate of the overall state of the cluster. These estimates, along with any control information, are shared after any satellite executes a control action. The second paradigm is an extension of the first, in which state estimates are never shared, and only the control information is passed. In each case, less information being passed results in a higher computational burden on each satellite. Simulation results show cyclic errors, likely induced by higher-order terms in eccentricity and inclinations. The controller that shares state estimates performs much better than the controller that passes only control information.

  10. Incoherent correlator system for satellite orientation control

    Science.gov (United States)

    Kouris, Aristodemos; Young, Rupert C. D.; Chatwin, Christopher R.; Birch, Philip M.

    2002-03-01

    An incoherent correlator configuration is proposed and experimentally demonstrated that is capable of recognizing star patterns. The device may thus be employed for the orientation and navigation of a satellite or spacecraft. The correlator employs starlight directly and requires no laser or input spatial light modulator for operation. The filter is constructed form an array of mirrors that may be individually appropriately tilted so as recognize a particular star arrangement. The only other components of the system are a converging lens and CCD array detector. The device is capable of determining the pointing direction and rotation of a satellite or space vehicle. Experimental results employing the mirror array device illuminated with a point source early to simulate starlight are presented.

  11. Efficient mission control for the 48-satellite Globalstar Constellation

    Science.gov (United States)

    Smith, Dan

    1994-11-01

    The Globalstar system is being developed by Globalstar, Limited Partnership and will utilize 48 satellites in low earth orbit (See Figure 1) to create a world-wide mobile communications system consistent with Vice President Gore's vision of a Global Information Infrastructure. As a large long term commercial system developed by a newly formed organization, Globalstar provides an excellent opportunity to explore innovative solutions for highly efficient satellite command and control. Design and operational concepts being developed are unencumbered by existing physical and organizational infrastructures. This program really is 'starting with a clean sheet of paper'. Globalstar operations challenges can appear enormous. Clearly, assigning even a single person around the clock to monitor and control each satellite is excessive for Globalstar (it would require a staff of 200] . Even with only a single contact per orbit per satellite, data acquisitions will start or stop every 45 seconds] Although essentially identical, over time the satellites will develop their own 'personalities'and will re quire different data calibrations and levels of support. This paper discusses the Globalstar system and challenges and presents engineering concepts, system design decisions, and operations concepts which address the combined needs and concerns of satellite, ground system, and operations teams. Lessons from past missions have been applied, organizational barriers broken, partnerships formed across the mission segments, and new operations concepts developed for satellite constellation management. Control center requirements were then developed from the operations concepts.

  12. Attitude Control Subsystem for the Advanced Communications Technology Satellite

    Science.gov (United States)

    Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

    1996-01-01

    This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

  13. Observation and control of blinking nitrogen-vacancy centres in discrete nanodiamonds.

    Science.gov (United States)

    Bradac, C; Gaebel, T; Naidoo, N; Sellars, M J; Twamley, J; Brown, L J; Barnard, A S; Plakhotnik, T; Zvyagin, A V; Rabeau, J R

    2010-05-01

    Nitrogen-vacancy colour centres in diamond can undergo strong, spin-sensitive optical transitions under ambient conditions, which makes them attractive for applications in quantum optics, nanoscale magnetometry and biolabelling. Although nitrogen-vacancy centres have been observed in aggregated detonation nanodiamonds and milled nanodiamonds, they have not been observed in very small isolated nanodiamonds. Here, we report the first direct observation of nitrogen-vacancy centres in discrete 5-nm nanodiamonds at room temperature, including evidence for intermittency in the luminescence (blinking) from the nanodiamonds. We also show that it is possible to control this blinking by modifying the surface of the nanodiamonds.

  14. Satellite Dynamic Damping via Active Force Control Augmentation

    Science.gov (United States)

    Varatharajoo, Renuganth

    2012-07-01

    An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for a satellite active dynamic damping towards a full attitude control. The AFC method has been established to facilitate a robust motion control of dynamical systems in the presence of disturbances, parametric uncertainties and changes that are commonly prevalent in the real-world environment. The usefulness of the method can be extended by introducing intelligent mechanisms to approximate the mass or inertia matrix of the dynamic system to trigger the compensation effect of the controller. AFC is a technique that relies on the appropriate estimation of the inertial or mass parameters of the dynamic system and the measurements of the acceleration and force signals induced by the system if practical implementation is ever considered. In AFC, it is shown that the system subjected to a number of disturbances remains stable and robust via the compensating action of the control strategy. We demonstrate that it is possible to design a spacecraft attitude feedback controller that will ensure the system dynamics set point remains unchanged even in the presence of the disturbances provided that the actual disturbances can be modeled effectively. In order to further facilitate this analysis, a combined energy and attitude control system (CEACS) is proposed as a model satellite attitude control actuator. All the governing equations are established and the proposed satellite attitude control architecture is made amenable to numerical treatments. The results show that the PD-AFC attitude damping performances are superiorly better than that of the solely PD type. It is also shown that the tunings of the AFC system gains are crucial to ensure a better attitude damping performance and this process is mandatory for AFC systems. Finally, the results demonstrate an important satellite dynamic damping enhancement capability using the AFC

  15. Retrospective exposure assessment and quality control in an international multi-centre case-control study

    DEFF Research Database (Denmark)

    Tinnerberg, H; Heikkilä, P; Huici-Montagud, A;

    2003-01-01

    The paper presents the exposure assessment method and quality control procedure used in an international, multi-centre case-control study within a joint Nordic and Italian cohort. This study was conducted to evaluate whether occupational exposure to carcinogens influenced the predictivity of high...... frequency of chromosomal aberrations (CA) in peripheral lymphocytes for increased cancer risk. Occupational hygienists assessed exposures in each participating country: Denmark, Finland, Italy, Norway and Sweden. The exposure status to a carcinogen or a clastogen was coded in the cohort according...... country-specific differences, differences in information available to the home assessor and the others and misunderstandings or difficulties in translation of information. To ensure the consistency of exposure assessments in international retrospective case-control studies it is important to have a well...

  16. Remote Sensing of the EnviSat and Cbers-2B satellites rotation around the centre of mass by photometry

    Science.gov (United States)

    Koshkin, N.; Korobeynikova, E.; Shakun, L.; Strakhova, S.; Tang, Z. H.

    2016-08-01

    During 2013-2015 the photometric observations of the EnviSat satellite, which became space debris after the failure in April 2012 in low Earth orbit, were performed. The rotation pole position and slow change in sidereal rotation period were updated on the basis of analysis of specular glints observed in 222 light curves using reduction of synodic periods. Apparently, there are minor oscillations of the rotation pole near the normal to the orbital plane. The sense of the EnviSat's spinning is opposite to the sense of its orbital rotation. The sidereal period is best approximated by the second-order polynomial: Psid (sec) = 0.000021534 ·T2 + 0.04936003 · T + 121.18195 where T is measured in days from the beginning of 2013. This method being applied to another representative of space debris, namely the Cbers-2B satellite, has shown a similar result: there is not precise solution for the rotation pole either as it undergoes oscillations with various time scale from several hours to several months. In 2014, the spin axis made the 10 ° angle with the normal to the orbital plane while the sense of spinning is direct in this case, i.e. coincides with the sense of orbital rotation. The sidereal period is best approximated by the following expression: Psid (sec) = 0.000029543 ·T2 + 0.08094931 · T + 81.31775 where T is measured in days starting from March 10, 2014. This method allows of controlling slow changes in the spatial orientation of the rotation axis of the satellites in which specular reflection of light from flat faces of the surface is inherent.

  17. Satellite cascade attitude control via fuzzy PD controller with active force control under momentum dumping

    Science.gov (United States)

    Ismail, Z.; Varatharajoo, R.

    2016-10-01

    In this paper, fuzzy proportional-derivative (PD) controller with active force control (AFC) scheme is studied and employed in the satellite attitude control system equipped with reaction wheels. The momentum dumping is enabled via proportional integral (PI) controller as the system is impractical without momentum dumping control. The attitude controllers are developed together with their governing equations and evaluated through numerical treatment with respect to a reference satellite mission. From the results, it is evident that the three axis attitudes accuracies can be improved up to ±0.001 degree through the fuzzy PD controller with AFC scheme for the attitude control. In addition, the three-axis wheel angular momentums are well maintained during the attitude control tasks.

  18. Reliable Control of Ship-mounted Satellite Tracking Antenna

    DEFF Research Database (Denmark)

    Soltani, Mohsen; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

    2010-01-01

    Motorized antenna is a key element in overseas satellite telecommunication. The control system directs the on-board antenna toward a chosen satellitewhile the high sea waves disturb the antenna. Certain faults (communication system malfunction or signal blocking) cause interruption in the communi......Motorized antenna is a key element in overseas satellite telecommunication. The control system directs the on-board antenna toward a chosen satellitewhile the high sea waves disturb the antenna. Certain faults (communication system malfunction or signal blocking) cause interruption...

  19. Game Theoretic Approach to Post-Docked Satellite Control

    Science.gov (United States)

    Hiramatsu, Takashi; Fitz-Coy, Norman G.

    2007-01-01

    This paper studies the interaction between two satellites after docking. In order to maintain the docked state with uncertainty in the motion of the target vehicle, a game theoretic controller with Stackelberg strategy to minimize the interaction between the satellites is considered. The small perturbation approximation leads to LQ differential game scheme, which is validated to address the docking interactions between a service vehicle and a target vehicle. The open-loop solution are compared with Nash strategy, and it is shown that less control efforts are obtained with Stackelberg strategy.

  20. Sliding mode control of electromagnetic tethered satellite formation

    Science.gov (United States)

    Hallaj, Mohammad Amin Alandi; Assadian, Nima

    2016-08-01

    This paper investigates the control of tethered satellite formation actuated by electromagnetic dipoles and reaction wheels using the robust sliding mode control technique. Generating electromagnetic forces and moments by electric current coils provides an attractive control actuation alternative for tethered satellite system due to the advantages of no propellant consumption and no obligatory rotational motion. Based on a dumbbell model of tethered satellite in which the flexibility and mass of the tether is neglected, the equations of motion in Cartesian coordinate are derived. In this model, the J2 perturbation is taken into account. The far-field and mid-field models of electromagnetic forces and moments of two satellites on each other and the effect of the Earth's magnetic field are presented. A robust sliding mode controller is designed for precise trajectory tracking purposes and to deal with the electromagnetic force and moment uncertainties and external disturbances due to the Earth's gravitational and magnetic fields inaccuracy. Numerical simulation results are presented to validate the effectiveness of the developed controller and its superiority over the linear controller.

  1. Controlling chaos in a satellite power supply subsystem

    Science.gov (United States)

    Macau, E. E. N.; Ramos Turci, L. F.; Yoneyama, T.

    2008-12-01

    In this work, we show that chaos control techniques can be used to increase the region that can be efficiently used to supply the power requests for an artificial satellite. The core of a satellite power subsystem relies on its DC/DC converter. This is a very nonlinear system that presents a multitude of phenomena ranging from bifurcations, quasi-periodicity, chaos, coexistence of attractors, among others. The traditional power subsystem design techniques try to avoid these nonlinear phenomena so that it is possible to use linear system theory in small regions about the equilibrium points. Here, we show that chaos control can be used to efficiently extend the applicability region of the satellite power subsystem when it operates in regions of high nonlinearity.

  2. Advanced Attitude Control af Pico Sized Satellites

    DEFF Research Database (Denmark)

    Larsen, Jesper A.; Amini, Rouzbeh; Izadi-Zamanabadi, Roozbeh

    2005-01-01

    accuracy of better than 5 degrees. Cost, size, weight and power requirements, on the other hand, impose selecting relative simple sensors and actuators which leads to an attitude control requirement of less than 1 degree. This precision is obtained by a combination of magnetorquers and momentum wheels...

  3. 78 FR 67132 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2013-11-08

    ... Department of the Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Space and Missile Systems Center, Global Positioning Systems (GPS) Directorate, Air Force, DoD. ACTION: Meeting notice..., 2013 Vol. 78 No. 206. This new meeting notice is to inform GPS simulator manufacturers, who supply...

  4. 77 FR 70421 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2012-11-26

    ... Department of the Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Space and Missile Systems Center, Global Positioning Systems (GPS) Directorate, Department of the Air Force, DoD. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS simulator manufacturers, who supply products...

  5. 78 FR 63459 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2013-10-24

    ... Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Department of the Air Force. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS simulator manufacturers, who supply products to the Department of Defense (DoD), and GPS simulator users, both government and DoD contractors...

  6. Uplink Power Control For Earth/Satellite/Earth Communication

    Science.gov (United States)

    Chakraborty, Dayamoy

    1994-01-01

    Proposed control subsystem adjusts power radiated by uplink transmitter in Earth station/satellite relay station/ Earth station communication system. Adjustments made to compensate for anticipated changes in attenuation by rain. Raw input is a received downlink beacon singal, amplitude of which affected not only by rain fade but also by scintillation, attenuation in atmospheric gases, and diurnal effects.

  7. A Fault tolerant Control Supervisory System development Procedurefor Small Satellites

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Larsen, Jesper Abildgaard

    The paper presents a stepwise procedure to develop a fault tolerant control system for small satellites. The procedure is illustrated through implementation on the AAUSAT-II spacecraft. As it is shown the presented procedure requires expertise from several disciplines that are nevertheless...

  8. Attitude Control of a Satellite by using Digital Signal Processing

    Directory of Open Access Journals (Sweden)

    Adirelle C. Santana

    2012-03-01

    Full Text Available This article has discussed the development of a three-axis attitude digital controller for an artificial satellite using a digital signal processor. The main motivation of this study is the attitude control system of the satellite Multi-Mission Platform, developed by the Brazilian National Institute for Space Research for application in different sort of missions. The controller design was based on the theory of the Linear Quadratic Gaussian Regulator, synthesized from the linearized model of the motion of the satellite, i.e., the kinematics and dynamics of attitude. The attitude actuators considered in this study are pairs of cold gas jets powered by a pulse width/pulse frequency modulator. In the first stage of the project development, a system controller for continuous time was studied with the aim of testing the adequacy of the adopted control. The next steps had included an analysis of discretization techniques, the setting time of sampling rate, and the testing of the digital version of the Linear Quadratic Gaussian Regulator controller in the MATLAB/SIMULINK. To fulfill the study, the controller was implemented in a digital signal processor, specifically the Blackfin BF537 from Analog Devices, along with the pulse width/pulse frequency modulator. The validation tests used a scheme of co-simulation, where the model of the satellite was simulated in MATLAB/SIMULINK, while the controller and modulator were processed in the digital signal processor with a tool called Processor-In-the-Loop, which acted as a data communication link between both environments.function and required time to achieve a given mission accuracy are determined, and results are provided as illustration.

  9. Automatic charge control system for satellites

    Science.gov (United States)

    Shuman, B. M.; Cohen, H. A.

    1985-01-01

    The SCATHA and the ATS-5 and 6 spacecraft provided insights to the problem of spacecraft charging at geosychronous altitudes. Reduction of the levels of both absolute and differential charging was indicated, by the emission of low energy neutral plasma. It is appropriate to complete the transition from experimental results to the development of a system that will sense the state-of-charge of a spacecraft, and, when a predetermined threshold is reached, will respond automatically to reduce it. A development program was initiated utilizing sensors comparable to the proton electrostatic analyzer, the surface potential monitor, and the transient pulse monitor that flew in SCATHA, and combine these outputs through a microprocessor controller to operate a rapid-start, low energy plasma source.

  10. Applying human factors to the design of control centre and workstation of a nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Isaac J.A. Luquetti dos; Carvalho, Paulo V.R.; Goncalves, Gabriel de L., E-mail: luquetti@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Souza, Tamara D.M.F.; Falcao, Mariana A. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Desenho Industrial

    2013-07-01

    Human factors is a body of scientific factors about human characteristics, covering biomedical, psychological and psychosocial considerations, including principles and applications in the personnel selection areas, training, job performance aid tools and human performance evaluation. Control Centre is a combination of control rooms, control suites and local control stations which are functionally related and all on the same site. Digital control room includes an arrangement of systems, equipment such as computers and communication terminals and workstations at which control and monitoring functions are conducted by operators. Inadequate integration between control room and operators reduces safety, increases the operation complexity, complicates operator training and increases the likelihood of human errors occurrence. The objective of this paper is to present a specific approach for the conceptual and basic design of the control centre and workstation of a nuclear reactor used to produce radioisotope. The approach is based on human factors standards, guidelines and the participation of a multidisciplinary team in the conceptual and basic phases of the design. Using the information gathered from standards and from the multidisciplinary team, an initial sketch 3D of the control centre and workstation are being developed. (author)

  11. Role of the Poison Control Centre of Morocco in the Improvement of Public Health

    Directory of Open Access Journals (Sweden)

    Naima Rhalem

    2013-09-01

    How to cite this article: Rhalem N, Aghandous R, Chaoui H, Eloufir R, Badrane N, Windy M, et al. Role of the Poison Control Centre of Morocco in the Improvement of Public Health. Asia Pac J Med Toxicol 2013;2:82-6.

  12. Doping strategies to control A-centres in silicon: Insights from hybrid density functional theory

    KAUST Repository

    Wang, Hao

    2014-01-01

    Hybrid density functional theory is used to gain insights into the interaction of intrinsic vacancies (V) and oxygen-vacancy pairs (VO, known as A-centres) with the dopants (D) germanium (Ge), tin (Sn), and lead (Pb) in silicon (Si). We determine the structures as well as binding and formation energies of the DVO and DV complexes. The results are discussed in terms of the density of states and in view of the potential of isovalent doping to control A-centres in Si. We argue that doping with Sn is the most efficient isovalent doping strategy to suppress A-centres by the formation of SnVO complexes, as these are charge neutral and strongly bound. © 2014 the Owner Societies.

  13. Testing a satellite automatic nutation control system. [on synchronous meteorological satellite

    Science.gov (United States)

    Hrasiar, J. A.

    1974-01-01

    Testing of a particular nutation control system for the synchronous meteorological satellite (SMS) is described. The test method and principles are applicable to nutation angle control for other satellites with similar requirements. During its ascent to synchronous orbit, a spacecraft like the SMS spins about its minimum-moment-of-inertia axis. An uncontrolled spacecraft in this state is unstable because torques due to fuel motion increase the nutation angle. However, the SMS is equipped with an automatic nutation control (ANC) system which will keep the nutation angle close to zero. Because correct operation of this system is critical to mission success, it was tested on an air-bearing table. The ANC system was mounted on the three-axis air-bearing table which was scaled to the SMS and equipped with appropriate sensors and thrusters. The table was spun up in an altitude chamber and nutation induced so that table motion simulated spacecraft motion. The ANC system was used to reduce the nutation angle. This dynamic test of the ANC system met all its objectives and provided confidence that the ANC system will control the SMS nutation angle.

  14. Autonomous Attitude Determination and Control System for the Ørsted Satellite

    DEFF Research Database (Denmark)

    Bak, Thomas; Wisniewski, Rafal; Blanke, M.

    1996-01-01

    The Ørsted Satellite mission imposes comparatively high requirements on autonomy of the attitude control system.......The Ørsted Satellite mission imposes comparatively high requirements on autonomy of the attitude control system....

  15. A sit-ski design aimed at controlling centre of mass and inertia.

    Science.gov (United States)

    Langelier, Eve; Martel, Stéphane; Millot, Anne; Lessard, Jean-Luc; Smeesters, Cécile; Rancourt, Denis

    2013-01-01

    This article introduces a sit-ski developed for the Canadian Alpine Ski Team in view of the Vancouver 2010 Paralympic games. The design is predominantly based on controlling the mass distribution of the sit-ski, a critical factor in skiing performance and control. Both the antero-posterior location of the centre of mass and the sit-ski moment of inertia were addressed in our design. Our design provides means to adjust the antero-posterior centre of mass location of a sit-ski to compensate for masses that would tend to move the antero-posterior centre of mass location away from the midline of the binding area along the ski axis. The adjustment range provided is as large as 140 mm, thereby providing sufficient adaptability for most situations. The suspension mechanism selected is a four-bar linkage optimised to limit antero-posterior seat movement, due to suspension compression, to 7 mm maximum. This is about 5% of the maximum antero-posterior centre of mass control capacity (151 mm) of a human participant. Foot rest inclination was included in the design to modify the sit-ski inertia by as much as 11%. Together, these mass adjustment features were shown to drastically help athletes' skiing performance.

  16. Groebner Basis Solutions to Satellite Trajectory Control by Pole Placement

    Science.gov (United States)

    Kukelova, Z.; Krsek, P.; Smutny, V.; Pajdla, T.

    2013-09-01

    Satellites play an important role, e.g., in telecommunication, navigation and weather monitoring. Controlling their trajectories is an important problem. In [1], an approach to the pole placement for the synthesis of a linear controller has been presented. It leads to solving five polynomial equations in nine unknown elements of the state space matrices of a compensator. This is an underconstrained system and therefore four of the unknown elements need to be considered as free parameters and set to some prior values to obtain a system of five equations in five unknowns. In [1], this system was solved for one chosen set of free parameters with the help of Dixon resultants. In this work, we study and present Groebner basis solutions to this problem of computation of a dynamic compensator for the satellite for different combinations of input free parameters. We show that the Groebner basis method for solving systems of polynomial equations leads to very simple solutions for all combinations of free parameters. These solutions require to perform only the Gauss-Jordan elimination of a small matrix and computation of roots of a single variable polynomial. The maximum degree of this polynomial is not greater than six in general but for most combinations of the input free parameters its degree is even lower. [1] B. Palancz. Application of Dixon resultant to satellite trajectory control by pole placement. Journal of Symbolic Computation, Volume 50, March 2013, Pages 79-99, Elsevier.

  17. Attitude control for part actuator failure of agile small satellite

    Institute of Scientific and Technical Information of China (English)

    J. R. Zhang; A. Rachid; Y. Zhang

    2008-01-01

    The stability and singularity problem of agile small satellite (ASS) with actuator failure is discussed in this paper. Firstly, the three-axis stabilized controller of an ASS is designed, where micro control moment gyros (MCMG's) in pyramid configuration (PC) is used as the actuator. By using the same controller and steering law, the control results before and after one gyro fails are compared by simulation. The variation of singular momentum envelope before and after one gyro fails is also compared. The simulation results show that the failure intensively decreases the capacity of output torque, which leads to the emergence of more singular points and the rapid saturation of MCMG's. Finally, the parameters of system controller are changed to compare the control effect.

  18. Application of altitude control techniques for low altitude earth satellites

    Science.gov (United States)

    Nickerson, K. G.; Herder, R. W.; Glass, A. B.; Cooley, J. L.

    1977-01-01

    The applications sensors of many low altitude earth satellites designed for recording surface or atmospheric data require near zero orbital eccentricities for maximum usefulness. Coverage patterns and altitude profiles require specified values of orbit semimajor axis. Certain initial combinations of semimajor axis, eccentricity, and argument of perigee can produce a so called 'frozen orbit' and minimum altitude variation which enhances sensor coverage. This paper develops information on frozen orbits and minimum altitude variation for all inclinations, generalizing previous results. In the altitude regions where most of these satellites function (between 200 and 1000 kilometers) strong atmospheric drag effects influence the evolution of the initial orbits. Active orbital maneuver control techniques to correct evolution of orbit parameters while minimizing the frequency of maneuvers are presented. The paper presents the application of theoretical techniques for control of near frozen orbits and expands upon the methods useful for simultaneously targeting several inplane orbital parameters. The applications of these techniques are illustrated by performance results from the Atmosphere Explorer (AE-3 and -5) missions and in preflight maneuver analysis and plans for the Seasat Oceanographic Satellite.

  19. A study of multiple access schemes in satellite control network

    Science.gov (United States)

    Mo, Zijian; Wang, Zhonghai; Xiang, Xingyu; Wang, Gang; Chen, Genshe; Nguyen, Tien; Pham, Khanh; Blasch, Erik

    2016-05-01

    Satellite Control Networks (SCN) have provided launch control for space lift vehicles; tracking, telemetry and commanding (TTC) for on-orbit satellites; and, test support for space experiments since the 1960s. Currently, SCNs encounter a new challenge: how to maintain the high reliability of services when sharing the spectrum with emerging commercial services. To achieve this goal, the capability of multiple satellites reception is deserved as an update/modernization of SCN in the future. In this paper, we conducts an investigation of multiple access techniques in SCN scenario, e.g., frequency division multiple access (FDMA) and coded division multiple access (CDMA). First, we introduce two upgrade options of SCN based on FDMA and CDMA techniques. Correspondingly, we also provide their performance analysis, especially the system improvement in spectrum efficiency and interference mitigation. Finally, to determine the optimum upgrade option, this work uses CRISP, i.e., Cost, Risk, Installation, Supportability and Performance, as the baseline approach for a comprehensive trade study of these two options. Extensive numerical and simulation results are presented to illustrate the theoretical development.

  20. A Comparative Study of Actuator Configurations for Satellite Attitude Control

    Directory of Open Access Journals (Sweden)

    Raymond Kristiansen

    2005-10-01

    Full Text Available In this paper a controllability study of different actuator configurations consisting of magnetic torquers, reaction wheels and a gravity boom is presented. The theoretical analysis is performed with use of controllability gramians, and simulation results with the different configurations are presented and compared regarding settling time and power consumption to substantiate the theoretical analysis. A reference model is also introduced to show how the power consumption can he lowered to the same magnitude as when magnetic torquers are used, without degrading the satellite response significantly.

  1. Satellite Formation Control Using the Approximating Sequence Riccati Equations

    Directory of Open Access Journals (Sweden)

    Ashraf H. Owis

    2013-11-01

    Full Text Available In this study we develop a reliable algorithm to control the satellite formation using the Approximating Sequence of Riccati Equations(ASRE minimizing the fuel consumption and the deviation of the orbit from the nominal orbit. The nonlinear Clohessy -Wiltshire(CW equations of motions are used to describe the motion of the satellite formation about a virtual reference position maintained at the formation center. The nonlinear dynamics of the system will be factorized in such a way that the new factorized system is accessible. The problem is tackled using the Approximating Sequence Riccati Equations(ASRE method. The technique is based on Linear Quadratic Regulator (LQR with fixed terminal state, which guarantees closed loop solution.

  2. Handsearching the EMHJ for reports of randomized controlled trials by U.K. Cochrane Centre (Bahrain).

    Science.gov (United States)

    Al Hajeri, A; Al Sayyad, J; Eisinga, A

    2006-01-01

    This study used handsearching to find reports of randomized controlled trials in the Eastern Mediterranean Health Journal (EMHJ). EMBASE and MEDLINE were also searched electronically to identify if the reports found by the handsearch were already included in either of these databases. Nine reports were identified: 7 randomized controlled trials and 2 controlled clinical trials. The added value of the handsearch over EMBASE was 6 additional reports and over MEDLINE was 4. Reports identified were sent to the UK Cochrane Centre for verification and publication in The Cochrane Central Register of Controlled Trials (CENTRAL).

  3. On-orbit control of the Communications Technology Satellite (CTS)/HERMES

    Science.gov (United States)

    Raine, H. R.

    1980-01-01

    A variety of control functions for the CIS HERMES satellite are reviewed. Its mission, to demonstrate high power SHF (12 GHz) transmission is discussed. The satellite was controlled in geostationary orbit for nearly four years from the satellite control center in Ottawa, Canada. Highlights of these operations are outlined. The interactions between many of the automatic onboard control functions and control from the ground are described. Special emphasis is placed on the characteristics and performance of the three axis attitude control system.

  4. The CERN Control Centre Setting Standards for the 21st Century

    CERN Document Server

    Manglunki, Django

    2008-01-01

    In 2003, CERN decided to build a unified control centre to replace four of its control rooms: the â€ワMeyrin Control Room” which controlled the PS complex, the â€ワPrevessin Control Room” (PCR) which controlled the SPS and until 2000 LEP, the Technical Control Room (TCR), and the Cryogenics Control Room (QCR). After first contemplating a possible implementation next to the â€ワGlobe of Science and Innovation”, it was decided for budgetary reasons to build the new CERN Control Centre (CCC) on the same location as the PCR. This represented a 50% saving in construction costs as most of the technical infrastructure (computer network, water, electricity, ventilation) was already in place, but added stringent time constraints: civil engineering could not begin before the SPS shutdown in November 2004, yet the room had to be ready for the accelerator operations to resume in March 2006. Although this presented a strict construction schedule, it allowed the project to be completely driven by th...

  5. Ultrafast all-optical coherent control of single silicon vacancy colour centres in diamond

    Science.gov (United States)

    Becker, Jonas Nils; Görlitz, Johannes; Arend, Carsten; Markham, Matthew; Becher, Christoph

    2016-11-01

    Complete control of the state of a quantum bit (qubit) is a fundamental requirement for any quantum information processing (QIP) system. In this context, all-optical control techniques offer the advantage of a well-localized and potentially ultrafast manipulation of individual qubits in multi-qubit systems. Recently, the negatively charged silicon vacancy centre (SiV-) in diamond has emerged as a novel promising system for QIP due to its superior spectral properties and advantageous electronic structure, offering an optically accessible Λ-type level system with large orbital splittings. Here, we report on all-optical resonant as well as Raman-based coherent control of a single SiV- using ultrafast pulses as short as 1 ps, significantly faster than the centre's phonon-limited ground state coherence time of about 40 ns. These measurements prove the accessibility of a complete set of single-qubit operations relying solely on optical fields and pave the way for high-speed QIP applications using SiV- centres.

  6. Guidance, Navigation, and Control System for Maneuverable Pico-Satellites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Pico-satellites are an emerging new class of spacecraft. Maneuverable pico-satellites require active guidance, navigation, and control (GN&C) systems to perform...

  7. Efficient medium access control protocol for geostationary satellite systems

    Institute of Scientific and Technical Information of China (English)

    王丽娜; 顾学迈

    2004-01-01

    This paper proposes an efficient medium access control (MAC) protocol based on multifrequency-time division multiple access (MF-TDMA) for geostationary satellite systems deploying multiple spot-beams and onboard processing,which uses a method of random reservation access with movable boundaries to dynamically request the transmission slots and can transmit different types of traffic. The simulation results have shown that our designed MAC protocol can achieve a high bandwidth utilization, while providing the required quality of service (QoS) for each class of service.

  8. Anti-Satellite Weapons, Countermeasures, and Arms Control

    Science.gov (United States)

    2007-11-02

    From Kosmos 1500 38 3-3. Imagery Obtained by Synthetic-Aperture Satellite Radar 40 Chapter 3 MILSATs, ASATs, and National Security THE ROLE AND...satellite capabil- ities, such as resolution. For example, Soviet oceanographic radar satellites of the Kosmos - 1500 class can obtain radar imagery with...surveillance satellite ( Kosmos 1500) equipped with a side-looking radar and in the same year placed two satellites (Venera 15 and Venera 16) equipped

  9. Controlling the Chaos Using Fuzzy Estimation in a Gyrostat Satellite

    Science.gov (United States)

    Guran, Ardeshir

    In this paper, we present a study of the dynamical behavior in a Kelvin type gyrostat satellite. We firstly obtain the Hamiltonian equations of our model by using Cardan angles as generalized coordinates. Then, we make this Hamiltonian dimensionless and calculate motion equations for this dimensionless system. The study of the Poincare's sections of this system shows us that chaotic motion regimes are present for specific parameter values. The main goal of this work is the finding of stabilizing orbits by using a control technique, the fuzzy control of Poincare map method, so that it can be applied to stabilize special periodic orbits in this system. Finally, we expect that the technique can be useful for a better understanding of control theory and their applications in gyrostat problems.

  10. TCP-ATCA: Improved Transmission Control Algorithm in Satellite Network

    Institute of Scientific and Technical Information of China (English)

    Liu Feng; Liu Hengna; Zhao Han

    2008-01-01

    An adaptive transmission control algorithm based on TCP (TCP-ATCA) is proposed to reduce the effects of long propagation de- lay and high link error rate of the satellite network on the performances. The flow control and the error recovery are differentiated by combined dynamic random early detection-explicit congestion notification (DRED-ECN) algorithm, and, moreover, the pertaining con- gestion control methods are used in TCP-ATCA to improve the throughput. By introducing the entire recovery algorithm, the unneces- sary congestion window decrease is reduced, and the throughput and fairness are improved. Simulation results show that, compared with TCP-Reno, TCP-ATCA provides a better throughput performance when the link capacity is higher (≥ 600 packet/s), and roughly the same when it is lower. At the same time, TCP-ATCA also increases fairness and reduces transmission delay.

  11. A System for Receiving and Analyzing Meteorological Satellite Data at Small Meteorological/Oceanographic Centres or Aboard Ship,

    Science.gov (United States)

    1983-10-01

    variability. Used wih SACLANTCEN’s growing archive of satellite data and its SONDA data base of environmental data <A.2> it assists in pre-cruise planning . It...SATDI General image display program (menu driven) $ TAREA Temperature/Albedo/Pixel level histogram over an an defined irregular area (trackball driven...can be determined. This allows flexibility in further pro- cessing by other routines (GRUTM, GRD, TCURV, TAREA ). A.2.2 The GRUTM routine (’GR’) In

  12. Novel architecture for data management and control for small satellite

    Science.gov (United States)

    Adami, G.; Fossati, D.; Turri, M.

    1995-12-01

    The paper introduces an innovative architecture for the on-board units that are responsible to provide the data interface, control and processing capability normally allocated in separated electronics boxes in the data handling subsystem of the space system. A new solution for the attitude control of the space vehicle has been studied and developed and the utilization of this technological growth, in particular that concerns the GPS receiver, is matter for novel architecture. This new approach also involves in general the small satellite ground segment product as matter of a dedicated development approach. Small and medium satellites are considered an attractive solution for the low cost scientific experimentation, communication or remote sensing satellites. The functional and performance capability of the studied on-board units and ground segment are assessed in tight conjunction with the evolution of the European and the USA market. The design of these units has to be based on few and simple driving requirements, directly derived from the new modified scenario: (1) The limited budgets available for space system. (2) The quick mission data return, i.e., low development time by specific and tailored system development tools. The quick availability of data to scientists/user is requested without jeopardizing the maximum and guaranteed scientific or commercial return. The proposed system is then given thinking to an architecture based on a high degree of modularity (and reuse of existing library of modules) thus allowing to keep down costs and to speed up the time to market. The design ground rules are so established in order to cope with the following performance: (1) capability to adapt with few impacts the system interfaces, in particular for attitude sensors and actuators that are tightly mission dependent; (2) easy adaptation of on board computational performances and memory capacity (including mass memory storage capability); (3) definition of a hierarchical

  13. Bodies or organisms? Medical encounter as a control apparatus at a primary care centre in Barcelona

    Directory of Open Access Journals (Sweden)

    Alejandro Zaballos Samper

    2013-07-01

    Full Text Available Medical practice is driven by technology, discourses, and knowledge about health and illness. This has resulted in its gaining a dominating position in power relations achieved by means of diagnosis, medicalization, and habit and conduct creation and maintenance. Interaction at primary care centres is built on mainstream biomedical views of both the medical discourse and the social practices related to health, illness and the human body. Moreover, it is also rooted on the ideologies conveyed by those social concepts, which in turn, permeate interaction all through with power relations. The present paper takes ethnographic data and in-depth interviews as a departing point to analyse how diagnosis, medicalization, and biopolicies for health prevention and improvement carried out in primary care centres in Barcelona make up a control apparatus. Furthermore, this essay also explores how the apparatus is developed in the medical encounter and turns the body into an organism.

  14. Evaluating performance indices of a shopping centre and implementing HVAC control principles to minimize energy usage

    Energy Technology Data Exchange (ETDEWEB)

    Canbay, C.S. [Energy Engineering Programme, Izmir Institute of Technology, Izmir (Turkey); Hepbasli, A. [Faculty of Engineering, Mechanical Engineering Department, Ege University, Izmir (Turkey); Gokcen, G. [Faculty of Engineering, Mechanical Engineering Department, Izmir Institute of Technology, Izmir (Turkey)

    2004-07-01

    Heating, ventilation and air-conditioning (HVAC) systems in buildings must be integrated with an efficient control scheme to maintain comfort under any load conditions. Efficient HVAC control is often the most cost-effective option to improve the energy efficiency of a building. However, HVAC processes are non-linear, and characteristics change on a seasonal basis, so the effect of changing the control strategy is usually difficult to predict. The present study aims to reduce energy consumption by defining new HVAC control strategies and tuning control loops in a shopping centre. First, an energy audit was performed to investigate the potential for energy savings and to redefine the control scenarios, while a methodology for the shopping centre was developed. Performance indices were then calculated and compared with the yardsticks. Next, normalised performance indices were computed to reach out a better understanding of the building's efficiency. Finally, new strategies were implemented with the help of the existing building management system (BMS) and about 22% of energy saving was achieved. (author)

  15. Attitude control of a small satellite using magnetic bearing momentum wheel

    OpenAIRE

    Terui, Fuyuto; Nakajima, Atsushi; 照井 冬人; 中島 厚

    1996-01-01

    An attitude controller for a 50 kg-class micro satellite which could be launched by H-2 rocket as a piggyback payload of a main satellite is considered. The survey of the proposals of the mission using a micro satellite from national institutes, universities and private companies shows that the development of a small, light and inexpensive three axis attitude controller is widely expected. One of the candidate configurations for such an attitude controller is bias momentum control using a mag...

  16. Between-centre differences and treatment effects in randomized controlled trials: A case study in traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Roberts Ian

    2011-08-01

    Full Text Available Abstract Background In Traumatic Brain Injury (TBI, large between-centre differences in outcome exist and many clinicians believe that such differences influence estimation of the treatment effect in randomized controlled trial (RCTs. The aim of this study was to assess the influence of between-centre differences in outcome on the estimated treatment effect in a large RCT in TBI. Methods We used data from the MRC CRASH trial on the efficacy of corticosteroid infusion in patients with TBI. We analyzed the effect of the treatment on 14 day mortality with fixed effect logistic regression. Next we used random effects logistic regression with a random intercept to estimate the treatment effect taking into account between-centre differences in outcome. Between-centre differences in outcome were expressed with a 95% range of odds ratios (OR for centres compared to the average, based on the variance of the random effects (tau2. A random effects logistic regression model with random slopes was used to allow the treatment effect to vary by centre. The variation in treatment effect between the centres was expressed in a 95% range of the estimated treatment ORs. Results In 9978 patients from 237 centres, 14-day mortality was 19.5%. Mortality was higher in the treatment group (OR = 1.22, p = 0.00010. Using a random effects model showed large between-centre differences in outcome (95% range of centre effects: 0.27- 3.71, but did not substantially change the estimated treatment effect (OR = 1.24, p = 0.00003. There was limited, although statistically significant, between-centre variation in the treatment effect (OR = 1.22, 95% treatment OR range: 1.17-1.26. Conclusion Large between-centre differences in outcome do not necessarily affect the estimated treatment effect in RCTs, in contrast to current beliefs in the clinical area of TBI.

  17. Passivity Based Nonlinear Attitude Control of the Rømer Satellite

    DEFF Research Database (Denmark)

    Quottrup, Michael Melholt; Krogh-Sørensen, J.; Wisniewski, Rafal

    2001-01-01

    This paper suggests nonlinear attitude control of the Danish satellite Rømer. This satellite will be designed to fulfil two scientific objectives: The observation of stellar oscillations and the detection and localisation of gamma-ray bursts. The satellite will be equipped with a tetrahedron...

  18. Passivity based nonlinear attitude control of the Rømer satellite

    DEFF Research Database (Denmark)

    Quottrup, Michael Melholt; Krogh-Sørensen, J.; Wisniewski, Rafal

    This paper suggests nonlinear attitude control of the Danish satellite Rømer. This satellite will be designed to fulfil two scientific objectives: The observation of stellar oscillations and the detection and localisation of gamma-ray bursts. The satellite will be equipped with a tetrahedron...

  19. Phase control system concepts and simulations. [solar power satellite system

    Science.gov (United States)

    Lindsay, V. C.

    1980-01-01

    A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier.

  20. Acupuncture for persistent allergic rhinitis: a multi-centre, randomised, controlled trial protocol

    Directory of Open Access Journals (Sweden)

    Kang Kyung-Won

    2009-07-01

    Full Text Available Abstract Background Allergic rhinitis is one of the most common health complaints worldwide. Complementary and alternative medical approaches have been employed to relieve allergic rhinitis symptoms and to avoid the side effects of conventional medication. Acupuncture has been widely used to treat patients with allergic rhinitis, but the available evidence of its effectiveness is insufficient. Our objective is to evaluate the effectiveness of acupuncture in patients in Korea and China with persistent allergic rhinitis compared to sham acupuncture treatment or waitlist control. Methods This study consists of a multi-centre (two centres in Korea and two centres in China, randomised, controlled trial with three parallel arms (active acupuncture, sham acupuncture, and waitlist group. The active acupuncture and sham acupuncture groups will receive real or sham acupuncture treatment, respectively, three times per week for a total of 12 sessions over four weeks. Post-treatment follow-up will be performed a month later to complement these 12 acupuncture sessions. Participants in the waitlist group will not receive real or sham acupuncture treatments during this period but will only be required to keep recording their symptoms in a daily diary. After four weeks, the same treatment given to the active acupuncture group will be provided to the waitlist group. Discussion This trial will provide evidence for the effectiveness of acupuncture as a treatment for persistent allergic rhinitis. The primary outcome between groups is a change in the self-reported total nasal symptom score (i.e., nasal obstruction, rhinorrhea, sneezing, and itching from baseline at the fourth week. Secondary outcome measures include the Rhinitis Quality of Life Questionnaire score and total non-nasal symptom score (i.e., headache, itching, pain, eye-dropping. The quantity of conventional relief medication used during the follow-up period is another secondary outcome measure. Trial

  1. A comparing design of satellite attitude control system based on reaction wheel

    Institute of Scientific and Technical Information of China (English)

    CHENG Hao; GE Sheng-min; SHEN Yi

    2008-01-01

    The disturbance caused by the reaction wheel with a current controller greatly influences the accuracy and stability of the satellite attitude control system.To solve this problem,the idea of speed feedback compensation control reaction wheel is put forward.This paper introduces the comparison on design and performance of two satellite attitude control systems,which are separately based on the current control reaction wheel and the speed feedback compensation control reaction wheel.Analysis shows that the speed feedback compensation control flywheel system may effectively suppress the torque fluctuation.Simulation results indicate that the satellite attitude control system with the speed feedback compensation control flywheel has improved performance.

  2. Vaccine-preventable diseases: the role of the European Centre for Disease Prevention and Control.

    Science.gov (United States)

    Kramarz, P; Lopalco, P L; Huitric, E; Pastore Celentano, L

    2014-05-01

    The role of the European Centre for Disease Prevention and Control (ECDC) is to strengthen the capacity of the European Union (EU) Member States to protect human health through the prevention and control of infectious diseases. The main objective of the programme on vaccine-preventable diseases and invasive bacterial infections (VPD) is to provide robust evidence and high-quality technical support to the EU Member States to help them in their efforts to prevent and control VPD. Since the establishment of ECDC, several existing VPD surveillance networks have been transferred to ECDC, namely EU-IBIS, DIPNET and EUVAC. In addition to surveillance of diseases, ECDC is collecting information and monitoring other parameters that are of crucial importance for a well-functioning immunization system, including vaccination coverage. The VPD programme also provides independent scientific opinions in the area of immunization and initiates and coordinates scientific studies in the area of vaccination to answer specific questions of public health importance, including risk perception and analysis of behaviour in different population groups. One of the overall ECDC priorities over recent years is the Centre's involvement in measles elimination. The 'Message' tool and the 'Measles Atlas' are examples of work aiming at supporting the efforts of Member States in the elimination phase.

  3. Cognitive task load in a naval ship control centre: from identification to prediction.

    Science.gov (United States)

    Grootjen, M; Neerincx, M A; Veltman, J A

    Deployment of information and communication technology will lead to further automation of control centre tasks and an increasing amount of information to be processed. A method for establishing adequate levels of cognitive task load for the operators in such complex environments has been developed. It is based on a model distinguishing three load factors: time occupied, task-set switching, and level of information processing. Application of the method resulted in eight scenarios for eight extremes of task load (i.e. low and high values for each load factor). These scenarios were performed by 13 teams in a high-fidelity control centre simulator of the Royal Netherlands Navy. The results show that the method provides good prediction of the task load that will actually appear in the simulator. The model allowed identification of under- and overload situations showing negative effects on operator performance corresponding to controlled experiments in a less realistic task environment. Tools proposed to keep the operator at an optimum task load are (adaptive) task allocation and interface support.

  4. Method of Time-Delay Calculating and Correcting to Control Spin-Stabilized Satellite Synchronously

    Institute of Scientific and Technical Information of China (English)

    YangTianshe; LiJisheng; HuangYongxuan

    2005-01-01

    The key to control Spin-Stabilized Satellites Synchronously is to determine the models for calculating and correcting of time-delay at the different situations. Based on the principle of Synchronous-Control mode, the methods of determining the models of calculating and correcting of time-delay are proposed. The methods have been proved to be effective in real satellite control engineering.

  5. Evaluation of Satellite-based Global Hydrologic Simulation using the Distributed CREST Model and Global Runoff Data Centre Archives

    Science.gov (United States)

    Xue, X.; Hong, Y.; Gourley, J. J.; Wang, X.

    2011-12-01

    Flooding is one of the most deadly natural hazards around the world. Distributed hydrologic models can provide the spatial and temporal distribution of precipitation, soil moisture, evapotranspiration and runoff. Implementation of a flood prediction and/or forecast system using a distributed hydrologic model can potentially help mitigate flood-induced hazards. In this study, we propose the use of the Coupled Routing and Excess STorage (CREST) distributed hydrological model driven by real-time rainfall forcing from TRMM-based multi-satellite products and/or precipitation forecast data from the Global Forecast System model (GFS), combined with automatic parameter optimization methods, to estimate hydrological fluxes, storages and inundated areas. Evaluations show that: 1) the capability of real-time streamflow prediction and/or forecast at drainage outlets and identification of inundated areas upstream is an achievable goal even for ungauged basins; 2) a-priori, physically-based parameter estimates with CREST reduce the dependence on rainfall-runoff data often required to calibrate distributed hydrologic models; and 3) the validation of CREST simulations of basin discharge are skillful in several basins throughout the world.

  6. On Optimization Control Parameters in an Adaptive Error-Control Scheme in Satellite Networks

    Directory of Open Access Journals (Sweden)

    Ranko Vojinović

    2011-09-01

    Full Text Available This paper presents a method for optimization of control parameters of an adaptive GBN scheme in error-prone satellite channel. Method is based on the channel model with three state, where channel have the variable noise level.

  7. Attitude Control of a Satellite Simulator Using Reaction Wheels and a PID Controller

    Science.gov (United States)

    2010-03-01

    Rohe, and Welty in the development of AFIT’s second- generation satellite simulator, SimSat II [40]. Instead of building another dumbbell-style spherical...Nathan F. Welty . A Systems Engineering Approach to the Design of a Spacecraft Dynamics and Control Testbed. MS thesis, Air Force Institute of

  8. Guidance and adaptive-robust attitude & orbit control of a small information satellite

    Science.gov (United States)

    Somov, Ye.; Butyrin, S.; Somov, S.; Somova, T.; Testoyedov, N.; Rayevsky, V.; Titov, G.; Yakimov, Ye.; Ovchinnikov, A.; Mathylenko, M.

    2017-01-01

    We consider a small information satellite which may be placed on an orbit with altitude from 600 up to 1000 km. The satellite attitude and orbit control system contains a strap-down inertial navigation system, cluster of four reaction wheels, magnetic driver and a correcting engine unit with eight electro-reaction engines. We study problems on design of algorithms for spatial guidance, in-flight identification and adaptive-robust control of the satellite motion on sun-synchronous orbit.

  9. Nanoscale magnetometry through quantum control of nitrogen-vacancy centres in rotationally diffusing nanodiamonds

    CERN Document Server

    Maclaurin, D; Martin, A M; Hollenberg, L C L

    2012-01-01

    The confluence of quantum physics and biology is driving a new generation of quantum-based sensing and imaging technology capable of harnessing the power of quantum effects to provide tools to understand the fundamental processes of life. One of the most promising systems in this area is the nitrogen-vacancy centre in diamond - a natural spin qubit which remarkably has all the right attributes for nanoscale sensing in ambient biological conditions. Typically the nitrogen-vacancy qubits are fixed in tightly controlled/isolated experimental conditions. In this work quantum control principles of nitrogen-vacancy magnetometry are developed for a randomly diffusing diamond nanocrystal. We find that the accumulation of geometric phases, due to the rotation of the nanodiamond plays a crucial role in the application of a diffusing nanodiamond as a bio-label and magnetometer. Specifically, we show that a freely diffusing nanodiamond can offer real-time information about local magnetic fields and its own rotational beh...

  10. Enantiopure Ferrocene-Based Planar-Chiral Iridacycles: Stereospecific Control of Iridium-Centred Chirality.

    Science.gov (United States)

    Arthurs, Ross A; Ismail, Muhammad; Prior, Christopher C; Oganesyan, Vasily S; Horton, Peter N; Coles, Simon J; Richards, Christopher J

    2016-02-24

    Reaction of [IrCp*Cl2 ]2 with ferrocenylimines (Fc=NAr, Ar=Ph, p-MeOC6 H4 ) results in ferrocene C-H activation and the diastereoselective synthesis of half-sandwich iridacycles of relative configuration Sp *,RIr *. Extension to (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline gave highly diastereoselective control over the new elements of planar chirality and metal-based pseudo-tetrahedral chirality, to give both neutral and cationic half-sandwich iridacycles of absolute configuration Sc ,Sp ,RIr . Substitution reactions proceed with retention of configuration, with the planar chirality controlling the metal-centred chirality through an iron-iridium interaction in the coordinatively unsaturated cationic intermediate.

  11. A randomised controlled trial of a client-centred self-care intervention after stroke

    DEFF Research Database (Denmark)

    Guidetti, Susanne; Ytterberg, Charlotte

    2011-01-01

    services and the caregiver burden. METHOD: An intervention group (IG) received CCSCI and a control group (CG) received ordinary training. Forty individuals with stroke (IG n = 19, CG n = 21) were included. Data were collected at 3, 6 and 12 months using established instruments. RESULTS: After 12 months 24......PURPOSE: The aim of this randomised controlled pilot study of a client-centred self-care intervention (CCSCI) in individuals with stroke was to study (i) the feasibility of the study design, (ii) effects up to 12 months on activities of daily living (ADL), use of informal care and home help...... people remained in the study (IG = 10, CG = 14). The data collection method was acceptable to most participants. At 12 months there were no differences in ADL, use of services or caregiver's burden. Both groups improved significantly and clinically important improvements were achieved by 80% in the IG...

  12. Three-Axis Satellite Attitude Control Based on Magnetic Torquing

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1995-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics.......Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics....

  13. Three-Axis Satellite Attitude Control Based on Magnetic Torquing

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1995-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics.......Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics....

  14. Onboard Supervisor for the Ørsted Satellite Attitude Control System

    DEFF Research Database (Denmark)

    Bøgh, S.A.; Izadi-Zamanabadi, Roozbeh; Blanke, M.

    1995-01-01

    The increasing operational requirements for onboard autonomy in satellite control systems necessitates structural methods that support the design of a complete and reliable supervisory system.......The increasing operational requirements for onboard autonomy in satellite control systems necessitates structural methods that support the design of a complete and reliable supervisory system....

  15. Using the centre of percussion to design a steering controller for an autonomous race car

    Science.gov (United States)

    Kritayakirana, Krisada; Gerdes, J. Christian

    2012-01-01

    Understanding how a race car driver controls a vehicle at its friction limits can provide insights into the development of vehicle safety systems. In this paper, a race car driver's behaviour inspires the design of an autonomous racing controller. The resulting controller uses the vehicle's centre of percussion (COP) to design feedforward and feedback steering. At the COP, the effects of rotation and translation from the rear tire force cancel each other out; consequently, the feedforward steering command is robust to the disturbances from the rear tire force. Using the COP also simplifies the equations of motion, as the vehicle's lateral motion is decoupled from the vehicle's yaw motion and highlights the challenge of controlling a vehicle when the rear tires are highly saturated. The resulting dynamics can be controlled with a linear state feedback based on a lane-keeping system with additional yaw damping. Utilising Lyapunov theory, the closed-loop system is shown to remain stable even when the rear tires are highly saturated. The experimental results demonstrate that an autonomous vehicle can operate at its limits while maintaining a minimal lateral error.

  16. Manual handling risks and controls in a soft drinks distribution centre.

    Science.gov (United States)

    Wright, E J; Haslam, R A

    1999-08-01

    This paper describes an investigation into manual handling risks and controls within a soft drinks distribution centre, presented as a case study regarding compliance with the requirements of the Manual Handling Operations Regulations 1992. Methods used included semi-structured interviews, document analysis, analysis of training, OWAS postural analysis and use of the NIOSH equation. Warehouse operators and delivery drivers were studied, and two methods of work compared involving pallets and cages. Significant differences were found between the two work methods with respect to harmful postures. Manual handling risks were found in both warehouse and delivery areas, some being classed as "excessive" using the NIOSH equation. As this company has a good safety record and considers itself proactive in the area of health and safety, the investigation raises concerns about how organisations have responded to the Manual Handling Operations Regulations.

  17. Model predictive control of attitude maneuver of a geostationary flexible satellite based on genetic algorithm

    Science.gov (United States)

    TayyebTaher, M.; Esmaeilzadeh, S. Majid

    2017-07-01

    This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

  18. Miniature Reaction Wheel for Small Satellite Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of this project is to design, develop, demonstrate, and deliver a miniature, high torque, low-vibration reaction wheel for use on small satellites....

  19. Use of charging control guidelines for geosynchronous satellite design studies

    Science.gov (United States)

    Steves, N. J.

    1980-01-01

    Several of the principle guidelines from the Spacecraft Charging Design Guidelines Handbook are presented with illustrative examples. Use of the geomagnetic substorm specification to qualify satellite designs, the evaluation of satellite designs by using analytical modelling techniques, the use of selected materials and coatings to minimize charging, the tying of all conducting elements to a common ground, and the use of electrical filtering to protect circuits from discharge induced upsets are discussed. Discharge criteria and SCATHA data are excluded.

  20. Satellite de-orbiting via controlled solar radiation pressure

    Science.gov (United States)

    Deienno, Rogerio; Sanchez, Diogo Merguizo; de Almeida Prado, Antonio Fernando Bertachini; Smirnov, Georgi

    2016-06-01

    The goal of the present research was to study the use of solar radiation pressure to place a satellite in an orbit that makes it to re-enter the atmosphere of the Earth. This phase of the mission is usual, since the orbital space around the Earth is crowded and all satellites have to be discarded after the end of their lifetimes. The technique proposed here is based on a device that can increase and decrease the area-to-mass ratio of the satellite when it is intended to reduce its altitude until a re-entry point is reached. Equations that predict the evolution of the eccentricity and semi-major axis of the orbit of the satellite are derived and can be used to allow the evaluation of the time required for the decay of the satellite. Numerical simulations are made, and they show the time required for the decay as a function of the area-to-mass ratio and the evolution of the most important orbital elements. The results show maps that indicate regions of fast decays as a function of the area-to-mass ratio and the initial inclination of the orbit of the satellite. They also confirmed the applicability of the equations derived here. The numerical results showed the role played by the evection and the Sun-synchronous resonances in the de-orbiting time.

  1. Performance of TCP Vegas, Bic and Reno Congestion Control Algorithms on Iridium Satellite Constellations

    Directory of Open Access Journals (Sweden)

    M.Nirmala

    2012-11-01

    Full Text Available Satellite networking is different from wired or wireless networks. The behavior and the performance of TCP/IP in normal wireless network as well as in wired network are different from one another. The TCP/IP protocol was not designed to perform well over high-latency or noisy channels so its performance over satellite networks are totally different. Each satellite networks/constellations have different properties. The deployment height, motion, direction, link capacity – all differ from one satellite constellations to another. So, certainly the behavior of TCP/IP will considerably differ from one satellite constellations than another.The Performance of three different TCP Congestion algorithms, Vegas, Reno and Bic are taken for evaluation on the simulated satellite network Iridium and the performance of the three algorithms under the satellites constellation is measured using suitable metrics. It is observed that, irrespective of the high end to end delay, the behavior of TCP/IP under Satellite network is somewhat resembling a high latency wired network. TCP under satellite network is not like that of a mobile ADHOC network. The observation resulted that the overall performance of Vegas was good in Iridium constellations. These reasons should be explored for designing a better congestion control algorithm exclusively for Satellite Networks.

  2. CMS Centre at CERN

    CERN Multimedia

    2007-01-01

    A new "CMS Centre" is being established on the CERN Meyrin site by the CMS collaboration. It will be a focal point for communications, where physicists will work together on data quality monitoring, detector calibration, offline analysis of physics events, and CMS computing operations. Construction of the CMS Centre begins in the historic Proton Synchrotron (PS) control room. The historic Proton Synchrotron (PS) control room, Opened by Niels Bohr in 1960, will be reused by CMS to built its control centre. TThe LHC@FNAL Centre, in operation at Fermilab in the US, will work very closely with the CMS Centre, as well as the CERN Control Centre. (Photo Fermilab)The historic Proton Synchrotron (PS) control room is about to start a new life. Opened by Niels Bohr in 1960, the room will be reused by CMS to built its control centre. When finished, it will resemble the CERN Contro...

  3. Active-passive integrated vibration control for control moment gyros and its application to satellites

    Science.gov (United States)

    Zhang, Yao; Zang, Yue; Li, Mou; Wang, Youyi; Li, Wenbo

    2017-04-01

    The strategy of active-passive integrated vibration control on the truss enveloping control moment gyroscopes (CMGs) is presented and its characteristics of time domain and frequency domain are analyzed. Truss enveloping CMGs contains pyramid-type CMGs, which are enveloped by multiple struts. These struts can be employed to realize the active-passive integrated vibration control. In addition, the struts of the trusses can maintain the working space of CMGs. Firstly, the disturbance characteristics of CMGs are analyzed considering static and dynamic imbalances of the CMG's rotor; then, an active-passive integrated vibration isolation truss structure is developed based on its characteristics. This structure can restrain the CMG vibration as much as possible and reduce its influence on the photographic quality of optical payloads. Next, the dynamic model of the active-passive vibration isolation truss structure is established. The frequency domain analysis of this model shows that the active-passive integrated vibration control method can restrain the high-frequency vibration and also improve the characteristics of low-frequency vibration. Finally, the dynamic model for the whole satellite is built with this type of CMGs. The time domain simulations of satellite attitude control verify the attitude control improvements resulting from the CMGs vibration control strategy.

  4. ESTABLISHMENT OF SATELLITE FORMATION WITH INITIAL UNCERTAINTY BY CONTROL LYAPUNOV FUNCTION APPROACH

    Directory of Open Access Journals (Sweden)

    M. Navabi

    2012-03-01

    Full Text Available In recent years, dynamics and control of satellite formation flying have been active areas of research. From the mission planning perspective, three main areas namely formation establishment, maintenance and reconfiguration have been discussed. In this paper, a study of formation establishment under initial uncertainty is presented. In this regard, dynamics of low Earth orbit satellite formation is discussed. Control Lyapunov function approach is adopted to bring a deputy satellite, with perturbed initial conditions into formation with a chief satellite. In order to take account of the initial orbit insertion error, uncertainty in initial conditions of the deputy satellite is considered. For a case study, a relatively small formation is adopted, with air-launched Pegasus as the launch vehicle. For several initial conditions, control function and required time to achieve a given mission accuracy are determined, and results are provided as illustration.

  5. New insights into the epigenetic control of satellite cells

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Epigenetics finely tunes gene expression at a functionallevel without modifying the DNA sequence, therebycontributing to the complexity of genomic regulation.Satellite cells (SCs) are adult muscle stem cells thatare important for skeletal post-natal muscle growth,homeostasis and repair. The understanding of theepigenome of SCs at different stages and of themultiple layers of the post-transcriptional regulationof gene expression is constantly expanding. Dynamicinteractions between different epigenetic mechanismsregulate the appropriate timing of muscle-specific geneexpression and influence the lineage fate of SCs. Inthis review, we report and discuss the recent literatureabout the epigenetic control of SCs during the myogenicprocess from activation to proliferation and from theircommitment to a muscle cell fate to their differentiationand fusion to myotubes. We describe how the coordinatedactivities of the histone methyltransferasefamilies Polycomb group (PcG), which represses theexpression of developmentally regulated genes, andTrithorax group, which antagonizes the repressive activityof the PcG, regulate myogenesis by restricting geneexpression in a time-dependent manner during eachstep of the process. We discuss how histone acetylationand deacetylation occurs in specific loci throughoutSC differentiation to enable the time-dependent transcriptionof specific genes. Moreover, we describe themultiple roles of microRNA, an additional epigeneticmechanism, in regulating gene expression in SCs, byrepressing or enhancing gene transcription or translationduring each step of myogenesis. The importance ofthese epigenetic pathways in modulating SC activationand differentiation renders them as promising targetsfor disease interventions. Understanding the mostrecent findings regarding the epigenetic mechanismsthat regulate SC behavior is useful from the perspectiveof pharmacological manipulation for improving muscleregeneration and for promoting muscle homeostasisunder

  6. Spacecraft flight control system design selection process for a geostationary communication satellite

    Science.gov (United States)

    Barret, C.

    1992-01-01

    The Earth's first artificial satellite, Sputnik 1, slowly tumbled in orbit. The first U.S. satellite, Explorer 1, also tumbled out of control. Now, as we launch the Mars observer and the Cassini spacecraft, stability and control have become higher priorities. The flight control system design selection process is reviewed using as an example a geostationary communication satellite which is to have a life expectancy of 10 to 14 years. Disturbance torques including aerodynamic, magnetic, gravity gradient, solar, micrometeorite, debris, collision, and internal torques are assessed to quantify the disturbance environment so that the required compensating torque can be determined. Then control torque options, including passive versus active, momentum control, bias momentum, spin stabilization, dual spin, gravity gradient, magnetic, reaction wheels, control moment gyros, nutation dampers, inertia augmentation techniques, three-axis control, reactions control system (RCS), and RCS sizing, are considered. A flight control system design is then selected and preliminary stability criteria are met by the control gains selection.

  7. Testing command and control of the satellites in formation flight

    Science.gov (United States)

    Gheorghe, Popan; Gheorghe, Gh. Ion; Gabriel, Todoran

    2013-10-01

    The topics covered in the paper are mechatronic systems for determining the distance between the satellites and the design of the displacement system on air cushion table for satellites testing. INCDMTM has the capability to approach the collaboration within European Programms (ESA) of human exploration of outer space through mechatronic systems and accessories for telescopes, mechatronics systems used by the launchers, sensors and mechatronic systems for the robotic exploration programs of atmosphere and Mars. This research has a strong development component of industrial competitiveness many of the results of space research have direct applicability in industrial fabrication.

  8. Integrated power and attitude control of a rigid satellite with onboard magnetic bearing suspended rigid flywheels

    Science.gov (United States)

    Kim, Yeonkyu

    2003-10-01

    A system of differential equations governing the translational and rotational motion of a system model consisting of a rigid satellite and multiple MB suspended rigid flywheels in general configuration is developed. Flywheel modules are contained in a housing rigidly mounted on the satellite and floated by an active MB suspension system, therefore each flywheel module has six degrees of freedom (DOF) as well as the satellite module. Equations of motion for the satellite and flywheels are naturally coupled and the satellite rotational motion and translational motion are coupled. A nonlinear state feedback tracking control law, which is globally asymptotically stable, is developed following a Lyapunov stability theory for integrated power and attitude control using the MB suspended flywheels. The stability, robustness, and tracking and disturbance rejection performance of the present control law with respect to initial attitude error, system modeling error, an imbalance disturbance, is demonstrated by case studies. The satellite departure motion equation derived from the definition of the angular velocity error and the system dynamics equations is presented. Application study of existing power tracking algorithm with this control law shows perfect power tracking for both power charging from and power delivery to the satellite operations and the power tracking can be performed simultaneously with and independent of the attitude control function.

  9. The WHO Collaborating Centre for Research and Control of Schistosomiasis at Niamey, Niger

    Directory of Open Access Journals (Sweden)

    Chippaux J-P

    1997-01-01

    Full Text Available The Centre de Recherche sur les Méningites et les Schistosomes (CERMES is a research institute depending on the Organisation de Coordination et de Coopération pour la lutte contre les Grandes Endémies - a West African Organization for Public Health - devoted to the studies on schistosomiasis and meningitis. The staff includes 32 persons with 11 scientists and one financial officer. The activities of the CERMES involving schistosomiasis concern three research units: (a ecology of human and animal schistosomiasis transmission; the CERMES defined the different patterns of schistosomiasis transmission in Niger (involving African dry savana; in this field, we have shown, (i the existence of important variability in conditions of transmission of S. haematobium and, (ii natural hybridization between parasitic species of the ruminants (S. bovis and S. curassoni and genetic interaction between human and animal parasites; (b definition of morbidity indicators usable for rapid assessment methods, for appraisal of the severity of the disease and for the evaluation of the efficiency of control methods; we have established the correlation between ultrasonographic data and some cheap and simple field indicators; (c immune response and protective immunity induced by recombinant glutathion S-transferase (Sm28, Sb28 and Sh28 in homologous and heterologous animal models including goats, sheep and non human primates (Erythrocebus patas. In Niger, we participate in all control programs against schistosomiasis to define control strategies, to supervise operations and to participate in their evaluation with external experts. International collaborations constitute a frame including four laboratories in Africa and six laboratories in developed countries (Europe and USA

  10. Predictors of employment for people with severe mental illness : results of an international six-centre randomised controlled trial

    NARCIS (Netherlands)

    Catty, Jocelyn; Lissouba, Pascale; White, Sarah; Becker, Thomas; Drake, Robert E.; Fioritti, Angelo; Knapp, Martin; Lauber, Christoph; Roessler, Wulf; Tomov, Toma; Van Busschbach, Jooske; Wiersma, Durk; Burns, Tom; Rossler, W.

    2008-01-01

    Background An international six-centre randomised controlled trial comparing individual placement and support (IPS) with usual vocational rehabilitation for people with serious mental illness found IPS to be more effective for all vocational outcomes. Aims To determine which patients with severe men

  11. Mosquito-borne disease surveillance by the European Centre for Disease Prevention and Control.

    Science.gov (United States)

    Zeller, H; Marrama, L; Sudre, B; Van Bortel, W; Warns-Petit, E

    2013-08-01

    For a few years, a series of traditionally tropical mosquito-borne diseases, such as chikungunya fever and dengue, have posed challenges to national public health authorities in the European region. Other diseases have re-emerged, e.g. malaria in Greece, or spread to other countries, e.g. West Nile fever. These diseases are reportable within the European Union (EU), and the European Centre for Disease Prevention and Control collects information in various ways to provide EU member states with topical assessments of disease threats, risks and trends for prompt and appropriate public health action. Using disease-specific expert networks, the European Surveillance System (TESSy) collects standardized comparable information on all statutory communicable diseases in a database. In addition, the event-based surveillance aims to detect potential public health threats early, and to allow timely response and support to blood deferral decisions for pathogens that can be transmitted through blood donation. Laboratory capacity for early detection is implemented through external quality assessments. Other activities include the development of guidelines for the surveillance of mosquito vectors, and the production of regularly updated maps on the currently known occurrence of mosquito vector species.

  12. Animal poisoning in Italy: 10 years of epidemiological data from the Poison Control Centre of Milan.

    Science.gov (United States)

    Caloni, F; Cortinovis, C; Rivolta, M; Davanzo, F

    2012-04-21

    From 2000 to 2010, the Poison Control Centre of Milan (CAV), in collaboration with the University of Milan, Faculty of Veterinary Medicine, Department of Veterinary Sciences and Technologies for Food Safety, Toxicology Section, collected epidemiological information related to animal poisoning and classified it in an organised and computerised data bank. Data recorded were predominantly related to small animals and to some extent to horses, ruminants and other food-production animals. Few calls were registered involving exotics and no information was recorded on wildlife. The dog was reported to be the most common species involved in animal poisoning, and pesticides constituted the primary group of toxicants. In the case of pets, 'drugs' including veterinary parasiticide and drugs for human use constituted the second class of toxicants responsible for poisoning followed by household products, plants, zootoxins and metals. With regard to horses and farm animals, the second group consisted of phytotoxins, even if only episodically. In Italy, published data on this subject are scarce but this information is crucial for better management of the poisoning of domestic animals in an effort to reduce mortality.

  13. The Particle Physicists’ Song : the CERN Choir in full voice in the CERN Control Centre, with writer Danuta Orlowska

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    The song was submitted to CERN Courier by Danuta Orlowska, a clinical psychologist with Guy’s and St Thomas’ NHS Foundation Trust in London. It is written to be sung to the tune of The Hippopotamus Song, by Michael Flanders and Donald Swann, which will be well known to many British readers. On 3 February, members of the CERN choir gathered to give a rendition in the CERN Control Centre – the nerve centre of the LHC, which lies at the heart of the lyrics.

  14. Adaptive sliding mode control of tethered satellite deployment with input limitation

    Science.gov (United States)

    Ma, Zhiqiang; Sun, Guanghui

    2016-10-01

    This paper proposes a novel adaptive sliding mode tension control method for the deployment of tethered satellite, where the input tension limitation is taken into account. The underactuated governing equations of the tethered satellites system are firstly derived based on Lagrangian mechanics theory. Considering the fact that the tether can only resist axial stretching, the tension input is modelled as input limitation. New adaptive sliding mode laws are addressed to guarantee the stability of the tethered satellite deployment with input disturbance, meanwhile to eliminate the effect of the limitation features of the tension input. Compared with the classic control strategy, the newly proposed adaptive sliding mode control law can deploy the satellite with smaller overshoot of the in-plane angle and implement the tension control reasonably and effectively in engineering practice. The numerical results validate the effectiveness of the proposed methods.

  15. Design and simulation of satellite attitude control system based on Simulink and VR

    Science.gov (United States)

    Zhang, Yang; Gan, Qingbo; Kang, Jingshu

    2016-01-01

    In order to research satellite attitude control system design and visual simulation, the simulation framework of satellite dynamics and attitude control using Simulink were established. The design of satellite earth-oriented control system based on quaternion feedback was completed. The 3D scene based on VR was created and models in the scene were driven by simulation data of Simulink. By coordinate transformation. successful observing the scene in inertial coordinate system, orbit coordinate system and body coordinate system. The result shows that application of simulation method of Simulink combined with VR in the design of satellite attitude control system field, has the advantages of high confidence level, hard real-time property, multi-perspective and multi-coordinate system observing the scene, and improves the comprehensibility and accuracy of the design.

  16. The historic Proton Synchrotron (PS) control room is about to start a new life. Opened by Niels Bohr in 1960, the room will be reused by CMS to built its control centre. When finished, it will resemble the CERN Control Centre for LHC operations, located in Prevessin.

    CERN Multimedia

    Husi C.

    2007-01-01

    The historic Proton Synchrotron (PS) control room is about to start a new life. Opened by Niels Bohr in 1960, the room will be reused by CMS to built its control centre. When finished, it will resemble the CERN Control Centre for LHC operations, located in Prevessin.

  17. Two way satellite communication for telemetrology and remote control

    Science.gov (United States)

    Hanebrekke, H.

    Low-data-rate satellite communication to fixed and floating buoys at sea, remote observation stations, and fishing vessels is studied. Particular attention is paid to Norwegian conditions, that is, high latitude and high mountains. Coverage and reliability measurements utilizing Inmarsat C and Prodat stations have been done along the coast of western and northern Norway, and on major roads in southern Norway. Good coverage is found in the coastal areas, with only 5 percent loss of messages when both the AOR and IOR satellites are used from the same location, whereas the land mobile experiments gave 40 percent to 70 percent loss, depending on the elevation angle. The possibility of using Inmarsat C or Prodat stations in the major fishing areas between Norway, Greenland, and Svalbard and in the Barents Sea are also being investigated. A method of data collection from ocean areas based on the fishing fleet is proposed.

  18. Orbit Control of Fly-around Satellite with Highly Eccentric Orbit Using Solar Radiation Pressure

    Science.gov (United States)

    Yong-gang, Hou; Chang-yin, Zhao; Ming-jiang, Zhang; Rong-yu, Sun

    2017-01-01

    The method of controlling highly eccentric accompanying flight orbit using the solar wing is proposed in this paper. The formation is maintained by controlling the orbit of the accompanying satellite (follower). The accompanying satellite rotates around its inertial principal axis with a constant angular velocity. The control on the accompanying satellite is divided into the in-plane control and out-of-plane control. The in-plane control is superior to the out-of-plane control. The out-of-plane control force is applied when the in-plane error is eliminated or the in-plane control force can not be supplied due to some geometrical factors. By the sliding mode control method, the magnitude and direction of the control force required by the in-plane orbit control are calculated. Then accordingly, the expression of the solar wing orientation with respect to the satellite body in the control process is derived, so that by adjusting the orientation of the solar wing, the required control force can be obtained. Finally, the verification on this method is performed by numerical simulations, including the orbit adjustment, error elimination, and the orbit maintenance. It is shown that this method can keep the error less than 5 m, and it is feasible for the space formation flight.

  19. The manned space-laboratories control centre - MSCC. Operational functions and its implementation

    Science.gov (United States)

    Brogl, H.; Kehr, J.; Wlaka, M.

    This paper describes the functions of the MSCC during the operations of the Columbus Attached Laboratory and the Free Flying Laboratory as part of the In-Orbit-Infrastructure Ground Segment. For the Attached Laboratory, MSCC payload operations coordination for European experiments within the Attached Laboratory and elsewhere on the Space Station Freedom will be explained. The Free Flying Laboratory will be operated and maintained exclusively from the MSCC during its 30 years lifetime. Several operational scenarios will demonstrate the role of the MSCC during routine - and servicing operations: of main importance are the servicing activities of the Attached Laboratory and the Free Flyer at the Space Station as well as servicing of the Free Flyer by the European Space Plane Hermes. The MSCC will have complex operational-, communications-and management interfaces with the IOI Ground Segment, the Space Station User community and with the international partners. Columbus User Support Centres will be established in many European member states, which have to be coordinated by the MSCC to ensure the proper reception of the scientific data and to provide them with quick access to their experiments in space. For operations planning and execution of experiments in the Attached Laboratory, a close cooperation with the Space Station control authorities in the USA will be established. The paper will show the development of the MSCC being initially used for the upcoming Spacelab Mission D-2 (MSCC Phase-1) and later upgraded to a Columbus dedicated control centre (MSCC Phase-2). For the initial construction phase the establishing of MSCC requirements, the philosophie used for the definition of the 'basic infrastructure' and key features of the installed facilities will be addressed. Resulting from Columbus and D-2 requirements, the sizing of the building with respect to controlrooms, conference rooms, office spare and simulation high-bay areas will be discussed. The defined 'basic

  20. Crustal accretion at high temperature spreading centres: Rheological control of crustal thickness

    Science.gov (United States)

    Schmeling, Harro

    2010-12-01

    New determinations of lateral crustal thickness variations at anomalous oceanic spreading centres such as Iceland have shown that the crust may be thinner at the ridge axis above the plume thickening towards the sides ( Bjarnason and Schmeling, 2009). To understand this behaviour crustal accretion models have been carried out solving the conservation equations of mass, momentum and energy with melting, melt extraction, and feedback of extracted material as newly formed crust for an extending lithosphere system underlain by a hot mantle plume. The dynamics of rifting are thermally and rheologically controlled by the feedback due to accreted new crust. Four accretional modes with characteristic crustal thickness variations are identified depending on the width of the volcanic emplacement zone, the accretional heating rate, which can be associated with the thickness of the surface layer in which magmatic emplacement takes place, and the spreading rate. Mode 1: zero crustal thickness at the spreading axis develops for cool accretion and a wide emplacement zone. Mode 2: strongly or moderately crustal thickening away from the axis develops in case of warm (deep reaching) accretion and wide emplacement zones. Mode 3: nearly constant crustal thickness develops in case of warm (deep reaching) accretion but narrow emplacement zones. Dynamic topography of mode 3 shows only a weak or no regional minimum at all near the axis. Modes 2 or 3 may be identified with the situation in Iceland. Mode 4: a stagnating central crustal block evolves for cool accretion and narrow emplacement. This mode disappears for increasing spreading rates. No accretional mode with maximum crustal thickness above the plume at the rift axis has been found. The absence of mode 1 accretion (with zero crust at ridge axis) on earth may be an indication that in general crustal accretion is not cold (and shallow). The model is also applied to other hotspot-ridge settings (Azores, Galapagos) and suggests modes 2

  1. Attitude dynamics of gyrostat-satellites under control by magnetic actuators at small perturbations

    Science.gov (United States)

    Doroshin, Anton V.

    2017-08-01

    The angular motion of gyrostat-satellites with one axial rotor is considered under control by magnetic actuators and at the action of small polyharmonic perturbations of the own dipole magnetic moment's components which are created proportionally to components of the angular velocity of the satellite. The attitude dynamics is investigated in conditions of the coincidence of the vector of magnetic induction of the external magnetic field and the initial angular momentum vector of the satellite. General and heteroclinic analytical solutions are obtained for dynamical parameters at the relative smallness of the magnetic torques. The chaotic regimes are examined on the base of the Melnikov method and Poincaré sections.

  2. Evaluating implementation of a fire-prevention injury prevention briefing in children's centres: Cluster randomised controlled trial

    Science.gov (United States)

    Deave, Toity; Hawkins, Adrian; Kumar, Arun; Hayes, Mike; Cooper, Nicola; Watson, Michael; Ablewhite, Joanne; Coupland, Carol; Sutton, Alex; Majsak-Newman, Gosia; McDaid, Lisa; Goodenough, Trudy; Beckett, Kate; McColl, Elaine; Reading, Richard; Kendrick, Denise

    2017-01-01

    Background Many developed countries have high mortality rates for fire-related deaths in children aged 0–14 years with steep social gradients. Evidence-based interventions to promote fire safety practices exist, but the impact of implementing a range of these interventions in children’s services has not been assessed. We developed an Injury Prevention Briefing (IPB), which brought together evidence about effective fire safety interventions and good practice in delivering interventions; plus training and facilitation to support its use and evaluated its implementation. Methods We conducted a cluster randomised controlled trial, with integrated qualitative and cost-effectiveness nested studies, across four study sites in England involving children’s centres in disadvantaged areas; participants were staff and families attending those centres. Centres were stratified by study site and randomised within strata to one of three arms: IPB plus facilitation (IPB+), IPB only, usual care. IPB+ centres received initial training and facilitation at months 1, 3, and 8. Baseline data from children’s centres were collected between August 2011 and January 2012 and follow-up data were collected between June 2012 and June 2013. Parent baseline data were collected between January 2012 and May 2012 and follow-up data between May 2013 and September 2013. Data comprised baseline and 12 month parent- and staff-completed questionnaires, facilitation contact data, activity logs and staff interviews. The primary outcome was whether families had a plan for escaping from a house fire. Treatment arms were compared using multilevel models to account for clustering by children’s centre. Results 1112 parents at 36 children’s centres participated. There was no significant effect of the intervention on families’ possession of plans for escaping from a house fire (adjusted odds ratio (AOR) IPB only vs. usual care: 0.93, 95%CI 0.58, 1.49; AOR IPB+ vs. usual care 1.41, 95%CI 0.91, 2

  3. Linear Time Varying Approach to Satellite Attitude Control Using only Electromagnetic Actuation

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1997-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technological improvement of micro-electronics. Required pointing accuracy of small, inexpensive satellites is often relatively loose, within a couple of degrees. Application of cheap......, lightweight, and power efficient actuators is therefore crucial and viable. This paper discusses linear attitude control strategies for a low earth orbit satellite actuated by a set of mutually perpendicular electromagnetic coils. The principle is to use the interaction between the Earth's magnetic field...... and the magnetic field generated by the coils. A key challenge is the fact that the mechanical torque can only be produced in a plane perpendicular to the local geomagnetic field vector, therefore the satellite is not controllable when considered at fixed time. Availability of design methods for time varying...

  4. Linear Time Varying Approach to Satellite Attitude Control Using only Electromagnetic Actuation

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technological improvemant of micro-electronics. Required pointing accuracy of small, inexpensive satellites is often relatively loose, within a couple of degrees. Application of cheap......, lightweight, and power efficient actuators is therefore crucial and viable. This paper discusser linear attitude control strategies for a low earth orbit satellite actuated by a set of mutually perpendicular electromagnetic coils. The principle is to use the interaction between the Earth's magnetic field...... and the magnetic field generated by the coils. A key challenge is the fact that the mechanical torque can only be produced in a plane perpendicular to the local geomagnetic field vector, therefore the satellite is not controllable at fixed time. Avaliability of design methods for time varying systems is limited...

  5. Upper atomosphere and Thermal control of the Super Low Altitude Test Satellite

    OpenAIRE

    2013-01-01

    The Super Low Altitude Test Satellite (SLATS) is an engineering test satellite currently under development in JAXA in an attempt to open a new frontier of space utilization on extremely low earth orbits. The altitude of SLATS orbit is around200km altitude. In this altitude, rarefied aerodynamics and high-density atomic oxygen effect on the thermal design of SLATS. The thermal control of SLATS was introduced in this paper. And, the equilibrium temperature on the bumper of SLATS was estimated w...

  6. Infection Control in Child Day Care Centres : Development and evaluation of a hand hygiene intervention

    NARCIS (Netherlands)

    T.P. Zomer (Tizza)

    2015-01-01

    markdownabstract__Abstract__ Children attending child day care centres are at increased risk of acquiring gastrointestinal and respiratory infections compared to children cared for at home. Hand hygiene is known to be an effective measure to prevent infections. However, compliance with hand

  7. Mechatronic Design, Dynamic Modeling and Results of a Satellite Flight Simulator for Experimental Validation of Satellite Attitude Determination and Control Schemes in 3-Axis

    Directory of Open Access Journals (Sweden)

    M.A. Mendoza-Bárcenas

    2014-06-01

    Full Text Available This paper describes the integration and implementation of a satellite flight simulator based on an air bearing system, which was designed and instrumented in our laboratory to evaluate and to perform research in the field of Attitude Determination and Control Systems for satellites, using the hardware-in-the-loop technique. The satellite flight simulator considers two main blocks: an instrumented mobile platform and an external computer executing costume-made Matlab® software. The first block is an air bearing system containing an FPGA based on-board computer with capabilities to integrate digital architectures for data acquisition from inertial navigation sensors, control of actuators and communications data handling. The second block is an external personal computer, which runs in parallel Matlab® based algorithms for attitude determination and control. Both blocks are linked by means of radio modems. The paper also presents the analysis of the satellite flight simulator dynamics in order to obtain its movement equation which allows a better understanding of the satellite flight simulator behavior. In addition, the paper shows experimental results about the automated tracking of the satellite flight simulator based a virtual reality model developed in Matlab®. It also depicts two different versions of FPGA based on-board computers developed in-house to integrate embedded and polymorphic digital architectures for spacecrafts applications. Finally, the paper shows successful experimental results for an attitude control test using the satellite flight simulator based on a linear control law.

  8. Attitude-Tracking Control with Path Planning for Agile Satellite Using Double-Gimbal Control Moment Gyros

    Directory of Open Access Journals (Sweden)

    Peiling Cui

    2012-01-01

    Full Text Available In view of the issue of rapid attitude maneuver control of agile satellite, this paper presents an attitude-tracking control algorithm with path planning based on the improved genetic algorithm, adaptive backstepping control as well as sliding mode control. The satellite applies double gimbal control moment gyro as actuator and is subjected to the external disturbance and uncertain inertia properties. Firstly, considering the comprehensive mathematical model of the agile satellite and the double gimbal control moment gyro, an improved genetic algorithm is proposed to solve the attitude path-planning problem. The goal is to find an energy optimal path which satisfies certain maneuverability under the constraints of the input saturation, actuator saturation, slew rate limit and singularity measurement limit. Then, the adaptive backstepping control and sliding mode control are adopted in the design of the attitude-tracking controller to track accurately the desired path comprised of the satellite attitude quaternion and velocity. Finally, simulation results indicate the robustness and good tracking performance of the derived controller as well as its ability to avert the singularity of double gimbal control moment gyro.

  9. Robust control of entanglement in a Nitrogen-vacancy centre coupled to a Carbon-13 nuclear spin in diamond

    OpenAIRE

    Said, R S; Twamley, J.

    2009-01-01

    We address a problem of generating a robust entangling gate between electronic and nuclear spins in the system of a single nitrogen-vacany centre coupled to a nearest Carbon-13 atom in diamond against certain types of systematic errors such as pulse-length and off-resonance errors. We analyse the robustness of various control schemes: sequential pulses, composite pulses and numerically-optimised pulses. We find that numerically-optimised pulses, produced by the gradient ascent pulse engineeri...

  10. Singularity Avoidance Strategies For Satellite Mounted Manipulators Using Attitude Control

    Science.gov (United States)

    1998-05-01

    assumed that 6c = 0. This allows a stabilizing control law using only a feedforward velocity term. If Hie assumption is not made, the control law...configuration, a reasonable first choice is to let Cavg = 0. The resulting control law is r = -K2e2 (200) This is also the stabilizing control law that

  11. Precise Ground-In-the-Loop Orbit Control for Low Earth Observation Satellites

    Science.gov (United States)

    Arbinger, C.; D'Amico, S.; Eineder, M.

    The growing interest in earth observation missions equipped with space-borne optical and synthetic aperture radar (SAR) sensors drives the accuracy requirements with respect to orbit determination and control. Especially SAR interferometry with its capability to resolve the velocity of on-ground objects (e.g. for traffic monitoring, ocean currents and glacier monitoring) and to determine highly precise digital elevation models is of significant interest for scientific applications. These goals may be achieved using along-track and repeat-pass interferometry with a satellite formation, based on the precise orbit control of one satellite with respect to the osculating trajectory of the second satellite. Such a control concept will be realized by the German TerraSAR-X mission, with an expected launch in 2006, using a virtual formation, where a single satellite will be controlled in a tight manner with respect to a predefined osculating reference trajectory. This is very challenging, since common orbit disturbances, like for close twin formations, do not cancel out in this scenario. The predefined trajectory in the TerraSAR-X case could also be the orbit of a second satellite. The paper describes the generation of such a virtual reference orbit, discusses the ground-in-the-loop control concept and presents results from a long-term simulation.

  12. Drag-Free Motion Control of Satellite for High-Precision Gravity Field Mapping

    DEFF Research Database (Denmark)

    2002-01-01

    , sensors, actuators and environmental disturbances to the required micro-Newton accuracy. A control system is designed to compensate the non-gravitational disturbances on the satellite in three axes using an H∞-design. Performance is validated against mission requirements. Keywords: Spacecraft Attitude......High precision mapping of the geoid and the Earth's gravity field are of importance to a wide range of ongoing studies in areas like ocean circulation, solid Earth physics and ice sheet dynamics. Using a satellite in orbit around the Earth gives the opportunity to map the Earth's gravity field in 3...... dimensions with much better accuracy and spatial resolution than ever accomplished. To reach the desired quality of measurements, the satellite must fly in a low Earth orbit where disturbances from atmospheric drag and the Earth's magnetic field will perturb the satellite's motion. These effects...

  13. Spectrum management considerations of adaptive power control in satellite networks

    Science.gov (United States)

    Sawitz, P.; Sullivan, T.

    1983-01-01

    Adaptive power control concepts for the compensation of rain attenuation are considered for uplinks and downlinks. The performance of example power-controlled and fixed-EIRP uplinks is compared in terms of C/Ns and C/Is. Provisional conclusions are drawn with regard to the efficacy of uplink and downlink power control orbit/spectrum utilization efficiency.

  14. Human factors dimensions in the evolution of increasingly automated control rooms for near-earth satellites

    Science.gov (United States)

    Mitchell, C. M.

    1982-01-01

    The NASA-Goddard Space Flight Center is responsible for the control and ground support for all of NASA's unmanned near-earth satellites. Traditionally, each satellite had its own dedicated mission operations room. In the mid-seventies, an integration of some of these dedicated facilities was begun with the primary objective to reduce costs. In this connection, the Multi-Satellite Operations Control Center (MSOCC) was designed. MSOCC represents currently a labor intensive operation. Recently, Goddard has become increasingly aware of human factors and human-machine interface issues. A summary is provided of some of the attempts to apply human factors considerations in the design of command and control environments. Current and future activities with respect to human factors and systems design are discussed, giving attention to the allocation of tasks between human and computer, and the interface for the human-computer dialogue.

  15. A COMBINED ADMISSION CONTROL ALGORITHM WITH DA PROTOCOL FOR SATELLITE ATM NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Lu Rong; Cao Zhigang

    2006-01-01

    Admission control is an important strategy for Quality of Service (QoS) provisioning in Asynchronous Transfer Mode (ATM) networks. Based on a control-theory model of resources on-Demand Allocation (DA) protocol, the paper studies the effect of the protocol on the statistical characteristics of network traffic,and proposes a combined connection admission control algorithm with the DA protocol to achieve full utilization of link resources in satellite communication systems. The proposed algorithm is based on the cross-layer-design approach. Theoretical analysis and system simulation results show that the proposed algorithm can admit more connections within certain admission thresholds than one that does not take into account the DA protocol. Thus, the proposed algorithm can increase admission ratio of traffic sources for satellite ATM networks and improve satellite link utilization.

  16. Human factors dimensions in the evolution of increasingly automated control rooms for near-earth satellites

    Science.gov (United States)

    Mitchell, C. M.

    1982-01-01

    The NASA-Goddard Space Flight Center is responsible for the control and ground support for all of NASA's unmanned near-earth satellites. Traditionally, each satellite had its own dedicated mission operations room. In the mid-seventies, an integration of some of these dedicated facilities was begun with the primary objective to reduce costs. In this connection, the Multi-Satellite Operations Control Center (MSOCC) was designed. MSOCC represents currently a labor intensive operation. Recently, Goddard has become increasingly aware of human factors and human-machine interface issues. A summary is provided of some of the attempts to apply human factors considerations in the design of command and control environments. Current and future activities with respect to human factors and systems design are discussed, giving attention to the allocation of tasks between human and computer, and the interface for the human-computer dialogue.

  17. A Topology Control Strategy with Reliability Assurance for Satellite Cluster Networks in Earth Observation.

    Science.gov (United States)

    Chen, Qing; Zhang, Jinxiu; Hu, Ze

    2017-02-23

    This article investigates the dynamic topology control problemof satellite cluster networks (SCNs) in Earth observation (EO) missions by applying a novel metric of stability for inter-satellite links (ISLs). The properties of the periodicity and predictability of satellites' relative position are involved in the link cost metric which is to give a selection criterion for choosing the most reliable data routing paths. Also, a cooperative work model with reliability is proposed for the situation of emergency EO missions. Based on the link cost metric and the proposed reliability model, a reliability assurance topology control algorithm and its corresponding dynamic topology control (RAT) strategy are established to maximize the stability of data transmission in the SCNs. The SCNs scenario is tested through some numeric simulations of the topology stability of average topology lifetime and average packet loss rate. Simulation results show that the proposed reliable strategy applied in SCNs significantly improves the data transmission performance and prolongs the average topology lifetime.

  18. Unified Desktop for Monitoring & Control Applications - The Open Navigator Framework Applied for Control Centre and EGSE Applications

    Science.gov (United States)

    Brauer, U.

    2007-08-01

    The Open Navigator Framework (ONF) was developed to provide a unified and scalable platform for user interface integration. The main objective for the framework was to raise usability of monitoring and control consoles and to provide a reuse of software components in different application areas. ONF is currently applied for the Columbus onboard crew interface, the commanding application for the Columbus Control Centre, the Columbus user facilities specialized user interfaces, the Mission Execution Crew Assistant (MECA) study and EADS Astrium internal R&D projects. ONF provides a well documented and proven middleware for GUI components (Java plugin interface, simplified concept similar to Eclipse). The overall application configuration is performed within a graphical user interface for layout and component selection. The end-user does not have to work in the underlying XML configuration files. ONF was optimized to provide harmonized user interfaces for monitoring and command consoles. It provides many convenience functions designed together with flight controllers and onboard crew: user defined workspaces, incl. support for multi screens efficient communication mechanism between the components integrated web browsing and documentation search &viewing consistent and integrated menus and shortcuts common logging and application configuration (properties) supervision interface for remote plugin GUI access (web based) A large number of operationally proven ONF components have been developed: Command Stack & History: Release of commands and follow up the command acknowledges System Message Panel: Browse, filter and search system messages/events Unified Synoptic System: Generic synoptic display system Situational Awareness : Show overall subsystem status based on monitoring of key parameters System Model Browser: Browse mission database defintions (measurements, commands, events) Flight Procedure Executor: Execute checklist and logical flow interactive procedures Web

  19. Chinese Surveying and Control Network for Earth-Orbit Satellites and Deep Space Detection

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The relationship between the surveying and control network(CSN) for earth-orbit satellite and spatial geodesy, and the relationship between the CSN for deep space celestial bodies and detectors, and deep space detection are briefly summarized, and so are the basic technical needs of the deep space surveying and control network(DSN). Then, the techniques, the constituents and the distributing of Chinese satellite CSN (CSCSN) and other radio observing establishments in China are introduced. Lastly, with the primary CSCSN and other observing establishments, some projects for China to rebuild a more perfect CSCSN, and to establish a DSN are analyzed and stated.

  20. A Piecewise Affine Hybrid Systems Approach to Fault Tolerant Satellite Formation Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Larsen, Jesper Abildgaard; Bak, Thomas

    2008-01-01

    In this paper a procedure for modelling satellite formations   including failure dynamics as a piecewise-affine hybrid system is   shown. The formulation enables recently developed methods and tools   for control and analysis of piecewise-affine systems to be applied   leading to synthesis of fault...... tolerant controllers and analysis of   the system behaviour given possible faults.  The method is   illustrated using a simple example involving two satellites trying   to reach a specific formation despite of actuator faults occurring....

  1. A Piecewise Affine Hybrid Systems Approach to Fault Tolerant Satellite Formation Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Larsen, Jesper Abildgaard; Bak, Thomas

    2008-01-01

    In this paper a procedure for modelling satellite formations   including failure dynamics as a piecewise-affine hybrid system is   shown. The formulation enables recently developed methods and tools   for control and analysis of piecewise-affine systems to be applied   leading to synthesis of fault...... tolerant controllers and analysis of   the system behaviour given possible faults.  The method is   illustrated using a simple example involving two satellites trying   to reach a specific formation despite of actuator faults occurring....

  2. Design Considerations for Miniaturized Control Moment Gyroscopes for Rapid Retargeting and Precision Pointing of Small Satellites

    OpenAIRE

    Patankar, Kunal; Fitz-Coy, Norman; Roithmayr, Carlos

    2014-01-01

    This paper presents the design as well as characterization of a practical control moment gyroscope (CMG) based attitude control system (ACS) for small satellites in the 15-20 kg mass range performing rapid retargeting and precision pointing maneuvers. The paper focuses on the approach taken in the design of miniaturized CMGs while considering the constraints imposed by the use of commercial off-the-shelf (COTS) components as well as the size of the satellite. It is shown that a hybrid mode is...

  3. Controlled assembly and plasmonic properties of asymmetric core-satellite nanoassemblies.

    Science.gov (United States)

    Yoon, Jun Hee; Lim, Jonghui; Yoon, Sangwoon

    2012-08-28

    The assembly of noble metal nanoparticles offers an appealing means to control and enhance the plasmonic properties of nanostructures. However, making nanoassemblies with easily modifiable gap distances with high efficiency has been challenging. Here, we report a novel strategy to assemble gold nanoparticles (AuNPs) into Janus-type asymmetric core-satellite nanostructures. Markedly different desorption efficiency between large and small AuNPs in ethanol allows us to prepare the asymmetric core-satellite nanoassemblies in a dispersed colloidal state with near 100% purity. The resulting nanoassemblies have well-defined structures in which a core AuNP (51 nm) is covered by an average of 13 ± 3 satellite AuNPs (13 nm) with part of the core surfaces left unoccupied. Strong surface plasmon coupling is observed from these nanoassemblies as a result of the close proximity between the core and the satellites, which appears significantly red-shifted from the surface plasmon resonance frequencies of the constituting nanoparticles. The dependence of the surface plasmon coupling on a gap distance of less than 3 nm is systematically investigated by varying the length of the alkanedithiol linkers. The asymmetric core-satellite nanoassemblies also serve as an excellent surface-enhanced Raman scattering substrate with an enhancement factor of ~10(6). Finally, we demonstrate that the presented assembly method is extendible to the preparation of compositionally heterogeneous core-satellite nanoassemblies.

  4. Closed-Loop Control of Satellite Formations Using a Quasi-Rigid Body Formulation

    Science.gov (United States)

    Blake, Christopher; Misra, Arun K.

    2011-04-01

    Satellites in formation work together to fulfill the role of a larger satellite. The purpose of this article is to develop a quasi-rigid body formulation for modeling and controlling such a formation as a single entity. In this article, a definition of a quasi-rigid body coordinate frame is presented, which, when attached to a formation, conveniently describes its orientation in space. Using this formulation, the equations of motion for a satellite formation are recast, and natural circular formations are expressed more succinctly. When the J 2 perturbation is considered, a correction factor on the formation's spin rate is introduced. The control of a satellite formation can effectively be separated into (1) a control torque to maintain the attitude and (2) control forces that maintain the rigidity of the formation. With this in mind, a nonlinear Lyapunov controller is derived using the formulation, which acts on the formation as a whole. Simulations validate this controller and illustrate its utility for maintaining circular formations, in particular, in the presence of gravitational perturbations.

  5. Error control techniques for satellite and space communications

    Science.gov (United States)

    Costello, Daniel J., Jr.

    1989-01-01

    Two aspects of the work for NASA are examined: the construction of multi-dimensional phase modulation trellis codes and a performance analysis of these codes. A complete list is contained of all the best trellis codes for use with phase modulation. LxMPSK signal constellations are included for M = 4, 8, and 16 and L = 1, 2, 3, and 4. Spectral efficiencies range from 1 bit/channel symbol (equivalent to rate 1/2 coded QPSK) to 3.75 bits/channel symbol (equivalent to 15/16 coded 16-PSK). The parity check polynomials, rotational invariance properties, free distance, path multiplicities, and coding gains are given for all codes. These codes are considered to be the best candidates for implementation of a high speed decoder for satellite transmission. The design of a hardware decoder for one of these codes, viz., the 16-state 3x8-PSK code with free distance 4.0 and coding gain 3.75 dB is discussed. An exhaustive simulation study of the multi-dimensional phase modulation trellis codes is contained. This study was motivated by the fact that coding gains quoted for almost all codes found in literature are in fact only asymptotic coding gains, i.e., the coding gain at very high signal to noise ratios (SNRs) or very low BER. These asymptotic coding gains can be obtained directly from a knowledge of the free distance of the code. On the other hand, real coding gains at BERs in the range of 10(exp -2) to 10(exp -6), where these codes are most likely to operate in a concatenated system, must be done by simulation.

  6. Nutation and precession control of the High Energy Solar Physics (HESP) satellite

    Science.gov (United States)

    Jayaraman, C. P.; Robertson, B. P.

    1993-01-01

    The High Energy Solar Physics (HESP) spacecraft is an intermediate class satellite proposed by NASA to study solar high-energy phenomena during the next cycle of high solar activity in the 1998 to 2005 time frame. The HESP spacecraft is a spinning satellite which points to the sun with stringent pointing requirements. The natural dynamics of a spinning satellite includes an undesirable effect: nutation, which is due to the presence of disturbances and offsets of the spin axis from the angular momentum vector. The proposed Attitude Control System (ACS) attenuates nutation with reaction wheels. Precessing the spacecraft to track the sun in the north-south and east-west directions is accomplished with the use of torques from magnetic torquer bars. In this paper, the basic dynamics of a spinning spacecraft are derived, control algorithms to meet HESP science requirements are discussed and simulation results to demonstrate feasibility of the ACS concept are presented.

  7. Evolvable work-centred support systems for command and control: creating systems users can adapt to meet changing demands.

    Science.gov (United States)

    Roth, E; Scott, R; Deutsch, S; Kuper, S; Schmidt, V; Stilson, M; Wampler, J

    2006-06-10

    Military command and control (C2) organizations are complex socio-technical systems which must constantly adapt to meet changing operational requirements. We describe our experiences in developing a work-centred support system (WCSS) to aid weather forecasting and monitoring in a military airlift C2 organization as an illustrative case. As part of the development process we conducted field observations both before and after introduction of the WCSS in their operations centre. A striking finding was the constant changes that operations personnel faced (changes in goals and priorities, changes in scale of operations, changes in team roles and structure, and changes in information sources and systems). We describe the changes in workplace demands that we observed and the modifications we needed to make to the WCSS in response. For today's fielded systems, it is seldom possible to make changes that are responsive to users' changing requirements in a timely manner. We argue for the need to incorporate facilities that enable users to adapt their systems to the changing requirements of work and point to some promising directions towards evolvable work-centred support systems.

  8. Closed-Loop Acoustic Control of Reverberant Room for Satellite Environmental Testing

    Science.gov (United States)

    Janssens, Karl; Bianciardi, Fabio; Sabbatini, Danilo; Debille, Jan; Carrella, Alex

    2012-07-01

    The full satellite acoustic test is an important milestone in a satellite launch survivability verification campaign. This test is required to verify the satellite’s mechanical design against the high-level acoustic loads induced by the launch vehicle during the atmospheric flight. During the test, the satellite is subjected to a broadband diffuse acoustic field, reproducing the pressure levels observed during launch. The excitation is in most cases provided by a combination of horns for the low frequencies and noise generators for the higher frequencies. Acoustic control tests are commonly performed in reverberant rooms, controlling the sound pressure levels in third octave bands over the specified target spectrum. This paper discusses an automatic feedback control system for acoustic control of large reverberation rooms for satellite environmental testing. The acoustic control system consists of parallel third octave PI (Proportional Integral) feedback controllers that take the reverberation characteristics of the room into consideration. The drive output of the control system is shaped at every control step based on the comparison of the average third octave noise spectrum, measured from a number of microphones in the test room, with the target spectrum. Cross-over filters split the output drive into band- limited signals to feed each of the horns. The control system is realized in several steps. In the first phase, a dynamic process model is developed, including the non-linear characteristics of the horns and the reverberant properties of the room. The model is identified from dynamic experiments using system identification techniques. In the next phase, an adequate control strategy is designed which is capable of reaching the target spectrum in the required time period without overshoots. This control strategy is obtained from model-in-the-loop (MIL) simulations, evaluating the performance of various potential strategies. Finally, the proposed strategy is

  9. Adaptive FTC based on Control Allocation and Fault Accommodation for Satellite Reaction Wheels

    OpenAIRE

    Baldi, P.; Blanke, Mogens; P. Castaldi; Mimmo, N.; S. Simani

    2016-01-01

    This paper proposes an active fault tolerant control scheme to cope with faults or failures affecting the flywheel spin rate sensors or satellite reaction wheel motors. The active fault tolerant control system consists of a fault detection and diagnosis module along with a control allocationand fault accommodation module directly exploiting the on-line fault estimates. The use of the nonlinear geometric approach and radial basis function neural networks allows to obtain a precise fault isolat...

  10. Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty

    Science.gov (United States)

    Wu, Shunan; Liu, Yufei; Radice, Gianmarco; Tan, Shujun

    2017-01-01

    With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna’s optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional–derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness. PMID:28287450

  11. Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty.

    Science.gov (United States)

    Wu, Shunan; Liu, Yufei; Radice, Gianmarco; Tan, Shujun

    2017-03-10

    With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna's optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional-derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness.

  12. Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty

    Directory of Open Access Journals (Sweden)

    Shunan Wu

    2017-03-01

    Full Text Available With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna’s optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional–derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness.

  13. Multiagent Attitude Control System for Satellites Based in Momentum Wheels and Event-Driven Synchronization

    Science.gov (United States)

    Garcia, Juan L.; Moreno, Jose Sanchez

    2012-12-01

    Attitude control is a requirement always present in spacecraft design. Several kinds of actuators exist to accomplish this control, being momentum wheels one of the most employed. Usually satellites carry redundant momentum wheels to handle any possible single failure, but the controller remains as a single centralized element, posing problems in case of failures. In this work a decentralized agent-based event-driven algorithm for attitude control is presented as a possible solution. Several agents based in momentum wheels will interact among them to accomplish the satellite control. A simulation environment has been developed to analyze the behavior of this architecture. This environment has been made available through the web page http://www.dia.uned.es.

  14. A university-based distributed satellite mission control network for operating professional space missions

    Science.gov (United States)

    Kitts, Christopher; Rasay, Mike

    2016-03-01

    For more than a decade, Santa Clara University's Robotic Systems Laboratory has operated a unique, distributed, internet-based command and control network for providing professional satellite mission control services for a variety of government and industry space missions. The system has been developed and is operated by students who become critical members of the mission teams throughout the development, test, and on-orbit phases of these missions. The mission control system also supports research in satellite control technology and hands-on student aerospace education. This system serves as a benchmark for its comprehensive nature, its student-centric nature, its ability to support NASA and industry space missions, and its longevity in providing a consistent level of professional services. This paper highlights the unique features of this program, reviews the network's design and the supported spacecraft missions, and describes the critical programmatic features of the program that support the control of professional space missions.

  15. Identifying and controlling a multiresistant pseudomonas aeruginosa outbreak in a latin-american cancer centre and its associated risk factors

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Cortes

    2009-04-01

    Full Text Available Pseudomonas aeruginosa is an important and frightening microorganism for patients suffering from cancer. Multiresistant P. aeruginosa (MRPA may appear as a consequence of exposure to multiple antibiotics or from a breakdown in infection control practices. This article reports an MRPA outbreak in a cancer treatment centre and the consequent case control study. Mechanical ventilation was identified as being the main risk factor for developing MRPA colonisation or infection; molecular analysis confirmed the outbreak. A multifaceted strategy was adopted, involving reinforcing hand-washing practices, contact isolation, antibiotic restriction and suction devices for mechanically-ventilated patients. MRPA was controlled and the outbreak ended. Such strategy may be effective in controlling MRPS in low-resource environments amongst high risk cancer patients.

  16. Identifying and controlling a multiresistant pseudomonas aeruginosa outbreak in a latin-american cancer centre and its associated risk factors

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Cortes

    Full Text Available Pseudomonas aeruginosa is an important and frightening microorganism for patients suffering from cancer. Multiresistant P. aeruginosa (MRPA may appear as a consequence of exposure to multiple antibiotics or from a breakdown in infection control practices. This article reports an MRPA outbreak in a cancer treatment centre and the consequent case control study. Mechanical ventilation was identified as being the main risk factor for developing MRPA colonisation or infection; molecular analysis confirmed the outbreak. A multifaceted strategy was adopted, involving reinforcing hand-washing practices, contact isolation, antibiotic restriction and suction devices for mechanically-ventilated patients. MRPA was controlled and the outbreak ended. Such strategy may be effective in controlling MRPS in low-resource environments amongst high risk cancer patients.

  17. Automatic phase control in solar power satellite systems

    Science.gov (United States)

    Lindsey, W. C.; Kantak, A. V.

    1978-01-01

    Various approaches to the problem of generating, maintaining and distributing a coherent, reference phase signal over a large area are suggested, mathematically modeled and analyzed with respect to their ability to minimize: phase build-up, beam diffusion and beam steering phase jitter, cable length, and maximize power transfer efficiency. In addition, phase control configurations are suggested which alleviate the need for layout symmetry.

  18. Communication and Control in the Canadian North: The Role of Interactive Satellites.

    Science.gov (United States)

    Valaskakis, Gail G.

    In 1972 the Canadian government launched its first domestic communications satellite, Anik A, which relays direct broadcast television and telephone messages to northern communities. The impact of television on Inuit life has raised issues and concerns pertaining to native language broadcasting, media access and control, and cultural identity…

  19. Solar attitude control including active nutation damping in a fixed-momentum wheel satellite

    Science.gov (United States)

    Azor, Ruth

    1992-08-01

    In geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances, caused mainly by solar pressure. This work presents a roll/yaw control, which is obtained by the use of solar arrays and fixed flaps as actuators, with a horizon sensor for roll measurement. The design also includes an active nutation damping.

  20. A person-centred and thriving-promoting intervention in nursing homes - study protocol for the U-Age nursing home multi-centre, non-equivalent controlled group before-after trial.

    Science.gov (United States)

    Edvardsson, David; Sjögren, Karin; Lood, Qarin; Bergland, Ådel; Kirkevold, Marit; Sandman, Per-Olof

    2017-01-17

    The literature suggests that person-centred care can contribute to quality of life and wellbeing of nursing home residents, relatives and staff. However, there is sparse research evidence on how person-centred care can be operationalised and implemented in practice, and the extent to which it may promote wellbeing and satisfaction. Therefore, the U-Age nursing home study was initiated to deepen the understanding of how to integrate person-centred care into daily practice and to explore the effects and meanings of this. The study aims to evaluate effects and meanings of a person-centred and thriving-promoting intervention in nursing homes through a multi-centre, non-equivalent controlled group before-after trial design. Three nursing homes across three international sites have been allocated to a person-centred and thriving-promoting intervention group, and three nursing homes have been allocated to an inert control group. Staff at intervention sites will participate in a 12-month interactive educational programme that operationalises thriving-promoting and person-centred care three dimensions: 1) Doing a little extra, 2) Developing a caring environment, and 3) Assessing and meeting highly prioritised psychosocial needs. A pedagogical framework will guide the intervention. The primary study endpoints are; residents' thriving, relatives' satisfaction with care and staff job satisfaction. Secondary endpoints are; resident, relative and staff experiences of the caring environment, relatives' experience of visiting their relative and the nursing home, as well as staff stress of conscience and perceived person-centredness of care. Data on study endpoints will be collected pre-intervention, post-intervention, and at a six-month follow up. Interviews will be conducted with relatives and staff to explore experiences and meanings of the intervention. The study is expected to provide evidence that can inform further research, policy and practice development on if and how

  1. 23rd June 2010 - University of Bristol Head of the Aerospace Engineering Department and Professor of Aerospace Dynamics N. Lieven visiting CERN control centre with Beams Department Head P. Collier, visiting the LHC superconducting magnet test hall with R. Veness and CMS control centre with Collaboration Spokesperson G. Tonelli and CMS User J. Goldstein.

    CERN Multimedia

    Jean-Claude Gadmer

    2010-01-01

    23rd June 2010 - University of Bristol Head of the Aerospace Engineering Department and Professor of Aerospace Dynamics N. Lieven visiting CERN control centre with Beams Department Head P. Collier, visiting the LHC superconducting magnet test hall with R. Veness and CMS control centre with Collaboration Spokesperson G. Tonelli and CMS User J. Goldstein.

  2. Dynamics and chaos control of asymmetric gyrostat satellites

    Science.gov (United States)

    Aslanov, V. S.; Yudintsev, V. V.

    2014-05-01

    The motion of a free gyrostat consisting of a platform with a triaxial ellipsoid of inertia and a rotor with a slight asymmetry with respect to the axis of rotation is considered. Dimensionless equations of motion for a system with perturbations caused by the small asymmetries of the rotor are written in Andoyer-Deprit variables. These perturbations result in a chaotic layer in the separatrix vicinity. Heteroclinic and homoclinic trajectories are written in analytical form for gyrostats with different ratios of their moments of inertia. These trajectories are used to construct a modified Melnikov function, and to produce control that eliminates separatrix chaos. The Poincare sections and Melnikov function are constructed via numerical modeling that demonstrates the effectiveness of control.

  3. The geo-control system for station keeping and colocation of geostationary satellites

    Science.gov (United States)

    Montenbruck, O.; Eckstein, M. C.; Gonner, J.

    1993-01-01

    GeoControl is a compact but powerful and accurate software system for station keeping of single and colocated satellites, which has been developed at the German Space Operations Center. It includes four core modules for orbit determination (including maneuver estimation), maneuver planning, monitoring of proximities between colocated satellites, and interference and event prediction. A simple database containing state vector and maneuver information at selected epochs is maintained as a central interface between the modules. A menu driven shell utilizing form screens for data input serves as the central user interface. The software is written in Ada and FORTRAN and may be used on VAX workstations or mainframes under the VMS operating system.

  4. Satellite Dynamics and Control in a Quaternion Formulation (2nd edition)

    DEFF Research Database (Denmark)

    Blanke, Mogens; Larsen, Martin Birkelund

    This lecture note treats modelling and attitude control design using a quaternion description of attitude for a rigid body in space. Dynamics and kinematics of a satellite is formulated as a non-linear model from Euler’s moment equations and a description of kinematics using the attitude quaternion...... to represent rotation. A general linearised model is derived such that the user can specify an arbitrary point of operation in angular velocity and wheel angular momentum, specifying the a inertia matrix for a rigid satellite. A set of Simulink® models that simulate the satellite’s nonlinear behaviour...

  5. Controlled pericardiocentesis in patients with cardiac tamponade complicating aortic dissection: experience of a centre without cardiothoracic surgery.

    Science.gov (United States)

    Cruz, Inês; Stuart, Bruno; Caldeira, Daniel; Morgado, Gonçalo; Gomes, Ana C; Almeida, Ana R; Loureiro, Maria J; João, Isabel; Cotrim, Carlos; Pereira, Hélder

    2015-04-01

    Cardiac tamponade has been reported in 18.7% of patients with acute type A aortic dissection and its presence is associated with worse outcomes. Emergency aortic repair together with intra-operative pericardial drainage is the recommended treatment approach. However, controversy surrounds how to manage patients with haemopericardium and cardiac tamponade who cannot survive until surgery. To describe a case series of patients with critical cardiac tamponade complicating aortic dissection admitted to a hospital without cardiothoracic surgery, and in whom preoperative controlled pericardial drainage was performed. Single centre retrospective study: during a nine-year period, 21 patients with Stanford type A aortic dissection were admitted at our centre; six of them (28.6%) presented clinical and echocardiographic signs of cardiac tamponade (four males; mean age 58±17 years). In this subgroup, controlled pericardiocentesis was safely performed with no major immediate complications and it was effective in five patients, improving haemodynamic instability and allowing transfer to the operating room. Preoperative controlled pericardiocentesis can be lifesaving when managing patients with critical cardiac tamponade (pulseless electrical activity or refractory hypotension) complicating acute type A aortic dissection, namely when cardiac surgery is not immediately available. © The European Society of Cardiology 2014.

  6. Role of the "National Reference Centre for Genetically Modified Organisms (GMO) detection" in the official control of food and feed.

    Science.gov (United States)

    Ciabatti, I; Marchesi, U; Froiio, A; Paternò, A; Ruggeri, M; Amaddeo, D

    2005-08-01

    The National Reference Centre for Genetically Modified Organisms (GMO) detection was established in 2002 within the Istituto Zooprofilattico Sperimentale Lazio e Toscana, with the aim of providing scientific and technical support to the National Health System and to the Ministry of Health within the scope of the regulation of GMO use in food and feed.The recently adopted EU legislation on GMOs (Regulation CE no. 1829/2003 and no. 1830/2003) introduced more rigorous procedures for the authorisation, labelling and analytical control of food and feed consisting, containing or derived from GMOs. The National Reference Centre, besides its institutional tasks as one of the laboratories of the Italian National Health System, collects and analyses data and results of the national official control of GMOs; carries out scientific research aimed at developing, improving, validating and harmonising detection and quantification methods, in cooperation with other scientific institutions, the Community Reference Laboratory and within the European Network of GMOs laboratories (ENGL); collaborates with the Ministry of Health in the definition of control programmes and promotes educational and training initiatives. Objectives defined for 2004-2006, activities in progress and goals already achieved are presented.

  7. Guidance, Navigation, and Control Techniques and Technologies for Active Satellite Removal

    Science.gov (United States)

    Ortega Hernando, Guillermo; Erb, Sven; Cropp, Alexander; Voirin, Thomas; Dubois-Matra, Olivier; Rinalducci, Antonio; Visentin, Gianfranco; Innocenti, Luisa; Raposo, Ana

    2013-09-01

    This paper shows an internal feasibility analysis to de- orbit a non-functional satellite of big dimensions by the Technical Directorate of the European Space Agency ESA. The paper focuses specifically on the design of the techniques and technologies for the Guidance, Navigation, and Control (GNC) system of the spacecraft mission that will capture the satellite and ultimately will de-orbit it on a controlled re-entry.The paper explains the guidance strategies to launch, rendezvous, close-approach, and capture the target satellite. The guidance strategy uses chaser manoeuvres, hold points, and collision avoidance trajectories to ensure a safe capture. It also details the guidance profile to de-orbit it in a controlled re-entry.The paper continues with an analysis of the required sensing suite and the navigation algorithms to allow the homing, fly-around, and capture of the target satellite. The emphasis is placed around the design of a system to allow the rendezvous with an un-cooperative target, including the autonomous acquisition of both the orbital elements and the attitude of the target satellite.Analysing the capture phase, the paper provides a trade- off between two selected capture systems: the net and the tentacles. Both are studied from the point of view of the GNC system.The paper analyses as well the advanced algorithms proposed to control the final compound after the capture that will allow the controlled de-orbiting of the assembly in a safe place in the Earth.The paper ends proposing the continuation of this work with the extension to the analysis of the destruction process of the compound in consecutive segments starting from the entry gate to the rupture and break up.

  8. 3-Axis magnetic control: flight results of the TANGO satellite in the PRISMA mission

    Science.gov (United States)

    Chasset, C.; Noteborn, R.; Bodin, P.; Larsson, R.; Jakobsson, B.

    2013-09-01

    PRISMA implements guidance, navigation and control strategies for advanced formation flying and rendezvous experiments. The project is funded by the Swedish National Space Board and run by OHB-Sweden in close cooperation with DLR, CNES and the Danish Technical University. The PRISMA test bed consists of a fully manoeuvrable MANGO satellite as well as a 3-axis controlled TANGO satellite without any Δ V capability. PRISMA was launched on the 15th of June 2010 on board DNEPR. The TANGO spacecraft is the reference satellite for the experiments performed by MANGO, either with a "cooperative" or "non-cooperative" behaviour. Small, light and low-cost were the keywords for the TANGO design. The attitude determination is based on Sun sensors and magnetometers, and the active attitude control uses magnetic torque rods only. In order to perform the attitude manoeuvres required to fulfil the mission objectives, using any additional gravity gradient boom to passively stabilize the spacecraft was not allowed. After a two-month commissioning phase, TANGO separated from MANGO on the 11th of August 2010. All operational modes have been successfully tested, and the pointing performance in flight is in accordance with expectations. The robust Sun Acquisition mode reduced the initial tip-off rate and placed TANGO into a safe attitude in TANGO points its GPS antenna towards zenith with sufficient accuracy to track as many GPS satellites as MANGO. At the same time, it points its solar panel towards the Sun, and all payload equipments can be switched on without any restriction. This paper gives an overview of the TANGO Attitude Control System design. It then presents the flight results in the different operating modes. Finally, it highlights the key elements at the origin of the successful 3-axis magnetic control strategy on the TANGO satellite.

  9. Analytical derivation and verification of zero-gyro control for the IUE satellite

    Science.gov (United States)

    Bowles, Tiffany; Croft, John

    1989-01-01

    The International Ultraviolet Explorer (IUE) satellite was launched January 26, 1978 into a geosynchronous orbit over South America. From its stationary position, the telescope maintains continuous communication with the control centers at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and at the European Space Agency's (ESA's) Villagranca del Castillo Satellite Tracking Station in Spain. Since its launch in 1978, the satellite has gradually lost four of the original six gyroscopes in the Inertial Reference Assembly (IRA). In August 1985, the fourth of the original six gyros failed and a two-gyro system developed by NASA-GSFC was uplinked to the satellite and is currently in use. A one-gyro system also developed by NASA-GSFC is ready for use in case of another gyro failure. In the event that the sixth gyro should also fail, a zero-gyro system is being developed. The goal of this system is to provide interial target pointing without the use of gyroscopes. The satellite has sun sensors to provide attitude information about two of the three axes. It relies upon the exchange of reaction wheel momenta to determine angular position and rate of the third axis.

  10. Experimental verification of chaotic control of an underactuated tethered satellite system

    Science.gov (United States)

    Pang, Zhaojun; Jin, Dongping

    2016-03-01

    This paper studies chaotic control of a tethered satellite system (TSS) driven only by a momentum-exchange device during its attitude adjustment. In dealing with such the underactuated system, an extended time-delay autosynchronization (ETDAS) is employed to stabilize the chaotic motion to a periodic motion. To obtain the control domains of the ETDAS method, a stability analysis of the controlled tethered satellite system in elliptical orbit is implemented. According to the principle of dynamic similarity, then, ground-based experiment setups are proposed and designed to emulate the in-plane motions of the TSS. Representative experiments are presented to demonstrate the effectiveness of the ETDAS scheme in controlling the chaotic motion of the underactuated TSS.

  11. SPOT satellite family: Past, present, and future of the operations in the mission and control center

    Science.gov (United States)

    Philippe, Pacholczyk

    1993-01-01

    SPOT sun-synchronous remote sensing satellites are operated by CNES since February 1986. Today, the SPOT mission and control center (CCM) operates SPOT1, SPOT2, and is ready to operate SPOT3. During these seven years, the way to operate changed and the CCM, initially designed for the control of one satellite, has been modified and upgraded to support these new operating modes. All these events have shown the performances and the limits of the system. A new generation of satellite (SPOT4) will continue the remote sensing mission during the second half of the 90's. Its design takes into account the experience of the first generation and supports several improvements. A new generation of control center (CMP) has been developed and improves the efficiency, quality, and reliability of the operations. The CMP is designed for operating two satellites at the same time during launching, in-orbit testing, and operating phases. It supports several automatic procedures and improves data retrieval and reporting.

  12. Search for an eventual control of Saturnian kilometric radiation by Titan satellite

    Science.gov (United States)

    Boudjada, Mohammed Y.; Galopeau, Patrick H. M.; Lecacheux, Alain; Rucker, Helmut

    2013-04-01

    The Cassini Radio and Plasma Wave Science Experiment (RPWS) revealed prominent arcs when the data are displayed in time-frequency coordinates, in the so-called dynamic spectra. We show that the Saturnian Kilometric Radiation (SKR) presents different kinds of characteristic appearances like arc structures. Those arcs may be classified in two sets: the 'vertex early arcs' (VEA) and the 'vertex late arcs' (VLA), and are observed in the frequency range between 80 kHz and 1 MHz. We investigate the probable control of the SKR arcs by the Titan satellite. We emphasis in this study on the arc observational parameters (e.g. the probability of occurrence, the local time and the gyro-frequency) and their eventual relations to the geometrical configuration between Saturn, Titan, and the observed (i.e. Cassini spacecraft). We follow in this analysis a similar method applied to the control of Jovian decametric emissions by the Io satellite. This method consists principally to observe, on one side, the arc curvatures and their corresponding maximum frequency, and on the other side the orbital phase of the Titan satellite around the planet. This leads us to provide a first attempt concerning the 'controls' of non-thermal Jovian and Saturnian radio emissions, respectively, by Io and Titan satellites.

  13. Tilted wheel satellite attitude control with air-bearing table experimental results

    Science.gov (United States)

    Inumoh, Lawrence O.; Forshaw, Jason L.; Horri, Nadjim M.

    2015-12-01

    Gyroscopic actuators for satellite control have attracted significant research interest over the years, but their viability for the control of small satellites has only recently started to become clear. Research on variable speed gyroscopic actuators has long been focused on single gimbal actuators; double gimbal actuators typically operate at constant wheel spin rate and allow tilt angle ranges far larger than the ranges needed to operate most satellite missions. This research examines a tilted wheel, a newly proposed type of inertial actuator that can generate torques in all three principal axes of a rigid satellite using a spinning wheel and a double tilt mechanism. The tilt mechanism tilts the angular momentum vector about two axes providing two degree of freedom control, while variation of the wheel speed provides the third. The equations of motion of the system lead to a singularity-free system during nominal operation avoiding the need for complex steering logic. This paper describes the hardware design of the tilted wheel and the experimental setup behind both standalone and spherical air-bearing tables used to test it. Experimental results from the air bearing table are provided with the results depicting the high performance capabilities of the proposed actuator in torque generation.

  14. Adaptive FTC based on Control Allocation and Fault Accommodation for Satellite Reaction Wheels

    DEFF Research Database (Denmark)

    Baldi, P.; Blanke, Mogens; Castaldi, P.;

    2016-01-01

    This paper proposes an active fault tolerant control scheme to cope with faults or failures affecting the flywheel spin rate sensors or satellite reaction wheel motors. The active fault tolerant control system consists of a fault detection and diagnosis module along with a control allocation...... estimation filters, which do not need a priori information about the internal model of the signal to be estimated. The adaptive control allocation and sensor fault accommodation can handle both temporal faults and failures. Simulation results illustrate the convincing fault correction and attitude control...

  15. Deploying process modeling and attitude control of a satellite with a large deployable antenna

    OpenAIRE

    Zhigang Xing; Gangtie Zheng

    2014-01-01

    Modeling and attitude control methods for a satellite with a large deployable antenna are studied in the present paper. Firstly, for reducing the model dimension, three dynamic models for the deploying process are developed, which are built with the methods of multi-rigid-body dynamics, hybrid coordinate and substructure. Then an attitude control method suitable for the deploying process is proposed, which can keep stability under any dynamical parameter variation. Subsequently, this attitude...

  16. Solar sail attitude control including active nutation damping in a fixed-momentum wheel satellite

    Science.gov (United States)

    Azor, Ruth

    1992-02-01

    In the geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances caused by solar radiation pressure. This work presents a roll/yaw control system with a horizon sensor for roll measurement. Roll/yaw control is obtained by the use of solar arrays and fixed flaps as actuators. The design also includes an active nutation damping method.

  17. 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.

  18. Compliance with infection control practices in sputum microscopy centres: a study from Kerala, India.

    Science.gov (United States)

    Aslesh, O P; Ubaid, N P; Nagaraja, S B; Shewade, H D; Padmanabhan, K V; Naik, B R; Satpati, M; Blesson, S; Jayasree, A K

    2015-12-21

    Contexte : Une des stratégies du Programme national révisé de lutte contre la tuberculose (RNTCP) en Inde consiste à lutter contre la tuberculose en augmentant la détection des cas à travers un réseau national de Centres de Diagnostic par Microscopie (DMC). La mise en oeuvre des précautions standard de lutte contre les infections dans ces DMC est très importante pour prévenir la transmission des infections, non seulement vis-à-vis du personnel de laboratoire, mais également vis-à-vis de la population générale. Cependant, en Inde, ceci n'a pas été évalué par une agence externe.Méthode : Une étude transversale a été réalisée pour évaluer les connaissances, la structure et l'adhésion aux pratiques de lutte contre l'infection (ICP) dans les 38 DMC du district de Kannur, état du Kerala, Inde en 2015. Grâce à des observations et à des entretiens, les investigateurs ont recueilli des données dans un format structuré.Résultats : Les connaissances d'ensemble relatives à la lutte contre l'infection ont été jugées satisfaisantes pour 29% des techniciens de laboratoire. Le niveau d'ensemble des centres en matière de lutte contre l'infection a été satisfaisant dans 61% des DMC. L'adhésion aux pratiques de lutte contre l'infection a été satisfaisante dans 45% des DMC. Les connaissances relatives aux pratiques d'ICP ont été meilleures dans les DMC du gouvernement tandis que les installations et l'adhésion aux directives de gestion des déchets biomédicaux ont été meilleures dans les DMC privés.Conclusion : Connaissant le risque très élevé d'infection parmi les techniciens de laboratoire, il y a un besoin urgent de corriger les déficiences des pratiques de lutte contre l'infection.

  19. Dynamical modelling and control of a spacecraft-mounted manipulator capturing a spinning satellite

    Science.gov (United States)

    Cyril, Xavier; Jaar, Gilbert J.; Misra, Arun K.

    1995-01-01

    Issues associated with the modelling and control of a spacecraft-mounted manipulator capturing a spinning satellite are presented. The Lagrangian formulation is used to derive the dynamical equations of the system immediately following the capture. The formulation is carried out by writing Lagrange's equations for the individual bodies, and then assembling them to obtain the constrained dynamical equations of the system. The non-working constraint forces/torques are then eliminated by using the natural orthogonal complement which produces a set of independent dynamical equations. A control algorithm whose objective is to produce a set of feedback-linearized, homogeneous and uncoupled equations is designed and implemented. The initial conditions of the state variables needed to achieve smooth berthing of the satellite are computed, and the dynamics simulation of both the controlled and uncontrolled systems is carried out. The manipulator's structural flexibility is included in the dynamics simulation model.

  20. A modeling and simulation of control system of satellite tracking platform an- tenna

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaojun; GONG Lihong

    2012-01-01

    Based on the platform of mobile carrier satellite tracking has a wide range of applications. The paper adopts the advanced method of to step response identify, using the data obtained by the experiment model of high-speed acquisition, using the method of the least squares, finally the antenna control system model function was identified. Make use of integral separation algorithm, simu- link simulation and experiment analysis to set the control parameters of it. Stimulate the signal antenna control system under inter- fering. The experiment of the simulation experiment showed that the antenna control system model is stable with little error.

  1. Orbit and Attitude Control of Asymmetric Satellites in Polar Near-Circular Orbit

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2009-10-01

    Full Text Available In this paper, the general problem about the orbit and attitude dynamic model is discussed. A feedback linearization control method is introduced for this model. Due to the asymmetric structure, the orbital properties of such satellites are the same as traditional symmetric ones, but the attitude properties are greatly different from the symmetric counterparts. With perturbations accumulate with time, the attitude angles increase periodically with time, but the orbital elements change much slower than the attitude angles. In the attitude dynamic model, chaos could appear. Traditional linear controllers can not compensate enough for asymmetric satellite when the mission is complex, especially in maneuver missions. Thus nonlinear control method is required to solve such problem in large scale. A feedback linearization method, one robust nonlinear control method, is introduced and applied to the asymmetric satellite in this paper. Some simulations are also given and the results show that feedback linearization controller not only stabilizes the system, but also exempt the chaos in the system.

  2. Obstetric and neonatal outcomes in a home-like birth centre: a case-control study.

    Science.gov (United States)

    Gaudineau, Adrien; Sauleau, Erik-André; Nisand, Israël; Langer, Bruno

    2013-02-01

    To compare the intervention rates associated with labor in low-risk women who began their labor in the "home-like birth centre" (HLBC) and the traditional labor ward (TLW). This retrospective study used data that were collected from January 2005 to June 2008, from women admitted to the HLBC (n = 316) and compared to a group of randomly selected low-risk women admitted to the TLW (n = 890) using the Baysian information criterion to select the best predictive model. Women in the HLBC had spontaneous vaginal deliveries more often (88.6 vs. 82.8 %, p value 0.034) and perineal lesions less often (60.1 vs. 62.5 %, p value 0.013). The frequency of adverse neonatal outcomes did not differ statistically between the two groups, although the mean clamped at birth umbilical arterial pH level was higher in the HLBC group. The transfer rate from HLBC to TLW was 31.3 % of which 75.8 % were nulliparae. It appears that women could benefit from HLBC care in settings such as the one studied. Larger observational studies are warranted to validate these results.

  3. Free Electron Laser For The Siberian Centre For Photochemical Research The Control System

    CERN Document Server

    Avlasov, Y K; Miginskaya, E G; Oreshkov, A D; Ovchar, A V; Salikova, T V; Selivanov, P A; Serednyakov, S I; Tararyshkin, S V; Tribendis, A G; Vinokurov, N A

    2004-01-01

    This article describes the software for the control system of the Free Electron Laser for the Siberian Center for photochemical research. The main components of subsystems composing the control system as well as their hardware and software components are considered. Also main features of each of the subsystems and of the whole control system are mentioned. The prospects of control system development to meet the future requirements are discussed.

  4. Pilates based core stability training in ambulant individuals with multiple sclerosis: protocol for a multi-centre randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Freeman Jennifer

    2012-04-01

    Full Text Available Abstract Background People with Multiple Sclerosis (MS frequently experience balance and mobility impairments, including reduced trunk stability. Pilates-based core stability training, which is aimed at improving control of the body's stabilising muscles, is popular as a form of exercise with people with MS and therapists. A replicated single case series study facilitated by the Therapists in MS Group in the United Kingdom (UK provides preliminary evidence that this approach can improve balance and mobility in ambulant people with MS; further evidence is needed to substantiate these findings to ensure that limited time, energy, finances and resources are used to best effect. This study builds upon the pilot work undertaken in the case series study by implementing a powered randomised controlled study, with the aims of: 1 Establishing the effectiveness of core stability training 2 Comparing core stability training with standardised physiotherapy exercise 3 Exploring underlying mechanisms of change associated with this intervention Methods This is a multi-centre, double blind, block randomised, controlled trial. Eligible participants will be recruited from 4 UK centres. Participants will be randomly allocated to one of three groups: Pilates based core stability training, standardised physiotherapy exercise or contract-relax relaxation sessions (placebo control. All will receive face to face training sessions over a 12 week period; together with a 15 minute daily home programme. All will be assessed by a blinded assessor before training, at the end of the 12 week programme and at 4 week follow-up. The primary outcome measure is the 10 metre timed walk. Secondary outcome measures are the MS walking Scale (MSWS-12, the Functional Reach (forwards and lateral, a 10 point Numerical Rating Scale to determine "Difficulty in carrying a drink when walking", and the Activities-specific Balance Confidence (ABC Scale. In addition, ultrasound imaging of the

  5. Evaluating performance indices of a shopping centre and implementing HVAC control principles to minimize energy usage

    OpenAIRE

    Canbay, Çağlar Selçuk; Hepbaşlı, Arif; Gökçen Akkurt, Gülden

    2004-01-01

    Heating, ventilating and air-conditioning (HVAC) systems in buildings must be integrated with an efficient control scheme to maintain comfort under any load conditions. Efficient HVAC control is often the most cost-effective option to improve the energy efficiency of a building. However, HVAC processes are non-linear, and characteristics change on a seasonal basis so the effect of changing the control strategy is usually difficult to predict. The present study aims to reduce energy consumptio...

  6. Design Considerations for Miniaturized Control Moment Gyroscopes for Rapid Retargeting and Precision Pointing of Small Satellites

    Science.gov (United States)

    Patankar, Kunal; Fitz-Coy, Norman; Roithmayr, Carlos M.

    2014-01-01

    This paper presents the design as well as characterization of a practical control moment gyroscope (CMG) based attitude control system (ACS) for small satellites in the 15-20 kilogram mass range performing rapid retargeting and precision pointing maneuvers. The paper focuses on the approach taken in the design of miniaturized CMGs while considering the constraints imposed by the use of commercial off-the-shelf (COTS) components as well as the size of the satellite. It is shown that a hybrid mode is more suitable for COTS based moment exchange actuators; a mode that uses the torque amplification of CMGs for rapid retargeting and direct torque capabilities of the flywheel motors for precision pointing. A simulation is provided to demonstrate on-orbit slew and pointing performance.

  7. Optimality of incompletely measurable active and passive attitude control systems. [for satellites

    Science.gov (United States)

    Schiehlen, W.; Popp, K.

    1973-01-01

    Passive attitude control systems and active systems with incomplete state measurements are only suboptimal systems in the sense of optimal control theory, since optimal systems require complete state measurements or state estimations. An optimal system, then, requires additional hardware (especially in the case of flexible spacecraft) which results in higher costs. Therefore, it is a real engineering problem to determine how much an optimal system exceeds the suboptimal system, or in other words, what is the suboptimal system's degree of optimality. The problem will be treated in three steps: (1) definition of the degree of optimality for linear, time-invariant systems; (2) a computation method using the quadratic cost functional; (3) application to a gravity-gradient stabilized three-body satellite and a spinning flexible satellite.

  8. CONTACT: An Air Force technical report on military satellite control technology

    Science.gov (United States)

    Weakley, Christopher K.

    1993-07-01

    This technical report focuses on Military Satellite Control Technologies and their application to the Air Force Satellite Control Network (AFSCN). This report is a compilation of articles that provide an overview of the AFSCN and the Advanced Technology Program, and discusses relevant technical issues and developments applicable to the AFSCN. Among the topics covered are articles on Future Technology Projections; Future AFSCN Topologies; Modeling of the AFSCN; Wide Area Communications Technology Evolution; Automating AFSCN Resource Scheduling; Health & Status Monitoring at Remote Tracking Stations; Software Metrics and Tools for Measuring AFSCN Software Performance; Human-Computer Interface Working Group; Trusted Systems Workshop; and the University Technical Interaction Program. In addition, Key Technology Area points of contact are listed in the report.

  9. Optimizing the Attitude Control of Small Satellite Constellations for Rapid Response Imaging

    Science.gov (United States)

    Nag, S.; Li, A.

    2016-12-01

    Distributed Space Missions (DSMs) such as formation flight and constellations, are being recognized as important solutions to increase measurement samples over space and time. Given the increasingly accurate attitude control systems emerging in the commercial market, small spacecraft now have the ability to slew and point within few minutes of notice. In spite of hardware development in CubeSats at the payload (e.g. NASA InVEST) and subsystems (e.g. Blue Canyon Technologies), software development for tradespace analysis in constellation design (e.g. Goddard's TAT-C), planning and scheduling development in single spacecraft (e.g. GEO-CAPE) and aerial flight path optimizations for UAVs (e.g. NASA Sensor Web), there is a gap in open-source, open-access software tools for planning and scheduling distributed satellite operations in terms of pointing and observing targets. This paper will demonstrate results from a tool being developed for scheduling pointing operations of narrow field-of-view (FOV) sensors over mission lifetime to maximize metrics such as global coverage and revisit statistics. Past research has shown the need for at least fourteen satellites to cover the Earth globally everyday using a LandSat-like sensor. Increasing the FOV three times reduces the need to four satellites, however adds image distortion and BRDF complexities to the observed reflectance. If narrow FOV sensors on a small satellite constellation were commanded using robust algorithms to slew their sensor dynamically, they would be able to coordinately cover the global landmass much faster without compensating for spatial resolution or BRDF effects. Our algorithm to optimize constellation satellite pointing is based on a dynamic programming approach under the constraints of orbital mechanics and existing attitude control systems for small satellites. As a case study for our algorithm, we minimize the time required to cover the 17000 Landsat images with maximum signal to noise ratio fall

  10. Attitude Control Synthesis for Small Satellites Using Gradient Method. Part I - Nonlinear Equations

    Directory of Open Access Journals (Sweden)

    Teodor-Viorel CHELARU

    2012-12-01

    Full Text Available The paper presents some aspects for synthesis of small satellites attitude control. Thesatellite nonlinear model presented here will be with six degrees of freedom. After movement equationlinearization the stability and command matrixes will be established and the controller will beobtained using gradient and gradient method. Two attitude control cases will be analysed: thereaction wheels and the micro thrusters. The results will be used in the project European Space MoonOrbit - ESMO founded by European Space Agency in which the University POLITEHNICA ofBucharest is involved.

  11. Attitude Control Synthesis for Small Satellites Using Gradient Method. Part II Linear Equations, Synthesis

    Directory of Open Access Journals (Sweden)

    Adrian CHELARU

    2013-03-01

    Full Text Available In order to continue paper [5] which presented the nonlinear equations of the movement for small satellite, this paper presents some aspects regarding the synthesis of the attitude control. Afterthe movement equation linearization, the stability and command matrixes will be established and by using the gradient methods controller we will obtain them. Two attitude control cases will beanalysed: the reaction wheels and the micro thrusters. The results will be used in the project European Space Moon Orbit - ESMO, founded by the European Space Agency in which the POLITEHNICA University of Bucharest is involved.

  12. Satellite-based assessment of climate controls on US burned area

    OpenAIRE

    D. C. Morton; G. J. Collatz; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2013-01-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate–fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burne...

  13. Wildland fire management. Volume 2: Wildland fire control 1985-1995. [satellite information system for California fire problems

    Science.gov (United States)

    Saveker, D. R. (Editor)

    1973-01-01

    The preliminary design of a satellite plus computer earth resources information system is proposed for potential uses in fire prevention and control in the wildland fire community. Suggested are satellite characteristics, sensor characteristics, discrimination algorithms, data communication techniques, data processing requirements, display characteristics, and costs in achieving the integrated wildland fire information system.

  14. Semi-active Attitude Control and Off-line Attitude Determination for the SEETI-Express Student Micro-satellite

    DEFF Research Database (Denmark)

    Alminde, Lars

    This paper concerns the development of the Attitude Determination and Control System (ADCS) for the SSETI-Express micro-satellite mission. The mission is an educational project involving 14 universities and the European Space Agency (ESA). The satellite has been designed and built, by students...

  15. Semi-active Attitude Control and Off-line Attitude Determination for the SSETI-Express Student Micro-satellite

    DEFF Research Database (Denmark)

    Alminde, Lars

    2005-01-01

    This paper concerns the development of the Attitude Determination and Control System (ADCS) for the SSETI-Express micro-satellite mission. The mission is an educational project involving 14 universities and the European Space Agency (ESA). The satellite has been designed and built, by students...

  16. Mapping Neglected Swimming Pools from Satellite Data for Urban Vector Control

    Science.gov (United States)

    Barker, C. M.; Melton, F. S.; Reisen, W. K.

    2010-12-01

    Neglected swimming pools provide suitable breeding habit for mosquitoes, can contain thousands of mosquito larvae, and present both a significant nuisance and public health risk due to their inherent proximity to urban and suburban populations. The rapid increase and sustained rate of foreclosures in California associated with the recent recession presents a challenge for vector control districts seeking to identify, treat, and monitor neglected pools. Commercial high resolution satellite imagery offers some promise for mapping potential neglected pools, and for mapping pools for which routine maintenance has been reestablished. We present progress on unsupervised classification techniques for mapping both neglected pools and clean pools using high resolution commercial satellite data and discuss the potential uses and limitations of this data source in support of vector control efforts. An unsupervised classification scheme that utilizes image segmentation, band thresholds, and a change detection approach was implemented for sample regions in Coachella Valley, CA and the greater Los Angeles area. Comparison with field data collected by vector control personal was used to assess the accuracy of the estimates. The results suggest that the current system may provide some utility for early detection, or cost effective and time efficient annual monitoring, but additional work is required to address spectral and spatial limitations of current commercial satellite sensors for this purpose.

  17. Integrating of renewable energy in operation system: the Special Regime Control Centre (CECRE); Integracion de la energia renovable en la operacion del sistema: El Centro de Control de regimen especial (CECRE)

    Energy Technology Data Exchange (ETDEWEB)

    Division, M.

    2007-07-01

    The implementation of Red Electrica de Espana Special Regime Control Centre (CECRE) has demonstrated the Spanish System Operators commitment of integrating the maximum possible wind power generation into the electrical system compatible with secure operation. With this leadership initiative,for the first time in the world, a System Operator Control Centre (CECRE) has succeeded in sending power control instructions to wind power generators over the country through Generation Control Centres (CGC) to which these generators must be connected complying with the Spanish Rules. (Author)

  18. High Accuracy Attitude Control System Design for Satellite with Flexible Appendages

    Directory of Open Access Journals (Sweden)

    Wenya Zhou

    2014-01-01

    Full Text Available In order to realize the high accuracy attitude control of satellite with flexible appendages, attitude control system consisting of the controller and structural filter was designed. When the low order vibration frequency of flexible appendages is approximating the bandwidth of attitude control system, the vibration signal will enter the control system through measurement device to bring impact on the accuracy or even the stability. In order to reduce the impact of vibration of appendages on the attitude control system, the structural filter is designed in terms of rejecting the vibration of flexible appendages. Considering the potential problem of in-orbit frequency variation of the flexible appendages, the design method for the adaptive notch filter is proposed based on the in-orbit identification technology. Finally, the simulation results are given to demonstrate the feasibility and effectiveness of the proposed design techniques.

  19. Blood phenylalanine control in phenylketonuria : a survey of 10 European centres

    NARCIS (Netherlands)

    Ahring, K.; Belanger-Quintana, A.; Dokoupil, K.; Gokmen-Ozel, H.; Lammardo, A. M.; MacDonald, A.; Motzfeldt, K.; Nowacka, M.; van Rijn, M.; Robert, M.

    Background: Only limited data are available on the blood phenylalanine (Phe) concentrations achieved in European patients with phenylketonuria (PKU) on a low-Phe diet. Objective: A survey was conducted to compare blood Phe control achieved in diet-treated patients with PKU of different age groups in

  20. Blood phenylalanine control in phenylketonuria : a survey of 10 European centres

    NARCIS (Netherlands)

    Ahring, K.; Belanger-Quintana, A.; Dokoupil, K.; Gokmen-Ozel, H.; Lammardo, A. M.; MacDonald, A.; Motzfeldt, K.; Nowacka, M.; van Rijn, M.; Robert, M.

    2011-01-01

    Background: Only limited data are available on the blood phenylalanine (Phe) concentrations achieved in European patients with phenylketonuria (PKU) on a low-Phe diet. Objective: A survey was conducted to compare blood Phe control achieved in diet-treated patients with PKU of different age groups in

  1. Quality Control of Boar Sperm Processing : Implications from European AI Centres and Two Spermatology Reference Laboratories

    NARCIS (Netherlands)

    Riesenbeck, A; Schulze, M; Rüdiger, K; Henning, H; Waberski, D

    2015-01-01

    In recent years, increased automatization has resulted in a higher efficiency of boar semen processing in AI laboratories. Sophisticated laboratory management and efficient quality control programmes are needed for current tendencies in major pork-producing countries to reduce the sperm number per A

  2. Real-time horizontality adjusting and control system of a large platform applied to satellite experiment

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shi-sheng; ZHANG Shi-peng; WANG Rui

    2007-01-01

    In order to satisfy a satellite horizontality requirement in an experiment, it is indispensable to monitor and adjust the horizontality of a large platform loading the satellite under the condition of ultra-low temperature with real time. So the control system design and control strategy are described in detail to accomplish the horizontality monitoring and adjusting. The system adopts the industry control computer as the upper computer and the SIEMENS S7-300 PLC as the lower computer. The upper computer that bases on industry configuration software IFIX takes charge of monitoring the platform and puts forward the control strategy. PLC takes charge of receiving the adjusting instructions and controlling the legs moving to accomplish the horizontality adjusting. The horizontality adjusting strategy is emphasized and the concept of grads is introduced to establish a mathematics model of the platform inclined state, so the adjusting method is obtained. Accordingly the key question of the automatic horizontality adjusting is solved in this control system.

  3. Eigensensitivity in integrated design. [of earth-pointing satellite's control system

    Science.gov (United States)

    Kenny, Sean P.; Hou, Gene J.; Belvin, W. K.

    1990-01-01

    An application of eigensensitivity analysis to the control-structure integrated design process is presented with an emphasis placed on computational efficiency improvement of the overall design optimization process. The computational efficiency of eigenvalue/vector sensitivity analysis is demonstrated using the Earth Pointing Satellite in the context of a control-structure integrated design program. Results for a 2 percent design variable perturbation with and without the effects of the actuator mass show a 42 and 52 percent reduction in CPU time, respectively.

  4. Synchronization and Antisynchronization of a Planar Oscillation of Satellite in an Elliptic Orbit via Active Control

    Directory of Open Access Journals (Sweden)

    Mohammad Shahzad

    2011-01-01

    Full Text Available We have investigated the synchronization and antisynchronization behaviour of two identical planar oscillation of a satellite in elliptic orbit evolving from different initial conditions using the active control technique based on the Lyapunov stability theory and the Routh-Hurwitz criteria. The designed controller, with our own choice of the coefficient matrix of the error dynamics that satisfy the Lyapunov stability theory and the Routh-Hurwitz criteria, is found to be effective in the stabilization of the error states at the origin, thereby, achieving synchronization and antisynchronization between the states variables of two nonlinear dynamical systems under consideration. The results are validated by numerical simulations using mathematica.

  5. Antenna pointing system for satellite tracking based on Kalman filtering and model predictive control techniques

    Science.gov (United States)

    Souza, André L. G.; Ishihara, João Y.; Ferreira, Henrique C.; Borges, Renato A.; Borges, Geovany A.

    2016-12-01

    The present work proposes a new approach for an antenna pointing system for satellite tracking. Such a system uses the received signal to estimate the beam pointing deviation and then adjusts the antenna pointing. The present work has two contributions. First, the estimation is performed by a Kalman filter based conical scan technique. This technique uses the Kalman filter avoiding the batch estimator and applies a mathematical manipulation avoiding the linearization approximations. Secondly, a control technique based on the model predictive control together with an explicit state feedback solution are obtained in order to reduce the computational burden. Numerical examples illustrate the results.

  6. Graph-tree-based software control flow checking for COTS processors on pico-satellites

    Institute of Scientific and Technical Information of China (English)

    Yang Mu; Wang Hao; Zheng Yangming; Jin Zhonghe

    2013-01-01

    This paper proposes a generic high-performance and low-time-overhead software control flow checking solution,graph-tree-based control flow checking (GTCFC) for space-borne commercial-off-the-shelf (COTS) processors.A graph tree data structure with a topology similar to common trees is introduced to transform the control flow graphs of target programs.This together with design of IDs and signatures of its vertices and edges allows for an easy check of legality of actual branching during target program execution.As a result,the algorithm not only is capable of detecting all single and multiple branching errors with low latency and time overheads along with a linear-complexity space overhead,but also remains generic among arbitrary instruction sets and independent of any specific hardware.Tests of the algorithm using a COTS-processor-based on-board computer (OBC) of in-service ZDPS-1A pico-satellite products show that GTCFC can detect over 90% of the randomly injected and all-pattern-covering branching errors for different types of target programs,with performance and overheads consistent with the theoretical analysis; and beats well-established preeminent control flow checking algorithms in these dimensions.Furthermore,it is validated that GTCGC not only can be accommodated in pico-satellites conveniently with still sufficient system margins left,but also has the ability to minimize the risk of control flow errors being undetected in their space missions.Therefore,due to its effectiveness,efficiency,and compatibility,the GTCFC solution is ready for applications on COTS processors on pico-satellites in their real space missions.

  7. Robust optimal sun-pointing control of a large solar power satellite

    Science.gov (United States)

    Wu, Shunan; Zhang, Kaiming; Peng, Haijun; Wu, Zhigang; Radice, Gianmarco

    2016-10-01

    The robust optimal sun-pointing control strategy for a large geostationary solar power satellite (SPS) is addressed in this paper. The SPS is considered as a huge rigid body, and the sun-pointing dynamics are firstly proposed in the state space representation. The perturbation effects caused by gravity gradient, solar radiation pressure and microwave reaction are investigated. To perform sun-pointing maneuvers, a periodically time-varying robust optimal LQR controller is designed to assess the pointing accuracy and the control inputs. It should be noted that, to reduce the pointing errors, the disturbance rejection technique is combined into the proposed LQR controller. A recursive algorithm is then proposed to solve the optimal LQR control gain. Simulation results are finally provided to illustrate the performance of the proposed closed-loop system.

  8. Control of industrial robots for hardware-in-the-loop simulation of satellite docking

    Science.gov (United States)

    Ma, Ou; Zebenay, Melak; Boge, Toralf

    2011-06-01

    One of the most challenging and risky missions for spacecraft is to perform Rendezvous and Docking (RvD) autonomously in space. To ensure a safe and reliable operation, such a mission must be carefully designed and thoroughly verified before a real space mission can be launched. This paper describes the impact-contact dynamics simulation capability of a new, robotics-based, hardware-in-the-loop (HIL) RvD simulation facility which uses two industrial robots to simulate 6-DOF dynamic maneuvering of two docking satellites. The facility is capable of physically simulating the final approaching within 25-meter range and the entire docking/capturing process in a satellite on-orbit servicing mission. The paper briefly discusses the difficulties of using industrial robots for HIL contact dynamics simulation and how these problems are solved. Admittance control strategy is proposed to control the robotic system to make the robot dynamically behave like the spacecraft during a physical interception. The control strategy works as an outer loop on the top of the existing control system of the industrial robot and hence, it does not require altering the joint control hardware and software which are inaccessible for an industrial robot. A simulation study has shown that the methodology can accurately simulate the impact-contact dynamics behavior of the spacecraft in a docking operation.

  9. 6th July 2010 - United Kingdom Science and Technology Facilities Council W. Whitehorn signing the guest book with Head of International relations F. Pauss, visiting the Computing Centre with Information Technology Department Head Deputy D. Foster, the LHC superconducting magnet test hall with Technology Department P. Strubin,the Centre Control Centre with Operation Group Leader M. Lamont and the CLIC/CTF3 facility with Project Leader J.-P. Delahaye.

    CERN Multimedia

    Teams : M. Brice, JC Gadmer

    2010-01-01

    6th July 2010 - United Kingdom Science and Technology Facilities Council W. Whitehorn signing the guest book with Head of International relations F. Pauss, visiting the Computing Centre with Information Technology Department Head Deputy D. Foster, the LHC superconducting magnet test hall with Technology Department P. Strubin,the Centre Control Centre with Operation Group Leader M. Lamont and the CLIC/CTF3 facility with Project Leader J.-P. Delahaye.

  10. Quality control at the Regional Centre of Nuclear Sciences chemical dosimetry laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne L.B. de; Melo, Roberto T. de; Silva, Danubia B. da; Pedroza, Eryka H.; Rodrigues, Kelia R.G.; Cunha, Manuela S. da; Figueiredo, Marcela D.C. de [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Oliveira, Aristides, E-mail: vlsouza@cnen.gov.b, E-mail: rtmelo@cnen.gov.b [Hospital de Cancer de Pernambuco, Recife, PE (Brazil)

    2011-07-01

    Standards for accreditation of laboratories as in ISO 9001 in section: 4.11 require inspection, measuring and equipment testing; likewise, IEC 17025: 2005 in section: 5.5.2 requires the equipment to be calibrated or verified before being put into use. In our laboratory, quality control is often accomplished by standards set done by the laboratory scientists themselves; however, at present, Hellma secondary calibration standards (4026 - Holmium oxide - Filters: F0, F2, F3, F4 and filter didymium - F7) have been used in order to verify if errors in the laboratory have been close to the 1-2% margin. Control graphs were made by using the results of synthetically prepared standards and standardized spectral calibration certificates. The set of secondary calibration standards permits to check the accuracy of the spectrophotometers used in research for both the absorbance in the visible spectrum (at 440, 465, 546, 590 and 635 nm wavelengths) and for the wavelengths (270, 280, 300, 320 nm) of the ultraviolet light. Filters (F0, F2, F3, F4 and F7) are stable and do not suffer the influence of temperature (the influence is negligible), the F0 filter was being used as a blank. The purpose is to verify whether the spectrometer needs adjustments, an important procedure to check absorbance stability, baseline flatness, slit width accuracy and stray radiation. The calibration tests are performed annually in our laboratory and recalibration of Hellma secondary standards is recommended every two years. The results show that the Chemical Dosimetry Laboratory in CRCN has a calibrated spectrophotometer and their synthetic standards for Fricke dosimetry could be used as an alternative method for testing the proficiency and competence of calibration laboratories in accordance with the regulations and standards. (author)

  11. Over Exploitation of Groundwater in the Centre of Amman Zarqa Basin—Jordan: Evaluation of Well Data and GRACE Satellite Observations

    Directory of Open Access Journals (Sweden)

    Sana’a Al-Zyoud

    2015-11-01

    Full Text Available Jordan faces a sincere water crisis. Groundwater is the major water resource in Jordan and most of the ground water systems are already exploited beyond their estimated safe yield. The Amman Zarqa Basin is one of the most important groundwater systems in Jordan, which supplies the three largest cities in Jordan with drinking and irrigation water. Based on new data the groundwater drawdown in the Amman Zarqa Basin is studied. This basin is the most used drainage area in Jordan. Groundwater drawdown in eight central representative monitoring wells is outlined. Based on almost continuous data for the last 15 years (2000–2015 an average drawdown for the whole basin in the order of 1.1 m·a−1 is calculated. This result is in accordance with results of previous studies in other areas in Jordan and shows that, until now, no sustainable water management is applied. Groundwater management in such a basin presents a challenge for water managers and experts. The applicability of satellite data for estimating large-scale groundwater over exploitation, such as gravity products of the Gravity Recovery and Climate Experiment (GRACE mission, along with supplementary data, is discussed. Although the size of the basin is below the minimum resolution of GRACE, the data generally support the measured drawdown.

  12. Fibromodulin: a master regulator of myostatin controlling progression of satellite cells through a myogenic program.

    Science.gov (United States)

    Lee, Eun Ju; Jan, Arif Tasleem; Baig, Mohammad Hassan; Ashraf, Jalaluddin Mohammad; Nahm, Sang-Soep; Kim, Yong-Woon; Park, So-Young; Choi, Inho

    2016-08-01

    Differentiation of muscle satellite cells (MSCs) involves interaction of the proteins present in the extracellular matrix (ECM) with MSCs to regulate their activity, and therefore phenotype. Herein, we report fibromodulin (FMOD), a member of the proteoglycan family participating in the assembly of ECM, as a novel regulator of myostatin (MSTN) during myoblast differentiation. In addition to having a pronounced effect on the expression of myogenic marker genes [myogenin (MYOG) and myosin light chain 2 (MYL2)], FMOD was found to maintain the transcriptional activity of MSTN Moreover, coimmunoprecipitation and in silico studies performed to investigate the interaction of FMOD helped confirm that it antagonizes MSTN function by distorting its folding and preventing its binding to activin receptor type IIB. Furthermore, in vivo studies revealed that FMOD plays an active role in healing by increasing satellite cell recruitment to sites of injury. Together, these findings disclose a hitherto unrecognized regulatory role for FMOD in MSCs and highlight new mechanisms whereby FMOD circumvents the inhibitory effects of MSTN and triggers myoblast differentiation. These findings offer a basis for the design of novel MSTN inhibitors that promote muscle regeneration after injury or for the development of pharmaceutical agents for the treatment of different muscle atrophies.-Lee, E. J., Jan, A. T., Baig, M. H., Ashraf, J. M., Nahm, S.-S., Kim, Y.-W., Park, S.-Y., Choi, I. Fibromodulin: a master regulator of myostatin controlling progression of satellite cells through a myogenic program.

  13. Attitude Control of Satellite With Pulse-Width Pulse- Frequency (PWPF Modulator Using Generalized Incremental Predictive Control

    Directory of Open Access Journals (Sweden)

    Ehsan Chegeni

    2014-09-01

    Full Text Available In this paper, we use generalized incremental predictive control (GIPC to stabilize attitude of satellite. We compare Generalized Predictive Control (GPC with GIPC algorithm and present that GIPC has better performance. The three-axis attitude control systems are activated in pulse mode. Consequently, a modulation of the torque command is compelling in order to avoid high non-linear control action. This work considers the Pulse-Width Pulse-Frequency modulator (PWPF is composed of a Schmitt trigger, a first order filter, and a feedback loop. PWPF modulator has several advantages over classical bang-bang controllers such as close to linear operation, high accuracy, and reduced propellant consumption

  14. A distributed model predictive control (MPC) fault reconfiguration strategy for formation flying satellites

    Science.gov (United States)

    Esfahani, N. R.; Khorasani, K.

    2016-05-01

    In this paper, an active distributed (also referred to as semi-decentralised) fault recovery control scheme is proposed that employs inaccurate and unreliable fault information into a model-predictive-control-based design. The objective is to compensate for the identified actuator faults that are subject to uncertainties and detection time delays, in the attitude control subsystems of formation flying satellites. The proposed distributed fault recovery scheme is developed through a two-level hierarchical framework. In the first level, or the agent level, the fault is recovered locally to maintain as much as possible the design specifications, feasibility, and tracking performance of all the agents. In the second level, or the formation level, the recovery is carried out by enhancing the entire team performance. The fault recovery performance of our proposed distributed (semi-decentralised) scheme is compared with two other alternative schemes, namely the centralised and the decentralised fault recovery schemes. It is shown that the distributed (semi-decentralised) fault recovery scheme satisfies the recovery design specifications and also imposes lower fault compensation control effort cost and communication bandwidth requirements as compared to the centralised scheme. Our proposed distributed (semi-decentralised) scheme also outperforms the achievable performance capabilities of the decentralised scheme. Simulation results corresponding to a network of four precision formation flight satellites are also provided to demonstrate and illustrate the advantages of our proposed distributed (semi-decentralised) fault recovery strategy.

  15. A controlled multi-centre study of herbal versus synthetic secretolytic drugs for acute bronchitis.

    Science.gov (United States)

    Ernst, E; März, R; Sieder, C

    1997-12-01

    Herbal expectorants and secretolytic drugs hold a sizeable share of the European market. Therefore it is essential to test their clinical effectiveness and safety. The aim of the present study was to compare the herbal medication Bronchipret(®) with various other pharmacotherapeutical options for acute bronchitis. The study was designed as a matched-pair comparison of 7783 patients. Clinical outcomes of bronchitis and adverse reactions were documented. The data were evaluated by comparing the treatment success of the test medication and 3 control groups using ordinal regression. The results suggest that clinical effectiveness of Bronchipret(®) was not less than with synthetic drugs. There was a tendency for better results with Bronchipret(®), particularly in the treatment of adults. Similar results were obtained with respect to adverse reactions. Particularly in the adult sub-group, these were markedly less with herbals as compared to synthetic drugs. These findings imply that a risk/benefit evaluation would favour Bronchipret(®) over synthetic drugs for acute bronchitis. Their interpretation is limited through the fact that this study could not be randomised nor blinded. The results therefore require confirmation through randomised, double-blind trials.

  16. Adaptive sliding mode controller based on super-twist observer for tethered satellite system

    Science.gov (United States)

    Keshtkar, Sajjad; Poznyak, Alexander

    2016-09-01

    In this work, the sliding mode control based on the super-twist observer is presented. The parameters of the controller as well as the observer are admitted to be time-varying and depending on available current measurements. In view of that, the considered controller is referred to as an adaptive one. It is shown that the deviations of the generated state estimates from real state values together with a distance of the closed-loop system trajectories to a desired sliding surface reach a μ-zone around the origin in finite time. The application of the suggested controller is illustrated for the orientation of a tethered satellite system in a required position.

  17. Nonlinear dynamics of mini-satellite respinup by weak internal controllable torques

    Energy Technology Data Exchange (ETDEWEB)

    Somov, Yevgeny, E-mail: e-somov@mail.ru [Samara State Technical University, Department for Guidance, Navigation and Control, 244 Molodogvardeyskaya Str., Samara 443100 (Russian Federation)

    2014-12-10

    Contemporary space engineering advanced new problem before theoretical mechanics and motion control theory: a spacecraft directed respinup by the weak restricted control internal forces. The paper presents some results on this problem, which is very actual for energy supply of information mini-satellites (for communication, geodesy, radio- and opto-electronic observation of the Earth et al.) with electro-reaction plasma thrusters and gyro moment cluster based on the reaction wheels or the control moment gyros. The solution achieved is based on the methods for synthesis of nonlinear robust control and on rigorous analytical proof for the required spacecraft rotation stability by Lyapunov function method. These results were verified by a computer simulation of strongly nonlinear oscillatory processes at respinuping of a flexible spacecraft.

  18. Collaborative Depression Trial (CADET: multi-centre randomised controlled trial of collaborative care for depression - study protocol

    Directory of Open Access Journals (Sweden)

    Kessler David

    2009-10-01

    Full Text Available Abstract Background Comprising of both organisational and patient level components, collaborative care is a potentially powerful intervention for improving depression treatment in UK primary Care. However, as previous models have been developed and evaluated in the United States, it is necessary to establish the effect of collaborative care in the UK in order to determine whether this innovative treatment model can replicate benefits for patients outside the US. This Phase III trial was preceded by a Phase II patient level RCT, following the MRC Complex Intervention Framework. Methods/Design A multi-centre controlled trial with cluster-randomised allocation of GP practices. GP practices will be randomised to usual care control or to "collaborative care" - a combination of case manager coordinated support and brief psychological treatment, enhanced specialist and GP communication. The primary outcome will be symptoms of depression as assessed by the PHQ-9. Discussion If collaborative care is demonstrated to be effective we will have evidence to enable the NHS to substantially improve the organisation of depressed patients in primary care, and to assist primary care providers to deliver a model of enhanced depression care which is both effective and acceptable to patients. Trial Registration Number ISRCTN32829227

  19. Controlling laser beam irradiation area using an optical duplicate system to improve satellite-ground laser communications

    Science.gov (United States)

    Nakayama, Tomoko; Takayama, Yoshihisa; Fujikawa, Chiemi; Kodate, Kashiko

    2016-08-01

    To improve the quality of ground to satellite laser communications, we propose an optical duplicate system of the optical ground station. Our proposed approach can be used to control the beam irradiation area for a satellite position without changing the total power of the output beam and the mechanical drive unit; this is performed by controlling the input pattern of a liquid crystal filter inserted in the input plane of the optical duplicate system. Most of the power of the diffracted laser beam emitted from the ground is focused on the optical axis. By distributing the power to side lobes, it is possible to extend the coverage area for a satellite position. This system allows the laser beam irradiation area to be controlled by a sufficient degree by adjusting the threshold of the satellite reception level. We verify the efficacy of the system using wave optics numerical calculations.

  20. Azithromycin for Indigenous children with bronchiectasis: study protocol for a multi-centre randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Valery Patricia C

    2012-08-01

    Full Text Available Abstract Background The prevalence of chronic suppurative lung disease (CSLD and bronchiectasis unrelated to cystic fibrosis (CF among Indigenous children in Australia, New Zealand and Alaska is very high. Antibiotics are a major component of treatment and are used both on a short or long-term basis. One aim of long-term or maintenance antibiotics is to reduce the frequency of acute pulmonary exacerbations and symptoms. However, there are few studies investigating the efficacy of long-term antibiotic use for CSLD and non-CF bronchiectasis among children. This study tests the hypothesis that azithromycin administered once a week as maintenance antibiotic treatment will reduce the rate of pulmonary exacerbations in Indigenous children with bronchiectasis. Methods/design We are conducting a multicentre, randomised, double-blind, placebo controlled clinical trial in Australia and New Zealand. Inclusion criteria are: Aboriginal, Torres Strait Islander, Maori or Pacific Island children aged 1 to 8 years, diagnosed with bronchiectasis (or probable bronchiectasis with no underlying disease identified (such as CF or primary immunodeficiency, and having had at least one episode of pulmonary exacerbation in the last 12 months. After informed consent, children are randomised to receive either azithromycin (30 mg/kg once a week or placebo (once a week for 12–24 months from study entry. Primary outcomes are the rate of pulmonary exacerbations and time to pulmonary exacerbation determined by review of patient medical records. Secondary outcomes include length and severity of pulmonary exacerbation episodes, changes in growth, school loss, respiratory symptoms, forced expiratory volume in 1-second (FEV1; for children ≥6 years, and sputum characteristics. Safety endpoints include serious adverse events. Antibiotic resistance in respiratory bacterial pathogens colonising the nasopharynx is monitored. Data derived from medical records and clinical

  1. Command Generation and Control of Momentum Exchange Electrodynamic Reboost Tethered Satellite

    Science.gov (United States)

    Robertson, Michael J.

    2005-01-01

    The research completed for this NASA Graduate Student Research Program Fellowship sought to enhance the current state-of-the-art dynamic models and control laws for Momentum Exchange Electrodynamic Reboost satellite systems by utilizing command generation, specifically Input Shaping. The precise control of tethered spacecraft with flexible appendages is extremely difficult. The complexity is magnified many times when the satellite must interact with other satellites as in a momentum exchange via a tether. The Momentum Exchange Electronic Reboost Tether (MXER) concept encapsulates all of these challenging tasks [l]. Input Shaping is a command generation technique that allows flexible spacecraft to move without inducing residual vibration [2], limit transient deflection [3] and utilize fuel-efficient actuation [4]. Input shaping is implemented by convolving a sequence of impulses, known as the input shaper, with a desired system command to produce a shaped input that is then used to drive the system. This process is demonstrated in Figure 1. The shaped command is then use to drive the system without residual vibration while meeting many other performance specifications. The completed work developed tether control algorithms for retrieval. A simple model of the tether response has been developed and command shaping was implemented to minimize unwanted dynamics. A model of a flexible electrodynamic tether has been developed to investigate the tether s response during reboost. Command shaping techniques have been developed to eliminate the tether oscillations and reduce the tether s deflection to pre-specified levels during reboost. Additionally, a model for the spin-up of a tethered system was developed. This model was used in determining the parameters for optimization the resulting angular velocity.

  2. Stepping characteristics and Centre of Mass control during stair descent: Effects of age, fall risk and visual factors.

    Science.gov (United States)

    Zietz, Doerte; Johannsen, Leif; Hollands, Mark

    2011-06-01

    Stair edges provide important visual cues for appropriate foot placement on the stair and balance control during stair descent. Previous studies explored age-related changes in stepping performance and balance control during stair descent and included fit older adults. The present study investigates both age- and frailty-related changes to stepping parameters and Centre of Mass (COM) control during stair descent and how these measures are affected by visual factors. Older adults were split into two groups containing participants with the lowest (LROA, n=7) and highest (HROA, n=8) combined scores on tests of balance and confidence to negotiate stairs. Data were also collected from younger adult participants (YA, n=8). Kinematic data were collected from participants while they descended stairs under combinations of ambient light (bright and dimmed) and stair edge contrast conditions (high and low). A three (group) × two (illumination)×two (contrast) ANCOVA was performed with average stair walking speed as covariate. HROA cleared the stair edge vertically (p=0.001) and horizontally (pstair edge contrast led to reduced vertical COM acceleration variability in HROA (p=0.009) and increased distance between COM and anterior base of support (p=0.017) in LROA. YA increased horizontal foot clearance (p=0.011) when stair edge contrast was high. We conclude that the aforementioned differences in stepping behaviour shown by HROA may contribute towards an increased risk of tripping and that high stair edge contrast has a beneficial effect on balance control in older adults. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Flight results from the gravity-gradient-controlled RAE-1 satellite

    Science.gov (United States)

    Blanchard, D. L.

    1986-01-01

    The in-orbit dynamics of a large, flexible spacecraft has been modeled with a computer simulation, which was used for designing the control system, developing a deployment and gravity-gradient capture procedure, predicting the steady-state behavior, and designing a series of dynamics experiments for the Radio Astronomy Explorer (RAE) satellite. This flexible body dynamics simulator permits three-dimensional, large-angle rotation of the total spacecraft and includes effects of orbit eccentricity, thermal bending, solar pressure, gravitational accelerations, and the damper system. Flight results are consistent with the simulator predictions and are presented for the deployment and capture phases, the steady-state mission, and the dynamics experiments.

  4. Monolithic sensors for low frequency motion measurement and control of spacecrafts and satellites

    Science.gov (United States)

    Barone, F.; Giordano, G.; Acernese, F.; Romano, R.

    2016-10-01

    In this paper we describe the characteristics and performances of a monolithic sensor designed for low frequency motion measurement and control of spacecrafts and satellites, whose mechanics is based on the UNISA Folded Pendulum. The latter, developed for ground-based applications, exhibits unique features (compactness, lightness, scalability, low resonance frequency and high quality factor), consequence of the action of the gravitational force on its inertial mass. In this paper we introduce and discuss the general methodology used to extend the application of ground-based folded pendulums to space, also in total absence of gravity, still keeping all their peculiar features and characteristics.

  5. Control of the Soft X-ray Polychromator on the Solar Maximum Mission Satellite

    Science.gov (United States)

    Springer, L. A.; Levay, M.; Gilbreth, C. W.; Finch, M. L.; Bentley, R. D.; Firth, J. G.

    1981-01-01

    The Soft X-ray Polychromator on the Solar Maximum Mission Satellite consists of two largely independent instruments: the Flat Crystal Spectrometer, a highly collimated scanning spectrometer mounted on a raster platform, and the Bent Crystal Spectrometer, a broadly collimated spectrometer providing high time-resolution (128 ms) spectra for the study of rapidly evolving phenomena. Each instrument is controlled by a microcomputer system built around an RCA 1802 microprocessor. This paper presents a discussion of the motivation for using a microprocessor in this application, and the design concepts that were implemented. The effectiveness of the approach as seen after several months of operation will also be discussed.

  6. Failure-tolerant control for small agile satellites using single-gimbal control moment gyros and magnetic torquers

    Institute of Scientific and Technical Information of China (English)

    Tao Meng; Saburo Matunaga

    2012-01-01

    This paper focuses on the attitude control problem of small agile satellites using single-gimbal control moment gyros (CMG) and magnetic torquers (MTQ).CMGs are regarded as effective torque generators for agile satellites because of their torque amplification capability.However,they are vulnerable to failure due to their complex inner mechanism.In this paper,different failure cases of CMGs are analyzed.A flexible failure-tolerant control strategy is developed by automatically redistributing the required control torque among the operating CMGs and MTQs,with a variable limiter to accommodate the actuator dynamics changes introduced by CMG failures.The performances of maneuvers about different directions under different failure cases are also discussed and examined.Numerical simulations demonstrate that the proposed strategy maintains certain agility in the cases of one or two CMGs failing.Moreover,a survival strategy with only one CMG left is also verified.Both sun-pointing stabilization and earth-pointing stabilization can be achieved in this case,which fulfill some basic mission requirements.

  7. A Topology Control Strategy with Reliability Assurance for Satellite Cluster Networks in Earth Observation

    Science.gov (United States)

    Chen, Qing; Zhang, Jinxiu; Hu, Ze

    2017-01-01

    This article investigates the dynamic topology control problem of satellite cluster networks (SCNs) in Earth observation (EO) missions by applying a novel metric of stability for inter-satellite links (ISLs). The properties of the periodicity and predictability of satellites’ relative position are involved in the link cost metric which is to give a selection criterion for choosing the most reliable data routing paths. Also, a cooperative work model with reliability is proposed for the situation of emergency EO missions. Based on the link cost metric and the proposed reliability model, a reliability assurance topology control algorithm and its corresponding dynamic topology control (RAT) strategy are established to maximize the stability of data transmission in the SCNs. The SCNs scenario is tested through some numeric simulations of the topology stability of average topology lifetime and average packet loss rate. Simulation results show that the proposed reliable strategy applied in SCNs significantly improves the data transmission performance and prolongs the average topology lifetime. PMID:28241474

  8. Splinting after contracture release for Dupuytren's contracture (SCoRD: protocol of a pragmatic, multi-centre, randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Chojnowski Adrian J

    2008-04-01

    Full Text Available Abstract Background Splinting as part of the overall post-surgical management of patients after release of Dupuytren's contracture has been widely reported, though there is variation in practice and criteria for using it. The evidence on its effectiveness is sparse, of poor quality and contradictory with studies reporting negative and positive effects. Methods/Design A multi-centre, pragmatic, randomized, controlled trial is being conducted to evaluate the effect of static night splinting for six months on hand function, range of movement, patient satisfaction and recurrence at 1 year after fasciectomy or dermofasciectomy. Using a centrally administered computer randomization system consented patients will be allocated to one of two groups: i splint group who will be given a static splint at approximately 10 to 14 days after surgery to be worn for 6 months at night time only as well as hand therapy; ii non-splint group, who will receive hand therapy only. The primary outcome measure is the patient-reported Disabilities of the Arm, Hand and Shoulder Questionnaire (DASH. Secondary outcomes are total active flexion and extension of fingers, patient satisfaction and recurrence of contracture. Outcome measures will be collected prior to surgery, 3 months, 6 months and 1 year after surgery. Using the DASH as the primary outcome measure, where a difference of 15 points is considered to be a clinically important difference a total of 51 patients will be needed in each group for a power of 90%. An intention-to-treat analysis will be used. Discussion This pragmatic randomized controlled trial will provide much needed evidence on the clinical effectiveness of post-operative night splinting in patients who have undergone fasciectomy or dermofasciectomy for Dupuytren's contracture of the hand. Trial Registration Current Controlled Trials ISRCTN 57079614

  9. Adaptive Hierarchical Sliding Mode Control with Input Saturation for Attitude Regulation of Multi-satellite Tethered System

    Science.gov (United States)

    Ma, Zhiqiang; Sun, Guanghui

    2017-06-01

    This paper proposes a novel adaptive hierarchical sliding mode control for the attitude regulation of the multi-satellite inline tethered system, where the input saturation is taken into account. The governing equations for the attitude dynamics of the three-satellite inline tethered system are derived firstly by utilizing Lagrangian mechanics theory. Considering the fact that the attitude of the central satellite can be adjusted by using the simple exponential stabilization scheme, the decoupling of the central satellite and the terminal ones is presented, and in addition, the new adaptive sliding mode control law is applied to stabilize the attitude dynamics of the two terminal satellites based on the synchronization and partial contraction theory. In the adaptive hierarchical sliding mode control design, the input is modeled as saturated input due to the fact that the flywheel torque is bounded, and meanwhile, an adaptive update rate is introduced to eliminate the effect of the saturated input and the external perturbation. The proposed control scheme can be applied on the two-satellite system to achieve fixed-point rotation. Numerical results validate the effectiveness of the proposed method.

  10. Adaptive Hierarchical Sliding Mode Control with Input Saturation for Attitude Regulation of Multi-satellite Tethered System

    Science.gov (United States)

    Ma, Zhiqiang; Sun, Guanghui

    2016-11-01

    This paper proposes a novel adaptive hierarchical sliding mode control for the attitude regulation of the multi-satellite inline tethered system, where the input saturation is taken into account. The governing equations for the attitude dynamics of the three-satellite inline tethered system are derived firstly by utilizing Lagrangian mechanics theory. Considering the fact that the attitude of the central satellite can be adjusted by using the simple exponential stabilization scheme, the decoupling of the central satellite and the terminal ones is presented, and in addition, the new adaptive sliding mode control law is applied to stabilize the attitude dynamics of the two terminal satellites based on the synchronization and partial contraction theory. In the adaptive hierarchical sliding mode control design, the input is modeled as saturated input due to the fact that the flywheel torque is bounded, and meanwhile, an adaptive update rate is introduced to eliminate the effect of the saturated input and the external perturbation. The proposed control scheme can be applied on the two-satellite system to achieve fixed-point rotation. Numerical results validate the effectiveness of the proposed method.

  11. Shift control method for the local time at descending node based on sun-synchronous orbit satellite

    Institute of Scientific and Technical Information of China (English)

    Yang Yong'an; Feng Zuren; Sun Linyan; Tan Wei

    2009-01-01

    This article analyzes the shift factors of the descending node local time for sun-synchronous satellites and proposes a shift control method to keep the local time shift within an allowance range. It is found that the satellite orbit design and the orbit injection deviation are the causes for the initial shift velocity, whereas the atmospheric drag and the sun gravitational perturbation produce the shift acceleration. To deal with these shift factors, a shift control method is put forward, through such methods as orbit variation design, orbit altitude, and inclination keeping control. The simulation experiment and practical application have proved the effectiveness of this control method.

  12. Risk factors of diabetic foot Charcot arthropathy: a case-control study at a Malaysian tertiary care centre

    Science.gov (United States)

    Fauzi, Aishah Ahmad; Chung, Tze Yang; Latif, Lydia Abdul

    2016-01-01

    INTRODUCTION This study aimed to determine the risk factors of diabetic Charcot arthropathy of the foot among diabetic patients with and without foot problems. METHODS This was a case-control study involving diabetic patients attending the Diabetic Foot Care and Wound Management Clinic at University Malaya Medical Centre, Kuala Lumpur, Malaysia, from June 2010 to June 2011. Data on sociodemographic profiles, foot factors and diabetes characteristics was collected and analysed. RESULTS A total of 48 diabetic patients with Charcot arthropathy of the foot were identified. Data from these 48 patients was compared with those of 52 diabetic patients without foot problems. Up to 83.3% of patients with diabetic Charcot arthropathy presented with unilateral Charcot foot, most commonly located at the midfoot (45.8%). Patients with a history of foot problems, including foot ulcer, amputation, surgery or a combination of problems, had the highest (26-time) likelihood of developing Charcot arthropathy (odds ratio 26.4; 95% confidence interval 6.4–109.6). Other significant risk factors included age below 60 years, more than ten years’ duration of diabetes mellitus and the presence of nephropathy. CONCLUSION A history of prior diabetic foot problems is the greatest risk factor for developing diabetic Charcot arthropathy, compared with other risk factors such as diabetes characteristics and sociodemographic profiles. Preventive management of diabetic foot problems in the primary care setting and multidisciplinary care are of paramount importance, especially among chronic diabetic patients. PMID:27075668

  13. Screening report : Municipality of Leamington : Leamington Pollution Control Centre stand-by emergency power class environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-03-15

    The Leamington Pollution Control Centre (PCC) is located in Ontario and treats residential and commercial wastewater collected from the Municipality of Leamington. The Leamington PCC currently has one standby diesel generator with a rated capacity of 545 kW. This generator provides power to the plant's disinfection facilities to reduce the risk of back-up into the collection system during power failures. The Municipality of Leamington plans to provide treatment in addition to disinfection during power outages. In order to achieve this, additional standby power is required to run the primary clarifiers, the aeration system and the secondary clarifiers. This document presented a screening report for the new standby generator, whose installation is considered a Schedule B under the Municipal Class Environmental Assessment process. The report reviewed background information on the proposed project; Ontario's Environmental Assessment Act; and the Class Environmental Assessment Act. It outlined the problem statement; identification of solutions; existing conditions; impacts and mitigation during construction and operation; and public consultation procedures. 2 refs., 4 figs., 1 appendix.

  14. Use of platelet rich plasma to treat plantar fasciitis: design of a multi centre randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Peerbooms Joost C

    2010-04-01

    Full Text Available Abstract Background If conservative treatment for chronic plantar fasciitis fails, often a corticosteroid injection is given. Corticosteroid injection gives temporarily pain reduction, but no healing. Blood platelets initiate the natural healing rate. GPS® gives an eightfold concentrate platelets of patients own blood. Injection of these platelets in the attachment of the fascia to the os calcis might induce a healing rate. Methods and design A randomized controlled multi centre trial will be performed. The study population consists of 120 patients of 18 years and older. Patients with chronic plantar fasciitis will be allocated randomly to have a steroid injection or an autologous platelet concentrate injections. Data will be collected before the procedure, 4,8,12,26 weeks and 1 year after the procedure. The main outcome measures of this study are pain and function measured with questionnaires. Conclusion Recent literature show positive effects for the treatment of tendinosis with autologous platelet injections. The forthcoming trial will compare treatment for chronic plantar fasciitis with a steroid injection versus an autologous platelet injection. Our results will be published as soon as they become available. Trial Registration Trial registration number: http://www.clinicaltrials.gov NCT00758641.

  15. Reusable Reentry Satellite (RRS) system design study. Phase B, appendix E: Attitude control system study

    Science.gov (United States)

    1991-01-01

    A study which consisted of a series of design analyses for an Attitude Control System (ACS) to be incorporated into the Re-usable Re-entry Satellite (RRS) was performed. The main thrust of the study was associated with defining the control laws and estimating the mass and power requirements of the ACS needed to meet the specified performance goals. The analyses concentrated on the different on-orbit control modes which start immediately after the separation of the RRS from the launch vehicle. The three distinct on-orbit modes considered for these analyses are as follows: (1) Mode 1 - A Gravity Gradient (GG) three-axis stabilized spacecraft with active magnetic control; (2) Mode 2 - A GG stabilized mode with a controlled yaw rotation rate ('rotisserie') using three-axis magnetic control and also incorporating a 10 N-m-s momentum wheel along the (Z) yaw axis; and (3) Mode 3 - A spin stabilized mode of operation with the spin about the pitch (Y) axis, incorporating a 20 N-m-s momentum wheel along the pitch (Y) axis and attitude control via thrusters. To investigate the capabilities of the different controllers in these various operational modes, a series of computer simulations and trade-off analyses have been made to evaluate the achievable performance levels, and the necessary mass and power requirements.

  16. CERN Control Centre Animations

    CERN Multimedia

    2014-01-01

    Individual particles from each beam can stray off their foreseen path and hit the beam pipe or even the inner part of a detector with the risk of damaging them. Therefore, the beam has to be ‘cleaned’ from these stray particles before coming close to the collision regions. At each side of the experiments, there are collimators installed which do this job. These devices consist of jaws that close around the beam and absorb stray particles.

  17. CERN Control Centre Animations

    CERN Multimedia

    2014-01-01

    Particles make 11,245 turns per second in the LHC. Every time a particle has made a turn in the LHC, it passes by a region where it is accelerated by electric fields. These fields are produced inside so-called “Radiofrequency Cavities”. Inside each cavity, the direction of the field oscillates between positive (red) and negative (blue) voltage. The particle bunches is synchronized in order that incoming particles always see an accelerating electric field.

  18. CERN Control Centre Animations

    CERN Multimedia

    2014-01-01

    The journey of the LHC protons begin in a hydrogen bottle. Hydrogen is the simplest element: its atom has a single proton with one electron orbiting around it. The pressure in the bottle forces the hydrogen atoms out, where they are captured in a device, the proton source. Inside, a powerful electrical discharge strips the electrons away from the protons. Under the force of an electric field, the protons whizz off into a cavity where they are accelerated and concentrated.

  19. CERN Control Centre Animations

    CERN Multimedia

    2014-01-01

    Two particle beams circulate in the LHC, in opposite directions. Superconducting dipole magnets are used to bend the paths of the particles in order to keep them on their circular track. These magnets are formed of two superconducting coils producing magnetic fields pointing in opposite direction for the two counterrotating beams. Cooled down to the very low temperature of -271.2°C, the superconducting coils allow the high currents to flow without losing any energy to electrical resistance. The current going trough the coils reach 11080 amps in order to generate a magnetic field of 7.8 Teslas. Such high magnetic fields could not be reached with classic resistive electromagnets. Each dipole magnet only deflects the path by 0.3 degrees, so there are 1232 dipole magnets needed to bend the beams around the LHC.

  20. CERN Control Centre Animations

    CERN Multimedia

    2014-01-01

    The LHC beam is formed of many bunches of particles (up to 2808), each measuring a few centimetres long and a millimetre wide. Their width is smaller than the size of Spain on a 1 Euro coin. However, the bunch size is not constant around the ring. Each bunch, as it circulates around the LHC, gets squeezed and expanded. It gets squeezed as much as possible around the interaction points to increase the probability of a collision. As they approach the collision points, they are squeezed to about 16 micrometers (a human hair is about 50 micrometers thick) to allow for a greater chance of collisions.

  1. CERN Control Centre Animations

    CERN Multimedia

    2014-01-01

    LHC operators need to adjust the machine parameters for optimizing the injection and acceleration of particles in the LHC. They inject low intensity pilot beams into the machine. To monitor their position and their movement after the injection, they can use actuators to move a radiator screen into the beam pipe. When the beams pass through the screen, they make the radiator material emit light that is recorded by a camera.

  2. Semi-active Attitude Control and Off-line Attitude Determination for the SSETI-Express Student Micro-satellite

    OpenAIRE

    Alminde, Lars

    2005-01-01

    This paper concerns the development of the Attitude Determination and Control System (ADCS) for the SSETI-Express micro-satellite mission. The mission is an educational project involving 14 universities and the European Space Agency (ESA). The satellite has been designed and built, by students, over a period of only 18 months. This paper emphasises on the trade-offs required to build an operational ADCS system within such a rapidly developing project.

  3. Investigation of a possible control by Saturn satellites of auroral kilometric radiation

    Science.gov (United States)

    Boudjada, M. Y.; Galopeau, P. H. M.; Rucker, H. O.

    2013-09-01

    We attempt in this contribution to investigate the possible control of the Saturnian kilometric radiation by the planet's satellites. We use the observation of the Radio and Plasma Wave Science (RPWS) onboard the Cassini spacecraft. We consider the variation of the flux density versus the observation in time and frequency. The auroral kilometric emissions of Saturn are recorded in the frequency band from few kilohertz up to 1 MHz. The investigated period started from 01 Jan. 2004 to 31 Dec. 2007. We distinguish in this analysis between different Saturnian 'sources' which can be recognized by their spectral characteristics. We define two kinds of arc structures: the 'vertex early arcs' (VEA) and the 'vertex late arcs' (VLA). The arcs of the first group set open toward increasing time, while the arcs of the other one open towards decreasing time. A total of 556 arcs have been observed during the four investigated years, where 310 and 246 correspond, respectively, to the vertex early and late arcs. We show how the occurrence of arcs may be related to the position of the satellite around the planet Saturn. We emphasis in this analysis on the eventual control of the Saturnian kilometric radiation by Titan. Our results are compared with previous investigations performed by Daigne et al. (1982) and Kurth et al. (2006) using, respectively, Voyager and Cassini observations.

  4. Simultaneous state and actuator fault estimation for satellite attitude control systems

    Institute of Scientific and Technical Information of China (English)

    Cheng Yao; Wang Rixin; Xu Minqiang; Li Yuqing

    2016-01-01

    In this paper, a new nonlinear augmented observer is proposed and applied to satellite attitude control systems. The observer can estimate system state and actuator fault simultaneously. It can enhance the performances of rapidly-varying faults estimation. Only original system matrices are adopted in the parameter design. The considered faults can be unbounded, and the proposed augmented observer can estimate a large class of faults. Systems without disturbances and the fault whose finite times derivatives are zero piecewise are initially considered, followed by a discussion of a general situation where the system is subject to disturbances and the finite times derivatives of the faults are not null but bounded. For the considered nonlinear system, convergence conditions of the observer are provided and the stability analysis is performed using Lyapunov direct method. Then a feasible algorithm is explored to compute the observer parameters using linear matrix inequalities (LMIs). Finally, the effectiveness of the proposed approach is illustrated by considering an example of a closed-loop satellite attitude control system. The simulation results show satisfactory perfor-mance in estimating states and actuator faults. It also shows that multiple faults can be estimated successfully.

  5. The study protocol for a randomized controlled trial of a family-centred tobacco control program about environmental tobacco smoke (ETS to reduce respiratory illness in Indigenous infants

    Directory of Open Access Journals (Sweden)

    Segan Catherine

    2010-03-01

    Full Text Available Abstract Background Acute respiratory illness (ARI is the most common cause of acute presentations and hospitalisations of young Indigenous children in Australia and New Zealand (NZ. Environmental tobacco smoke (ETS from household smoking is a significant and preventable contributor to childhood ARI. This paper describes the protocol for a study which aims to test the efficacy of a family-centred tobacco control program about ETS to improve the respiratory health of Indigenous infants in Australia and New Zealand. For the purpose of this paper 'Indigenous' refers to Australia's Aboriginal and Torres Strait Islander peoples when referring to Australian Indigenous populations. In New Zealand, the term 'Indigenous' refers to Māori. Methods/Design This study will be a parallel, randomized, controlled trial. Participants will be Indigenous women and their infants, half of whom will be randomly allocated to an 'intervention' group, who will receive the tobacco control program over three home visits in the first three months of the infant's life and half to a control group receiving 'usual care' (i.e. they will not receive the tobacco control program. Indigenous health workers will deliver the intervention, the goal of which is to reduce or eliminate infant exposure to ETS. Data collection will occur at baseline (shortly after birth and when the infant is four months and one year of age. The primary outcome is a doctor-diagnosed, documented case of respiratory illness in participating infants. Discussion Interventions aimed at reducing exposure of Indigenous children to ETS have the potential for significant benefits for Indigenous communities. There is currently a dearth of evidence for the effect of tobacco control interventions to reduce children's exposure to ETS among Indigenous populations. This study will provide high-quality evidence of the efficacy of a family-centred tobacco control program on ETS to reduce respiratory illness. Outcomes of

  6. Rectification of single and multiple frames of satellite scanner imagery using points and edges as control

    Science.gov (United States)

    Paderes, F. C., Jr.; Mikhail, E. M.; Foerstner, W.

    1984-01-01

    Rectification of single and overlapping multiple scanner frames produced by such satellite-borne scanners as the LANDSAT MSS was carried out using a newly developed comprehensive parametric model. Tests with both simulated and real image data demonstrate conclusively that this model in general is superior to the widely used polynomial model, and that the simultaneous rectification of overlapping frames using least squares techniques yields a high accuracy than sngle frame rectification due to the inclusion of tie points between the image frames. Used to control, edges or lines, whic are much more likely to be found in images, can replace conventional control points and can easily be implemented into the least squares approach. An efficient algorithm for findng corresponding points in image paris was developed which can be used for determining tie points between image frames and thus increase the ecnomy of the whole rectification procedure.

  7. Analysis of broadcasting satellite service feeder link power control and polarization

    Science.gov (United States)

    Sullivan, T. M.

    1982-01-01

    Statistical analyses of carrier to interference power ratios (C/Is) were performed in assessing 17.5 GHz feeder links using (1) fixed power and power control, and (2) orthogonal linear and orthogonal circular polarizations. The analysis methods and attenuation/depolarization data base were based on CCIR findings to the greatest possible extent. Feeder links using adaptive power control were found to neither cause or suffer significant C/I degradation relative to that for fixed power feeder links having similar or less stringent availability objectives. The C/Is for sharing between orthogonal linearly polarized feeder links were found to be significantly higher than those for circular polarization only in links to nominally colocated satellites from nominally colocated Earth stations in high attenuation environments.

  8. Guidance, Navigation, and Control System for Maneuverable Pico-Satellites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A compact, low-power GN&C system is essential to the success of pico-satellite Automated Rendezvous and Docking (AR&D). Austin Satellite Design (ASD)...

  9. A cluster randomized controlled trial of a client-centred, activities of daily living intervention for people with stroke: one year follow-up of caregivers.

    Science.gov (United States)

    Bertilsson, Ann-Sofie; Eriksson, Gunilla; Ekstam, Lisa; Tham, Kerstin; Andersson, Magnus; von Koch, Lena; Johansson, Ulla

    2016-08-01

    Compare caregiver burden, provision of informal care, participation in everyday occupations and life satisfaction of caregivers to people with stroke, who either had received a client-centred, activities of daily living intervention or usual activities of daily living interventions. A multicentre cluster randomized controlled trial in which 16 rehabilitation units were randomly assigned to deliver a client-centred, activities of daily living intervention or usual activities of daily living interventions. Caregiver outcomes were compared cross-sectionally at 12 months and changes in outcomes between three and 12 months after people with stroke were included in the study. Inpatient and outpatient rehabilitation. Caregivers of people with stroke enrolled in the trial. A client-centred, activities of daily living intervention aiming to increase agency in daily activities and participation in everyday life for people after stroke. Caregiver Burden Scale, Occupational Gaps Questionnaire, LiSat-11. There were no differences in outcomes between caregivers in the client-centred, activities of daily living (n = 88) and the usual activities of daily living (n = 95) group at 12 months. The caregiver burden score was 42.7 vs. 41.8, p = 0.75, mean occupational gaps were 3.5 vs. 4.0, p = 0.52 and satisfaction with life was 53% vs. 50%, p = 0.87. There were no differences in changes between three and 12 months. However, within groups there were significant differences in caregiver burden, factor general strain, for caregivers in the client-centred, activities of daily living group, and in provision of informal care for the usual activities of daily living group. The client-centred intervention did not bring about any difference between caregiver-groups, but within groups some difference was found for caregiver burden and informal care. © The Author(s) 2015.

  10. Effectiveness of a hospital-based work support intervention for female cancer patients - a multi-centre randomised controlled trial.

    Directory of Open Access Journals (Sweden)

    Sietske J Tamminga

    Full Text Available OBJECTIVE: One key aspect of cancer survivorship is return-to-work. Unfortunately, many cancer survivors face problems upon their return-to-work. For that reason, we developed a hospital-based work support intervention aimed at enhancing return-to-work. We studied effectiveness of the intervention compared to usual care for female cancer patients in a multi-centre randomised controlled trial. METHODS: Breast and gynaecological cancer patients who were treated with curative intent and had paid work were randomised to the intervention group (n = 65 or control group (n = 68. The intervention involved patient education and support at the hospital and improvement of communication between treating and occupational physicians. In addition, we asked patient's occupational physician to organise a meeting with the patient and the supervisor to make a concrete gradual return-to-work plan. Outcomes at 12 months of follow-up included rate and time until return-to-work (full or partial, quality of life, work ability, work functioning, and lost productivity costs. Time until return-to-work was analyzed with Kaplan-Meier survival analysis. RESULTS: Return-to-work rates were 86% and 83% (p = 0.6 for the intervention group and control group when excluding 8 patients who died or with a life expectancy of months at follow-up. Median time from initial sick leave to partial return-to-work was 194 days (range 14-435 versus 192 days (range 82-465 (p = 0.90 with a hazard ratio of 1.03 (95% CI 0.64-1.6. Quality of life and work ability improved statistically over time but did not differ statistically between groups. Work functioning and costs did not differ statistically between groups. CONCLUSION: The intervention was easily implemented into usual psycho-oncological care and showed high return-to-work rates. We failed to show any differences between groups on return-to-work outcomes and quality of life scores. Further research is needed to study which

  11. HIV and childhood disability: a case-controlled study at a paediatric antiretroviral therapy centre in Lilongwe, Malawi.

    Directory of Open Access Journals (Sweden)

    Akash Devendra

    Full Text Available BACKGROUND: As paediatric antiretroviral therapy (ART is rapidly scaled up in Southern Africa, Human Immunodeficiency Virus (HIV infection is becoming a chronic illness. Children growing up with HIV may begin to encounter disabilities. The relationship between HIV, disability and the need for rehabilitation has added an additional element that needs to be addressed by paediatric HIV treatment programmes. STUDY OBJECTIVES: 1 Estimate the prevalence of disabilities in HIV-infected and HIV-uninfected children in Lilongwe, Malawi. 2 Examine types of disability and associated clinical and socio-demographic factors. 3 Identify needs, opportunities and barriers for rehabilitation in Malawi. METHODS: A case-controlled study of 296 HIV-infected children aged 2-9 years attending an ART centre in Lilongwe (cases and their uninfected siblings (controls was conducted. Disability was assessed using the WHO Ten Question Screen (TQS. Socio-demographic and clinical data were collected using a parent-proxy questionnaire and medical records. RESULTS: Of 296 case and control pairs recruited, 33% (98 versus 7% (20 screened positive for a disability (OR 8.4, 4.4-15.7 respectively. Of these 98 HIV-infected cases, 6%, 36%, 33%, 53%, 46% and 6% had a vision, hearing; physical, learning/comprehension, speech or seizure-related disability respectively and 51% had multiple coexisting disabilities. HIV-infected cases with a disability were more likely to be WHO stage III or IV at enrolment (71% vs. 52%, OR 2.7, 1.5-4.2, to have had TB (58% vs. 39%, OR 2.3, 1.4-3.8 and to have below-average school grades (18% vs. 2%, OR 11.1, 2.2-54.6 than those without. Sixty-seven percent of cases with a disability had never attended any rehabilitative service. Twenty-nine percent of caregivers reported facing stigma and discrimination because of the child's disability. CONCLUSION: This study reveals the magnitude of disability among HIV-infected children and the large unmet need for

  12. Formation Flying Satellite Control Around the L2 Sun-Earth Libration Point

    Science.gov (United States)

    Hamilton, Nicholas H.

    2001-12-01

    A growing interest in formation flying satellites demands development and analysis of control and estimation algorithms for station-keeping and formation maneuvering. This thesis discusses the development of a discrete linear-quadratic- regulator control algorithm for formations in the vicinity of the L2 sun-earth libration point. The development of an appropriate Kalman filter is included as well. Simulations are created for the analysis of the station-keeping and various formation maneuvers of the Stellar Imager mission. The simulations provide tracking error, estimation error, and control effort results. From the control effort, useful design parameters such as AV and propellant mass are determined. For formation maneuvering, the drone spacecraft track to within 4 meters of their desired position and within 1.3 millimeters per second of their desired zero velocity. The filter, with few exceptions, keeps the estimation errors within their three-sigma values. Without noise, the controller performs extremely well, with the drones tracking to within several micrometers. Bach drone uses around 1 to 2 grams of propellant per maneuver, depending on the circumstances.

  13. A multi-centre randomised controlled trial of rehabilitation aimed at improving outdoor mobility for people after stroke: Study protocol for a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Logan Pip A

    2012-06-01

    Full Text Available Abstract Background Up to 42% of all stroke patients do not get out of the house as much as they would like. This can impede a person’s quality of life. This study is testing the clinical effectiveness and cost effectiveness of a new outdoor mobility rehabilitation intervention by comparing it to usual care. Methods/design This is a multi-centre parallel group individually randomised, controlled trial. At least 506 participants will be recruited through 15 primary and secondary care settings and will be eligible if they are over 18 years of age, have had a stroke and wish to get out of the house more often. Participants are being randomly allocated to either the intervention group or the control group. Intervention group participants receive up to 12 rehabilitation outdoor mobility sessions over up to four months. The main component of the intervention is repeated practice of outdoor mobility with a therapist. Control group participants are receiving the usual intervention for outdoor mobility limitations: verbal advice and provision of leaflets provided over one session. Outcome measures are being collected using postal questionnaires, travel calendars and by independent assessors. The primary outcome measure is the Social Function domain of the SF36v2 quality of life assessment six months after recruitment. The secondary outcome measures include: functional ability, mobility, the number of journeys (monthly travel diaries, satisfaction with outdoor mobility, mood, health-related quality of life, resource use of health and social care. Carer mood information is also being collected. The mean Social Function score of the SF-36v2 will be compared between treatment arms using a multiple membership form of mixed effects multiple regression analysis adjusting for centre (as a fixed effect, age and baseline Social Function score as covariates and therapist as a multiple membership random effect. Regression coefficients and 95% confidence

  14. The control of satellites with microgravity constraints: The COMET Control System

    Science.gov (United States)

    Grossman, Walter; Freesland, Douglas

    1994-01-01

    The COMET attitude determination and control system, using inverse dynamics and a novel torque distribution/momentum management technique, has shown great flexibility, performance, and robustness. Three-axis control with two wheels is an inherent consequence of inverse dynamics control which allows for reduction in spacecraft weight and cost, or alternatively, provides a simple means of failure-redundancy for three-wheel spacecraft. The control system, without modification, has continued to perform well in spite of large changes in spacecraft mass properties and mission orbit altitude that have occurred during development. This flexibility has obviated imposition of early stringent ADACS design constraints and has greatly reduced commonly incurred ADACS modification costs and delay associated with program maturation.

  15. Efficacy and safety of acupuncture for chronic pain caused by gonarthrosis: A study protocol of an ongoing multi-centre randomised controlled clinical trial [ISRCTN27450856

    Directory of Open Access Journals (Sweden)

    Krämer Jürgen

    2004-03-01

    Full Text Available Abstract Background Controlled clinical trials produced contradictory results with respect to a specific analgesic effect of acupuncture. There is a lack of large multi-centre acupuncture trials. The German Acupuncture Trial represents the largest multi-centre study of acupuncture in the treatment of chronic pain caused by gonarthrosis up to now. Methods 900 patients will be randomised to three treatment arms. One group receives verum acupuncture, the second sham acupuncture, and the third conservative standard therapy. The trial protocol is described with eligibility criteria, detailed information on the treatment definition, blinding, endpoints, safety evaluation, statistical methods, sample size determination, monitoring, legal aspects, and the current status of the trial. Discussion A critical discussion is given regarding the considerations about standardisation of the acupuncture treatment, the choice of the control group, and the blinding of patients and observers.

  16. Proposal for the award of a contract, without competitive tendering, for the supply of five numerically-controlled machining centres to BINP using money from the Russian fund

    CERN Document Server

    2001-01-01

    For the reasons set out in this document, the Finance Committee is invited to approve the negotiation of a contract, without competitive tendering, using money from the Budker Institute of Nuclear Physics (BINP) in the Russian Fund RF-LHC I, for the purchase of five numerically-controlled machining centres and the corresponding tooling from the firm MIKRON (CH) for an amount not exceeding 2 000 000 Swiss francs (DDU Novosibirsk).

  17. Reflecting on the methodological challenges of recruiting to a United Kingdom-wide, multi-centre, randomised controlled trial in gynaecology outpatient settings

    OpenAIRE

    2013-01-01

    Background Successful recruitment of participants to any trial is central to its success. Trial results are routinely published, and recruitment is often cited to be slower and more difficult than anticipated. This article reflects on the methodological challenges of recruiting women with prolapse attending United Kingdom (UK) gynaecology outpatient clinics to a multi-centre randomised controlled trial (RCT) of physiotherapy, and the systems put in place in an attempt to address them. Methods...

  18. Job strain and supervisor support in primary care health centres and glycaemic control among patients with type 2 diabetes: a cross-sectional study

    OpenAIRE

    Koponen, Anne; Vahtera, Jussi; Pitkäniemi, Janne; Virtanen, Marianna; Pentti, Jaana; Simonsen-Rehn, Nina; Kivimäki, Mika; Suominen, Sakari

    2013-01-01

    Objectives This study investigates associations between healthcare personnel's perceived job strain, supervisor support and the outcome of care in terms of glycaemic control among patients with type 2 diabetes. Design A cross-sectional study from 2006. Setting 18 primary care health centres (HCs) from five municipalities in Finland. Participants Aggregated survey data on perceived job strain and supervisor support from healthcare personnel (doctors, n=122, mean age 45.5 years, nurses, n=300, ...

  19. Remote Synchronization Experiments for Quasi-Zenith Satellite System Using Multiple Navigation Signals as Feedback Control

    Directory of Open Access Journals (Sweden)

    Toshiaki Iwata

    2011-01-01

    Full Text Available The remote synchronization system for the onboard crystal oscillator (RESSOX is a remote control method that permits synchronization between a ground station atomic clock and Japanese quasi-zenith satellite system (QZSS crystal oscillators. To realize the RESSOX of the QZSS, the utilization of navigation signals of QZSS for feedback control is an important issue. Since QZSS transmits seven navigation signals (L1C/A, L1CP, L1CD, L2CM, L2CL, L5Q, and L5I, all combinations of these signals should be evaluated. First, the RESSOX algorithm will be introduced. Next, experimental performance will be demonstrated. If only a single signal is available, ionospheric delay should be input from external measurements. If multiple frequency signals are available, any combination, except for L2 and L5, gives good performance with synchronization error being within two nanoseconds that of RESSOX. The combination of L1CD and L5Q gives the best synchronization performance (synchronization error within 1.14 ns. Finally, in the discussion, comparisons of long-duration performance, computer simulation, and sampling number used in feedback control are considered. Although experimental results do not correspond to the simulation results, the tendencies are similar. For the overlapping Allan deviation of long duration, the stability of 1.23×10−14 at 100,160 s is obtained.

  20. ERROR-CONTROL CODING OF ADS-B MESSAGES FOR IRIDIUM SATELLITES

    Directory of Open Access Journals (Sweden)

    Volodymyr Kharchenko

    2013-12-01

    Full Text Available For modelling of ADS-B messages transmitting on the base of low-orbit satellite constellation Іrіdіum the model of a communication channel “Aircraft - Satellite - Ground Station” was built using MATLAB Sіmulіnk. This model allowed to investigate dependences of the Bit Error Rate on a type of  signal coding/decoding, ratio Eb/N0 and satellite repeater gain

  1. A close examination of under-actuated attitude control subsystem design for future satellite missions' life extension

    Science.gov (United States)

    Lam, Quang M.; Barkana, Itzhak

    2014-12-01

    Satellite mission life, maintained and prolonged beyond its typical norm of their expectancy, are primarily dictated by the state of health of its Reaction Wheel Assembly (RWA), especially for commercial GEO satellites since torquer bars are no longer applicable while thruster assistant is unacceptable due to pointing accuracy impact during jet firing. The RWA is the primary set of actuators (as compared to thrusters for orbit maintenance and maneuvering) mainly responsible for the satellite mission for accurately and precisely pointing its payloads to the right targets to conduct its mission operations. The RWA consisting of either a set of four in pyramid or three in orthogonal is the primary set of actuators to allow the satellite to achieve accurate and precise pointing of the satellite payloads towards the desired targets. Future space missions will be required to achieve much longer lives and are currently perceived by the GEO satellite community as an "expected norm" of 20 years or longer. Driven by customers' demands/goals and competitive market have challenged Attitude Control Subsystems (ACS) engineers to develop better ACS algorithms to address such an emerging need. There are two main directions to design satellite's under-actuated control subsystem: (1) Attitude Feedback with Zero Momentum Principle and (2) Attitude Control by Angular Velocity Tracking via Small Time Local Controllability concept. Successful applications of these control laws have been largely demonstrated via simulation for the rest to rest case. Limited accuracy and oscillatory behaviors are observed in three axes for non-zero wheel momentum while realistic loss of a wheel scenario (i.e., fully actuated to under-actuated) has not been closely examined! This study revisits the under-actuated control design with detailed set ups of multiple scenarios reflecting real life operating conditions which have put current under-actuated control laws mentioned earlier into a re-evaluation mode

  2. How a structured vibrational environment controls the performance of a photosystem II reaction centre-based photocell

    CERN Document Server

    Stones, Richard; van Grondelle, Rienk; Olaya-Castro, Alexandra

    2016-01-01

    Photosynthetic reaction centres are pigment-protein complexes that can transform photo-induced electronic excitations into stable charge separated states with near-unit quantum efficiency. Here we consider a theoretical photovoltaic device that places a single photosystem II reaction centre between electrodes to investigate how the mean photo-current and its fluctuations depend on the vibrational environment that assists energy and electron transfer. Our results indicate that selective coupling to well resolved vibrational modes does not necessarily offer an advantage in terms of power output but does lead to photo-currents with suppressed noise levels. The exciton manifold and the structured vibrations assisting electron transfer can also support the emergence of a phenomenon akin to dynamical channel blockade, whereby excitonic traps can impose competing routes for population transfer under steady state operation. Our results help characterizing the device-like functionality of these complexes for their pot...

  3. Integrated Orbit, Attitude, and Structural Control Systems Design for Space Solar Power Satellites

    Science.gov (United States)

    Wie, Bong; Roithmayr, Carlos M.

    2001-01-01

    The major objective of this study is to develop an integrated orbit, attitude, and structural control systems architecture for very large Space Solar Power Satellites (SSPS) in geosynchronous orbit. This study focuses on the 1.2-GW Abacus SSPS concept characterized by a 3.2 x 3.2 km solar-array platform, a 500-m diameter microwave beam transmitting antenna, and a 500 x 700 m earth-tracking reflector. For this baseline Abacus SSPS configuration, we derive and analyze a complete set of mathematical models, including external disturbances such as solar radiation pressure, microwave radiation, gravity-gradient torque, and other orbit perturbation effects. The proposed control systems architecture utilizes a minimum of 500 1-N electric thrusters to counter, simultaneously, the cyclic pitch gravity-gradient torque, the secular roll torque caused by an offset of the center-of-mass and center-of-pressure, the cyclic roll/yaw microwave radiation torque, and the solar radiation pressure force whose average value is about 60 N.

  4. Rare occurrence of occult hepatitis C virus in apparently uninfected injecting drug users: a two-centre, masked, case-control study.

    Science.gov (United States)

    Sugden, P B; Pham, T N Q; Ratnarajah, S; Cameron, B; Bull, R; White, P A; Michalak, T I; Lloyd, A R

    2013-10-01

    Occult hepatitis C virus (HCV) is a phenomenon where serum HCV RNA is not detected by sensitive commercial assays, but viral RNA is detected by ultrasensitive techniques. Occult HCV infection has not previously been studied in highly exposed, but apparently uninfected (EU) individuals. Two studies examining occult infection in EU subjects were undertaken - an initial two-centre, masked, case-control study based on cross-sectional samples (n = 35 subjects) and a single-centre confirmatory study based on longitudinal samples (n = 32 subjects). Plasma and peripheral blood mononuclear cells were tested for HCV RNA using an ultrasensitive nested polymerase chain reaction assays. Two EU subjects in the first study (10%) and one in the second study (3%) were found to have consistently detectable HCV RNA. Occult HCV infection occurs in high-risk, apparently uninfected subjects.

  5. Target setting in intensive insulin management is associated with metabolic control: the Hvidoere Childhood Diabetes Study Group Centre Differences Study 2005

    DEFF Research Database (Denmark)

    Swift, P.G.F.; Skinner, T.C.; de Beaufort, C.E.

    2010-01-01

    Objective: To evaluate glycaemic targets set by diabetes teams, their perception by adolescents and parents, and their influence on metabolic control. Methods: Clinical data and questionnaires were completed by adolescents, parents/carers and diabetes teams in 21 international centres. HbA1c...... was measured centrally. Results: A total of 2062 adolescents completed questionnaires (age 14.4 +/- 2.3 yr; diabetes duration 6.1 +/- 3.5 yr). Mean HbA 1c = 8.2 +/- 1.4% with significant differences between centres (F = 12.3; p parent...... (r = 0.20) and adolescent (r = 0.21) reports of their perceived ideal HbA1c and their actual HbA1c result (p parents' (r = 0.39) and adolescents' (r = 0.4) reports of the HbA1c they would be happy with and their actual HbA1c result. There were significant...

  6. Wavelet Transform Analysis of the Power Spectrum of Centre of Pressure Signals to Detect the Critical Point Interval of Postural Control

    Science.gov (United States)

    Singh, Neeraj Kumar; Snoussi, Hichem; Hewson, David; Duchêne, Jacques

    The aim of this study was to develop a method to detecting the critical point interval (CPI) when sensory feedback is used as part of a closed-loop postural control strategy. Postural balance was evaluated using centre of pressure (COP) displacements from a force plate for 17 control and 10 elderly subjects under eyes open, eyes closed, and vibration conditions. A modified local-maximum-modulus wavelet transform analysis using the power spectrum of COP signals was used to calculate CPI. Lower CPI values indicate increased closed-loop postural control with a quicker response to sensory input. Such a strategy requires greater energy expenditure due to the repeated muscular interventions to remain stable. The CPI for elderly occurred significantly quicker than for controls, indicating tighter control of posture. Similar results were observed for eyes closed and vibration conditions. The CPI parameter can be used to detect differences in postural control due to ageing.

  7. KWARTA (Quality Assurance in the Radiotherapy centres of the Antwerp province): Quality control of the contract therapy machine and treatment planning system

    Energy Technology Data Exchange (ETDEWEB)

    De Ost, B.; Schaeken, B.; Vanregemorter, J. [Algemeen Ziekenhuis Middelheim, Antwerp (Belgium); Bellekens, L. [Sint-Vincentius Ziekenhuis, Antwerp (Belgium); Cardoen, R.; Pieters, D. [Medisch Instituut Sint Augustinus, Wilrijk (Belgium); Goossens, H. [Sint-Elisabeth Ziekenhuis, Turnhout (Belgium); Haest, K.; Mertens, N. [Sint Norbertus Ziekenhuis, Duffel (Belgium)

    1995-12-01

    During the first year of the provincial QA project, joint procedures were set up for the routine quality control of linear accelerators, Cobalt treatment machines and simulators. A set of standard forms was produced for use in all centres, respecting the differences in each individual machine. Since forms are now in use in all centres, the second year of the project mainly focused on the QA/QC of the contract therapy machine and treatment planning system. QC measurements for the contract therapy machines were performed in air or in a phantom. Since the output was checked with the same ionisation chamber (0.33 cc flat chamber calibrated for 50 kV) and the same type of electrometer in all centres, the results could be compared mutually and with the reference values. The major parameter groups, tested for the treatment planning system were: isodose distribution (visual control of all square fields in the database of the system), PDD data (analysing of 10 x 10 cm{sup 2}, 20 x 20 cm{sup 2}, 30 x 30 cm{sup 2} and 40 x 40 cm{sup 2} open or wedged fields), output factors, wedge and tray factors, inverse square law, geometrical testing of the digitizer - screen - printer and geometrical and densitometrical testing of the CT images - screen - printer. Between 496 and 1243 parameters were investigated in the different centres (depending on the presence of the electron data). Irregularities (0 % to 4 % of the total investigated parameters) were reported to the respective physicist.

  8. RFP for CNES micro satellite program

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Jørgensen, Finn E; Betto, Maurizio

    1999-01-01

    This document descibes the ASC STAR TRACKER (performance, functionality, requirements etc.) to the Centre National d'Etudes Spatiales (CNES) for their micro Satellites.......This document descibes the ASC STAR TRACKER (performance, functionality, requirements etc.) to the Centre National d'Etudes Spatiales (CNES) for their micro Satellites....

  9. Robust Fault-Tolerant Control for Satellite Attitude Stabilization Based on Active Disturbance Rejection Approach with Artificial Bee Colony Algorithm

    OpenAIRE

    Fei Song; Shiyin Qin

    2014-01-01

    This paper proposed a robust fault-tolerant control algorithm for satellite stabilization based on active disturbance rejection approach with artificial bee colony algorithm. The actuating mechanism of attitude control system consists of three working reaction flywheels and one spare reaction flywheel. The speed measurement of reaction flywheel is adopted for fault detection. If any reaction flywheel fault is detected, the corresponding fault flywheel is isolated and the spare reaction flywhe...

  10. The centre of the action

    CERN Multimedia

    2008-01-01

    The CERN Control Centre (CCC) has all the ingredients of an action movie control room: hundreds of screens, technicians buzzing in and out, huge floor-to-ceiling windows revealing the looming vista of a mountain range, flashing lights, microphones… This is the place where not just the LHC, but the whole of CERN’s accelerator complex and technical support is based - truly the centre of the action at CERN.

  11. Call centres: constructing flexibility

    OpenAIRE

    Arzbächer, Sandra; Holtgrewe, Ursula; Kerst, Christian

    2002-01-01

    "The development of call centres as a flexible interface between firms and their environments has been seen as exemplary or even symptomatic of flexible capitalism (Sennett 1998). We are going to point out that they do not just stand for organisational change but also for changes of institutions towards deregulation. Employers and managers hoped for gains of flexibility, decreasing labour costs, and market gains by an expanded 24-hour-service. Surveillance and control by flexib...

  12. Autonomous Satellite Command and Control Through the World Wide Web. Phase 3

    Science.gov (United States)

    Cantwell, Brian; Twiggs, Robert

    1998-01-01

    The Automated Space System Experimental Testbed (ASSET) system is a simple yet comprehensive real-world operations network being developed. Phase 3 of the ASSET Project was January-December 1997 and is the subject of this report. This phase permitted SSDL and its project partners to expand the ASSET system in a variety of ways. These added capabilities included the advancement of ground station capabilities, the adaptation of spacecraft on-board software, and the expansion of capabilities of the ASSET management algorithms. Specific goals of Phase 3 were: (1) Extend Web-based goal-level commanding for both the payload PI and the spacecraft engineer. (2) Support prioritized handling of multiple (PIs) Principle Investigators as well as associated payload experimenters. (3) Expand the number and types of experiments supported by the ASSET system and its associated spacecraft. (4) Implement more advanced resource management, modeling and fault management capabilities that integrate the space and ground segments of the space system hardware. (5) Implement a beacon monitoring test. (6) Implement an experimental blackboard controller for space system management. (7) Further define typical ground station developments required for Internet-based remote control and for full system automation of the PI-to-spacecraft link. Each of those goals are examined. Significant sections of this report were also published as a conference paper. Several publications produced in support of this grant are included as attachments. Titles include: 1) Experimental Initiatives in Space System Operations; 2) The ASSET Client Interface: Balancing High Level Specification with Low Level Control; 3) Specifying Spacecraft Operations At The Product/Service Level; 4) The Design of a Highly Configurable, Reusable Operating System for Testbed Satellites; 5) Automated Health Operations For The Sapphire Spacecraft; 6) Engineering Data Summaries for Space Missions; and 7) Experiments In Automated Health

  13. A practical small satellite variable-speed control moment gyroscope for combined energy storage and attitude control

    Science.gov (United States)

    Richie, David J.; Lappas, Vaios J.; Prassinos, George

    2009-12-01

    A recent effort to develop single-gimbal variable-speed control moment gyroscopes (VSCMGs) for a combined energy storage and attitude control subsystem (ESACS) on small satellites has culminated in laboratory validation of the concept. A single actuator prototype comprised of a cutting-edge Carbon Fiber rotor and COTS motor/generator components has been developed, balanced, bench tested, and integrated onto a spherical air-bearing structure. This structure is used to demonstrate the primary capability of a VSCMG to act as a dynamo whilst simultaneously changing a spacecraft's orientation in a controlled fashion. As originally predicted, the actuator's flywheel spins up when energy is supplied (supported via a direct energy transfer power architecture), then spins down when the energy source is removed, porting the energy released to run a resistive load. The work presented gives an overview of the governing principles of the technology, addresses the underlying mission and design requirements, and presents the prototype design. Then, effectiveness of the prototype integrated on a three-axis test article is presented along with its associated test data. Finally, discussion of these results and identification of future research concludes the work. The benefits of this technology for future space missions are that system consolidation permits mass reduction, higher instantaneous peak power is available as compared to conventional secondary battery systems, state-of-charge measurement is readily available from wheel speed feedback, and torque amplification through gimballing permits efficient actuator control. The technology demonstrated is exciting and leaves the door open for future development via inclusion of magnetic levitation.

  14. Design of Satellite Attitude Control Algorithm Based on the SDRE Method Using Gas Jets and Reaction Wheels

    Directory of Open Access Journals (Sweden)

    Luiz C. G. de Souza

    2013-01-01

    Full Text Available An experimental attitude control algorithm design using prototypes can minimize space mission costs by reducing the number of errors transmitted to the next phase of the project. The Space Mechanics and Control Division (DMC of INPE is constructing a 3D simulator to supply the conditions for implementing and testing satellite control hardware and software. Satellite large angle maneuver makes the plant highly nonlinear and if the parameters of the system are not well determined, the plant can also present some level of uncertainty. As a result, controller designed by a linear control technique can have its performance and robustness degraded. In this paper the standard LQR linear controller and the SDRE controller associated with an SDRE filter are applied to design a controller for a nonlinear plant. The plant is similar to the DMC 3D satellite simulator where the unstructured uncertainties of the system are represented by process and measurements noise. In the sequel the State-Dependent Riccati Equation (SDRE method is used to design and test an attitude control algorithm based on gas jets and reaction wheel torques to perform large angle maneuver in three axes. The SDRE controller design takes into account the effects of the plant nonlinearities and system noise which represents uncertainty. The SDRE controller performance and robustness are tested during the transition phase from angular velocity reductions to normal mode of operation with stringent pointing accuracy using a switching control algorithm based on minimum system energy. This work serves to validate the numerical simulator model and to verify the functionality of the control algorithm designed by the SDRE method.

  15. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  16. Implications of intravital imaging of murine germinal centres on the control of B cell selection and division

    Directory of Open Access Journals (Sweden)

    Sebastian C. Binder

    2016-12-01

    Full Text Available Intravital imaging of antibody optimization in germinal centre (GC reactions hasset a new dimension in the understanding of the humoral immune response duringthe last decade. The inclusion of spatio-temporal cellular dynamics inthe research on GCs required analysis with agent-based mathematical models.Here, we integrate the available intravital imaging data from various researchgroups and incorporate these into a quantitative mathematical model ofGC reactions and antibody affinity maturation. Interestingly, the integrationof data concerning the spatial organisation of GCs and B cell motility allows to drawconclusions on the strength of the selection pressure and the controlof B cell division by T follicular helper cells.

  17. Factors influencing choice of care-seeking for acute fever comparing private chemical shops with health centres and hospitals in Ghana: a study using case-control methodology.

    Science.gov (United States)

    Ansah, Evelyn K; Gyapong, Margaret; Narh-Bana, Solomon; Bart-Plange, Constance; Whitty, Christopher J M

    2016-05-25

    Several public health interventions to improve management of patients with fever are largely focused on the public sector yet a high proportion of patients seek care outside the formal healthcare sector. Few studies have provided information on the determinants of utilization of the private sector as against formal public sector. Understanding the differences between those who attend public and private health institutions, and their pathway to care, has significant practical implications. The chemical shop is an important source of care for acute fever in Ghana. Case-control methodology was used to identify factors associated with seeking care for fever in the Dangme West District, Ghana. People presenting to health centres, or hospital outpatients, with a history or current fever were compared to counterparts from the same community with fever visiting a chemical shop. Of 600 patients, 150 each, were recruited from the district hospital and two health centres, respectively, and 300 controls from 51 chemical shops. Overall, 103 (17.2 %) patients tested slide positive for malaria. Specifically, 13.7 % (41/300) of chemical shop patients, 30.7 % (46/150) health centre and 10.7 % (16/150) hospital patients were slide positive. While it was the first option for care for 92.7 % (278/300) chemical shop patients, 42.7 % (64/150) of health centre patients first sought care from a chemical shop. More health centre patients (61.3 %; 92/150) presented with fever after more than 3 days than chemical shop patients (27.7 %; 83/300) [AOR = 0.19; p < 0.001 CI 0.11-0.30]. Although the hospital was the first option for 83.3 % (125/150) of hospital patients, most (63.3 %; 95/150) patients arrived there over 3 days after their symptoms begun. Proximity was significantly associated with utilization of each source of care. Education, but not other socioeconomic or demographic factors were significantly associated with chemical shop use. The private drug retail sector is

  18. Flexible Low Cost Avionics for NanoSatellite Launch Vehicle Control and GPS Metric Tracking Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, Tyvak Nano-Satellite Systems LLC (Tyvak) will develop nano-launch vehicle avionics solutions based on the latest commercial electronics products...

  19. 1 April 2011 - Indian Saha Institute of Nuclear Physics Director M. K. Sanyal in CERN Control Centre with Head of Operation M. Lamont and Adviser R. Voss; signing the guest book with CERN Director-General R. Heuer.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    1 April 2011 - Indian Saha Institute of Nuclear Physics Director M. K. Sanyal in CERN Control Centre with Head of Operation M. Lamont and Adviser R. Voss; signing the guest book with CERN Director-General R. Heuer.

  20. 7 March 2013 -Stanford University Professor N. McKeown FREng, Electrical Engineering and Computer Science and B. Leslie, Creative Labs visiting CERN Control Centre and the LHC tunnel with Director for Accelerators and Technology S. Myers.

    CERN Multimedia

    Anna Pantelia

    2013-01-01

    7 March 2013 -Stanford University Professor N. McKeown FREng, Electrical Engineering and Computer Science and B. Leslie, Creative Labs visiting CERN Control Centre and the LHC tunnel with Director for Accelerators and Technology S. Myers.

  1. Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

    CERN Document Server

    2012-01-01

    Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

  2. 27 May 2010 - UCLA Chancellor G. Block signing the guest book with Coordinator for External Relations F. Pauss and visiting CMS control centre at building 354 with Collaboration Former Deputy Spokesperson B. Cousins and Deputy Spokesperson J. Incandela.

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    27 May 2010 - UCLA Chancellor G. Block signing the guest book with Coordinator for External Relations F. Pauss and visiting CMS control centre at building 354 with Collaboration Former Deputy Spokesperson B. Cousins and Deputy Spokesperson J. Incandela.

  3. 15th March 2011 - Singapore National Research Foundation Permanent Secretary(National Research and Development)T. M. Kian signing the guest book with Head of International Relations F. Pauss and visiting CMS control centre with Collaboration Spokesperson G. Tonelli.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    15th March 2011 - Singapore National Research Foundation Permanent Secretary(National Research and Development)T. M. Kian signing the guest book with Head of International Relations F. Pauss and visiting CMS control centre with Collaboration Spokesperson G. Tonelli.

  4. Development and Validation of the On-Board Control Procedures Subsystem for the Herschel and Planck Satellites

    Science.gov (United States)

    Ferraguto, M.; Wittrock, T.; Barrenscheen, M.; Paakko, M.; Sipinen, V.; Pelttari, L.

    2009-05-01

    The On-Board Control Procedures (OBCP) subsystem of Herschel and Planck Satellites' Central Data Management Unit (CDMU) Application SW (ASW) provides means to control the spacecraft through small script-like programs written in a specific language called On-board Command Language (OCL). The implementation for Herschel and Planck satellites is an adaptation from previous experiences on instruments like Rosetta/OSIRIS, Venus Express/VMC and Dawn/FC, but it had also been adapted successfully for the GOCE satellite already. A thorough validation campaign has been conducted to qualify the H&P SW implementation for flight. The purpose of having on-board control procedures is to allow the ground operators to be able to prepare and up-link complex operations sequences (more complex than simple sequences of mission time-line telecommands) to be executed on-board during the mission operational phase. This is possible because the OBCPs run in a quite separate subsystem, so the creation of a new procedure does not require modification, uplink and re-validation of the whole on-board software. The OBCP subsystem allows these control procedures to be developed, tested on ground, and executed on the spacecraft.

  5. The Scandinavian Propaten(®) trial - 1-year patency of PTFE vascular prostheses with heparin-bonded luminal surfaces compared to ordinary pure PTFE vascular prostheses - a randomised clinical controlled multi-centre trial

    DEFF Research Database (Denmark)

    Lindholt, J S; Gottschalksen, B; Johannesen, N

    2011-01-01

    To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten(®))] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study.......To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten(®))] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study....

  6. Application of Genetic Control with Adaptive Scaling Scheme to Signal Acquisition in Global Navigation Satellite System Receiver

    Directory of Open Access Journals (Sweden)

    Ho-Nien Shou

    2012-02-01

    Full Text Available This paper presents a genetic-based control scheme that not only utilizes evolutionary characteristics to find the signal acquisition parameters, but also employs an adaptive scheme to control the search space and avoid the genetic control converging to local optimal value so as to acquire the desired signal precisely and rapidly. Simulations and experiment results show that the proposed method can improve the precision of signal parameters and take less signal acquisition time than traditional serial search methods for global navigation satellite system (GNSS signals.

  7. Investigating the effects of 6 months extended duration, in-centre nocturnal versus conventional haemodialysis treatment: a non-randomised, controlled feasibility study

    Science.gov (United States)

    Graham-Brown, Matthew P M; Preston, Robert; Pickering, Warren; McCann, Gerry P

    2016-01-01

    Introduction In-centre nocturnal haemodialysis (INHD) is an underutilised dialysis regimen that can potentially provide patients with better clinical outcomes due to extended treatment times. We have established an INHD programme within our clinical network, fulfilling a previously unmet patient need. This feasibility study aims to gather sufficient data on numerous outcome measures to inform the design of a multicentre randomised controlled trial that will establish the potential benefits of INHD and increase the availability of this service nationally and internationally. Methods and analysis This will be a non-randomised controlled study. Prevalent patients on haemodialysis (HD) will electively change from a conventional in-centre HD regimen of 4 hours thrice weekly to a regimen of extended treatment times (5–8 hours) delivered in-centre overnight thrice weekly. After recruitment of the INHD cohort, a group of patients matched for age, gender and dialysis vintage will be selected from patients remaining on a conventional daytime dialysis programme. Outcome measures will include left ventricular mass as measured by MRI, physical performance measured by the short physical performance battery and physical activity measured by accelerometry. Additionally we will measure quality of life using validated questionnaires, nutritional status by bioimpedance spectroscopy and food diaries, and blood sampling for markers of cardiovascular disease, systemic inflammation. Suitable statistical tests shall be used to analyse the data. We will use omnibus tests to observe changes over the duration of the intervention and between groups. We will also look for associations between outcome measures that may warrant further investigation. These data will be used to inform the power calculation for future studies. Ethics and dissemination A favourable opinion was granted by Northampton Research Ethics Committee (15/EM/0268). It is anticipated that results of this study will be

  8. A fault tolerant design for autonomous attitude control of the DSCS-III communication satellite

    Science.gov (United States)

    Matijevic, J.; Mettler, E.

    1983-01-01

    The first of a new series of satellites, which will provide the principal elements in the Defense Space Communications System (DSCS), was launched on Oct. 31, 1982. This satellite, DSCS-III, is part of a system which will consist of super-high frequency communications satellites in synchronous, equatorial orbits, continuously operating in four widely separate geographic regions. The DSCS-III is designed both to maintain critical communications in the presence of an electronic jamming threat and to survive nuclear radiation exposure. The results of the present investigation are to provide a basis for the design of a spacecraft tolerant of on-board failures, survivable against external threats, and capable of performing its mission autonomously for periods as long as six months.

  9. Satellite-based assessment of climate controls on US burned area

    Directory of Open Access Journals (Sweden)

    D. C. Morton

    2013-01-01

    Full Text Available Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate–fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA, the Global Fire Emissions Database (GFED, 1997–2010 and Monitoring Trends in Burn Severity (MTBS, 1984–2009 BA products. For each US National Climate Assessment (NCA region, we analyzed the relationships between monthly BA and potential evaporation (PE derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for the entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE and fire activity in Alaska, while water deficit (precipitation – PE was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6–12 months. Fire season PE increased from the 1980's–2000's, enhancing climate-driven fire risk in the southern and western US where PE–BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990's–2000's highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the

  10. Satellite-based assessment of climate controls on US burned area

    Directory of Open Access Journals (Sweden)

    D. C. Morton

    2012-06-01

    Full Text Available Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate-fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA, the Global Fire Emissions Database (GFED, 1997–2010 and Monitoring Trends in Burn Severity (MTBS, 1984–2009 BA products. For each US National Climate Assessment (NCA region, we analyzed the relationships between monthly BA and potential evaporation (PE derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE} and fire activity in the Alaska, while water deficit (precipitation – PE was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6–12 months. Fire season PE increased from the 1980s–2000s, enhancing climate-driven fire risk in the southern and western US where PE-BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990s–2000s highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the diversity of

  11. Satellite-based assessment of climate controls on US burned area

    Science.gov (United States)

    Morton, D. C.; Collatz, G. J.; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2013-01-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate-fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA), the Global Fire Emissions Database (GFED, 1997-2010) and Monitoring Trends in Burn Severity (MTBS, 1984-2009) BA products. For each US National Climate Assessment (NCA) region, we analyzed the relationships between monthly BA and potential evaporation (PE) derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for the entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE and fire activity in Alaska, while water deficit (precipitation - PE) was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6-12 months). Fire season PE increased from the 1980's-2000's, enhancing climate-driven fire risk in the southern and western US where PE-BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990's-2000's highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the diversity of fire types

  12. Robust Fault-Tolerant Control for Satellite Attitude Stabilization Based on Active Disturbance Rejection Approach with Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Fei Song

    2014-01-01

    Full Text Available This paper proposed a robust fault-tolerant control algorithm for satellite stabilization based on active disturbance rejection approach with artificial bee colony algorithm. The actuating mechanism of attitude control system consists of three working reaction flywheels and one spare reaction flywheel. The speed measurement of reaction flywheel is adopted for fault detection. If any reaction flywheel fault is detected, the corresponding fault flywheel is isolated and the spare reaction flywheel is activated to counteract the fault effect and ensure that the satellite is working safely and reliably. The active disturbance rejection approach is employed to design the controller, which handles input information with tracking differentiator, estimates system uncertainties with extended state observer, and generates control variables by state feedback and compensation. The designed active disturbance rejection controller is robust to both internal dynamics and external disturbances. The bandwidth parameter of extended state observer is optimized by the artificial bee colony algorithm so as to improve the performance of attitude control system. A series of simulation experiment results demonstrate the performance superiorities of the proposed robust fault-tolerant control algorithm.

  13. A client-centred ADL intervention: three-month follow-up of a randomized controlled trial

    Science.gov (United States)

    Bertilsson, Ann-Sofie; Ranner, Maria; von Koch, Lena; Eriksson, Gunilla; Johansson, Ulla; Ytterberg, Charlotte; Tham, Kerstin

    2014-01-01

    Objective The aim was to study a client-centred activities of daily living (ADL) intervention (CADL) compared with the usual ADL intervention (UADL) in people with stroke regarding: independence in ADL, perceived participation, life satisfaction, use of home-help service, and satisfaction with training and, in their significant others, regarding: caregiver burden, life satisfaction, and informal care. Methods In this multicentre study, 16 rehabilitation units were randomly assigned to deliver CADL or UADL. The occupational therapists who provided the CADL were specifically trained. Eligible for inclusion were people with stroke treated in a stroke unit ≤3 months after stroke, dependent in ≥two ADL, not diagnosed with dementia, and able to understand instructions. Data were collected at inclusion and three months thereafter. To detect a significant difference between the groups in the Stroke Impact Scale (SIS) domain “participation”, 280 participants were required. Intention-to-treat analysis was applied. Results At three months, there was no difference in the outcomes between the CADL group (n = 129) and the UADL group (n = 151), or their significant others (n = 87/n = 93) except in the SIS domain “emotion” in favour of CADL (p = 0.04). Conclusion The CADL does not appear to bring about short-term differences in outcomes and longer follow-ups are required. PMID:24506231

  14. Four Step to Control in the Use of Satellite Format Simulation%四层梯阶控制在卫星编队的应用仿真

    Institute of Scientific and Technical Information of China (English)

    刘猛; 冯永新; 范增

    2012-01-01

    研究了四层阶梯控制在卫星编队的控制问题及仿真.利用卫星相对运动的线性方程组和轨道机动算法的基础上,结合卫星任务规划、行为决策、行为规划和操作控制的四层阶梯卫星编队结构,从而建立建立卫星编队绕飞半径的滤波控制.仿真结果表明了四层阶梯控制在卫星编队在上对运动过程中,缩小卫星之间相对距离变换范围,增强卫星编队的稳定性.%The satellite format control and emulation by four steps to control are studied in the thesis. Based on the research of the relative equations of linear equations and track the algorithms, combining satellite mission planning,decision-making,behavior planning and operation control of four step satellite formation structure, leading to the establishment of satellite formation flying around the radius of the filter control. The simulation results show that the cfour step control in satellite formation in relative motion process,reduce the satellite relative distance between the trasformation range,enhance the stability of satellite formation flying.

  15. Investigation of Separate Meter-In Separate Meter-Out Control Strategies for Systems with Over Centre Valves

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Andersen, Torben Ole; Hansen, Rico Hjerm

    2010-01-01

    of the system and the coupling between the two cylinder chambers. Based on the described controllers the different control strategies are evaluated through via simulations and experimentally on a scale model of an excavator arm. Based on the findings, the performance of the different controllers are discussed...

  16. Parallel satellite orbital situational problems solver for space missions design and control

    Science.gov (United States)

    Atanassov, Atanas Marinov

    2016-11-01

    Solving different scientific problems for space applications demands implementation of observations, measurements or realization of active experiments during time intervals in which specific geometric and physical conditions are fulfilled. The solving of situational problems for determination of these time intervals when the satellite instruments work optimally is a very important part of all activities on every stage of preparation and realization of space missions. The elaboration of universal, flexible and robust approach for situation analysis, which is easily portable toward new satellite missions, is significant for reduction of missions' preparation times and costs. Every situation problem could be based on one or more situation conditions. Simultaneously solving different kinds of situation problems based on different number and types of situational conditions, each one of them satisfied on different segments of satellite orbit requires irregular calculations. Three formal approaches are presented. First one is related to situation problems description that allows achieving flexibility in situation problem assembling and presentation in computer memory. The second formal approach is connected with developing of situation problem solver organized as processor that executes specific code for every particular situational condition. The third formal approach is related to solver parallelization utilizing threads and dynamic scheduling based on "pool of threads" abstraction and ensures a good load balance. The developed situation problems solver is intended for incorporation in the frames of multi-physics multi-satellite space mission's design and simulation tools.

  17. Link Performance Analysis for a Proposed Future Architecture of the Air Force Satellite Control Network

    Science.gov (United States)

    2011-12-01

    data to update the known location of their spacecraft. This, of course , differs from the way STK and, in turn, the AFSCN LP obtains spacecraft...Dynamic System - A Divide and Conquer Approach. Espoo, Finland: IEEE. Cuevas, E. G., & Rehwinkel, C. A. SPOCS : A System to Measure Satellite Link

  18. Satellite-based Dust Source Identification over North Africa: Diurnal Cycle, Meteorological Controls, and Interannual Variability

    Science.gov (United States)

    Schepanski, Kerstin; Tegen, Ina; Macke, Andreas

    2010-05-01

    Mineral dust aerosol emitted from arid and semi-arid areas impacts on the weather and climate system by affecting e.g. radiation fluxes and nutrient cycles. To estimate the effect of dust aerosol, detailed knowledge on the spatio-temporal distribution of active dust sources is necessary. For a better representation of dust-related processes in numerical models and climate change projections the knowledge on the natural variability of dust source activity has to be improved. As dust sources are mostly located over remote areas satellite observations are suitable for identifying active dust sources. The accuracy of dust source identification using such an indirect method is limited by the temporal resolution and the ambiguities of the retrieval. Here, a data set on the spatial (1°x1°) and temporal (3-hourly) distribution of dust source activations (DSA) over North Africa is compiled by analyzing 15-minute Meteosat Second Generation (MSG) infra-red (IR) dust index images since March 2006. The index is designed using radiances measured by the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) on-board MSG at 8.7 µm, 10.8 µm and 12.0 µm which are converted to brightness temperatures (BTs). To strengthen the dust signal, differences of BTs are used to compute RGB-composite images. This newly data set providing information on the diurnal cycle of dust emission has been used (1) to identify most active dust source areas, and (2) to investigate on the temporal distribution of DSAs. Over the Sahara Desert 65% of dust sources become active during 06-09 UTC pointing towards an important role of the break-down of the nocturnal low-level jet (LLJ) for dust mobilization besides other meteorological features like density currents, haboobs, and cyclones. Furthermore the role of the nocturnal LLJs for dust mobilization over the Sahara is investigated by weather observations and a regional modeling study. Four years of DSA observations indicate an interannual variability in

  19. Web application for the control and management of radioprotection equipment in the Cadarache centre; Application WEB pour le controle et la gestion des appareils de radioprotection sur le centre de Cadarache

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-07-01

    The author describes a web 2-type application which has been developed for the periodic calibration controls of radioprotection equipment in Cadarache. This application aims at offering an easy and immediate and even remote access to information, at selecting information with respect to uses (radioprotection department, administrator, and so on), at securing and safeguarding homogeneous data, at editing control statistics. The different functionalities are briefly presented with their displayed interface

  20. Activities of Radiation Protection Centre in 2000

    CERN Document Server

    Radiat. Prot. Cent. Vilnius

    2001-01-01

    Description of the activities of Radiation Protection Centre in 2000 is presented. Radiation Protection Centre is responsible for radiation protection issues. Currently there are six departments at Radiation Protection Centre: two in Vilnius - Department of Radiation Protection Supervision and Control and Department of Programs and Expertise, and four in the districts. Brief information on subject controlled by each departments is provided focusing on main achievements and events.

  1. Improving person-centred care in nursing homes through dementia-care mapping: design of a cluster-randomised controlled trial

    Directory of Open Access Journals (Sweden)

    van de Ven Geertje

    2012-01-01

    Full Text Available Abstract Background The effectiveness and efficiency of nursing-home dementia care are suboptimal: there are high rates of neuropsychiatric symptoms among the residents and work-related stress among the staff. Dementia-care mapping is a person-centred care method that may alleviate both the resident and the staff problems. The main objective of this study is to evaluate the effectiveness and cost-effectiveness of dementia-care mapping in nursing-home dementia care. Methods/Design The study is a cluster-randomised controlled trial, with nursing homes grouped in clusters. Studywise minimisation is the allocation method. Nursing homes in the intervention group will receive a dementia-care-mapping intervention, while the control group will receive usual care. The primary outcome measure is resident agitation, to be assessed with the Cohen-Mansfield Agitation Inventory. The secondary outcomes are resident neuropsychiatric symptoms, assessed with the Neuropsychiatric Inventory - Nursing Homes and quality of life, assessed with Qualidem and the EQ-5D. The staff outcomes are stress reactions, job satisfaction and job-stress-related absenteeism, and staff turnover rate, assessed with the Questionnaire about Experience and Assessment of Work, the General Health Questionnaire-12, and the Maastricht Job Satisfaction Scale for Health Care, respectively. We will collect the data from the questionnaires and electronic registration systems. We will employ linear mixed-effect models and cost-effectiveness analyses to evaluate the outcomes. We will use structural equation modelling in the secondary analysis to evaluate the plausibility of a theoretical model regarding the effectiveness of the dementia-care mapping intervention. We will set up process analyses, including focus groups with staff, to determine the relevant facilitators of and barriers to implementing dementia-care mapping broadly. Discussion A novelty of dementia-care mapping is that it offers an

  2. A randomized controlled trial of a senior centre group programme for increasing social support and preventing depression in elderly people living at home in Norway

    Directory of Open Access Journals (Sweden)

    Bøen Hege

    2012-05-01

    Full Text Available Abstract Background Late-life depression is a common condition and a challenging public health problem. A lack of social support is strongly associated with psychological distress. Senior centres seem to be suitable arenas for community-based health promotion interventions, although few studies have addressed this subject. The objectives were to examine the effect of a preventive senior centre group programme consisting of weekly meetings, on social support, depression and quality of life. Methods A questionnaire was sent to a random sample of 4,000 persons over 65 in Oslo, and a total of 2,387 completed questionnaires were obtained. These subjects served as a basis for recruitment of participants for a trial, with scores on HSCL-10 being used as a main inclusion criterion. A total of 138 persons were randomized into an intervention group (N = 77 and control group (N = 61. Final analyses included 92 persons. Social support (OSS-3, depression (BDI, life satisfaction and health were measured in interviews at baseline and after 12 months (at the end of the intervention programme. Perceptions of benefits from the intervention were also measured. Mean scores, SD, SE and CI were used to describe the changes in outcomes. Effect sizes were calculated based on the original scales and as Cohen’s d. Paired sample tests and ANOVA were used to test group differences. Results There was an increase in social support in both groups, but greatest in the intervention group. The level of depression increased for both groups, but more so in the control than the intervention group. There was a decrease in life satisfaction, although the decrease was largest among controls. There were almost no differences in reported health between groups. However, effect sizes were small and differences were not statistically significant. In contrast, most of the participants said the intervention meant much to them and led to increased use of the centre. Conclusions In

  3. The benefits of China's efforts on gaseous pollutant control indicated by the bottom-up emissions and satellite observation

    Science.gov (United States)

    Xia, Y.; Zhao, Y.

    2015-12-01

    To evaluate the effectiveness of national policies of air pollution control, the emissions of SO2, NOX, CO and CO2 in China are estimated with a bottom-up method from 2000 to 2014, and vertical column densities (VCD) from satellite observation are used to evaluate the inter-annual trends and spatial distribution of emissions and the temporal and spatial patterns of ambient levels of gaseous pollutants across the country. In particular, an additional emission case named STD case, which combines the most recent issued emission standards for specific industrial sources, is developed for 2012-2014. The inter-annual trends in emissions and VCDs match well except for SO2, and the revised emissions in STD case improve the comparison, implying the benefits of emission control for most recent years. Satellite retrieval error, underestimation of emission reduction and improved atmospheric oxidization caused the differences between emissions and VCDs trend of SO2. Coal-fired power plants play key roles in SO2 and NOX emission reduction. As suggested by VCD and emission inventory, the control of CO in 11th five year plan (FYP) period was more effective than that in the 12th FYP period, while the SO2 appeared opposite. As the new control target added in 12th FYP, NOX emissions have been clearly decreased 4.3 Mt from 2011 to 2014, in contrast to the fast growth before 2011. The inter-annual trends in NO2 VCDs has the poorest correlation with vehicle ownership (R=0.796), due to the staged emission standard of vehicles. In developed regions, transportation has become the main pollutants emission source and we prove this by comparing VCDs of NO2 to VCDs of SO2. Moreover, air quality in mega cities has been evaluated based on satellite observation and emissions, and results indicate that Beijing suffered heavily from the emissions from Hebei and Tianjin, while the local emissions tend to dominate in Shanghai.

  4. A pragmatic multi-centred randomised controlled trial of yoga for chronic low back pain: Trial protocol

    OpenAIRE

    Cox, Helen; Tilbrook, Helen; Aplin, John; Chuang, Ling-Hsiang; Hewitt, Catherine; Jayakody, Shalmini; Semlyen, Anna; Soares, Marta O; Torgerson, David; Trewhela, Alison; Watt, Ian; Worthy, Gill

    2010-01-01

    A systematic review revealed three small randomised controlled trials of yoga for low back pain, all of which showed effects on back pain that favoured the yoga group. To build on these studies a larger trial, with longer term follow-up, and a number of different yoga teachers delivering the intervention is required. This study protocol describes the details of a randomised controlled trial (RCT) to determine the effectiveness and cost-effectiveness of Yoga for chronic Low Back Pain, which is...

  5. Intensity modulated radiation therapy: Analysis of patient specific quality control results, experience of Rene-Gauducheau Centre; Radiotherapie conformationnelle avec modulation d'intensite: analyse des resultats des controles precliniques, experience du centre Rene-Gauducheau

    Energy Technology Data Exchange (ETDEWEB)

    Chiavassa, S.; Brunet, G.; Gaudaire, S.; Munos-Llagostera, C.; Delpon, G.; Lisbona, A. [Service de physique medicale, centre Rene-Gauducheau, CLCC Nantes Atlantique, site hospitalier Nord, boulevard Jacques-Monod, 44805 Nantes Saint-Herblain cedex (France)

    2011-07-15

    Purpose. - Systematic verifications of patient's specific intensity-modulated radiation treatments are usually performed with absolute and relative measurements. The results constitute a database which allows the identification of potential systematic errors. Material and methods. - We analyzed 1270 beams distributed in 232 treatment plans. Step-and-shoot intensity-modulated radiation treatments were performed with a Clinac (6 and 23 MV) and sliding window intensity-modulated radiation treatments with a Novalis (6 MV). Results. - The distributions obtained do not show systematic error and all the control meet specified tolerances. Conclusion. - These results allow us to reduce controls specific patients for treatments performed under identical conditions (location, optimization and segmentation parameters of treatment planning system, etc.). (authors)

  6. Preconsult interactive computer-assisted client assessment survey for common mental disorders in a community health centre: a randomized controlled trial

    Science.gov (United States)

    Ahmad, Farah; Lou, Wendy; Shakya, Yogendra; Ginsburg, Liane; Ng, Peggy T.; Rashid, Meb; Dinca-Panaitescu, Serban; Ledwos, Cliff; McKenzie, Kwame

    2017-01-01

    Background: Access disparities for mental health care exist for vulnerable ethnocultural and immigrant groups. Community health centres that serve these groups could be supported further by interactive, computer-based, self-assessments. Methods: An interactive computer-assisted client assessment survey (iCCAS) tool was developed for preconsult assessment of common mental disorders (using the Patient Health Questionnaire [PHQ-9], Generalized Anxiety Disorder 7-item [GAD-7] scale, Primary Care Post-traumatic Stress Disorder [PTSD-PC] screen and CAGE [concern/cut-down, anger, guilt and eye-opener] questionnaire), with point-of-care reports. The pilot randomized controlled trial recruited adult patients, fluent in English or Spanish, who were seeing a physician or nurse practitioner at the partnering community health centre in Toronto. Randomization into iCCAS or usual care was computer generated, and allocation was concealed in sequentially numbered, opaque envelopes that were opened after consent. The objectives were to examine the interventions' efficacy in improving mental health discussion (primary) and symptom detection (secondary). Data were collected by exit survey and chart review. Results: Of the 1248 patients assessed, 190 were eligible for participation. Of these, 148 were randomly assigned (response rate 78%). The iCCAS (n = 75) and usual care (n = 72) groups were similar in sociodemographics; 98% were immigrants, and 68% were women. Mental health discussion occurred for 58.7% of patients in the iCCAS group and 40.3% in the usual care group (p ≤ 0.05). The effect remained significant while controlling for potential covariates (language, sex, education, employment) in generalized linear mixed model (GLMM; adjusted odds ratio [OR] 2.2; 95% confidence interval [CI] 1.1-4.5). Mental health symptom detection occurred for 38.7% of patients in the iCCAS group and 27.8% in the usual care group (p > 0.05). The effect was not significant beyond potential

  7. Design and performance of a multi-centre randomised controlled trial and economic evaluation of joint tele-consultations [ISRCTN54264250

    Directory of Open Access Journals (Sweden)

    Thompson Simon

    2002-01-01

    Full Text Available Abstract Background Appropriate information flow is crucial to the care of patients, particularly at the interface between primary and secondary care. Communication problems can result from inadequate organisation and training, There is a major expectation that information and communication technologies may offer solutions, but little reliable evidence. This paper reports the design and performance of a multi-centre randomised controlled trial (RCT, unparalleled in telemedicine research in either scale or range of outcomes. The study investigated the effectiveness and cost implications in rural and inner-city settings of using videoconferencing to perform joint tele-consultations as an alternative to general practitioner referral to the hospital specialist in the outpatient clinic. Methods Joint tele-consultation services were established in both the Royal Free Hampstead NHS Trust in inner London, and the Royal Shrewsbury Hospitals Trust, in Shropshire. All the patients who gave consent to participate were randomised either to joint tele-consultation or to a routine outpatients appointment. The principal outcome measures included the frequency of decision by the specialist to offer a follow-up outpatient appointment, patient satisfaction (Ware Specific Questionnaire, wellbeing (SF12 and enablement (PEI, numbers of tests, investigations, procedures and treatments. Results A total of 134 general practitioners operating from 29 practices participated in the trial, referring a total of 3170 patients to 20 specialists in ENT medicine, general medicine (including endocrinology, and rheumatology, gastroenterology, orthopaedics, neurology and urology. Of these, 2094 patients consented to participate in the study and were correctly randomised. There was a 91% response rate to the initial assessment questionnaires, and analysis showed equivalence for all key characteristics between the treatment and control groups. Conclusion We have designed and

  8. China Land Observation Satellite Third User Conference Promotes The Applications Of Domestic Satellite Data

    Institute of Scientific and Technical Information of China (English)

    Zong He

    2009-01-01

    @@ China Land Observation Satellite Third User Conference with the theme of "Strengthening cooperation,enlarging sharing and promoting the application of domestic satellite data" was held on July 16,2009 in Beijing. The conference was hosted by China Centre for Resources Satellite Data and Applications(CRESDA),a subsidiary of China Aerospace Science and Technology Corporation (CASC).

  9. An organisational change intervention for increasing the delivery of smoking cessation support in addiction treatment centres: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Bonevski, Billie; Guillaumier, Ashleigh; Shakeshaft, Anthony; Farrell, Michael; Tzelepis, Flora; Walsberger, Scott; D'Este, Catherine; Paul, Chris; Dunlop, Adrian; Searles, Andrew; Kelly, Peter; Fry, Rae; Stirling, Robert; Fowlie, Carrie; Skelton, Eliza

    2016-06-14

    The provision of smoking cessation support in Australian drug and alcohol treatment services is sub-optimal. This study examines the cost-effectiveness of an organisational change intervention to reduce smoking amongst clients attending drug and alcohol treatment services. A cluster-randomised controlled trial will be conducted with drug and alcohol treatment centres as the unit of randomisation. Biochemically verified (carbon monoxide by breath analysis) client 7-day-point prevalence of smoking cessation at 6 weeks will be the primary outcome measure. The study will be conducted in 33 drug and alcohol treatment services in four mainland states and territories of Australia: New South Wales, Australian Capital Territory, Queensland, and South Australia. Eligible services are those with ongoing client contact and that include pharmacotherapy services, withdrawal management services, residential rehabilitation, counselling services, and case management services. Eligible clients are those aged over 16 years who are attending their first of a number of expected visits, are self-reported current smokers, proficient in the English language, and do not have severe untreated mental illness as identified by the service staff. Control services will continue to provide usual care to the clients. Intervention group services will receive an organisational change intervention, including assistance in developing smoke-free policies, nomination of champions, staff training and educational client and service resources, and free nicotine replacement therapy in order to integrate smoking cessation support as part of usual client care. If effective, the organisational change intervention has clear potential for implementation as part of the standard care in drug and alcohol treatment centres. Australian and New Zealand Clinical Trials Registry, ACTRN12615000204549 . Registered on 3 March 2015.

  10. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  11. Sentinel-3 Mission Performance Centre: a Summary of First Months of Activities

    Science.gov (United States)

    Bruniquel, Jerome; S3MPC Partners

    2016-08-01

    The Sentinel-3 Mission Performance Centre (S-3 MPC) is one of the facility part of the Payload Data Ground Segment (PDGS). It and aims at controlling the quality of all generated products, from L0 to L2. The S-3 MPC is composed of a Coordinating Centre (CC), where the core infrastructure is hosted, which is in charge of the main routine activities (especially the quality control of data) and the overall service management. Expert Support Laboratories (ESLs) are involved in calibration and validation activities and provide specific assessment of the products (e.g., analysis of trends, ad hoc analysis of anomalies, etc.). The S-3 MPC interacts with the Processing Archiving Centers (PACs) and the Marine Centre at EUMETSAT.The S3MPC covers both optical and topography missions, each of them composed of several instruments.Since S3-A launch on the 16th of February 2016, the S3- MPC has started its activities, mainly focused on: Calibration activities, done in close relationship with the satellite commissioning team at ESTEC; Processor verification and update of specifications; Validation of L1 products and assessment of instrument performances; Cross-checking of L1 products processed in various processing centres; Progressive implementation of Quality Control activities done at the S3-MPC; Validation of L2 products, in synergy with the Marine Centre for L2 marine products

  12. The Effects of Clinical Hypnosis versus Neurolinguistic Programming (NLP) before External Cephalic Version (ECV): A Prospective Off-Centre Randomised, Double-Blind, Controlled Trial.

    Science.gov (United States)

    Reinhard, Joscha; Peiffer, Swati; Sänger, Nicole; Herrmann, Eva; Yuan, Juping; Louwen, Frank

    2012-01-01

    Objective. To examine the effects of clinical hypnosis versus NLP intervention on the success rate of ECV procedures in comparison to a control group. Methods. A prospective off-centre randomised trial of a clinical hypnosis intervention against NLP of women with a singleton breech fetus at or after 37(0/7) (259 days) weeks of gestation and normal amniotic fluid index. All 80 participants heard a 20-minute recorded intervention via head phones. Main outcome assessed was success rate of ECV. The intervention groups were compared with a control group with standard medical care alone (n = 122). Results. A total of 42 women, who received a hypnosis intervention prior to ECV, had a 40.5% (n = 17), successful ECV, whereas 38 women, who received NLP, had a 44.7% (n = 17) successful ECV (P > 0.05). The control group had similar patient characteristics compared to the intervention groups (P > 0.05). In the control group (n = 122) 27.3% (n = 33) had a statistically significant lower successful ECV procedure than NLP (P = 0.05) and hypnosis and NLP (P = 0.03). Conclusions. These findings suggest that prior clinical hypnosis and NLP have similar success rates of ECV procedures and are both superior to standard medical care alone.

  13. The Effects of Clinical Hypnosis versus Neurolinguistic Programming (NLP before External Cephalic Version (ECV: A Prospective Off-Centre Randomised, Double-Blind, Controlled Trial

    Directory of Open Access Journals (Sweden)

    Joscha Reinhard

    2012-01-01

    Full Text Available Objective. To examine the effects of clinical hypnosis versus NLP intervention on the success rate of ECV procedures in comparison to a control group. Methods. A prospective off-centre randomised trial of a clinical hypnosis intervention against NLP of women with a singleton breech fetus at or after 370/7 (259 days weeks of gestation and normal amniotic fluid index. All 80 participants heard a 20-minute recorded intervention via head phones. Main outcome assessed was success rate of ECV. The intervention groups were compared with a control group with standard medical care alone (=122. Results. A total of 42 women, who received a hypnosis intervention prior to ECV, had a 40.5% (=17, successful ECV, whereas 38 women, who received NLP, had a 44.7% (=17 successful ECV (>0.05. The control group had similar patient characteristics compared to the intervention groups (>0.05. In the control group (=122 27.3% (=33 had a statistically significant lower successful ECV procedure than NLP (=0.05 and hypnosis and NLP (=0.03. Conclusions. These findings suggest that prior clinical hypnosis and NLP have similar success rates of ECV procedures and are both superior to standard medical care alone.

  14. [Effect of acupuncture on early cerebral palsy infants with parafunctional sitting position: a multi-centre, randomized, control research].

    Science.gov (United States)

    Zhang, Hong-yun; Sun, Qun-ying; Yang, Kun-peng; Chen, Yu-xia; Wang, Qi; Wang, Xi; Liu, Yuan

    2015-02-01

    To study the clinical effect of development theory based acupuncture on early cerebral palsy (CP) infants with parafunctional sitting position. Totally 120 early CP infants were randomly assigned to two groups equally, the treatment group and the control group. All received acupuncture combined with training rehabilitation. Patients in the treatment group adopted acupuncture based on infants development theory, while those in the control group were treated by head acupuncture. Sitting functional points in Gross motor function measure (GMFM) 88 were observed in different groups and infant patients of various types before and after treatment. Root mean square (RMS) signals of sitting correlated muscles (latissimus dorsi, erector spinae, rectus abdominis) were recorded by surface electromyography (sEMG). The effective rate was evaluated by Nimodipine method. Compared with before treatment, sitting functional points were significantly improved in the two groups (Ptreatment, it was higher in the treatment group than in the control group (Ptreatment group after treatment (all Ptreatment group than in the control group (89.29% vs. 77.78%, P<0.05). Infants development theory based acupuncture could effectively elevate dorsi-extensor muscles force, improve sitting position of 8 months to 1 year old CP infants with parafunctional sitting position.

  15. Risk factors and outcomes of fetal macrosomia in a tertiary centre in Tanzania: a case-control study.

    Science.gov (United States)

    Said, Aisha Salim; Manji, Karim Premji

    2016-08-24

    Fetal macrosomia is defined as birth weight ≥4000 g. Several risk factors have been shown to be associated with fetal macrosomia. There has been an increased incidence of macrosomic babies delivered and the antecedent complications. This study assessed the risk factors, maternal and neonatal complications of fetal macrosomia in comparison with normal birth weight neonates. A case-control study was conducted at the Muhimbili National Hospital (MNH) maternity and neonatal wards. Cases comprised of neonates with birth weight ≥4000 g; controls were matched for sex and included neonates weighing 2500-3999 g. Detailed clinical and demographic information and laboratory investigations which included blood glucose, hematocrit and plasma calcium were collected. The child was followed up to discharge/death. The prevalence of macrosomic babies was 2.3 % (103 out of 4528 deliveries). Mean birth weight of macrosomic babies was 4.2 ± 0.31 kg whereas in the controls it was 3.2 ± 0.35 kg. Maternal weight ≥80 kg, maternal age ranging between 30 and 39 years, multiparity, presence of diabetes mellitus, and gestational age ≥40 years, previous history of fetal macrosomia and delivery weight ≥80 kg were significantly associated with fetal macrosomia. Macrosomic infants were more likely to have birth asphyxia, shoulder dystocia, hypoglycemia, respiratory distress and perinatal trauma and increased risk of death compared to controls. Maternal complications such as postpartum hemorrhage, second degree perineal tears and prolonged labor occurred more frequently in the macrosomia group compared to controls (p-value macrosomia was an important cause of maternal and neonatal morbidity at Muhimbili National Hospital. Presence of risk factors should alert the obstetrician to closely monitor these pregnancies and plan on appropriate mode of delivery. Macrosomic neonates should be routinely screened and appropriately managed for hypoglycemia.

  16. Experiences and Lessons Learnt with Collaborative e-Research Infrastructure and the application of Identity Management and Access Control for the Centre for Environmental Data Analysis

    Science.gov (United States)

    Kershaw, P.

    2016-12-01

    CEDA, the Centre for Environmental Data Analysis, hosts a range of services on behalf of NERC (Natural Environment Research Council) for the UK environmental sciences community and its work with international partners. It is host to four data centres covering atmospheric science, earth observation, climate and space data domain areas. It holds this data on behalf of a number of different providers each with their own data policies which has thus required the development of a comprehensive system to manage access. With the advent of CMIP5, CEDA committed to be one of a number of centres to host the climate model outputs and make them available through the Earth System Grid Federation, a globally distributed software infrastructure developed for this purpose. From the outset, a means for restricting access to datasets was required, necessitating the development a federated system for authentication and authorisation so that access to data could be managed across multiple providers around the world. From 2012, CEDA has seen a further evolution with the development of JASMIN, a multi-petabyte data analysis facility. Hosted alongside the CEDA archive, it provides a range of services for users including a batch compute cluster, group workspaces and a community cloud. This has required significant changes and enhancements to the access control system. In common with many other examples in the research community, the experiences of the above underline the difficulties of developing collaborative e-Research infrastructures. Drawing from these there are some recurring themes: Clear requirements need to be established at the outset recognising that implementing strict access policies can incur additional development and administrative overhead. An appropriate balance is needed between ease of access desired by end users and metrics and monitoring required by resource providers. The major technical challenge is not with security technologies themselves but their effective

  17. Understanding satellite-based monthly-to-seasonal reservoir outflow estimation as a function of hydrologic controls

    Science.gov (United States)

    Bonnema, Matthew; Sikder, Safat; Miao, Yabin; Chen, Xiaodong; Hossain, Faisal; Ara Pervin, Ismat; Mahbubur Rahman, S. M.; Lee, Hyongki

    2016-05-01

    Growing population and increased demand for water is causing an increase in dam and reservoir construction in developing nations. When rivers cross international boundaries, the downstream stakeholders often have little knowledge of upstream reservoir operation practices. Satellite remote sensing in the form of radar altimetry and multisensor precipitation products can be used as a practical way to provide downstream stakeholders with the fundamentally elusive upstream information on reservoir outflow needed to make important and proactive water management decisions. This study uses a mass balance approach of three hydrologic controls to estimate reservoir outflow from satellite data at monthly and annual time scales: precipitation-induced inflow, evaporation, and reservoir storage change. Furthermore, this study explores the importance of each of these hydrologic controls to the accuracy of outflow estimation. The hydrologic controls found to be unimportant could potentially be neglected from similar future studies. Two reservoirs were examined in contrasting regions of the world, the Hungry Horse Reservoir in a mountainous region in northwest U.S. and the Kaptai Reservoir in a low-lying, forested region of Bangladesh. It was found that this mass balance method estimated the annual outflow of both reservoirs with reasonable skill. The estimation of monthly outflow from both reservoirs was however less accurate. The Kaptai basin exhibited a shift in basin behavior resulting in variable accuracy across the 9 year study period. Monthly outflow estimation from Hungry Horse Reservoir was compounded by snow accumulation and melt processes, reflected by relatively low accuracy in summer and fall, when snow processes control runoff. Furthermore, it was found that the important hydrologic controls for reservoir outflow estimation at the monthly time scale differs between the two reservoirs, with precipitation-induced inflow being the most important control for the Kaptai

  18. Nonlinear analysis and vibration suppression control for a rigid-flexible coupling satellite antenna system composed of laminated shell reflector

    Science.gov (United States)

    You, Bin Di; Wen, Jian Min; Zhao, Yang

    2014-03-01

    In this paper, a nonlinear dynamic modeling method for a rigid-flexible coupling satellite antenna system composed of laminated shell reflector is proposed undergoing a large overall motion. For the study of the characteristics of the reflector using laminated shell structure, the displacement field description of a point in a 3-noded shell element is acquired in conjunction with the length stretch, lateral bending and torsional deformation. Hence, a nonlinear dynamic model of the satellite antenna system is deduced based on Lagrange's equations. The complete expressions of nonlinear terms of elastic deformation and coupling terms between rigid motion and large deflection are considered in the dynamic equations, and the dynamic behavior of the rigid-flexible coupling system is analyzed using linear model and nonlinear model, respectively. In order to eliminate the system vibration, the PD with vibration force feedback control strategy is used to achieve its desired angles and velocity in a much shorter duration, and can further accomplish reduction of residual vibration. Then, the asymptotic stability of the system is proved based on the Lyapunov method. Through numerical computation, the results show that the linear model cannot capture the motion-induced coupling terms and geometric nonlinearity variations. However, the nonlinear model is suitable for dealing with large deformation rigid-flexible problem undergoing large overall motions. Hence, the satellite antenna pointing accuracy would be predicted based on the nonlinear model. Furthermore, the results also show that the proposed control strategy can suppress system vibration quickly. The above conclusions would have important academic significance and engineering value.

  19. Preventing hospital admissions by reviewing medication (PHARM in primary care: design of the cluster randomised, controlled, multi-centre PHARM-study

    Directory of Open Access Journals (Sweden)

    van den Bogert Sander CA

    2011-01-01

    Full Text Available Abstract Background Medication can be effective but can also be harmful and even cause hospital admissions. Medication review or pharmacotherapy review has often been proposed as a solution to prevent these admissions and to improve the effectiveness and safety of pharmacotherapy. However, most published randomised controlled trials on pharmacotherapy reviews showed no or little effect on morbidity and mortality. Therefore we designed the PHARM (Preventing Hospital Admissions by Reviewing Medication-study with the objective to study the effect of the total pharmaceutical care process on medication related hospital admissions and on adverse drug events, survival and quality of life. Methods/Design The PHARM-study is designed as a cluster randomised, controlled, multi-centre study in an integrated primary care setting. Patients with a high risk of a medication related hospital admission are included in the study with randomisation at GP (general practitioner level. We aim to include 14200 patients, 7100 in each arm, from at least 142 pharmacy practices. The intervention consists of a patient-centred, structured, pharmaceutical care process. This process consists of several steps, is continuous and occurrs over multiple encounters of patients and clinicians. The steps of this pharmaceutical care process are a pharmaceutical anamnesis, a review of the patient's pharmacotherapy, the formulation and execution of a pharmaceutical care plan combined with the monitoring and follow up evaluation of the care plan and pharmacotherapy. The patient's own pharmacist and GP carry out the intervention. The control group receives usual care. The primary outcome of the study is the frequency of hospital admissions related to medication within the study period of 12 months of each patient. The secondary outcomes are survival, quality of life, adverse drug events and severe adverse drug events. The outcomes will be analysed by using mixed-effects Cox models

  20. Preventing hospital admissions by reviewing medication (PHARM) in primary care: design of the cluster randomised, controlled, multi-centre PHARM-study.

    Science.gov (United States)

    Leendertse, Anne J; de Koning, Fred H P; Goudswaard, Alex N; Jonkhoff, Andries R; van den Bogert, Sander C A; de Gier, Han J; Egberts, Toine C G; van den Bemt, Patricia M L A

    2011-01-07

    Medication can be effective but can also be harmful and even cause hospital admissions. Medication review or pharmacotherapy review has often been proposed as a solution to prevent these admissions and to improve the effectiveness and safety of pharmacotherapy. However, most published randomised controlled trials on pharmacotherapy reviews showed no or little effect on morbidity and mortality. Therefore we designed the PHARM (Preventing Hospital Admissions by Reviewing Medication)-study with the objective to study the effect of the total pharmaceutical care process on medication related hospital admissions and on adverse drug events, survival and quality of life. The PHARM-study is designed as a cluster randomised, controlled, multi-centre study in an integrated primary care setting. Patients with a high risk of a medication related hospital admission are included in the study with randomisation at GP (general practitioner) level. We aim to include 14200 patients, 7100 in each arm, from at least 142 pharmacy practices.The intervention consists of a patient-centred, structured, pharmaceutical care process. This process consists of several steps, is continuous and occurs over multiple encounters of patients and clinicians. The steps of this pharmaceutical care process are a pharmaceutical anamnesis, a review of the patient's pharmacotherapy, the formulation and execution of a pharmaceutical care plan combined with the monitoring and follow up evaluation of the care plan and pharmacotherapy. The patient's own pharmacist and GP carry out the intervention. The control group receives usual care.The primary outcome of the study is the frequency of hospital admissions related to medication within the study period of 12 months of each patient. The secondary outcomes are survival, quality of life, adverse drug events and severe adverse drug events. The outcomes will be analysed by using mixed-effects Cox models. The PHARM-study is one of the largest controlled trials to

  1. Hand-movement-based in-vehicle driver/front-seat passenger discrimination for centre console controls

    Science.gov (United States)

    Herrmann, Enrico; Makrushin, Andrey; Dittmann, Jana; Vielhauer, Claus; Langnickel, Mirko; Kraetzer, Christian

    2010-01-01

    Successful user discrimination in a vehicle environment may yield a reduction of the number of switches, thus significantly reducing costs while increasing user convenience. The personalization of individual controls permits conditional passenger enable/driver disable and vice versa options which may yield safety improvement. The authors propose a prototypic optical sensing system based on hand movement segmentation in near-infrared image sequences implemented in an Audi A6 Avant. Analyzing the number of movements in special regions, the system recognizes the direction of the forearm and hand motion and decides whether driver or front-seat passenger touch a control. The experimental evaluation is performed independently for uniformly and non-uniformly illuminated video data as well as for the complete video data set which includes both subsets. The general test results in error rates of up to 14.41% FPR / 16.82% FNR and 17.61% FPR / 14.77% FNR for driver and passenger respectively. Finally, the authors discuss the causes of the most frequently occurring errors as well as the prospects and limitations of optical sensing for user discrimination in passenger compartments.

  2. [Role of quality control for improvement of blood components in the Regional Blood Centre of Ouagadougou in Burkina Faso, 2014].

    Science.gov (United States)

    Nebie, K; Sawadogo, S; Kafando, E; Bationo, E M; Dahourou, H; Ouattara, S; Kienou, K; Nana, S; Kaba, L; Fretz, C; Murphy, E L

    2017-06-02

    In Burkina Faso, blood components must comply with national standards. Then, all Transfusion services must implement a quality control process to ensure compliance. Our study aims to establish the main characteristics of blood components of the regional transfusion center of Ouagadougou, and evaluate the capability of this center to improve its manufacturing process. We conducted from marsh to December 2014 a pre-post study, assessing blood components' characteristics before and after the implementation of a six months' improvement plan. The assessed parameters were: volume, hematocrit (Ht) and hemoglobin (Hb) levels in RBCs; volume and the number of platelets in PPCs; and volume and concentration of clotting factor VIII in fresh frozen plasma (FFP), respectively. Three hundred and twelve RBCs and 280 PCs were randomly selected for the first series of controls, and 215 RBCs, 54 PCs and 60 FFP were selected for the second series of controls. We compared the mean values of the components parameters and the overall non-compliance rates for each series. The average Hb level of RBCs was respectively 47.8±8.9g and 54.7±7.2g in the first and second series compare to a standard of≥40g. Non-compliance rates of Hb level decreased significantly from 17.6% to 1.4%. For PCs units, the mean number of platelets was 0.14±0.10×10(11) and 0.30±0.15×10(11) in the first and second period compare to a standard of 0.5×10(11). Non-compliance rates for platelets number were high 97.1% and 72.2%. The study demonstrates that only RBCs complied with national standards. The study also demonstrates the capability of CRTSO to improve blood components' processing even if for PCs and FFP, NC rates remain high. QC must be maintained and expanded to the others regional blood centers of the country. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Control de eficiencia en accionamiento de bombas centrífugas para transporte de hidromezclas usando lógica difusa

    Directory of Open Access Journals (Sweden)

    Luis D Rojas Purón

    2011-02-01

    Full Text Available Se presenta un algoritmo de control difuso que tiene en cuenta las especificidades de los subsistemaseléctrico y mecánico del accionamiento. Es de interés un bloque compensador del torque electromagnéticoque mejora el trabajo del controlador difuso ante los fenómenos de cavitación que ocasiona pulsacionesdel momento y la resonancia mecánica que pueden aparecer durante el trabajo de la bomba centrífuga.Se muestran resultados experimentales de accionamientos de la planta de lixiviación de la empresaComandante Ernesto Che Guevara de Moa, con un efecto económico de aproximadamente 262 000 USDanuales por energía dejada de consumir en forma de pérdidas con el uso del controlador operando adiferentes niveles de cargas mecánicas, y que sirve para ser utilizado en accionamientos de bombas delas plantas metalúrgicas de Moa y Nicaro.  A fuzzy logic control algorithm offers the specificities of the electric subsystem and mechanic of theoperations. It is of interest a block compensator of the electromagnetic torque that improves the work ofthe fuzzy controller's before the cavitation phenomena that causes pulsations of the torque and themechanical resonance that can appear during the operation of the centrifugal pumps. Experimentalresults are shown with the controller operating at the leaching plant of the Ernesto Che Guevara Corporation,Moa for an economic effect of 262 000 USD per year. which most of the unused energy in form of losses,when the controller works to different mechanical loads and that it is good to be used in operations ofpumps of the metallurgical plants of Moa and Nicaro.

  4. A cancer help centre.

    Science.gov (United States)

    Daniel, R

    1996-06-01

    The diagnosis of cancer can be shattering to all involved. The treatment of cancer is intense and often very challenging. Prevailing attitudes to cancer are sometimes fearful, negative and depressing. This combination may leave those affected by cancer shocked, disorientated and without hope. Even worse than this, on asking consultants 'What can I do to help myself?' patients are frequently told 'Absolutely nothing'--crushing in one fell swoop their remaining fighting spirit. Not so in the case of Penny Brohn, who, when faced with the diagnosis of breast cancer, travelled the world to find alternative cancer treatments, and having successfully brought her own cancer under control, dedicated her life to creating a Centre for others wishing to fight their disease.

  5. Predictors of thickened carotid intima media thickness among well controlled lupus nephritis patients in a Malaysian tertiary centre

    Directory of Open Access Journals (Sweden)

    N.CT. Kong

    2012-12-01

    Full Text Available Objectives. To investigate the prevalence of thickened carotid intima media thickness (CIMT and its associated risk factors in patients with lupus nephritis (LN who were in remission. Methods. This was a cross sectional study in which consecutive LN patients who were in remission and attending our Nephrology/SLE Clinic were included. Their demographic profile, traditional cardiovascular risk factors and treatment medications were evaluated by clinical interview and review of medical records. Carotid intima media thickness (CIMT was measured using B Mode carotid ultrasonography. CIMT was considered to be abnormally thickened if it exceeded the 75th percentile matched for age-and sex-matched normal controls. The associated factors for thickened CIMT were examined. Results. A total of 39 patients with a mean remission duration of 29±24.3 months and on a mean prednisolone dose of 9.10±7.83 mg daily completed the study. Six patients (15.4% had thickened CIMT. On univariate analysis, male gender, patient age, older age at diagnosis, higher serum CRP levels, greater proteinuria and higher mean cumulative azathioprine dose were associated with thickened CIMT (PConclusions. Lupus factors particularly age at diagnosis and proteinuria were the associated factors of thickened CIMT. Larger prospective trials are indicated to confirm our findings.

  6. Auxin and ethylene interactions control mitotic activity of the quiescent centre, root cap size, and pattern of cap cell differentiation in maize.

    Science.gov (United States)

    Ponce, Georgina; Barlow, Peter W; Feldman, Lewis J; Cassab, Gladys I

    2005-06-01

    Root caps (RCs) are the terminal tissues of higher plant roots. In the present study the factors controlling RC size, shape and structure were examined. It was found that this control involves interactions between the RC and an adjacent population of slowly dividing cells, the quiescent centre, QC. Using the polar auxin transport inhibitor 1-N-naphthylphthalamic acid (NPA), the effects of QC activation on RC gene expression and border cell release was characterized. Ethylene was found to regulate RC size and cell differentiation, since its addition, or the inhibition of its synthesis, affected RC development. The stimulation of cell division in the QC following NPA treatment was reversed by ethylene, and quiescence was re-established. Moreover, inhibition of both ethylene synthesis and auxin polar transport triggered a new pattern of cell division in the root epidermis and led to the appearance of supernumerary epidermal cell files with cap-like characteristics. The data suggest that the QC ensures an ordered internal distribution of auxin, and thereby regulates not only the planes of growth and division in both the root apex proper and the RC meristem, but also regulates cell fate in the RC. Ethylene appears to regulate the auxin redistribution system that resides in the RC. Experiments with Arabidopsis roots also reveal that ethylene plays an important role in regulating the auxin sink, and consequently cell fate in the RC.

  7. Assessment for Operator Confidence in Automated Space Situational Awareness and Satellite Control Systems

    Science.gov (United States)

    Gorman, J.; Voshell, M.; Sliva, A.

    2016-09-01

    The United States is highly dependent on space resources to support military, government, commercial, and research activities. Satellites operate at great distances, observation capacity is limited, and operator actions and observations can be significantly delayed. Safe operations require support systems that provide situational understanding, enhance decision making, and facilitate collaboration between human operators and system automation both in-the-loop, and on-the-loop. Joint cognitive systems engineering (JCSE) provides a rich set of methods for analyzing and informing the design of complex systems that include both human decision-makers and autonomous elements as coordinating teammates. While, JCSE-based systems can enhance a system analysts' understanding of both existing and new system processes, JCSE activities typically occur outside of traditional systems engineering (SE) methods, providing sparse guidance about how systems should be implemented. In contrast, the Joint Director's Laboratory (JDL) information fusion model and extensions, such as the Dual Node Network (DNN) technical architecture, provide the means to divide and conquer such engineering and implementation complexity, but are loosely coupled to specialized organizational contexts and needs. We previously describe how Dual Node Decision Wheels (DNDW) extend the DNN to integrate JCSE analysis and design with the practicalities of system engineering and implementation using the DNN. Insights from Rasmussen's JCSE Decision Ladders align system implementation with organizational structures and processes. In the current work, we present a novel approach to assessing system performance based on patterns occurring in operational decisions that are documented by JCSE processes as traces in a decision ladder. In this way, system assessment is closely tied not just to system design, but the design of the joint cognitive system that includes human operators, decision-makers, information systems, and

  8. Gatifloxacin versus ceftriaxone for uncomplicated enteric fever in Nepal: an open-label, two-centre, randomised controlled trial

    Science.gov (United States)

    Arjyal, Amit; Basnyat, Buddha; Nhan, Ho Thi; Koirala, Samir; Giri, Abhishek; Joshi, Niva; Shakya, Mila; Pathak, Kamal Raj; Mahat, Saruna Pathak; Prajapati, Shanti Pradhan; Adhikari, Nabin; Thapa, Rajkumar; Merson, Laura; Gajurel, Damodar; Lamsal, Kamal; Lamsal, Dinesh; Yadav, Bharat Kumar; Shah, Ganesh; Shrestha, Poojan; Dongol, Sabina; Karkey, Abhilasha; Thompson, Corinne N; Thieu, Nga Tran Vu; Thanh, Duy Pham; Baker, Stephen; Thwaites, Guy E; Wolbers, Marcel; Dolecek, Christiane

    2016-01-01

    Summary Background Because treatment with third-generation cephalosporins is associated with slow clinical improvement and high relapse burden for enteric fever, whereas the fluoroquinolone gatifloxacin is associated with rapid fever clearance and low relapse burden, we postulated that gatifloxacin would be superior to the cephalosporin ceftriaxone in treating enteric fever. Methods We did an open-label, randomised, controlled, superiority trial at two hospitals in the Kathmandu valley, Nepal. Eligible participants were children (aged 2–13 years) and adult (aged 14–45 years) with criteria for suspected enteric fever (body temperature ≥38·0°C for ≥4 days without a focus of infection). We randomly assigned eligible patients (1:1) without stratification to 7 days of either oral gatifloxacin (10 mg/kg per day) or intravenous ceftriaxone (60 mg/kg up to 2 g per day for patients aged 2–13 years, or 2 g per day for patients aged ≥14 years). The randomisation list was computer-generated using blocks of four and six. The primary outcome was a composite of treatment failure, defined as the occurrence of at least one of the following: fever clearance time of more than 7 days after treatment initiation; the need for rescue treatment on day 8; microbiological failure (ie, blood cultures positive for Salmonella enterica serotype Typhi, or Paratyphi A, B, or C) on day 8; or relapse or disease-related complications within 28 days of treatment initiation. We did the analyses in the modified intention-to-treat population, and subpopulations with either confirmed blood-culture positivity, or blood-culture negativity. The trial was powered to detect an increase of 20% in the risk of failure. This trial was registered at ClinicalTrials.gov, number NCT01421693, and is now closed. Findings Between Sept 18, 2011, and July 14, 2014, we screened 725 patients for eligibility. On July 14, 2014, the trial was stopped early by the data safety and monitoring board because S Typhi

  9. Financial considerations in the conduct of multi-centre randomised controlled trials: evidence from a qualitative study

    Directory of Open Access Journals (Sweden)

    Grant Adrian M

    2006-12-01

    Full Text Available Abstract Background Securing and managing finances for multicentre randomised controlled trials is a highly complex activity which is rarely considered in the research literature. This paper describes the process of financial negotiation and the impact of financial considerations in four UK multicentre trials. These trials had met, or were on schedule to meet, recruitment targets agreed with their public-sector funders. The trials were considered within a larger study examining factors which might be associated with trial recruitment (STEPS. Methods In-depth semi-structured telephone interviews were conducted in 2003–04 with 45 individuals with various responsibilities to one of the four trials. Interviewees were recruited through purposive and then snowball sampling. Interview transcripts were analysed with the assistance of the qualitative package Atlas-ti. Results The data suggest that the UK system of dividing funds into research, treatment and NHS support costs brought the trial teams into complicated negotiations with multiple funders. The divisions were somewhat malleable and the funding system was used differently in each trial. The fact that all funders had the potential to influence and shape the trials considered here was an important issue as the perspectives of applicants and funders could diverge. The extent and range of industry involvement in non-industry-led trials was striking. Three broad periods of financial work (foundation, maintenance, and resourcing completion were identified. From development to completion of a trial, the trialists had to be resourceful and flexible, adapting to changing internal and external circumstances. In each period, trialists and collaborators could face changing costs and challenges. Each trial extended the recruitment period; three required funding extensions from MRC or HTA. Conclusion This study highlights complex financial aspects of planning and conducting trials, especially where multiple

  10. Case reports of lead poisoning in dogs from the National Animal Poison Control Center and the Centre National D'Informations Toxicologiques, Veterinaires: anecdotes or reality?

    Science.gov (United States)

    Berny, P J; Cote, L M; Buck, W B

    1992-02-01

    This paper presents case reports of lead toxicoses from 2 major animal poison control centers in Europe and North America, gathered from 1985 through 1989. All results examined here involved cases assessed as "toxicosis" or "suspected toxicosis" by the National Animal Poison Control Center (NAPCC) or the Centre National d'Informations Toxicologiques Veterinaries (CNITV). 537 cases were reported to the NAPCC, most of them concerning dogs (59%). In France, most of the 362 cases involved cattle (57.2%). There was an increased number of cases reported during late summer and early fall, and a decreased number of cases in November and December, in both centers. Dogs intoxicated were predominantly young animals (60% were less than 2 years old). No sex difference was noted. Pure bred dogs appeared more often involved than mixed-breed ones, but the breed distribution closely resembles dog breed distribution in the US. The source of lead was usually unknown and, when information was available, paint seemed to be the most common cause of poisoning. Clinical signs reported to the animal poison control centers involved the CNS and GI tract. Results from the French and the American database showed similar trends. They are compared to data from veterinary clinics and veterinary colleges in the US and Australia. In each case, data are very similar to what was reported to the CNITV and the NAPCC. It is concluded that animal poison control centers databases can provide a useful tool for better knowledge of animal poisoning. They can also help identify unexpected toxicologic problems related to drug administration or pesticide use.

  11. Oil Trading Centre to Reopen in Shanghai

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Chinese oil companies will likely resume activities at the oil trading centre in Shanghai this year, a move to further liberalize the once tightly controlled oil market. The centre will trade forward contracts for refined oil products,including gasoline, diesel oil, kerosene and fuel oil, industrial sources said.

  12. Support to Aviation Control Service (SACS: an online service for near real-time satellite monitoring of volcanic plumes

    Directory of Open Access Journals (Sweden)

    H. Brenot

    2013-10-01

    Full Text Available Volcanic eruptions emit plumes of ash and gases in the atmosphere, potentially at very high altitudes. Ash rich plumes are hazardous for airplanes as ash is very abrasive and easily melts inside their engines. With more than 50 active volcanoes per year and the ever increasing number of commercial flights, the safety of airplanes is a real concern. Satellite measurements are ideal for monitoring global volcanic activity and, in combination with atmospheric dispersion models, to track and forecast volcanic plumes. Here we present the Support to Aviation Control Service (SACS, http://sacs.aeronomie.be, which is a free online service initiated by ESA for the near real-time (NRT satellite monitoring of volcanic plumes of SO2 and ash. It combines data from two UV-visible (OMI, GOME-2 and two infrared (AIRS, IASI spectrometers. This new multi-sensor warning system of volcanic plumes, running since April 2012, is based on the detection of SO2 and is optimised to avoid false alerts while at the same time limiting the number of notifications in case of large plumes. The system shows successful results with 95% of our notifications corresponding to true volcanic activity.

  13. Protocol for the combined immunosuppression & radiotherapy in thyroid eye disease (CIRTED trial: A multi-centre, double-masked, factorial randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Kingston Laura

    2008-01-01

    Full Text Available Abstract Background Medical management of thyroid eye disease remains controversial due to a paucity of high quality evidence on long-term treatment outcomes. Glucocorticoids are known to be effective initially but have significant side-effects with long-term use and recrudescence can occur on cessation. Current evidence is conflicting on the efficacy of radiotherapy and non-steroid systemic immunosuppression, and the majority of previous studies have been retrospective, uncontrolled, small or poorly designed. The Combined Immunosuppression and Radiotherapy in Thyroid Eye Disease (CIRTED trial was designed to investigate the efficacy of radiotherapy and azathioprine in combination with a standard course of oral prednisolone in patients with active thyroid eye disease. Methods/design Patients with active thyroid eye disease will be randomised to receive (i azathioprine or oral placebo and (ii radiotherapy or sham-radiotherapy in this multi-centre, factorial randomised control trial. The primary outcome is improvement in disease severity (assessed using a composite binary measure at 12 months and secondary end-points include quality of life scores and health economic measures. Discussion The CIRTED trial is the first study to evaluate the role of radiotherapy and azathioprine as part of a long-term, combination immunosuppressive treatment regime for Thyroid Eye Disease. It will provide evidence for the role of radiotherapy and prolonged immunosuppression in the management of this condition, as well as pilot data on their use in combination. We have paid particular attention in the trial design to establishing (a robust placebo controls and masking protocols which are effective and safe for both radiotherapy and the systemic administration of an antiproliferative drug; (b constructing effective inclusion and exclusion criteria to select for active disease; and (c selecting pragmatic outcome measures. Trial registration Current controlled trials

  14. Visceral leishmaniasis on the Indian sub-continent: a multi-centre study of the costs of three interventions for the control of the sandfly vector, Phlebotomus argentipes.

    Science.gov (United States)

    Das, M; Banjara, M; Chowdhury, R; Kumar, V; Rijal, S; Joshi, A; Akhter, S; Das, P; Kroeger, A

    2008-12-01

    The sandflies that transmit the parasites causing human visceral leishmaniasis (VL) can be controlled by several methods, including indoor residual spraying (IRS), the use of long-lasting insecticidal nets (LLIN) and ecological vector management (EVM). The financial costs of each of these three methods of sandfly control have recently been assessed and compared, in a multi-centre study based on the Indian sub-continent. In each of the four study sites (two in Nepal and one each in India and Bangladesh), 24 neighbourhoods were randomly selected in districts with high incidences of VL. The costs of the three interventions were then prospectively assessed in each study neighbourhood, in the local currency, and then converted to U.S. dollars at the prevailing exchange rate in the country concerned. The costs of IRS, which ranged from U.S.$2.4-11.7 (mean = U.S.$5.9) per household-year, were greater than those of LLIN (U.S.$3.5-5.1/household-year, with a mean of U. S.$4.5) but less than those of EVM (U. S.$5.0- 14.0/household-year, with a mean of U.S.$8.7). These results indicate that LLIN and IRS may be the cheaper options for the control of sandflies on the Indian sub-continent, and that EVM should perhaps only be taken up as a complimentary and voluntary method. Various combinations of these interventions (based on country-specific social and economic factors) may, however, be the best and most cost-effective choice.

  15. Effects of person-centred care after an event of acute coronary syndrome: Two-year follow-up of a randomised controlled trial.

    Science.gov (United States)

    Fors, Andreas; Swedberg, Karl; Ulin, Kerstin; Wolf, Axel; Ekman, Inger

    2017-09-06

    To assess the long-term effect of person-centred care (PCC) in patients with acute coronary syndrome (ACS). Patients with ACS were randomly assigned to treatment as usual (control group) or an added PCC intervention for six months. The primary endpoint was a composite score of changes in general self-efficacy≥five units, return to work or to a prior activity level and re-hospitalisation or death. The composite score improved in the PCC intervention group (n=94) at a two-year follow-up compared with the control group (n=105) (18.1%, n=17 vs. 10.5%, n=11; P=0.127). In the per-protocol analysis (n=183) the improvement was significant in favour of the PCC intervention (n=78) compared with usual care (n=105) (21.8%, n=17 vs. 10.5%, n=11; P=0.039). This effect was driven by the finding that more patients in the PCC group improved their general self-efficacy score≥5units (32.2%, n=19 vs. 17.3%, n=14; P=0.046). The composite score improvement was significantly higher in the PCC intervention group without post-secondary education (n=33) in comparison with corresponding patients in the control group (n=50) (30.3%, n=10 vs. 10.0%, n=5; P=0.024). Implementation of PCC results in sustained improvements in health outcome in patients with ACS. PCC can be incorporated into conventional cardiac prevention programmes to improve equity in uptake and patient health outcomes. Swedish registry, Researchweb.org, ID NR 65791. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  16. The effects of a new mouthrinse containing chlorhexidine, cetylpyridinium chloride and zinc lactate on the microflora of oral halitosis patients : a dual-centre, double-blind placebo-controlled study

    NARCIS (Netherlands)

    Roldan, S; Winkel, EG; Herrera, D; Sanz, M; Van Winkelhoff, AJ

    2003-01-01

    Aim: This study evaluated the microbial effects of a newly formulated mouthwash (Halita((R)) ) on oral halitosis patients. Methods: Forty subjects were included in this dual-centre, double-blind, placebo-controlled parallel study. Inclusion and exclusion criteria were used to select patients. At bas

  17. Effect of the daily consumption of protein enriched bread and protein enriched drinking yoghurt on the total protein intake in older adults in a rehabilitation centre: a single blind randomised controlled trial

    NARCIS (Netherlands)

    Til, van A.J.; Naumann, E.; Cox-Claessens, I.J.H.M.; Kremer, S.; Boelsma, E.; Schueren, van der D.E.

    2014-01-01

    Objectives To investigate the effects of protein enriched bread and drinking yoghurt, substituting regular products, on the total protein intake and the distribution of protein intake over the day in older adults. Design A single blind randomised controlled trial. Setting Rehabilitation centre. Part

  18. Satellite assisted aerosol correlation in a sequestered CO2 leakage controlled site

    Science.gov (United States)

    Landulfo, Eduardo; da Silva Lopes, Fábio J.; Nakaema, Walter M.; de Medeiros, José A. G.; Moreira, Andrea

    2014-10-01

    Currently one of the main challenges in CO2 storage research is to grant the development, testing and validation of accurate and efficient Measuring, Monitoring and Verification (MMV) techniques to be deployed at the final storage site, targeting maximum storage efficiency at the minimal leakage risk levels. For such task a mimetic sequestration site has been deployed in Florianopolis, Brazil, in order to verify the performance of monitoring plataforms to detect and quantify leakages of ground injected CO2, namely a Cavity Ring Down System (CRDS) - Los Gatos Research - an Eddy Covariance System (Campbell Scientific and Irgason) and meteorological tower for wind, humidity, precipitation and temperature monitoring onsite. The measurement strategy for detecting CO2 leakages can be very challenging since environmental and phytogenic influence can be very severe and play a role on determining if the values measured are unambiguous or not. One external factor to be considered is the amount of incoming solar radiation which will be the driving force for the whole experimental setup and following this reasoning the amount of aerosols in the atmospheric column can be a determinant factor influencing the experimental results. Thus the investigation of measured fluxes CO2 and its concentration with the aforementioned experimental instruments and their correlation with the aerosol data should be taken into account by means of satellite borne systems dedicated to measure aerosol vertical distribution and its optical properties, in this study we have selected CALIPSO and MODIS instrumentation to help on deriving the aerosol properties and CO2 measurements.

  19. Impact of injection speed and volume on perceived pain during subcutaneous injections into the abdomen and thigh: a single-centre, randomized controlled trial.

    Science.gov (United States)

    Heise, T; Nosek, L; Dellweg, S; Zijlstra, E; Præstmark, K A; Kildegaard, J; Nielsen, G; Sparre, T

    2014-10-01

    The aim of this study was to assess pain associated with subcutaneous injection into the abdomen and thigh of different combinations of injection speeds and volumes. The study was a single-centre, one-visit, double-blinded, randomized controlled trial in 82 adults with type 1 or type 2 diabetes receiving daily injections of insulin or glucagon-like peptide-1 (GLP-1) agonists. Participants received 17 subcutaneous injections (12 in abdomen, 5 in thigh) of saline at different injection speeds (150, 300 and 450 µl/s), with different volumes (400, 800, 1200 and 1600 µl), and two needle insertions without any injection. Pain was evaluated on a 100-mm visual analogue scale (VAS) (0 mm no pain, 100 mm worst pain) and on a yes/no scale for pain acceptability. Injection speed had no impact on injection pain (p = 0.833). Injection of larger volumes caused significantly more pain [VAS least square mean differences 1600 vs. 400 µl, 7 · 2 mm (95% confidence interval - CI; 4.6-9.7; p Injection speed had no effect on injection pain, whereas higher injection volumes caused more pain. The results of this study may be of value for guiding patients to use the appropriate injection site and technique to reduce their injection pain. Furthermore, these findings may have important implications for the development of new injection devices and drug formulations for clinical practice. © 2014 John Wiley & Sons Ltd.

  20. Rheology of the Ronne Ice Shelf, Antarctica, Inferred from Satellite Radar Interferometry Data using an Inverse Control Method

    Science.gov (United States)

    Larour, E.; Rignot, E.; Joughin, I.; Aubry, D.

    2005-01-01

    The Antarctic Ice Sheet is surrounded by large floating ice shelves that spread under their own weight into the ocean. Ice shelf rigidity depends on ice temperature and fabrics, and is influenced by ice flow and the delicate balance between bottom and surface accumulation. Here, we use an inverse control method to infer the rigidity of the Ronne Ice Shelf that best matches observations of ice velocity from satellite radar interferometry. Ice rigidity, or flow law parameter B, is shown to vary between 300 and 900 kPa a(sup 1/3). Ice is softer along the side margins due to frictional heating, and harder along the outflow of large glaciers, which advect cold continental ice. Melting at the bottom surface of the ice shelf increases its rigidity, while freezing decreases it. Accurate numerical modelling of ice shelf flow must account for this spatial variability in mechanical characteristics.

  1. Rheology of the Ronne Ice Shelf, Antarctica, Inferred from Satellite Radar Interferometry Data using an Inverse Control Method

    Science.gov (United States)

    Larour, E.; Rignot, E.; Joughin, I.; Aubry, D.

    2005-01-01

    The Antarctic Ice Sheet is surrounded by large floating ice shelves that spread under their own weight into the ocean. Ice shelf rigidity depends on ice temperature and fabrics, and is influenced by ice flow and the delicate balance between bottom and surface accumulation. Here, we use an inverse control method to infer the rigidity of the Ronne Ice Shelf that best matches observations of ice velocity from satellite radar interferometry. Ice rigidity, or flow law parameter B, is shown to vary between 300 and 900 kPa a(sup 1/3). Ice is softer along the side margins due to frictional heating, and harder along the outflow of large glaciers, which advect cold continental ice. Melting at the bottom surface of the ice shelf increases its rigidity, while freezing decreases it. Accurate numerical modelling of ice shelf flow must account for this spatial variability in mechanical characteristics.

  2. Satellite communication antenna technology

    Science.gov (United States)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  3. Fractional order sliding mode control for tethered satellite deployment with disturbances

    Science.gov (United States)

    Kang, Junjie; Zhu, Zheng H.; Wang, Wei; Li, Aijun; Wang, Changqing

    2017-01-01

    This paper proposes a fractional order sliding mode control for the deployment of tethered space systems with the consideration of uncertainty of external disturbances and unmodeled system dynamics. The proposed fractional order sliding mode control consists of two sub-sliding manifolds that are defined separately for the actuated and unactuated states. This, in turn, generates a control scheme to make all states move toward to the desired states. The stability analysis of the proposed control law indicates not only all states converge to the desired states at equilibrium but also disturbances caused by the uncertainty can be suppressed satisfactorily. Parametric studies are conducted to investigate the influences of fractional order and sub-sliding manifold of unactuated states on the performance of the proposed control law. The performance is compared with the sliding mode, PD and fractional order PD control laws for a baseline scenario of tether deployment. The proposed control law performs better than others in the settling time and the maximum pitch angle control in the presence of unwanted disturbances. Effectiveness and robustness of the proposed control law are demonstrated by computer simulations.

  4. Small satellite attitude control for sun-oriented operations utilizing a momentum bias with magnetic actuators

    Science.gov (United States)

    Wolfe, Scott M.

    1995-03-01

    The feasibility of using a three axis control, momentum bias system with magnetic actuators for sun-oriented operations is explored. Relevant equations of motion are developed for a sun-oriented coordinate system and control laws are developed for initial spacecraft capture after launch vehicle separation; reorientation from Earth oriented to a sun oriented operations mode; sun-oriented attitude control; and momentum wheel control. Simulations demonstrating the stability and time responsiveness of the system are performed. Sensor noise input tests are performed to investigate the systems susceptibility to imperfect conditions. Cross product of inertia effects are also input to test for system instability.

  5. Attitude control system design and on-orbit performance analysis of nano-satellite--‘‘Tian Tuo 1’’

    Institute of Scientific and Technical Information of China (English)

    Ran Dechao; Sheng Tao; Cao Lu; Chen Xiaoqian; Zhao Yong

    2014-01-01

    ‘‘Tian Tuo 1’’ (TT-1) nano-satellite is the first single-board nano-satellite that was suc-cessfully launched in China. The main objective of TT-1 is technology demonstration and scientific measurements. The satellite carries out the significant exploration of single-board architecture fea-sibility validation, and it is tailored to the low-cost philosophy by adopting numerous commercial-off-the-shelf (COTS) components. The satellite is featured with three-axis stabilization control capability. A pitch bias momentum wheel and three magnetic coils are adopted as control actuators. The sun sensors, magnetometers and a three-axis gyro are employed as the measurement sensors. The quaternion estimator (QUEST) and unscented Kalman filter (UKF) method are adopted for the nano-satellite attitude determination. On-orbit data received by ground station is conducted to analysis the performance of attitude determination and control system (ADCS). The results show that the design of ADCS for TT-1 is suitable, robust and feasible.

  6. Client Centred Desing

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Nielsen, Janni; Levinsen, Karin

    2008-01-01

    In this paper we argue for the use of Client Centred preparation phases when designing complex systems. Through Client Centred Design human computer interaction can extend the focus on end-users to alse encompass the client's needs, context and resources....

  7. Attitude control system of the Delfi-n3Xt satellite

    NARCIS (Netherlands)

    Reijneveld, J.; Choukroun, D.

    2013-01-01

    This work is concerned with the development of the attitude control algorithms that will be implemented on board of the Delfi-n3xt nanosatellite, which is to be launched in 2013. One of the mission objectives is to demonstrate Sun pointing and three axis stabilization. The attitude control modes and

  8. Hwangryunhaedoktang in adult patients with Atopic Dermatitis: a randomised, double-blind, placebo-controlled, two-centre trial - study protocol

    Directory of Open Access Journals (Sweden)

    Seo Eun-Sung

    2011-08-01

    Full Text Available Abstract Background Atopic Dermatitis is a chronic relapsing eczematous skin disease with increasing prevalence and rising costs. It has a clear impact on a patient's quality of life. Many patients are worried about the use of usual care techniques, such as corticosteroids and antihistamine due to the widespread fear of adverse effects. Complementary and alternative medical approaches have been employed to relieve symptoms of Atopic Dermatitis. Hwangryunhaedoktang is among the most strongly preferred and widely used herbal medicines for Atopic Dermatitis in Korea, as it causes very few serious adverse effects. We aim to establish basic clinical efficacy and safety data for Hwangryunhaedoktang, which is approved as an herbal medication by the Korean Food and Drug Administration, in adult patients with Atopic Dermatitis. Methods/Designs This study is a randomised, double blind, placebo-controlled, two-centre trial with two parallel arms (Hwangryunhaedoktang and a placebo. The diagnosis of Atopic Dermatitis will be made according to the criteria of Hanifin and Rajka by two different Oriental medicine doctors. We will include participants experiencing typical conditions of intermittent or continuous Atopic Eczema for six or more months. Participants will receive Hwangryunhaedoktang or a placebo-drug for eight weeks. The total duration of each arm is eleven weeks. Each participant will be examined for signs and symptoms of Atopic Dermatitis before and after taking medication. A follow-up to evaluate the maintenance of safety will be performed two weeks after the final administration of medication. Discussion This trial will utilize high quality trial methodologies in accordance with consolidated standards of reporting trials guidelines. It will provide evidence for the clinical efficacy and safety evaluation of Hwangryunhaedoktang in adult patients with Atopic Dermatitis. Moreover, we will also employ health-related quality of life questionnaires to

  9. Safety of intramuscular influenza vaccine in patients receiving oral anticoagulation therapy: a single blinded multi-centre randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Benítez Mència

    2008-05-01

    Full Text Available Abstract Background Influenza vaccines are recommended for administration by the intramuscular route. However, many physicians use the subcutaneous route for patients receiving an oral anticoagulant because this route is thought to induce fewer hemorrhagic side effects. Our aim is to assess the safety of intramuscular administration of influenza vaccine in patients on oral anticoagulation therapy. Methods Design: Randomised, controlled, single blinded, multi-centre clinical trial. Setting: 4 primary care practices in Barcelona, Spain. Participants: 229 patients on oral anticoagulation therapy eligible for influenza vaccine during the 2003–2004 season. Interventions: intramuscular administration of influenza vaccine in the experimental group (129 patients compared to subcutaneous administration in the control group (100 patients. Primary outcome: change in the circumference of the arm at the site of injection at 24 hours. Secondary outcomes: appearance of local reactions and pain at 24 hours and at 10 days; change in INR (International Normalized Ratio at 24 hours and at 10 days. Analysis was by intention to treat using the 95% confidence intervals of the proportions or mean differences. Results Baseline variables in the two groups were similar. No major side effects or major haemorrhage during the follow-up period were reported. No significant differences were observed in the primary outcome between the two groups. The appearance of local adverse reactions was more frequent in the subcutaneous administration group (37,4% vs. 17,4%, 95% confidence interval of the difference 8,2% to 31,8%. Conclusion This study shows that the intramuscular administration route of influenza vaccine in patients on anticoagulant therapy does not have more side effects than the subcutaneous administration route. Registration number NCT00137579 at clinicaltrials.gov

  10. The Effect of Using Assessment Instruments on Substance-abuse Outpatients' Adherence to Treatment: a Multi-centre Randomised Controlled Trial

    Directory of Open Access Journals (Sweden)

    Broekaert Eric

    2011-05-01

    Full Text Available Abstract Background Drop-out is an important problem in the treatment of substance use disorder. The focus of this study was to investigate the effectiveness of within treatment assessment with feedback directly to patients with multiple substance use disorder on outpatient individual treatment adherence. Feedback consisted of personal resources' and readiness to change status and progress that facilitate or hinder change, thereby using graphical representation. Methods Informed consent was obtained from both the control and experimental groups to be involved in research and follow-up. Following Zelen's single consent design, baseline participants (n = 280 were randomised (sample-size-estimation: 80%power, p=.05, 2-sided and treatment consent was obtained from those allocated to the experiment (n = 142. In both groups, equal numbers of patients did not attend sessions after allocation. So, 227 persons were analyzed according to intention-to-treat analysis (ITT: experiment n = 116;control n = 111. Excluding refusals 211 participants remained for per-protocol analysis (PP: experiment n = 100; control n = 111, The study was conducted in five outpatient treatment-centres of a large network (De Sleutel in Belgium. Participants were people with multiple substance use disorder -abuse and dependence- who had asked for treatment and who had been advised to start individual treatment after a standardised admission assessment with the European Addiction Severity Index. The experimental condition consisted of informing the patient about the intervention and of subsequent assessments plus feedback following a protocol within the first seven sessions. Assessments were made with the Readiness to Change Questionnaire and the Personal Resources Diagnostic System. The control group received the usual treatment without within treatment assessment with feedback. The most important outcome measure in this analysis of the study was the level of adherence to treatment

  11. Laser Communication Experiments with Artemis Satellite

    Science.gov (United States)

    Kuzkov, Sergii; Sodnik, Zoran; Kuzkov, Volodymyr

    2013-10-01

    the data analysis was supported by the telemetry received from the ARTEMIS payload control centre in Redu (Belgium). Special attention was focused on the investigation of the impact of atmosphere turbulence on laser beam propagation, especially in cloudy conditions. A description of our telescope and ground based laser system as well as the experimental results will be presented.

  12. Associated factors and outcomes for OXA-232 Carbapenem-resistant Enterobacteriaceae infections in a tertiary care centre in Mexico City: A case-control-control study.

    Science.gov (United States)

    Torres-González, Pedro; Ortiz-Brizuela, Edgar; Cervera-Hernandez, Miguel Enrique; Bobadilla-Del Valle, Miriam; Martínez-Gamboa, Areli; Sifuentes-Osornio, José; Ponce-de-Leon, Alfredo

    2016-10-01

    We describe the outcomes and factors associated with OXA-232 producing carbapenem-resistant Enterobacteriaceae infections. A case-control-control study was performed; each case of infection by a carbapenem-resistant/OXA-232 (OXA-232-cases, n=27) was matched by isolation site, species, and date, with 2 cases of infection by carbapenem-susceptible/third-generation cephalosporin-susceptible (TGCS-controls, n=54) and 2 cases by carbapenem-susceptible/ESBL producing Enterobacteriaceae (ESBL-controls, n=54); 66% were urinary tract and 18.5% intra-abdominal infections. In the multivariable analysis with ESBL-controls, previous use β-lactam/β-lactamase antibiotics (OR 6.2; 95% CI 1.6-23.8) and, third-generation cephalosporins (OR 0.2; 95% CI 0.05-0.8) were associated with OXA-232 infection; with TGSC-controls previous use of β-lactam/β-lactamase antibiotics (OR 3.7; 95% 1.1-12.0) was associated. Among the OXA-232-cases, 29% received imipenem/cilastatin or meropenem, 11.1% ceftriaxone, 22.2% a carbapenem-based combination and 33.3% other antimicrobials as treatment. Previous β-lactam/β-lactamase antibiotics are associated with OXA-232 infections, and some may be treated with other active carbapenems or, in the absence of ESBL, third-generation cephalosporins.

  13. Demonstration of a Plug and Play Approach to Satellite Thermal Control System Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mainstream is proposing a methodology to reduce the development time and cost, and improve the reliability of future thermal control systems for the next decade of...

  14. Finite-Time Control for Attitude Tracking Maneuver of Rigid Satellite

    Directory of Open Access Journals (Sweden)

    Mingyi Huo

    2014-01-01

    Full Text Available The problem of finite-time control for attitude tracking maneuver of a rigid spacecraft is investigated. External disturbance, unknown inertia parameters are addressed. As stepping stone, a sliding mode controller is designed. It requires the upper bound of the lumped uncertainty including disturbance and inertia matrix. However, this upper bound may not be easily obtained. Therefore, an adaptive sliding mode control law is then proposed to release that drawback. Adaptive technique is applied to estimate that bound. It is proved that the closed-loop attitude tracking system is finite-time stable. The tracking errors of the attitude and the angular velocity are asymptotically stabilized. Moreover, the upper bound on the lumped uncertainty can be exactly estimated in finite time. The attitude tracking performance with application of the control scheme is evaluated through a numerical example.

  15. Pulmonary infection control window in treatment of severe respiratory failure of chronic obstructive pulmonary diseases: a prospective, randomized controlled, multi-centred study

    Institute of Scientific and Technical Information of China (English)

    Collaborating Research Group for Noninvasive Mecha

    2005-01-01

    Background Early withdraw from invasive mechanical ventilation (MV) followed by noninvasive MV is a new strategy for changing modes of treatment. This study was conducted to estimate the feasibility and the efficacy of early extubation and sequential noninvasive MV commenced at beginning of pulmonary infection control window in patients with exacerbated hypercapnic respiratory failure caused by chronic obstructive pulmonary diseases (COPD). Methods A prospective, randomized controlled study was conducted in eleven teaching hospitals' respiratory or medical intensive care units in China. Ninety intubated COPD patients with severe hypercapnic respiratory failure triggered by pulmonary infection (pneumonia or purulent bronchitis) were involved in the study. When the pulmonary infection had been controlled by antibiotics and comprehensive therapy, the "pulmonary infection control window (PIC window)" has been reached. Each case was randomly assigned to study group (extubation and noninvasive MV via facial mask immediately) or control group (invasive MV was received continuously after PIC window by using conventional weaning technique).Results Study group (n=47) and control group (n=43) had similar clinical characteristics initially and at the time of PIC window. Compared with control group, study group had shorter duration of invasive MV [(6.4±4.4) days vs (11.3±6.2) days, P=0.000], lower rate of ventilator associated pneumonia (VAP) (3/47 vs 12/43, P=0.014), fewer days in ICU [(12±8) days vs (16±11) days, P=0.047] and lower hospital mortality (1/47 vs 7/43, P=0.025).Conclusions In COPD patients requiring intubation and invasive MV for hypercapnic respiratory failure, which is exacerbated by pulmonary infection, early extubation followed by noninvasive MV initiated at the start of PIC window may decrease significantly the duration of invasive MV, the risk of VAP and hospital mortality.

  16. The IDvIP Trial: A two-centre randomised double-blind controlled trial comparing intramuscular diamorphine and intramuscular pethidine for labour analgesia

    Directory of Open Access Journals (Sweden)

    Thomas Peter

    2011-07-01

    Full Text Available Abstract Background Intramuscular pethidine is routinely used throughout the UK for labour analgesia. Studies have suggested that pethidine provides little pain relief in labour and has a number of side effects affecting mother and neonate. It can cause nausea, vomiting and dysphoria in mothers and can cause reduced fetal heart rate variability and accelerations. Neonatal effects include respiratory depression and impaired feeding. There are few large studies comparing the relative side effects and efficacy of different opioids in labour. A small trial comparing intramuscular pethidine with diamorphine, showed diamorphine to have some benefits over pethidine when used for labour analgesia but the study did not investigate the adverse effects of either opioid. Methods The Intramuscular Diamorphine versus Intramuscular Pethidine (IDvIP trial is a randomised double-blind two centre controlled trial comparing intramuscular diamorphine and pethidine regarding their analgesic efficacy in labour and their side effects in mother, fetus and neonate. Information about the trial will be provided to women in the antenatal period or in early labour. Consent and recruitment to the trial will be obtained when the mother requests opioid analgesia. The sample size requirement is 406 women with data on primary outcomes. The maternal primary outcomes are pain relief during the first 3 hours after trial analgesia and specifically pain relief after 60 minutes. The neonatal primary outcomes are need for resuscitation and Apgar Score Discussion If the trial demonstrates that diamorphine provides better analgesia with fewer side effects in mother and neonate this could lead to a change in national practice and result in diamorphine becoming the preferred intramuscular opioid for analgesia in labour. Trial Registration ISRCTN14898678 Eudra No: 2006-003250-18, REC Reference No: 06/Q1702/95, MHRA Authorisation No: 1443/0001/001-0001, NIHR UKCRN reference 6895, RfPB grant

  17. Media scanning and verification system as a supplemental tool to disease outbreak detection & reporting at National Centre for Disease Control, Delhi.

    Science.gov (United States)

    Sharma, Rajeev; Karad, A B; Dash, B; Dhariwal, A C; Chauhan, L S; Lal, S

    2012-03-01

    Media scanning for unusual health events can efficiently supplement conventional communicable disease surveillance systems for early detection and response to outbreaks. There is a need to rapidly process and appropriately disseminate the media reports on unusual health events for timely action. Hence to address this need in India a Media Scanning & Verification Cell (MSVC) was established in July 2008 at the National Centre for Disease Control, Delhi. MSVC is supervised by Epidemiologists working in Central Surveillance Unit of IDSP. This unique system monitors Global and National Media sources such as National and Regional print media, news on internet, news wires and websites, news channels and news shared by partners like Global Public Health Intelligence Network (GPHIN), Canada, WHO and other International and national agencies. The information is shared to the districts affected and District Surveillance Officer (DSO) and his team is expected to investigate and revert through the internet about the correctness and action taken. A mean number of 4 Media Alert reports are generated each day. A total of 1685 alerts were reported in a period between July 2008 to December 2011. Of these 1241 (73.7%) were verified as real events and 183 (10.9%) were considered outbreaks by local health officials. Most events were captured through internet (57%) followed by the print media (24%). The most common disease events identified were food-borne and diarrhea (29.1%), dengue (10.68%), influenza & respiratory disease (8.1%) and malaria (7.4%). The sensitivity of MSVC to detect outbreaks was 14.8% with more than half of outbreaks detected before they were identified by the conventional surveillance system. It has proven to be a highly effective supplemental tool to official surveillance system in the detection of early warning signals and hence timely detection and management of public health threats in India.

  18. The geo-spatial information infrastructure at the Centre for Control and Prevention of Zoonoses, University of Ibadan, Nigeria: an emerging sustainable One-Health pavilion.

    Science.gov (United States)

    Olugasa, B O

    2014-12-01

    The World-Wide-Web as a contemporary means of information sharing offers a platform for geo-spatial information dissemination to improve education about spatio-temporal patterns of disease spread at the human-animal-environment interface in developing countries of West Africa. In assessing the quality of exposure to geospatial information applications among students in five purposively selected institutions in West Africa, this study reviewed course contents and postgraduate programmes in zoonoses surveillance. Geospatial information content and associated practical exercises in zoonoses surveillance were scored.. Seven criteria were used to categorize and score capability, namely, spatial data capture; thematic map design and interpretation; spatio-temporal analysis; remote sensing of data; statistical modelling; the management of spatial data-profile; and web-based map sharing operation within an organization. These criteria were used to compute weighted exposure during training at the institutions. A categorical description of institution with highest-scoring of computed Cumulative Exposure Point Average (CEPA) was based on an illustration with retrospective records of rabies cases, using data from humans, animals and the environment, that were sourced from Grand Bassa County, Liberia to create and share maps and information with faculty, staff, students and the neighbourhood about animal bite injury surveillance and spatial distribution of rabies-like illness. Uniformly low CEPA values (0-1.3) were observed across academic departments. The highest (3.8) was observed at the Centre for Control and Prevention of Zoonoses (CCPZ), University of Ibadan, Nigeria, where geospatial techniques were systematically taught, and thematic and predictive maps were produced and shared online with other institutions in West Africa. In addition, a short course in zoonosis surveillance, which offers inclusive learning in geospatial applications, is taught at CCPZ. The paper

  19. I-MOVE multi-centre case control study 2010-11: overall and stratified estimates of influenza vaccine effectiveness in Europe.

    Directory of Open Access Journals (Sweden)

    Esther Kissling

    Full Text Available BACKGROUND: In the third season of I-MOVE (Influenza Monitoring Vaccine Effectiveness in Europe, we undertook a multicentre case-control study based on sentinel practitioner surveillance networks in eight European Union (EU member states to estimate 2010/11 influenza vaccine effectiveness (VE against medically-attended influenza-like illness (ILI laboratory-confirmed as influenza. METHODS: Using systematic sampling, practitioners swabbed ILI/ARI patients within seven days of symptom onset. We compared influenza-positive to influenza laboratory-negative patients among those meeting the EU ILI case definition. A valid vaccination corresponded to > 14 days between receiving a dose of vaccine and symptom onset. We used multiple imputation with chained equations to estimate missing values. Using logistic regression with study as fixed effect we calculated influenza VE adjusting for potential confounders. We estimated influenza VE overall, by influenza type, age group and among the target group for vaccination. RESULTS: We included 2019 cases and 2391 controls in the analysis. Adjusted VE was 52% (95% CI 30-67 overall (N = 4410, 55% (95% CI 29-72 against A(H1N1 and 50% (95% CI 14-71 against influenza B. Adjusted VE against all influenza subtypes was 66% (95% CI 15-86, 41% (95% CI -3-66 and 60% (95% CI 17-81 among those aged 0-14, 15-59 and ≥60 respectively. Among target groups for vaccination (N = 1004, VE was 56% (95% CI 34-71 overall, 59% (95% CI 32-75 against A(H1N1 and 63% (95% CI 31-81 against influenza B. CONCLUSIONS: Results suggest moderate protection from 2010-11 trivalent influenza vaccines against medically-attended ILI laboratory-confirmed as influenza across Europe. Adjusted and stratified influenza VE estimates are possible with the large sample size of this multi-centre case-control. I-MOVE shows how a network can provide precise summary VE measures across Europe.

  20. I-MOVE Multi-Centre Case Control Study 2010-11: Overall and Stratified Estimates of Influenza Vaccine Effectiveness in Europe

    Science.gov (United States)

    Kissling, Esther; Valenciano, Marta; Cohen, Jean Marie; Oroszi, Beatrix; Barret, Anne-Sophie; Rizzo, Caterina; Stefanoff, Pawel; Nunes, Baltazar; Pitigoi, Daniela; Larrauri, Amparo; Daviaud, Isabelle; Horvath, Judit Krisztina; O'Donnell, Joan; Seyler, Thomas; Paradowska-Stankiewicz, Iwona Anna; Pechirra, Pedro; Ivanciuc, Alina Elena; Jiménez-Jorge, Silvia; Savulescu, Camelia; Ciancio, Bruno Christian; Moren, Alain

    2011-01-01

    Background In the third season of I-MOVE (Influenza Monitoring Vaccine Effectiveness in Europe), we undertook a multicentre case-control study based on sentinel practitioner surveillance networks in eight European Union (EU) member states to estimate 2010/11 influenza vaccine effectiveness (VE) against medically-attended influenza-like illness (ILI) laboratory-confirmed as influenza. Methods Using systematic sampling, practitioners swabbed ILI/ARI patients within seven days of symptom onset. We compared influenza-positive to influenza laboratory-negative patients among those meeting the EU ILI case definition. A valid vaccination corresponded to > 14 days between receiving a dose of vaccine and symptom onset. We used multiple imputation with chained equations to estimate missing values. Using logistic regression with study as fixed effect we calculated influenza VE adjusting for potential confounders. We estimated influenza VE overall, by influenza type, age group and among the target group for vaccination. Results We included 2019 cases and 2391 controls in the analysis. Adjusted VE was 52% (95% CI 30-67) overall (N = 4410), 55% (95% CI 29-72) against A(H1N1) and 50% (95% CI 14-71) against influenza B. Adjusted VE against all influenza subtypes was 66% (95% CI 15-86), 41% (95% CI -3-66) and 60% (95% CI 17-81) among those aged 0-14, 15-59 and ≥60 respectively. Among target groups for vaccination (N = 1004), VE was 56% (95% CI 34-71) overall, 59% (95% CI 32-75) against A(H1N1) and 63% (95% CI 31-81) against influenza B. Conclusions Results suggest moderate protection from 2010-11 trivalent influenza vaccines against medically-attended ILI laboratory-confirmed as influenza across Europe. Adjusted and stratified influenza VE estimates are possible with the large sample size of this multi-centre case-control. I-MOVE shows how a network can provide precise summary VE measures across Europe. PMID:22110695

  1. Glycaemic control and antidiabetic treatment trends in primary care centres in patients with type 2 diabetes mellitus during 2007–2013 in Catalonia: a population-based study

    Science.gov (United States)

    Mata-Cases, Manel; Franch-Nadal, Josep; Real, Jordi; Mauricio, Dídac

    2016-01-01

    Objectives To assess trends in prescribing practices of antidiabetic agents and glycaemic control in patients with type 2 diabetes mellitus (T2DM). Design Cross-sectional analysis using yearly clinical data and antidiabetic treatments prescribed obtained from an electronic population database. Setting Primary healthcare centres, including the entire population attended by the Institut Català de la Salut in Catalonia, Spain, from 2007 to 2013. Participants Patients aged 31–90 years with a diagnosis of T2DM. Results The number of registered patients with T2DM in the database was 257 072 in 2007, increasing up to 343 969 in 2013. The proportion of patients not pharmacologically treated decreased by 9.7% (95% CI −9.48% to −9.92%), while there was an increase in the percentage of patients on monotherapy (4.4% increase; 95% CI 4.16% to 4.64%), combination therapy (2.8% increase; 95% CI 2.58% to 3.02%), and insulin alone or in combination (increasing 2.5%; 95% CI 2.2% to 2.8%). The use of metformin and dipeptidyl peptidase-IV inhibitors increased gradually, while sulfonylureas, glitazones and α-glucosidase inhibitors decreased. The use of glinides remained stable, and the use of glucagon-like peptide-1 receptor agonists was still marginal. Regarding glycaemic control, there were no relevant differences across years: mean glycated haemoglobin (HbA1c) value was around 7.2%; the percentage of patients reaching an HbA1c≤7% target ranged between 52.2% and 55.6%; and those attaining their individualised target from 72.8% to 75.7%. Conclusions Although the proportion of patients under pharmacological treatment increased substantially over time and there was an increase in the use of combination therapies, there have not been relevant changes in glycaemic control during the 2007–2013 period in Catalonia. PMID:27707830

  2. Improving the knowledge of labour and delivery nurses in India: a randomized controlled trial of mentoring and case sheets in primary care centres.

    Science.gov (United States)

    Bradley, Janet; Jayanna, Krishnamurthy; Shaw, Souradet; Cunningham, Troy; Fischer, Elizabeth; Mony, Prem; Ramesh, B M; Moses, Stephen; Avery, Lisa; Crockett, Maryanne; Blanchard, James F

    2017-01-07

    Birthing in health facilities in India has increased over the last few years, yet maternal and neonatal mortality rates remain high. Clinical mentoring with case sheets or checklists for nurses is viewed as essential for on-going knowledge transfer, particularly where basic training is inadequate. This paper summarizes a study of the effect of such a programme on staff knowledge and skills in a randomized trial of 295 nurses working in 108 Primary Health Centres (PHCs) in Karnataka, India. Stratifying by district, half of the PHCs were randomly assigned to be intervention sites and provided with regular mentoring visits where case sheet/checklists were a central job and teaching aid, and half to be control sites, where no support was provided except provision of case sheets. Nurses' knowledge and skills around normal labour, labour complications and neonate issues were tested before the intervention began and again one year later. Univariate and multivariate analyses were conducted to examine the effect of mentoring and case sheets. Overall, on none of the 3 measures, did case sheet use without mentoring add anything to the basic nursing training when controlling for other factors. Only individuals who used both case-sheets and received mentoring scored significantly higher on the normal labour and neonate indices, scoring almost twice as high as those who only used case-sheets. This group was also associated with significantly higher scores on the complications of labour index, with their scores 2.3 times higher on average than the case sheet only control group. Individuals from facilities with 21 or more deliveries in a month tended to fare worse on all 3 indices. There were no differences in outcomes according to district or years of experience. This study demonstrates that provision of case sheets or checklists alone is insufficient to improve knowledge and practices. However, on-site mentoring in combination with case sheets can have a demonstrable effect on

  3. A multi-centre, randomised controlled trial of the effectiveness of PDSAFE to prevent falls among people with Parkinson's: study protocol.

    Science.gov (United States)

    Goodwin, Victoria A; Pickering, Ruth; Ballinger, Claire; Roberts, Helen; McIntosh, Emma; Lamb, Sarah; Nieuwboer, Alice; Rochester, Lynn; Ashburn, Ann

    2015-05-15

    Falls amongst people with Parkinson's (PwP) result in significant disability and reduced quality of life. There is emerging evidence that exercise-based and physiotherapeutic interventions are of benefit for improving fall risk factors, such as balance. However, the benefit, in terms of preventing falls, is mixed. The development of effective interventions has been identified as the highest research priority for this population. The aim of this trial is to establish the effectiveness and cost-effectiveness of a novel, home-based physiotherapy programme, compared with usual care, on falls amongst PwP. A UK multi-centre, community-based, single blind, randomised controlled trial with twelve month follow-up, and nested economic evaluation and qualitative studies will be undertaken. Six hundred PwP who live in their own home, have had one or more falls in the previous year and an MMSE score of ≥24 will be recruited. Those living in care homes and those needing assistance from another person to walk indoors will not be eligible. The intervention is a physiotherapist delivered, individually tailored and progressive, home-based programme (PDSAFE) comprising task orientated movement strategy training, functional lower limb strengthening and balance training, of six months duration. Unsupervised daily home exercises and strategies will be practised and supported using technology. Control participants will receive usual care. Data collection will include falls, cognitive state, balance and mobility, fear of falling, freezing of gait, mood, quality of life, carer quality of life and resource use. Data will be collected at baseline, three, six and twelve months. Longitudinal semi-structured interviews will be undertaken with forty participants to explore the expectations and experiences of participants. The primary outcome is risk of repeat falling at six months post-randomisation. The aims of this trial are to establish the effectiveness and cost-effectiveness of a novel

  4. 基于Simulink仿真的用户星天线控制系统分析%Analysis of Simulink-based antenna control system on user satellite

    Institute of Scientific and Technical Information of China (English)

    龙甲禄; 闫剑虹

    2012-01-01

    To meet the need of the antenna pointing accuracy of data relay satellite system, the antenna pointing control concept is described, and the establishment process of the link between the user satellite and data relay satellite is analyzed. A scheme for satelite-borne autonomous control is designed, A mathematic simulation of the antenna pointing control system is conducted under the Simulink circumstance. The tracking performance of the antenna control system on the user satellite is verified by the analysis of the simulation results.%为满足中继卫星系统对天线指向精度的要求,首先描述了天线指向控制概念,对用户星与中继卫星星间链路的建立过程进行了分析,并且设计了星上自主控制方案,在Simulink环境下对所设计的天线指向控制系统进行了数学仿真,最后通过对仿真结果的分析验证了用户星天线控制系统的跟踪性能.

  5. Domestic Communication Satellites

    Science.gov (United States)

    Horowitz, Andrew

    1974-01-01

    A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

  6. Attitude and vibration control of a satellite containing flexible solar arrays by using reaction wheels, and piezoelectric transducers as sensors and actuators

    Science.gov (United States)

    da Fonseca, Ijar M.; Rade, Domingos A.; Goes, Luiz C. S.; de Paula Sales, Thiago

    2017-10-01

    The primary purpose of this paper is to provide insight into control-structure interaction for satellites comprising flexible appendages and internal moving components. The physical model considered herein aiming to attend such purpose is a rigid-flexible satellite consisting of a rigid platform containing two rotating flexible solar panels. The solar panels rotation is assumed to be in a sun-synchronous configuration mode. The panels contain surface-bonded piezoelectric patches that can be used either as sensors for the elastic displacements or as actuators to counteract the vibration motion. It is assumed that in the normal mode operation the satellite platform points towards the Earth while the solar arrays rotate so as to follow the Sun. The vehicle moves in a low Earth polar orbit. The technique used to obtain the mathematical model combines the Lagrangian formulation with the Finite Elements Method used to describe the dynamics of the solar panel. The gravity-gradient torque as well as the torque due to the interaction of the Earth magnetic field and the satellite internal residual magnetic moment is included as environmental perturbations. The actuators are three reaction wheels for attitude control and piezoelectric actuators to control the flexible motion of the solar arrays. Computer simulations are performed using the MATLAB® software package. The following on-orbit satellite operating configurations are object of analysis: i) Satellite pointing towards the Earth (Earth acquisition maneuver) by considering the initial conditions in the elastic displacement equal to zero, aiming the assessment of the flexible modes excitation by the referred maneuver; ii) the satellite pointing towards the Earth with the assumption of an initial condition different from zero for the flexible motion such that the attitude alterations are checked against the elastic motion disturbance; and iii) attitude acquisition accomplished by taking into account initial conditions

  7. Measurements by Mail: Satellite-Controlled Balloons for Making Real-Time Atmospheric Observations Anywhere on Earth

    Science.gov (United States)

    Voss, P. B.

    2008-12-01

    While most of the atmosphere is only a few tens of kilometers overhead, gaining access to this critical region of the earth system is notoriously difficult. Aircraft have been highly successful as atmospheric research platforms but their use can be limited by high costs, complex logistics, and need for ground-support infrastructure. While small Unmanned Aerial Systems (UAS) carry far fewer instruments, they promise to overcome some of these limitations, especially if regulatory and air safety issues can be resolved. Here we describe five years of development on a new type of unmanned platform that can be flown with far fewer restrictions than current UAS. This altitude-controlled balloon can be mailed to collaborators almost anywhere in the world, launched within hours, and flown remotely from our laboratory via satellite link. It can be commanded to perform soundings, track atmospheric layers, or navigate divergent wind fields over periods ranging from days to potentially weeks; meteorological and chemical observations from the balloon are processed on the ground and distributed via the internet in near real time. These controlled balloons have been used in several recent atmospheric research campaigns and are now providing new possibilities for long-distance collaboration, low-cost deployments, and research in previously inaccessible parts of the lower atmosphere.

  8. Evaluation and modeling of autonomous attitude thrust control for the Geostation Operational Environmental Satellite (GOES)-8 orbit determination

    Science.gov (United States)

    Forcey, W.; Minnie, C. R.; Defazio, R. L.

    1995-01-01

    The Geostationary Operational Environmental Satellite (GOES)-8 experienced a series of orbital perturbations from autonomous attitude control thrusting before perigee raising maneuvers. These perturbations influenced differential correction orbital state solutions determined by the Goddard Space Flight Center (GSFC) Goddard Trajectory Determination System (GTDS). The maneuvers induced significant variations in the converged state vector for solutions using increasingly longer tracking data spans. These solutions were used for planning perigee maneuvers as well as initial estimates for orbit solutions used to evaluate the effectiveness of the perigee raising maneuvers. This paper discusses models for the incorporation of attitude thrust effects into the orbit determination process. Results from definitive attitude solutions are modeled as impulsive thrusts in orbit determination solutions created for GOES-8 mission support. Due to the attitude orientation of GOES-8, analysis results are presented that attempt to absorb the effects of attitude thrusting by including a solution for the coefficient of reflectivity, C(R). Models to represent the attitude maneuvers are tested against orbit determination solutions generated during real-time support of the GOES-8 mission. The modeling techniques discussed in this investigation offer benefits to the remaining missions in the GOES NEXT series. Similar missions with large autonomous attitude control thrusting, such as the Solar and Heliospheric Observatory (SOHO) spacecraft and the INTELSAT series, may also benefit from these results.

  9. Virtual particle therapy centre

    CERN Multimedia

    2015-01-01

    Particle therapy is an advanced technique of cancer radiation therapy, using protons or other ions to target the cancerous mass. This advanced technique requires a multi-disciplinary team working in a specialised centre. 3D animation: Nymus3D

  10. The IGU Knowledge Centre

    NARCIS (Netherlands)

    Huizing, Bernardus

    2005-01-01

    This article describes an innovative service for members of the International Gas Union - IGU. The IGU Knowledge Centre provides members with relevant information and data. In this article is described why, how and where.

  11. CENTRE FOR GEOMETRICAL METROLOGY

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    The objective of this Annual Report is to give a general introduction to CGM as well as to give an account of the tasks carried out using the facilities of CGM's Instrument Centre during 1998 and 1999....

  12. A global network for the control of snail-borne disease using satellite surveillance and geographic information systems.

    Science.gov (United States)

    Malone, J B; Bergquist, N R; Huh, O K; Bavia, M E; Bernardi, M; El Bahy, M M; Fuentes, M V; Kristensen, T K; McCarroll, J C; Yilma, J M; Zhou, X N

    2001-04-27

    At a team residency sponsored by the Rockefeller Foundation in Bellagio, Italy, 10-14 April 2000 an organizational plan was conceived to create a global network of collaborating health workers and earth scientists dedicated to the development of computer-based models that can be used for improved control programs for schistosomiasis and other snail-borne diseases of medical and veterinary importance. The models will be assembled using GIS methods, global climate model data, sensor data from earth observing satellites, disease prevalence data, the distribution and abundance of snail hosts, and digital maps of key environmental factors that affect development and propagation of snail-borne disease agents. A work plan was developed for research collaboration and data sharing, recruitment of new contributing researchers, and means of access of other medical scientists and national control program managers to GIS models that may be used for more effective control of snail-borne disease. Agreement was reached on the use of compatible GIS formats, software, methods and data resources, including the definition of a 'minimum medical database' to enable seamless incorporation of results from each regional GIS project into a global model. The collaboration plan calls for linking a 'central resource group' at the World Health Organization, the Food and Agriculture Organization, Louisiana State University and the Danish Bilharziasis Laboratory with regional GIS networks to be initiated in Eastern Africa, Southern Africa, West Africa, Latin America and Southern Asia. An Internet site, www.gnosisGIS.org, (GIS Network On Snail-borne Infections with special reference to Schistosomiasis), has been initiated to allow interaction of team members as a 'virtual research group'. When completed, the site will point users to a toolbox of common resources resident on computers at member organizations, provide assistance on routine use of GIS health maps in selected national disease control

  13. Night-time splinting after fasciectomy or dermo-fasciectomy for Dupuytren's contracture: a pragmatic, multi-centre, randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Larson Debbie

    2011-06-01

    Full Text Available Abstract Background Dupuytren's disease is a progressive fibroproliferative disorder which can result in fixed flexion contractures of digits and impaired hand function. Standard treatment involves surgical release or excision followed by post-operative hand therapy and splinting, however the evidence supporting night splinting is of low quality and equivocal. Methods A multi-centre, pragmatic, open, randomised controlled trial was conducted to evaluate the effect of night splinting on self-reported function, finger extension and satisfaction in patients undergoing fasciectomy or dermofasciectomy. 154 patients from 5 regional hospitals were randomised after surgery to receive hand therapy only (n = 77 or hand therapy with night-splinting (n = 77. Primary outcome was self-reported function using the Disabilities of the Arm, Shoulder and Hand (DASH questionnaire. Secondary outcomes were finger range of motion and patient satisfaction. Primary analysis was by intention to treat. Results 148 (96% patients completed follow-up at 12 months. No statistically significant differences were observed on the DASH questionnaire (0-100 scale: adjusted mean diff. 0.66, 95%CI - 2.79 to 4.11, p = 0.703, total extension deficit of operated digits (degrees: adjusted mean diff 5.11, 95%CI -2.33 to 12.55, p = 0.172 or patient satisfaction (0-10 numerical rating scale: adjusted mean diff -0.35, 95%CI -1.04 to 0.34, p = 0.315 at 1 year post surgery. Similarly, in a secondary per protocol analysis no statistically significant differences were observed between the groups in any of the outcomes. Conclusions No differences were observed in self-reported upper limb disability or active range of motion between a group of patients who were all routinely splinted after surgery and a group of patients receiving hand therapy and only splinted if and when contractures occurred. Given the added expense of therapists' time, thermoplastic materials and the potential inconvenience to

  14. Multifactorial day hospital intervention to reduce falls in high risk older people in primary care: a multi-centre randomised controlled trial [ISRCTN46584556

    Directory of Open Access Journals (Sweden)

    Morris Rob

    2006-02-01

    Full Text Available Abstract Falls in older people are a major public health concern in terms of morbidity, mortality and cost. Previous studies suggest that multifactorial interventions can reduce falls, and many geriatric day hospitals are now offering falls intervention programmes. However, no studies have investigated whether these programmes, based in the day hospital are effective, nor whether they can be successfully applied to high-risk older people screened in primary care. The hypothesis is that a multidisciplinary falls assessment and intervention at Day hospitals can reduce the incidence of falls in older people identified within primary care as being at high risk of falling. This will be tested by a pragmatic parallel-group randomised controlled trial in which the participants, identified as at high risk of falling, will be randomised into either the intervention Day hospital arm or to a control (current practice arm. Those participants preferring not to enter the full randomised study will be offered the opportunity to complete brief diaries only at monthly intervals. This data will be used to validate the screening questionnaire. Three day hospitals (2 Nottingham, 1 Derby will provide the interventions, and the University of Nottingham's Departments of Primary Care, the Division of Rehabilitation and Ageing Unit, and the Trent Institute for Health Service Research will provide the methodological and statistical expertise. Four hundred subjects will be randomised into the two arms. The primary outcome measure will be the rate of falls over one year. Secondary outcome measures will include the proportion of people experiencing at least one fall, the proportion of people experiencing recurrent falls (>1, injuries, fear of falling, quality of life, institutionalisation rates, and use of health services. Cost-effectiveness analyses will be performed to inform health commissioners about resource allocation issues. The importance of this trial is that the

  15. EVerT2-needling versus non-surgical debridement for the treatment of verrucae: study protocol for a single-centre randomised controlled trial.

    Science.gov (United States)

    Hashmi, Farina; Torgerson, David; Fairhurst, Caroline; Cockayne, Sarah; Bell, Kerry; Cullen, Michelle; Harrison-Blount, Michael

    2015-11-24

    Verrucae are extremely common, and are experienced by most people at some time during their lives. Although most verrucae will spontaneously disappear without treatment, many patients seek treatment, often because they have persisted for many years, are unsightly or painful or prevent them from doing sports or other activities. There are many different treatments available; including the Falknor's needling procedure. To date, there has only been one small trial evaluating the clinical effectiveness of this treatment and no health economic analysis has been undertaken. The Effective Verruca Treatments (EVerT2) trial aims to evaluate the clinical and cost-effectiveness of the needling procedure for the treatment of verrucae. This single-centre randomised controlled trial will recruit 58 participants (aged 18 years and over with a plantar verruca) from Salford Podiatry Clinic patient lists and the surrounding area. If the participant presents with multiple verrucae, an 'index' verruca (largest and thickest lesion) will be identified and patients will be randomised 1:1 to the intervention group to receive the needling treatment or the control group to have the callus overlying the verruca debrided. The primary outcome is complete clearance of the index verruca at 12 weeks after randomisation. Secondary outcomes include clearance and recurrence of the treated verruca, clearance of all verrucae, number of verrucae remaining, change in size of the index verruca, pain, and participant satisfaction. A cost-effectiveness analysis of the needling versus callus debridement will be carried out from the perspective of health services over a time horizon of 12 weeks. Ethical approval has been obtained from the University of Salford, Department of Health Sciences Ethical Approval Committee (HSCR15/24) and the University of York, Department of Health Sciences Research Governance Committee (HSRGC/2014/98/B). Findings will be disseminated through publication and conference

  16. Complexity in Climatic Controls on Plant Species Distribution: Satellite Data Reveal Unique Climate for Giant Sequoia in the California Sierra Nevada

    OpenAIRE

    Waller, Eric Kindseth

    2014-01-01

    ABSTRACTComplexity in Climatic Controls on Plant Species Distribution: Satellite Data Reveal Unique Climate for Giant Sequoia in the California Sierra NevadabyEric Kindseth WallerDoctor of Philosophy in Environmental Science, Policy, and ManagementUniversity of California, BerkeleyProfessor Dennis D. Baldocchi, ChairA better understanding of the environmental controls on current plant species distribution is essential if the impacts of such diverse challenges as invasive species, changing fir...

  17. Operating project for the Renardieres Power Laboratory: System structure. Acquisition and control satellites

    Energy Technology Data Exchange (ETDEWEB)

    Castagnet, D. (GIXI, 91 - Les Ulis (France))

    The principles and the construction of the new operating system for the Power Test Laboratory are presented. Emphasis is laid on the similarity between the project and Architecture 3 type remote operation systems, the electromagnetic disturbance and high safety level aspects and the utilization of microcomputers. After a presentation of the basic principles, modularity, standartization, safety, surroundings and maintenance, the article offers an explanation of the checking system structure, constituted by a central core and a network of industrial computers (SAC). These latter are described from the point of view of operations (remote-signalling, remote-control, remote-measurements, subsidiary functions), equipment structure (central processing unit, input and output boards) and reflections on the software (design, implementation, etc.).

  18. Improving person-centred care in nursing homes through dementia-care mapping: design of a cluster-randomised controlled trial.

    NARCIS (Netherlands)

    Ven, G. van de; Draskovic, I.; Adang, E.M.M.; Donders, R.; Post, A.; Zuidema, S.U.; Koopmans, R.T.C.M.; Vernooij-Dassen, M.J.F.J.

    2012-01-01

    BACKGROUND: The effectiveness and efficiency of nursing-home dementia care are suboptimal: there are high rates of neuropsychiatric symptoms among the residents and work-related stress among the staff. Dementia-care mapping is a person-centred care method that may alleviate both the resident and the

  19. Improving person-centred care in nursing homes through dementia-care mapping: design of a cluster-randomised controlled trial.

    NARCIS (Netherlands)

    Ven, G. van de; Draskovic, I.; Adang, E.M.M.; Donders, R.; Post, A.; Zuidema, S.U.; Koopmans, R.T.C.M.; Vernooij-Dassen, M.J.F.J.

    2012-01-01

    BACKGROUND: The effectiveness and efficiency of nursing-home dementia care are suboptimal: there are high rates of neuropsychiatric symptoms among the residents and work-related stress among the staff. Dementia-care mapping is a person-centred care method that may alleviate both the resident and the

  20. Improving person-centred care in nursing homes through dementia-care mapping : design of a cluster-randomised controlled trial

    NARCIS (Netherlands)

    van de Ven, Geertje; Draskovic, Irena; Adang, Eddy M M; Donders, Rogier A R T; Post, Aukje; Zuidema, Sytse U; Koopmans, Raymond T C M; Vernooij-Dassen, Myrra J F J

    2012-01-01

    BACKGROUND: The effectiveness and efficiency of nursing-home dementia care are suboptimal: there are high rates of neuropsychiatric symptoms among the residents and work-related stress among the staff. Dementia-care mapping is a person-centred care method that may alleviate both the resident and the

  1. A Randomised Controlled Trial of Two Early Intervention Programs for Young Children with Autism: Centre-Based with Parent Program and Home-Based

    Science.gov (United States)

    Roberts, Jacqueline; Williams, Katrina; Carter, Mark; Evans, David; Parmenter, Trevor; Silove, Natalie; Clark, Trevor; Warren, Anthony

    2011-01-01

    This study compares outcomes of early intervention programs for young children with autism; an individualised home-based program (HB), a small group centre-based program for children combined with a parent training and support group (CB) and a non-treatment comparison group (WL). Outcome measures of interest include social and communication skill…

  2. Improving person-centred care in nursing homes through dementia-care mapping : design of a cluster-randomised controlled trial

    NARCIS (Netherlands)

    van de Ven, Geertje; Draskovic, Irena; Adang, Eddy M M; Donders, Rogier A R T; Post, Aukje; Zuidema, Sytse U; Koopmans, Raymond T C M; Vernooij-Dassen, Myrra J F J

    2012-01-01

    BACKGROUND: The effectiveness and efficiency of nursing-home dementia care are suboptimal: there are high rates of neuropsychiatric symptoms among the residents and work-related stress among the staff. Dementia-care mapping is a person-centred care method that may alleviate both the resident and the

  3. Autonomous Satellite Command and Control through the World Wide Web: Phase 3

    Science.gov (United States)

    Cantwell, Brian; Twiggs, Robert

    1998-01-01

    management, modeling and fault management capabilities that integrate the space and ground segments of the space system hardware; (5) Implement a beacon monitoring test; (6) Implement an experimental blackboard controller for space system management; (7) Further define typical ground station developments required for Internet-based remote control and for full system automation of the PI-to-spacecraft link. Each of those goals is examined in the next section. Significant sections of this report were also published as a conference paper.

  4. EFSA and ECDC (European Food Safety Authority and European Centre for Disease Prevention and Control), 2015. The European Union Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and Food-borne Outbreaks in 2013

    DEFF Research Database (Denmark)

    Helwigh, Birgitte

    This report of the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of the zoonoses monitoring activities carried out in 2013 in 32 European countries (28 Member States and four non-Member States). Campylobacter iosis was the most comm...... chain of tuberculosis due to Mycobacterium bovis, Brucella, Trichinella, Echinococcus, Toxoplasma , rabies, Coxiella burnetii (Q fever), West Nile Virus and tularaemia....

  5. Satellite RNAs and Satellite Viruses.

    Science.gov (United States)

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA.

  6. Innovative power management, attitude determination and control tile for CubeSat standard NanoSatellites

    Science.gov (United States)

    Ali, Anwar; Mughal, M. Rizwan; Ali, Haider; Reyneri, Leonardo

    2014-03-01

    Electric power supply (EPS) and attitude determination and control subsystem (ADCS) are the most essential elements of any aerospace mission. Efficient EPS and precise ADCS are the core of any spacecraft mission. So keeping in mind their importance, they have been integrated and developed on a single tile called CubePMT module. Modular power management tiles (PMTs) are already available in the market but they are less efficient, heavier in weight, consume more power and contain less number of subsystems. Commercial of the shelf (COTS) components have been used for CubePMT implementation which are low cost and easily available from the market. CubePMT is developed on the design approach of AraMiS architecture: a project developed at Politecnico di Torino that provides low cost and higher performance space missions with dimensions larger than CubeSats. The feature of AraMiS design approach is its modularity. These modules can be reused for multiple missions which helps in significant reduction of the overall budget, development and testing time. One has just to reassemble the required subsystems to achieve the targeted specific mission.

  7. Potential of Natural Ventilation in Shopping Centres

    DEFF Research Database (Denmark)

    Diederichsen, Alice; Friis, Kristina; Brohus, Henrik

    2008-01-01

    The indoor environmental quality (IEQ) is a fundamental requirement for a well performing shopping centre. This paper contains a pilot study of the potential of using hybrid ventilation (a combination of automatically controlled natural and mechanical ventilation - respectively NV and MV) in shop......The indoor environmental quality (IEQ) is a fundamental requirement for a well performing shopping centre. This paper contains a pilot study of the potential of using hybrid ventilation (a combination of automatically controlled natural and mechanical ventilation - respectively NV and MV......) in shopping centres with focus on both the achieved IEQ and energy consumptions for air movement. By thermal building simulations it is found that there exists an interesting potential for hybrid ventilation of shopping centres, which can lead to great savings in the electrical energy consumptions...

  8. Group support psychotherapy for depression treatment in people with HIV/AIDS in northern Uganda: a single-centre randomised controlled trial.

    Science.gov (United States)

    Nakimuli-Mpungu, Etheldreda; Wamala, Kizito; Okello, James; Alderman, Stephen; Odokonyero, Raymond; Mojtabai, Ramin; Mills, Edward J; Kanters, Steve; Nachega, Jean B; Musisi, Seggane

    2015-05-01

    Group support psychotherapy (GSP) is a culturally sensitive intervention that aims to treat depression by enhancing social support, teaching coping skills, and income-generating skills. We compared GSP with group HIV education (GHE) for treatment of depression in people with HIV in Uganda. In this open-label randomised controlled trial, we included men and women with HIV, aged 19 years or older, who met the Mini International Neuropsychiatric Interview criteria for major depression from an urban HIV care centre in Kitgum district, northern Uganda. Participants were randomly assigned to receive eight weekly sessions of either GSP or GHE. Randomisation was achieved by urn (men and women separately picked a paper containing the intervention allocation from a basket; ratio 1:1), and the intervention sessions were given to gender-specific groups. Participants were followed up immediately after the intervention and 6 months after the end of treatment. The primary outcomes were change in depressive symptom scores (measured with the Self-Reporting Questionnaire) and in function scores (measured with a locally developed method), analysed by intention to treat using cluster-adjusted t tests and permutation tests. This trial is registered with The Pan African Clinical Trials Registry, number PACTR201402000742370. Between Jan 6, and Jan 20, 2014, we assessed 150 individuals, of whom 109 were randomly assigned to receive eight weekly sessions of either GSP (n=57) or GHE (n=52). Change in mean depression scores immediately after intervention did not differ between groups (mean difference -0·19, 95% CI -1·77 to 1·39, p=0·78). Mean function scores did not differ between groups either (0·24, -0·41 to 0·88; p=0·41). At 6 months after end of treatment, participants in the GSP group had lower mean depression scores than did those in the GHE group (-2·50, -3·98 to 1·02, p value=0·005), and higher function scores (0·74, -0·17 to 1·65, p=0·09) than did participants in the

  9. Supporting Development of Satellite's Guidance Navigation and Control Software: A Product Line Approach

    Science.gov (United States)

    McComas, David; Stark, Michael; Leake, Stephen; White, Michael; Morisio, Maurizio; Travassos, Guilherme H.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    The NASA Goddard Space Flight Center Flight Software Branch (FSB) is developing a Guidance, Navigation, and Control (GNC) Flight Software (FSW) product line. The demand for increasingly more complex flight software in less time while maintaining the same level of quality has motivated us to look for better FSW development strategies. The GNC FSW product line has been planned to address the core GNC FSW functionality very similar on many recent low/near Earth missions in the last ten years. Unfortunately these missions have not accomplished significant drops in development cost since a systematic approach towards reuse has not been adopted. In addition, new demands are continually being placed upon the FSW which means the FSB must become more adept at providing GNC FSW functionality's core so it can accommodate additional requirements. These domain features together with engineering concepts are influencing the specification, description and evaluation of FSW product line. Domain engineering is the foundation for emerging product line software development approaches. A product line is 'A family of products designed to take advantage of their common aspects and predicted variabilities'. In our product line approach, domain engineering includes the engineering activities needed to produce reusable artifacts for a domain. Application engineering refers to developing an application in the domain starting from reusable artifacts. The focus of this paper is regarding the software process, lessons learned and on how the GNC FSW product line manages variability. Existing domain engineering approaches do not enforce any specific notation for domain analysis or commonality and variability analysis. Usually, natural language text is the preferred tool. The advantage is the flexibility and adapt ability of natural language. However, one has to be ready to accept also its well-known drawbacks, such as ambiguity, inconsistency, and contradictions. While most domain analysis

  10. Controls on slow-moving landslides revealed by satellite and airborne InSAR

    Science.gov (United States)

    Handwerger, Alexander L.; Fielding, Eric J.

    2017-04-01

    Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. To better constrain the mechanisms that control landslide motion, we use recent SAR data collected by Copernicus Sentinel-1A/B, NASA UAVSAR, JAXA ALOS-2, and DLR TerraSAR-X to quantify the time-dependent kinematics of over 200 slow-moving landslides in the Central and Northern California Coast Ranges. These landslides are ideally suited for InSAR investigations due to their size (up to 5 km in length and 0.5 km in width), persistent downslope motion with low velocities (m/yr), and sparse vegetation. We quantify the seasonal and multi-year changes in velocity driven by changes in precipitation and find that landslide velocity varies over both timescales. Over seasonal timescales, each landslide displays a period of acceleration that occurs within weeks of the onset of seasonal rainfall suggesting that motion is governed by precipitation-induced changes in pore-water pressure. We also examine the effects of multi-year climate variations (i.e., recent historic California drought and the possible wet period that began in late 2016) on the activity of landslides. We find that the drought has led to a decrease in annual displacement over the past several years and predict that a resurgence in annual displacement will occur with an increase in annual rainfall. Lastly, we use UAVSAR data acquired at 4 different look directions to quantify 3D surface displacement of multiple landslides and invert for their subsurface geometry (i.e. basal slip surface) using recently developed 3D mass conservation techniques. The application of NASA's UAVSAR data represents a major advance from previous InSAR studies on landslides in this region and provides one of the first 3D dataset that contains

  11. Supporting Development of Satellite's Guidance Navigation and Control Software: A Product Line Approach

    Science.gov (United States)

    McComas, David; Stark, Michael; Leake, Stephen; White, Michael; Morisio, Maurizio; Travassos, Guilherme H.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    The NASA Goddard Space Flight Center Flight Software Branch (FSB) is developing a Guidance, Navigation, and Control (GNC) Flight Software (FSW) product line. The demand for increasingly more complex flight software in less time while maintaining the same level of quality has motivated us to look for better FSW development strategies. The GNC FSW product line has been planned to address the core GNC FSW functionality very similar on many recent low/near Earth missions in the last ten years. Unfortunately these missions have not accomplished significant drops in development cost since a systematic approach towards reuse has not been adopted. In addition, new demands are continually being placed upon the FSW which means the FSB must become more adept at providing GNC FSW functionality's core so it can accommodate additional requirements. These domain features together with engineering concepts are influencing the specification, description and evaluation of FSW product line. Domain engineering is the foundation for emerging product line software development approaches. A product line is 'A family of products designed to take advantage of their common aspects and predicted variabilities'. In our product line approach, domain engineering includes the engineering activities needed to produce reusable artifacts for a domain. Application engineering refers to developing an application in the domain starting from reusable artifacts. The focus of this paper is regarding the software process, lessons learned and on how the GNC FSW product line manages variability. Existing domain engineering approaches do not enforce any specific notation for domain analysis or commonality and variability analysis. Usually, natural language text is the preferred tool. The advantage is the flexibility and adapt ability of natural language. However, one has to be ready to accept also its well-known drawbacks, such as ambiguity, inconsistency, and contradictions. While most domain analysis

  12. The Use of a Satellite Communications System for Command and Control of the National Aeronautics and Space Administration Surrogate Unmanned Aerial System Research Aircraft

    Science.gov (United States)

    Howell, Charles T.; Jones, Frank; Hutchinson, Brian; Joyce, Claude; Nelson, Skip; Melum, Mike

    2017-01-01

    The NASA Langley Research Center has transformed a Cirrus Design SR22 general aviation (GA) aircraft into an Unmanned Aerial Systems (UAS) Surrogate research aircraft which has served for several years as a platform for unmanned systems research and development. The aircraft is manned with a Safety Pilot and a Research Systems Operator (RSO) that allows for flight operations almost any-where in the national airspace system (NAS) without the need for a Federal Aviation Administration (FAA) Certificate of Authorization (COA). The UAS Surrogate can be remotely controlled from a modular, transportable ground control station (GCS) like a true UAS. Ground control of the aircraft is accomplished by the use of data links that allow the two-way passage of the required data to control the aircraft and provide the GCS with situational awareness. The original UAS Surrogate data-link system was composed of redundant very high frequency (VHF) data radio modems with a maximum range of approximately 40 nautical miles. A new requirement was developed to extend this range beyond visual range (BVR). This new requirement led to the development of a satellite communications system that provided the means to command and control the UAS Surrogate at ranges beyond the limits of the VHF data links. The system makes use of the Globalstar low earth orbit (LEO) satellite communications system. This paper will provide details of the development, implementation, and flight testing of the satellite data communications system on the UAS Surrogate research aircraft.

  13. Solid State Digital Propulsion "Cluster Thrusters" For Small Satellites Using High Performance Electrically Controlled Extinguishable Solid Propellants (ECESP)

    Science.gov (United States)

    Sawka, Wayne N.; Katzakian, Arthur; Grix, Charles

    2005-01-01

    Electrically controlled extinguishable solid propellants (ESCSP) are capable of multiple ignitions, extinguishments and throttle control by the application of electrical power. Both core and end burning no moving parts ECESP grains/motors to three inches in diameter have now been tested. Ongoing research has led to a newer family of even higher performance ECESP providing up to 10% higher performance, manufacturing ease, and significantly higher electrical conduction. The high conductivity was not found to be desirable for larger motors; however it is ideal for downward scaling to micro and pico- propulsion applications with a web thickness of less than 0.125 inch/ diameter. As a solid solution propellant, this ECESP is molecularly uniform, having no granular structure. Because of this homogeneity and workable viscosity it can be directly cast into thin layers or vacuum cast into complex geometries. Both coaxial and grain stacks have been demonstrated. Combining individual propellant coaxial grains and/or grain stacks together form three-dimensional arrays yield modular cluster thrusters. Adoption of fabless manufacturing methods and standards from the electronics industry will provide custom, highly reproducible micro-propulsion arrays and clusters at low costs. These stack and cluster thruster designs provide a small footprint saving spacecraft surface area for solar panels and/or experiments. The simplicity of these thrusters will enable their broad use on micro-pico satellites for primary propulsion, ACS and formation flying applications. Larger spacecraft may find uses for ECESP thrusters on extended booms, on-orbit refueling, pneumatic actuators, and gas generators.

  14. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  15. Probing orographic controls in the Himalayas during the monsoon using satellite imagery

    Directory of Open Access Journals (Sweden)

    A. P. Barros

    2004-01-01

    Full Text Available The linkages between the space-time variability of observed clouds, rainfall, large-circulation patterns and topography in northern India and the Himalayas were investigated using remote sensing data. The research purpose was to test the hypothesis that cloudiness patterns are dynamic tracers of rainstorms, and therefore their temporal and spatial evolution can be used as a proxy of the spatial and temporal organization of precipitation and precipitation processes in the Himalayan range during the monsoon. The results suggest that the space-time distribution of precipitation, the spatial variability of the diurnal cycle of convective activity, and the terrain (landform and altitudinal gradients are intertwined at spatial scales ranging from the order of a few kms (1–5km up to the continental-scale. Furthermore, this relationship is equally strong in the time domain with respect to the onset and intra-seasonal variability of the monsoon. Infrared and microwave imagery of cloud fields were analyzed to characterize the spatial and temporal evolution of mesoscale convective weather systems and short-lived convection in Northern India, the Himalayan range, and in the Tibetan Plateau during three monsoon seasons (1999, 2000 and 2001. The life cycle of convective systems suggests landform and orographic controls consistent with a convergence zone constrained to the valley of the Ganges and the Himalayan range, bounded in the west by the Aravalli range and the Garhwal mountains and in the East by the Khasi Hills and the Bay of Bengal, which we call the Northern India Convergence Zone (NICZ. The NICZ exhibits strong night-time activity along the south-facing slopes of the Himalayan range, which is characterized by the development of short-lived convection (1–3h aligned with protruding ridges between 1:00 and 3:00 AM. The intra-annual and inter-annual variability of convective activity in the NICZ were assessed with respect to large-scale synoptic

  16. Lifestyle modifications to prevent and control hypertension. 4. Recommendations on physical exercise training. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada.

    Science.gov (United States)

    Cléroux, J; Feldman, R D; Petrella, R J

    1999-05-04

    of moderate rhythmic exercise of the lower limbs, such as brisk walking or cycling, 3 or 4 times per week to reduce blood pressure, (2) Exercise should be prescribed as an adjunctive therapy for people who require pharmacologic therapy for hypertension, especially those who are not receiving beta-blockers. (3) People who do not have hypertension should participate in regular exercise as it will decrease blood pressure and reduce the risk of coronary artery disease, although there is no direct evidence that it will prevent hypertension. These recommendations agree with those of the World Hypertension League, the American College of Sports Medicine, the report of the US Surgeon General on physical activity and health, and the US National Institutes of Health Consensus Development Panel on Physical Activity and Cardiovascular Health. These guidelines have not been clinically tested. The Canadian Hypertension Society, the Canadian Coalition for High Blood Pressure Prevention and Control, the Laboratory Centre for Disease Control at Health Canada, and the Heart and Stroke Foundation of Canada.

  17. Satellite theory

    Science.gov (United States)

    Kozai, Y.

    1981-04-01

    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  18. CHINA LAUNCHES 2 SCIENTIFIC EXPERIMENT SATELLITES

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China placed 2 scientific experiment satellites into preset orbits atop a LM-4B launch vehicle on Sept. 9, 2004. A LM-4B blasted off at 7:14 am from Taiyuan Satellite Launch Center in Shanxi Province. Sources from the Xi'an Satellite Monitor and Control Center said that one satellite,

  19. Target setting in intensive insulin management is associated with metabolic control: the Hvidoere Childhood Diabetes Study Group Centre Differences Study 2005

    DEFF Research Database (Denmark)

    Swift, P.G.F.; Skinner, T.C.; de Beaufort, C.E.

    2010-01-01

    (r = 0.20) and adolescent (r = 0.21) reports of their perceived ideal HbA1c and their actual HbA1c result (p happy with and their actual HbA1c result. There were significant...... differences between centres on parent and adolescent reports of ideal and happy with HbA1c (8.1 17.4;p

  20. DFH-3 Satellite Platform

    Institute of Scientific and Technical Information of China (English)

    RenShufang

    2005-01-01

    The DFH-3 satellite platform is designed and developed by China Academy of Space Technology (CAST). It is a medium capability communications satellite platform. The platform adopts threeaxis attitude stabilization control system, having solar array output power of 1.7kW by the end of its design lifetime of 8 years. Its mass is 2100kg with payload capacity of 220kg.

  1. 21 June 2010 - TUBITAK Vice President A. Adli signing the guest book with CERN Director-General R. Heuer, visiting the ATLAS control room at Point 1 with Former Collaboration Spokesperson P. Jenni and CMS Control Centre, building 354, with Collaboration Spokesperson G. Tonelli. Throughout accompanied by Adviser J. Ellis.

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    21 June 2010 - TUBITAK Vice President A. Adli signing the guest book with CERN Director-General R. Heuer, visiting the ATLAS control room at Point 1 with Former Collaboration Spokesperson P. Jenni and CMS Control Centre, building 354, with Collaboration Spokesperson G. Tonelli. Throughout accompanied by Adviser J. Ellis.

  2. Academic Drug Discovery Centres

    DEFF Research Database (Denmark)

    Kirkegaard, Henriette Schultz; Valentin, Finn

    2014-01-01

    Academic drug discovery centres (ADDCs) are seen as one of the solutions to fill the innovation gap in early drug discovery, which has proven challenging for previous organisational models. Prior studies of ADDCs have identified the need to analyse them from the angle of their economic...... their performance....

  3. CENTRE IN NIGERIA.

    African Journals Online (AJOL)

    PATTERN OF NEURO-OPHTHALMIC DISORDERS IN A TERTIARY EYE. CENTRE IN NIGERIA. A E Omoti , M J M ... movement or light was determined. The external ... assessed by color desaturation tests and visual field assessment by the ...

  4. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  5. The GSO Data Centre

    CERN Document Server

    Paletou, F; Génot, V; Rouillard, A; Petit, P; Palacios, A; Caux, E; Wakelam, V

    2015-01-01

    Hereafter we describe the activities of the $Grand \\, Sud-Ouest$ Data Centre operated for INSU/CNRS by the OMP-IRAP and the Universit\\'e Paul Sabatier (Toulouse), in a collaboration with the OASU-LAB (Bordeaux) and OREME-LUPM (Montpellier).

  6. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  7. ATLAS Visitors Centre

    CERN Multimedia

    claudia Marcelloni

    2009-01-01

    ATLAS Visitors Centre has opened its shiny new doors to the public. Officially launched on Monday February 23rd, 2009, the permanent exhibition at Point 1 was conceived as a tour resource for ATLAS guides, and as a way to preserve the public’s opportunity to get a close-up look at the experiment in action when the cavern is sealed.

  8. Powering the Future Data Centre

    DEFF Research Database (Denmark)

    Zhang, Zhe

    2010-01-01

    The extended run Uninterruptible Power Supply system (UPSs) which powered by fuel cells and supercapcitors, is a promising solution for future data centre to obtain environmentfriendly energy efficient and cost effective. There are many challenges in power electronic interface circuits, because...... of the traditional cascaded converters, a novel hybrid bidirectional dcdc converter which combines a fuel cell with a boost-type half bridge converter, and supercaps with a DAB converter, is proposed. With phase-shift plus duty cycle, all the switches realize ZVS in a wide range of load variation. Duty cycle control...

  9. The impact of a disease management program (COACH on the attainment of better cardiovascular risk control in dyslipidaemic patients at primary care centres (The DISSEMINATE Study: a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Selvaraj Francis Jude

    2012-10-01

    Full Text Available Abstract Background To evaluate the efficacy of Counselling and Advisory Care for Health (COACH programme in managing dyslipidaemia among primary care practices in Malaysia. This open-label, parallel, randomised controlled trial compared the COACH programme delivered by primary care physicians alone (PCP arm and primary care physicians assisted by nurse educators (PCP-NE arm. Methods This was a multi-centre, open label, randomised trial of a disease management programme (COACH among dyslipidaemic patients in 21 Malaysia primary care practices. The participating centres enrolled 297 treatment naïve subjects who had the primary diagnosis of dyslipidaemia; 149 were randomised to the COACH programme delivered by primary care physicians assisted by nurse educators (PCP-NE and 148 to care provided by primary care physicians (PCP alone. The primary efficacy endpoint was the mean percentage change from baseline LDL-C at week 24 between the 2 study arms. Secondary endpoints included mean percentage change from baseline of lipid profile (TC, LDL-C, HDL-C, TG, TC: HDL ratio, Framingham Cardiovascular Health Risk Score and absolute risk change from baseline in blood pressure parameters at week 24. The study also assessed the sustainability of programme efficacy at week 36. Results Both study arms demonstrated improvement in LDL-C from baseline. The least squares (LS mean change from baseline LDL-C were −30.09% and −27.54% for PCP-NE and PCP respectively. The difference in mean change between groups was 2.55% (p=0.288, with a greater change seen in the PCP-NE arm. Similar observations were made between the study groups in relation to total cholesterol change at week 24. Significant difference in percentage change from baseline of HDL-C were observed between the PCP-NE and PCP groups, 3.01%, 95% CI 0.12-5.90, p=0.041, at week 24. There was no significant difference in lipid outcomes between 2 study groups at week 36 (12 weeks after the programme had

  10. Control system of satellite TV antenna of strapdown shipborne%捷联式船载卫星电视天线控制系统

    Institute of Scientific and Technical Information of China (English)

    秦爱民; 闫英敏; 闫建生; 靳英卫

    2011-01-01

    With the progress of the society and the improvements of information technology, people need more TV programmes through satellite networks while moving. A strapdown shipborne satellite TV antenna control system based on DSP is introduced. The architectures of the software and hardware of the control system are given, and the functions of different components are described in detail. The stabilization and the automatic tracking are realized in this antenna control system for satellite television.%随着社会的进步和信息化技术的提高,人们对移动中通过卫星网路接收卫星电视节目的需求越来越大.介绍了基于DSP的捷联式船载卫星电视天线控制系统,阐述了系统软硬件的结构及各部分的功能,实现了船载卫星电视天线的稳定与自动跟踪卫星.

  11. MicroRNA-133 Controls Brown Adipose Determination in Skeletal Muscle Satellite Cells by Targeting Prdm16

    DEFF Research Database (Denmark)

    Yin, Hang; Pasut, Alessandra; Soleimani, Vahab D

    2013-01-01

    (satellite cells) have long been considered uniformly determined toward the myogenic lineage. Here, we report that adult satellite cells give rise to brown adipocytes and that microRNA-133 regulates the choice between myogenic and brown adipose determination by targeting the 3'UTR of Prdm16. Antagonism...... are downregulated in mice exposed to cold, resulting in de novo generation of satellite cell-derived brown adipocytes. Therefore, microRNA-133 represents an important therapeutic target for the treatment of obesity....... of microRNA-133 during muscle regeneration increases uncoupled respiration, glucose uptake, and thermogenesis in local treated muscle and augments whole-body energy expenditure, improves glucose tolerance, and impedes the development of diet-induced obesity. Finally, we demonstrate that miR-133 levels...

  12. Self Assessment and Student-Centred Learning

    Science.gov (United States)

    McDonald, Betty

    2012-01-01

    This paper seeks to show how self assessment facilitates student-centred learning (SCL) and fills a gap in the literature. Two groups of students were selected from a single class in a tertiary educational institution. The control group of 25 was selected randomly by the tossing of an unbiased coin (heads = control group). They were trained in the…

  13. The group-based social skills training SOSTA-FRA in children and adolescents with high functioning autism spectrum disorder - study protocol of the randomised, multi-centre controlled SOSTA - net trial

    Directory of Open Access Journals (Sweden)

    Freitag Christine M

    2013-01-01

    Full Text Available Abstract Background Group-based social skills training (SST has repeatedly been recommended as treatment of choice in high-functioning autism spectrum disorder (HFASD. To date, no sufficiently powered randomised controlled trial has been performed to establish efficacy and safety of SST in children and adolescents with HFASD. In this randomised, multi-centre, controlled trial with 220 children and adolescents with HFASD it is hypothesized, that add-on group-based SST using the 12 weeks manualised SOSTA–FRA program will result in improved social responsiveness (measured by the parent rated social responsiveness scale, SRS compared to treatment as usual (TAU. It is further expected, that parent and self reported anxiety and depressive symptoms will decline and pro-social behaviour will increase in the treatment group. A neurophysiological study in the Frankfurt HFASD subgroup will be performed pre- and post treatment to assess changes in neural function induced by SST versus TAU. Methods/design The SOSTA – net trial is designed as a prospective, randomised, multi-centre, controlled trial with two parallel groups. The primary outcome is change in SRS score directly after the intervention and at 3 months follow-up. Several secondary outcome measures are also obtained. The target sample consists of 220 individuals with ASD, included at the six study centres. Discussion This study is currently one of the largest trials on SST in children and adolescents with HFASD worldwide. Compared to recent randomised controlled studies, our study shows several advantages with regard to in- and exclusion criteria, study methods, and the therapeutic approach chosen, which can be easily implemented in non-university-based clinical settings. Trial registration ISRCTN94863788 – SOSTA – net: Group-based social skills training in children and adolescents with high functioning autism spectrum disorder.

  14. The group-based social skills training SOSTA-FRA in children and adolescents with high functioning autism spectrum disorder--study protocol of the randomised, multi-centre controlled SOSTA--net trial.

    Science.gov (United States)

    Freitag, Christine M; Cholemkery, Hannah; Elsuni, Leyla; Kroeger, Anne K; Bender, Stephan; Kunz, Cornelia Ursula; Kieser, Meinhard

    2013-01-07

    Group-based social skills training (SST) has repeatedly been recommended as treatment of choice in high-functioning autism spectrum disorder (HFASD). To date, no sufficiently powered randomised controlled trial has been performed to establish efficacy and safety of SST in children and adolescents with HFASD. In this randomised, multi-centre, controlled trial with 220 children and adolescents with HFASD it is hypothesized, that add-on group-based SST using the 12 weeks manualised SOSTA-FRA program will result in improved social responsiveness (measured by the parent rated social responsiveness scale, SRS) compared to treatment as usual (TAU). It is further expected, that parent and self reported anxiety and depressive symptoms will decline and pro-social behaviour will increase in the treatment group. A neurophysiological study in the Frankfurt HFASD subgroup will be performed pre- and post treatment to assess changes in neural function induced by SST versus TAU. The SOSTA - net trial is designed as a prospective, randomised, multi-centre, controlled trial with two parallel groups. The primary outcome is change in SRS score directly after the intervention and at 3 months follow-up. Several secondary outcome measures are also obtained. The target sample consists of 220 individuals with ASD, included at the six study centres. This study is currently one of the largest trials on SST in children and adolescents with HFASD worldwide. Compared to recent randomised controlled studies, our study shows several advantages with regard to in- and exclusion criteria, study methods, and the therapeutic approach chosen, which can be easily implemented in non-university-based clinical settings. ISRCTN94863788--SOSTA--net: Group-based social skills training in children and adolescents with high functioning autism spectrum disorder.

  15. Analysis and Optimization of SSO Satellite Thermal Control Subsystem%太阳同步轨道卫星热控分系统分析及优化

    Institute of Scientific and Technical Information of China (English)

    吴文瑞; 黄海

    2012-01-01

    定义地心日照轨道坐标系,并在此坐标系下简化卫星与地球相对位置的复杂计算,以及卫星轨道外热流分析过程中相关角度的计算,使轨道外热流的分析仿真更加快速、简洁。以正六棱柱形卫星为例,建立热网络模型,对其表面在一圈轨道内所受的轨道外热流进行仿真,并结合仿真结果计算进出地影区时卫星内部的温度。在此基础上,建立以热控分系统多层隔热材料质量最小化为目标的优化问题;在满足高低温工况卫星内部温度在-10~+35℃范围内的约束下,对多层隔热材料厚度和散热窗大小进行了优化。%An Earth-original sunshine orbital coordinate system is defined.In this coordinate system,the complex computation of the relative position between satellite and the Earth can be bypassed,so the calculations of related angles in satellite orbital heat flux analysis become simple,and the satellite thermal analysis can be quickly accomplished.A thermal network model of a six-prism shaped satellite is built.The orbital heat flux on the surfaces of the satellite is simulated and applied in the model to obtain the satellite internal temperature at the start and end of eclipse period.Based on the model,an optimization of thermal control system to minimize multi-layer insulations mass in limitation of the satellite internal temperatures between-10℃ and +35℃ in both cold and hot cases is established.Multi-layer insulations thickness and radiator window area are optimized.

  16. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2013-01-01

    Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

  17. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  18. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    as slum clearence and urban renewal. To a certain extent parallels are drawn to international experiences, especially where these are of such a nature that they can be assumed transferred to Danish connctions. Conclusively, the strategies are discussed in the light of the turn of Danish urban planning...... urban planning and design strategieswhich have been practised in most of the larger Danish towns: pedestrian streets, shopping centres, preservation of historic features, waterfronts, concentration of offices, conference and sports facilities, improvement og traffic and transport conditions as well...... during late years, where increased internationalisation is in focus and where it seems as if the social dimension of the town centre planning is slipping out of the hands of the urban planners....

  19. Elderly Care Centre

    Science.gov (United States)

    Wagiman, Aliani; Haja Bava Mohidin, Hazrina; Ismail, Alice Sabrina

    2016-02-01

    The demand for elderly centre has increased tremendously abreast with the world demographic change as the number of senior citizens rose in the 21st century. This has become one of the most crucial problems of today's era. As the world progress into modernity, more and more people are occupied with daily work causing the senior citizens to lose the care that they actually need. This paper seeks to elucidate the best possible design of an elderly care centre with new approach in order to provide the best service for them by analysing their needs and suitable activities that could elevate their quality of life. All these findings will then be incorporated into design solutions so as to enhance the living environment for the elderly especially in Malaysian context.

  20. Historical centres: changing definitions

    Directory of Open Access Journals (Sweden)

    Roberta Lazzarotti

    2014-02-01

    Full Text Available Since the end of the Second World War, the architectural and planning culture has been showing a fluctuating attention to the theme of historical centres and their enhancement. First of all this uneven progress explains the difficulty to reach a homogeneous definition and this is still lacking. During a long phase of this period, the historical parts of the town were considered as objects to be preserved in an integral way, as urban monuments. This is mostly due to the high symbolic value of these settlements, that represent fundamental landmarks. Identity building and empowerment of local communities are indispensable conditions for any development programme, especially in the case of centres or other historic environments at risk of abandonment. The progressive evolution of this concept brings awareness of the impossibility of separating – either in analytical or in planning terms ­ historical centres from their urban and territorial contexts, which are linked by mutual, deep relationships. This article attempts to retrace the steps signaled by the publication of international documents and conventions, from the Charter of Gubbio (1960 to the Charter of Krakow and the European Landscape Convention (2000; they obviously represent particular points of view, not exhaustive of the richness of the positions in the debate, but extremely significant in terms of diffusion and consensus.

  1. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  2. Cibola flight experiment satellite

    Science.gov (United States)

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart

    2004-11-01

    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  3. Satellite (Natural)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  4. A web-based intervention (RESTORE) to support self-management of cancer-related fatigue following primary cancer treatment: a multi-centre proof of concept randomised controlled trial

    OpenAIRE

    Foster, Claire; Grimmett, Chloe; May, Christine M.; Ewings, Sean; Myall, Michelle; Hulme, Claire; Smith, Peter W.; Powers, Cassandra; Calman, Lynn; Armes, Jo; Breckons, Matthew; Corner, Jessica; Fenlon, Deborah; Batehup, Lynn; Lennan, Elaine

    2015-01-01

    Purpose: Cancer-related fatigue (CRF) is a frequent and distressing symptom experienced after cancer treatment. RESTORE is the first web-based resource designed to enhance self-efficacy to manage CRF following curative-intent treatment. The aim of this study is to test the proof of concept and inform the design of an effectiveness trial.\\ud \\ud Methods: A multi-centre parallel-group two-armed (1:1) exploratory randomised controlled trial (RCT) with qualitative process evaluation was employed ...

  5. Tele-centres in Ghana

    DEFF Research Database (Denmark)

    Falch, Morten

    2004-01-01

    Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access.......Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access....

  6. Effects of the daily consumption of protein enriched bread and protein enriched drinking yoghurt on the total protein intake in older adults in a rehabilitation centre: a single blind randomised controlled trial.

    Science.gov (United States)

    van Til, A J; Naumann, E; Cox-Claessens, I J H M; Kremer, S; Boelsma, E; de van der Schueren, M A E

    2015-05-01

    To investigate the effects of protein enriched bread and drinking yoghurt, substituting regular products, on the total protein intake and the distribution of protein intake over the day in older adults. A single blind randomised controlled trial. Rehabilitation centre. Older adults (≥ 55 years) admitted to a rehabilitation centre after hospital discharge (n=34). Participants received a high protein diet (protein enriched bread and protein enriched drinking yoghurt; n=17) or a regular diet (regular bread and regular drinking yoghurt; n=17) for three consecutive weeks. Total protein intake and protein intake per meal, measured twice weekly over a three weeks period (six measurements per participant). Compared with controls, patients who received the protein enriched products had a significantly higher protein intake (115.3 g/d vs 72.5 g/d, P<0.001; 1.6 g/kg/d vs 1.1 g/kg/d, P<0.001). The intervention group consumed quantities over the recommended level (25-30 g/meal) during each of the three meals (32.5 g, 30.0 g, 34.8 g/meal), where the control group consumed quantities below the recommended level during breakfast (17.7 g) and lunch (18.4 g). The use of protein enriched products, replacing regular products, results in a significant increased daily protein intake in older adults. In addition, the daily consumption of protein enriched products improves protein distribution over the day.

  7. Spanish Earth Observation Satellite System

    Science.gov (United States)

    Borges, A.; Cerezo, F.; Fernandez, M.; Lomba, J.; Lopez, M.; Moreno, J.; Neira, A.; Quintana, C.; Torres, J.; Trigo, R.; Urena, J.; Vega, E.; Vez, E.

    2010-12-01

    The Spanish Ministry of Industry, Tourism and Trade (MITyC) and the Ministry of Defense (MoD) signed an agreement in 2007 for the development of a "Spanish Earth Observation Satellite System" based, in first instance, on two satellites: a high resolution optical satellite, called SEOSAT/Ingenio, and a radar satellite based on SAR technology, called SEOSAR/Paz. SEOSAT/Ingenio is managed by MITyC through the Centre for the Development of Industrial Technology (CDTI), with technical and contractual support from the European Space Agency (ESA). HISDESA T together with the Spanish Instituto Nacional de Técnica Aeroespacial (INTA, National Institute for Aerospace Technology) will be responsible for the in-orbit operation and the commercial operation of both satellites, and for the technical management of SEOSAR/Paz on behalf of the MoD. In both cases EADS CASA Espacio (ECE) is the prime contractor leading the industrial consortia. The ground segment development will be assigned to a Spanish consortium. This system is the most important contribution of Spain to the European Programme Global Monitoring for Environment and Security, GMES. This paper presents the Spanish Earth Observation Satellite System focusing on SEOSA T/Ingenio Programme and with special emphasis in the potential contribution to the ESA Third Party Missions Programme and to the Global Monitoring for Environment and Security initiative (GMES) Data Access.

  8. Effectiveness of person-centred care after acute coronary syndrome in relation to educational level: Subgroup analysis of a two-armed randomised controlled trial.

    Science.gov (United States)

    Fors, Andreas; Gyllensten, Hanna; Swedberg, Karl; Ekman, Inger

    2016-10-15

    The aim of this study was to evaluate the effects of person-centred care (PCC) after acute coronary syndrome (ACS) in relation to educational level of participants. 199 Patients <75years with ACS were randomised to PCC plus usual care or usual care alone and followed for 6months from hospital to outpatient care and primary care. For the PCC group, patients and health care professionals co-created a PCC health plan reflecting both perspectives, which induced a continued collaboration in person-centred teams at each health care level. A composite score of changes that included general self-efficacy assessment, return to work or previous activity level, re-hospitalisation or death was used as outcome measure. In the group of patients without postsecondary education (n=90) the composite score showed a significant improvement in favour of the PCC intervention (n=40) vs. usual care (n=50) at six months (35.0%, n=14 vs. 16.0%, n=8; odds ratio (OR)=2.8, 95% confidence interval (CI): 1.0-7.7, P=0.041). In patients with postsecondary education (n=109), a non-significant difference in favour of the PCC intervention (n=54) vs. usual care (n=55) was observed in the composite score (13.0%, n=7 vs 3.6%, n=2; OR=3.9, 95% CI: 0.8-19.9, P=0.097). A PCC approach, which stresses the necessity of a patient-health care professional partnership, is beneficial in patients with low education after an ACS event. Because these patients have been identified as a vulnerable group in cardiac rehabilitation, we suggest that PCC can be integrated into conventional cardiac rehabilitation programmes to improve both equity in uptake and health outcomes. Swedish registry, Researchweb.org, ID NR 65 791. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  9. Dynamical friction and scratches of orbiting satellite galaxies on host systems

    Science.gov (United States)

    Ogiya, Go; Burkert, Andreas

    2016-04-01

    We study the dynamical response of extended systems, hosts, to smaller systems, satellites, orbiting around the hosts using extremely high-resolution N-body simulations with up to one billion particles. This situation corresponds to minor mergers which are ubiquitous in the scenario of hierarchical structure formation in the universe. According to Chandrasekhar, satellites create density wakes along the orbit and the wakes cause a deceleration force on satellites, i.e. dynamical friction. This study proposes an analytical model to predict the dynamical response of hosts as reflected in their density distribution and finds not only traditional wakes but also mirror images of over- and underdensities centred on the host. Our controlled N-body simulations with high resolutions verify the predictions of the analytical model. We apply our analytical model to the expected dynamical response of nearby interacting galaxy pairs, the Milky Way-Large Magellanic Cloud system and the M31-M33 system.

  10. Geostationary satellites collocation

    CERN Document Server

    Li, Hengnian

    2014-01-01

    Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

  11. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    After many years of urban growth Danish downtowns are facing some important choices. Shall the stake one-sidedly be on the town centres as driving forces for growth and 'city marketing', or do they still have a role to play in a broader socio-economic context? In the paper we look back on eight...... as slum clearence and urban renewal. To a certain extent parallels are drawn to international experiences, especially where these are of such a nature that they can be assumed transferred to Danish connctions. Conclusively, the strategies are discussed in the light of the turn of Danish urban planning...

  12. Attitude Control and Orbital Dynamics Challenges of Removing the First 3-Axis Stabilized Tracking and Data Relay Satellite from the Geosynchronous ARC

    Science.gov (United States)

    Benet, Charles A.; Hofman, Henry; Williams, Thomas E.; Olney, Dave; Zaleski, Ronald

    2011-01-01

    Launched on April 4, 1983 onboard STS 6 (Space Shuttle Challenger), the First Tracking and Data Relay Satellite (TDRS 1) was retired above the Geosynchronous Orbit (GEO) on June 27, 2010 after having provided real-time communications with a variety of low-orbiting spacecraft over a 26-year period. To meet NASA requirements limiting orbital debris 1, a team of experts was assembled to conduct an End-Of-Mission (EOM) procedure to raise the satellite 350 km above the GEO orbit. Following the orbit raising via conventional station change maneuvers, the team was confronted with having to deplete the remaining propellant and passivate all energy storage or generation sources. To accomplish these tasks within the time window, communications (telemetry and control links), electrical power, propulsion, and thermal constraints, a spacecraft originally designed as a three-axis stabilized satellite was turned into a spinner. This paper (a companion paper to Innovative Approach Enabled the Retirement of TDRS 1, paper # 1699, IEEE 2011 Aerospace Conference, March 5-12, 2011 sup 2) focuses on the challenges of maintaining an acceptable spinning dynamics, while repetitively firing thrusters. Also addressed are the effects of thruster firings on the orbit characteristics and how they were mitigated by a careful scheduling of the fuel depletion operations. Periodic thruster firings for spin rate adjustment, nutation damping, and precession of the momentum vector were also required in order to maintain effective communications with the satellite. All operations were thoroughly rehearsed and supported by simulations thus lending a high level of confidence in meeting the NASA EOM goals.

  13. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  14. OMV With Satellite

    Science.gov (United States)

    1986-01-01

    This 1986 artist's concept shows the Orbital Maneuvering Vehicle (OMV) towing a satellite. As envisioned by Marshall Space Flight Center plarners, the OMV would be a remotely-controlled free-flying space tug which would place, rendezvous, dock, and retrieve orbital payloads.

  15. Learning Styles of Independent Learning Centre Users

    Directory of Open Access Journals (Sweden)

    Tarik Uzun

    2014-09-01

    Full Text Available Learning style research has been a significant field within language teaching and learning. There have been very few attempts, however, to seek possible links between independent learning and learning style preferences. This paper aims to identify the learning styles of students who use the Independent Learning Centre (ILC on a regular basis at a state university in Turkey (n=102. The findings of the learning style analysis revealed that, contrary to expectations, most of the regular users of the centre were synoptic learners, which implies that these learners might not necessarily have conscious control over their own learning processes. An in-depth analysis of learning styles and recommendations to improve the services offered in the centre are also included in the paper.

  16. Stavanger Squash Centre, Norway

    Energy Technology Data Exchange (ETDEWEB)

    Rostvik, H. [Sunlab/ABB, Stavanger (Norway)

    1999-07-01

    Although Stavanger is the technological and financial oil-capital of Norway, the Stavanger Squash Centre was until recently the largest solar building in Norway, with 120 m{sup 2} of collectors. The active, building-integrated, solar air collector in the 45 {sup o} roof facing 15 {sup o} east of due south, has now been delivering solar-heated hot water for the showers for 15 years. The solar system consists of several standard products put together in a new way. Monitoring has shown that the system produced 18,000 kWh/m{sup 2} a (150 kWh/m{sub coll} {sup 2}a). If operated as planned, it could have had a solar contribution of 45,000 kWh/a) (375 kWh/m{sub coll} {sup 2}a), resulting in a 19% solar fraction of total demand. (author)

  17. Management of pancreatic injuries during damage control surgery: an observational outcomes analysis of 79 patients treated at an academic Level 1 trauma centre.

    Science.gov (United States)

    Krige, J E J; Kotze, U K; Setshedi, M; Nicol, A J; Navsaria, P H

    2017-06-01

    This study evaluated factors influencing mortality in a large cohort of patients who sustained pancreatic injuries and underwent DCS. A prospective database of consecutive patients with pancreatic injuries treated at a Level 1 academic trauma centre was reviewed to identify those who underwent DCS between 1995 and 2014. Seventy-nine (71 men, median age: 26 years, range 16-73 years, gunshot wounds = 62, blunt = 14, stab = 3) patients with pancreatic injuries (35 proximal, 44 distal) had DCS. Fifty-nine (74.7 %) patients had AAST grade 3, 4 or 5 pancreatic injuries. The 79 patients had a total of 327 associated injuries (mean: 3 per patient, range 0-6) and underwent a total of 187 (range 1-7) operations. Vascular injuries (60/327, 18.3 %) occurred in 41 patients. Twenty-seven (34.2 %) patients died without having a second operation. The remaining 52 patients had two or more laparotomies (range 2-7). Overall 28 (35 %) patients underwent a pancreatic resection either during DCS (n = 18) or subsequently as a secondary procedure (n = 10) including a Whipple (n = 6) when stable. Overall 43 (54.4 %) patients died. Mortality was related to associated vascular injuries overall (p vascular and total number of associated organs injured (p vascular injuries overall, major visceral venous injuries and the combination of vascular plus the total number of associated organs injured.

  18. Advanced communications technology satellite high burst rate link evaluation terminal power control and rain fade software test plan, version 1.0

    Science.gov (United States)

    Reinhart, Richard C.

    1993-01-01

    The Power Control and Rain Fade Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Power Control and Rain Fade Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Power Control and Rain Fade Software automatically controls the LET uplink power to compensate for signal fades. Besides power augmentation, the C&PM Software system is also responsible for instrument control during HBR-LET experiments, control of the Intermediate Frequency Switch Matrix on board the ACTS to yield a desired path through the spacecraft payload, and data display. The Power Control and Rain Fade Software User's Guide, Version 1.0 outlines the commands and procedures to install and operate the Power Control and Rain Fade Software. The Power Control and Rain Fade Software Maintenance Manual, Version 1.0 is a programmer's guide to the Power Control and Rain Fade Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Power Control and Rain Fade Software, computer algorithms, format representations, and computer hardware configuration. The Power Control and Rain Fade Test Plan provides a step-by-step procedure to verify the operation of the software using a predetermined signal fade event. The Test Plan also provides a means to demonstrate the capability of the software.

  19. Protocol for the ProFHER (PROximal Fracture of the Humerus: Evaluation by Randomisation trial: a pragmatic multi-centre randomised controlled trial of surgical versus non-surgical treatment for proximal fracture of the humerus in adults

    Directory of Open Access Journals (Sweden)

    Maffulli Nicola

    2009-11-01

    Full Text Available Abstract Background Proximal humeral fractures, which occur mainly in older adults, account for approximately 4 to 5% of all fractures. Approximately 40% of these fractures are displaced fractures involving the surgical neck. Management of this group of fractures is often challenging and the outcome is frequently unsatisfactory. In particular it is not clear whether surgery gives better outcomes than non-surgical management. Currently there is much variation in the use of surgery and a lack of good quality evidence to inform this decision. Methods/Design We aim to undertake a pragmatic UK-based multi-centre randomised controlled trial evaluating the effectiveness and cost-effectiveness of surgical versus standard non-surgical treatment for adults with an acute closed displaced fracture of the proximal humerus with involvement of the surgical neck. The choice of surgical intervention is left to the surgeon, who must use techniques that they are fully experienced with. This will avoid 'learning curve' problems. We will promote good standards of non-surgical care, similarly insisting on care-provider competence, and emphasize the need for comparable provision of rehabilitation for both groups of patients. We aim to recruit 250 patients from a minimum of 18 NHS trauma centres throughout the UK. These patients will be followed-up for 2 years. The primary outcome is the Oxford Shoulder Score, which will be collected via questionnaires completed by the trial participants at 6, 12 and 24 months. This is a 12-item condition-specific questionnaire providing a total score based on the person's subjective assessment of pain and activities of daily living impairment. We will also collect data for other outcomes, including general health measures and complications, and for an economic evaluation. Additionally, we plan a systematic collection of reasons for non-inclusion of eligible patients who were not recruited into the trial, and their baseline

  20. Effectiveness of two psychological interventions for pain management, emotional regulation and promotion of quality of life among adult Portuguese men with haemophilia (PSY-HaEMOPEQ): study protocol for a single-centre prospective randomised controlled trial

    Science.gov (United States)

    Pinto, Patrícia Ribeiro; Paredes, Ana Cristina; Costa, Patrício; Carvalho, Manuela; Lopes, Manuela; Fernandes, Susana; Almeida, Armando

    2017-01-01

    Introduction Haemophilia is a bleeding disorder associated with significant pain, emotional distress, quality of life (QoL) impairment and considerable healthcare costs. Psychosocial health and effective pain management are considered essential end points for optimal haemophilia care, but there is a significant gap in evidence-based treatments targeting these outcomes in people with haemophilia (PWH). Psychological interventions are cost-effective in promoting emotional well-being, QoL and pain control, although these have been scarcely used in haemophilia field. This investigation aims to evaluate the effectiveness of two psychological interventions for pain management, emotional regulation and promotion of QoL in PWH. Methods and analysis This is a single-centre parallel randomised controlled trial conducted at a European Haemophilia Comprehensive Care Centre in Portugal, with five assessment points: baseline (T0), postintervention (T1), 3 (T2), 6 (T3) and 12 (T4) months follow-up. Eligible adult males, with moderate or severe haemophilia A or B will be randomised to experimental (EG) or control (CG) group. Intervention is either cognitive-behavioural therapy (EG1) or hypnosis (EG2), both consisting of four weekly sessions following standardised scripts delivered by trained psychologists. Randomisation will be computer generated, allocation concealment will be guaranteed and outcome assessors will be blind to EG/CG allocation. Main outcomes are pain and haemophilia-related QoL and secondary outcomes include clinical (clotting factor replacement consumption, joint bleeding episodes, analgesic intake) and psychological (pain coping strategies, anxiety, depression, illness perceptions) variables, functional assessment of the joints, inflammatory biomarkers (cytokines, high-sensitivity C reactive protein) and white blood cell count. Ethics and dissemination This study was approved by the competent authorities and all procedures will comply with international ethical

  1. Spiritual Healing in the Treatment of Rheumatoid Arthritis: An Exploratory Single Centre, Parallel-Group, Double-Blind, Three-Arm, Randomised, Sham-Controlled Trial

    DEFF Research Database (Denmark)

    Bliddal, H.; Christensen, Robin Daniel Kjersgaard; Hojgaard, L.

    2014-01-01

    Our objective was to investigate the efficacy of "energy/spiritual healing" in rheumatoid arthritis (RA). Eligible patients were women with RA on stable medication. The design was a randomised, blinded, sham-controlled trial; the third group included an external unblinded control of the natural c...

  2. Call Centre- Computer Telephone Integration

    Directory of Open Access Journals (Sweden)

    Dražen Kovačević

    2012-10-01

    Full Text Available Call centre largely came into being as a result of consumerneeds converging with enabling technology- and by the companiesrecognising the revenue opportunities generated by meetingthose needs thereby increasing customer satisfaction. Regardlessof the specific application or activity of a Call centre, customersatisfaction with the interaction is critical to the revenuegenerated or protected by the Call centre. Physical(v, Call centreset up is a place that includes computer, telephone and supervisorstation. Call centre can be available 24 hours a day - whenthe customer wants to make a purchase, needs information, orsimply wishes to register a complaint.

  3. Should "Teacher Centred Teaching" Replace "Student Centred Learning"?

    Science.gov (United States)

    Bailey, Patrick D.

    2008-01-01

    Mission statements of most HEIs across the UK support "student centred learning". In this paper, it is suggested that "teacher centred teaching" should also have a major role to play, improving the quality of the learning experience in higher education. Students are extremely diverse in their skills, weaknesses, and learning…

  4. Integration of Earth Observation Satellite Data and Real Time 137Cs Measurements in the Greek Marine Environment to GIS for Advances in Radiological Remote Control

    Science.gov (United States)

    Mavrokefalou, Georgia; Florou, Heleny; Sykioti, Olga; Parcharidis, Issaak

    2016-08-01

    In the present study an innovative tool is explored in terms of the radiological remote control. The levels of radionuclides in the marine environment, especially the soluble ones, are associated with other physical parameters. For this purpose, sea parameters such as sea surface temperature and ocean colour issued from satellite and field measurements have been utilized, in order to investigate potential relations with 137Cs activity concentrations. Such potential relations are expected to lead to an innovative tool based on remote sensing data and in situ 137Cs measurements for the remote radioactivity detection of the Greek marine ecosystem both for routine control and emergency recordings. Here, the first findings on the spatial correlations of 137Cs measurements with MODIS L3 ocean data in the Aegean Sea are presented, whereas temporal correlations of 137Cs measurements with MODIS L2 ocean and POSEIDON buoy data in Souda Bay area (Crete island) are also shown.

  5. Optimizing Data Centre Energy and Environmental Costs

    Science.gov (United States)

    Aikema, David Hendrik

    Data centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10--50% potential savings in typical cases, and local renewable energy use could be increased by 10--80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use

  6. Theophylline as an add-on to thrombolytic therapy in acute ischaemic stroke (TEA-Stroke): A randomized, double-blinded, placebo-controlled, two-centre phase II study

    DEFF Research Database (Denmark)

    Modrau, Boris; Hjort, Niels; Østergaard, Leif;

    2016-01-01

    the collateral supply in acute ischaemic brain tissue and thus facilitate reperfusion despite proximal vessel occlusion. The primary study objective is to evaluate whether theophylline is safe and efficient in acute ischaemic stroke patients as an add-on to thrombolytic therapy.MethodsThe TEA-Stroke Trial...... is a two-centre, proof of concept phase II clinical study with a randomized, double-blinded, placebo-controlled design. One hundred and twenty patients with acute ischaemic stroke and significant perfusion?diffusion mismatch, as determined by magnetic resonance imaging, are randomized 1:1 to either...... theophylline or placebo as an add-on to standard thrombolytic therapy.Study outcomeThe dual primary outcome measures include penumbra salvage (penumbral tissue not developing into infarcted tissue) and clinical improvement at the 24-h follow-up.DiscussionResults from studies of theophylline in stroke animal...

  7. Small Satellite Formations for Distributed Surveillance: System Design and Optimal Control Considerations (Formations de petits satellites pour une surveillance distribuee: Considerations relatives la conception de systeme et a l’optimisation de commandes)

    Science.gov (United States)

    2009-04-01

    will be placed in orbit in order to provide higher temporal resolution in observation data and to achieve higher availability. Especially in emergency...l’observation terrestre , le potentiel d’innovation représenté par l’emploi d’un réseau distribué de satellites est devenu évident dès la réalisation...à ce jour, d’un tandem de deux satellites. A partir de 2008, des constellations de satellites seront placées en orbite pour obtenir une meilleure

  8. Lifestyle modifications to prevent and control hypertension. 4. Recommendations on physical exercise training. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada

    National Research Council Canada - National Science Library

    Cléroux, J; Feldman, R D; Petrella, R J

    1999-01-01

    To provide updated, evidence-based recommendations for health care professionals concerning the effects of regular physical activity on the prevention and control of hypertension in otherwise healthy adults...

  9. Exploring the association between chorangioma and infantile haemangioma in singleton and multiple pregnancies: a case-control study in a Swedish tertiary centre.

    Science.gov (United States)

    Sirotkina, Meeli; Douroudis, Konstantinos; Wahlgren, Carl-Fredrik; Westgren, Magnus; Papadogiannakis, Nikos

    2017-09-03

    Placenta or placental chorangioma could be the origin site of infantile haemangioma since they share various histochemical and genetic characteristics with placental vascular tissue. The aim of the current study was to investigate the association between chorangiomas and infantile haemangiomas in singleton and multiple pregnancies. An informative questionnaire enquiring about the presence or not of infantile haemangioma and including illustrative photos of haemangioma was sent to 469 (153 cases with chorangioma and 316 controls) mothers of 323 singleton (104 cases and 219 controls) and 146 multiple (49 cases and 97 controls) liveborn neonates registered in Sweden. Overall, 310 mothers (66.1%) from 216 singleton and 94 multiple pregnancies (96 cases and 214 controls) provided feedback and their consent to participate in the current case-control study. The incidence of infantile haemangioma showed no statistically significant differences between cases and controls (18.8% vs 18.2%) or between singleton and multiple pregnancies (18.9% vs 17.0%). The frequency of pre-eclampsia was significantly higher in cases with chorangioma compared with controls (41.7% vs 24.3%, OR=2.22, 95% CI 1.33 to 3.71, p=0.0022) and in singleton compared with multiple pregnancies (33.3% vs 21.3%, OR=1.85, 95% CI 1.04 to 3.26, p=0.034), whereas there were no significant differences in the incidence of infantile haemangioma in neonates of mothers with or without pre-eclampsia or in neonates of mothers with multiple compared with singleton pregnancies. There was no association between placental chorangiomas and infantile haemangiomas. Multiple pregnancies or pre-eclampsia were not significantly related to higher incidence of infantile haemangioma. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Study Protocol. IDUS – Instrumental delivery & ultrasound. A multi-centre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery

    Science.gov (United States)

    2012-01-01

    Background Instrumental deliveries are commonly performed in the United Kingdom and Ireland, with rates of 12 – 17% in most centres. Knowing the exact position of the fetal head is a pre-requisite for safe instrumental delivery. Traditionally, diagnosis of the fetal head position is made on transvaginal digital examination by delineating the suture lines of the fetal skull and the fontanelles. However, the accuracy of transvaginal digital examination can be unreliable and varies between 20% and 75%. Failure to identify the correct fetal head position increases the likelihood of failed instrumental delivery with the additional morbidity of sequential use of instruments or second stage caesarean section. The use of ultrasound in determining the position of the fetal head has been explored but is not part of routine clinical practice. Methods/Design A multi-centre randomised controlled trial is proposed. The study will take place in two large maternity units in Ireland with a combined annual birth rate of 13,500 deliveries. It will involve 450 nulliparous women undergoing instrumental delivery after 37 weeks gestation. The main outcome measure will be incorrect diagnosis of the fetal head position. A study involving 450 women will have 80% power to detect a 10% difference in the incidence of inaccurate diagnosis of the fetal head position with two-sided 5% alpha. Discussion It is both important and timely to evaluate the use of ultrasound to diagnose the fetal head position prior to instrumental delivery before routine use can be advocated. The overall aim is to reduce the incidence of incorrect diagnosis of the fetal head position prior to instrumental delivery and improve the safety of instrumental deliveries. Trial registration Current Controlled Trials ISRCTN72230496 PMID:22970933

  11. Study Protocol. IDUS – Instrumental delivery & ultrasound. A multi-centre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery

    Directory of Open Access Journals (Sweden)

    Murphy Deirdre J

    2012-09-01

    Full Text Available Abstract Background Instrumental deliveries are commonly performed in the United Kingdom and Ireland, with rates of 12 – 17% in most centres. Knowing the exact position of the fetal head is a pre-requisite for safe instrumental delivery. Traditionally, diagnosis of the fetal head position is made on transvaginal digital examination by delineating the suture lines of the fetal skull and the fontanelles. However, the accuracy of transvaginal digital examination can be unreliable and varies between 20% and 75%. Failure to identify the correct fetal head position increases the likelihood of failed instrumental delivery with the additional morbidity of sequential use of instruments or second stage caesarean section. The use of ultrasound in determining the position of the fetal head has been explored but is not part of routine clinical practice. Methods/Design A multi-centre randomised controlled trial is proposed. The study will take place in two large maternity units in Ireland with a combined annual birth rate of 13,500 deliveries. It will involve 450 nulliparous women undergoing instrumental delivery after 37 weeks gestation. The main outcome measure will be incorrect diagnosis of the fetal head position. A study involving 450 women will have 80% power to detect a 10% difference in the incidence of inaccurate diagnosis of the fetal head position with two-sided 5% alpha. Discussion It is both important and timely to evaluate the use of ultrasound to diagnose the fetal head position prior to instrumental delivery before routine use can be advocated. The overall aim is to reduce the incidence of incorrect diagnosis of the fetal head position prior to instrumental delivery and improve the safety of instrumental deliveries. Trial registration Current Controlled Trials ISRCTN72230496

  12. Study Protocol. IDUS -- Instrumental delivery & ultrasound. A multi-centre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery

    LENUS (Irish Health Repository)

    Murphy, Deirdre J

    2012-09-13

    AbstractBackgroundInstrumental deliveries are commonly performed in the United Kingdom and Ireland, with rates of 12 – 17% in most centres. Knowing the exact position of the fetal head is a pre-requisite for safe instrumental delivery. Traditionally, diagnosis of the fetal head position is made on transvaginal digital examination by delineating the suture lines of the fetal skull and the fontanelles. However, the accuracy of transvaginal digital examination can be unreliable and varies between 20% and 75%. Failure to identify the correct fetal head position increases the likelihood of failed instrumental delivery with the additional morbidity of sequential use of instruments or second stage caesarean section. The use of ultrasound in determining the position of the fetal head has been explored but is not part of routine clinical practice.Methods\\/DesignA multi-centre randomised controlled trial is proposed. The study will take place in two large maternity units in Ireland with a combined annual birth rate of 13,500 deliveries. It will involve 450 nulliparous women undergoing instrumental delivery after 37 weeks gestation. The main outcome measure will be incorrect diagnosis of the fetal head position. A study involving 450 women will have 80% power to detect a 10% difference in the incidence of inaccurate diagnosis of the fetal head position with two-sided 5% alpha.DiscussionIt is both important and timely to evaluate the use of ultrasound to diagnose the fetal head position prior to instrumental delivery before routine use can be advocated. The overall aim is to reduce the incidence of incorrect diagnosis of the fetal head position prior to instrumental delivery and improve the safety of instrumental deliveries.Trial registrationCurrent Controlled Trials ISRCTN72230496

  13. Fault Diagnosis Based on RO-NUIO/LMI for Flexible Satellite Attitude Control Systems during Orbit Control%基于RO-NUIO/LMI的挠性卫星轨控期间姿控系统故障诊断

    Institute of Scientific and Technical Information of China (English)

    侯倩; 程月华; 姜斌; 陆宁云

    2011-01-01

    During satellite orbit maneuver, the orbit control force causes disturbing torque and affects attitude of a satellite if the control force does not pass through the mass center of the satellite. In this paper, a set of reduced order nonlinear unknown input observers (RO-NUIO) are designed to detect and isolate faults. During the design process, the system is divided into three sub-systems to ensure that some states are not affected by the disturbance. Observers are designed by using the observable information. Meanwhile, some parameters of the observers can be obtained by using the LMI approach to reduce effects of nonlinear part on observers. The existence conditions of the observer proposed in this paper only depend on the inherent feature of the system. Combination of the reduced order idea and the LMI method make the structure of observers easy to be applied to nonlinear satellite attitude control systems. Numerical simulation is carried out to demonstrate the efficiency of the proposed fault diagnosis scheme for satellite attitude control systems.%卫星轨控期间,由于推力偏心,会产生较大的干扰力矩,直接影响卫星姿态.针对轨道控制期间的挠性卫星姿态控制系统,设计了干扰解耦的降阶非线性未知输入观测器(RO-NUIO),用于故障检测与故障隔离.在设计过程中,首先通过坐标变换,使得不可观的状态及部分可观状态不受干扰影响,然后针对不可观的子系统利用可观状态的信息设计观测器,观测器中的部分参数利用LMI方法获得,可以弱化非线性部分对观测器的影响.所设计观测器的存在条件仅依赖于系统本身特性,无需在线验证.观测器采用降阶设计,同时借助LMI思想,结构简单,适合于非线性卫星姿态控制系统.仿真结果验证了降阶非线性未知输入观测器实现卫星姿态控制故障诊断的可行性与有效性.

  14. Management based on exhaled nitric oxide levels adjusted for atopy reduces asthma exacerbations in children: A dual centre randomized controlled trial.

    Science.gov (United States)

    Petsky, Helen L; Li, Albert M; Au, Chun T; Kynaston, Jennifer A; Turner, Catherine; Chang, Anne B

    2015-06-01

    While several randomized control trials (RCTs) have evaluated the use of fractional exhaled nitric oxide (FeNO) to improve asthma outcomes, none used FeNO cut-offs adjusted for atopy, a determinant of FeNO levels. In a dual center RCT, we assessed whether a treatment strategy based on FeNO levels, adjusted for atopy, reduces asthma exacerbations compared with the symptoms-based management (controls). Children with asthma from hospital clinics of two hospitals were randomly allocated to receive an a-priori determined treatment hierarchy based on symptoms or FeNO levels. There was a 2-week run-in period and they were then reviewed 10 times over 12-months. The primary outcome was the number of children with exacerbations over 12-months. Sixty-three children were randomized (FeNO = 31, controls = 32); 55 (86%) completed the study. Although we did achieve our planned sample size, significantly fewer children in the FeNO group (6 of 27) had an asthma exacerbation compared to controls (15 of 28), P = 0.021; number to treat for benefit = 4 (95% CI 3-24). There was no difference between groups for any secondary outcomes (quality of life, symptoms, FEV1 ). The final daily inhaled corticosteroids (ICS) dose was significantly (P = 0.037) higher in the FeNO group (median 400 µg, IQR 250-600) compared to the controls (200, IQR100-400). Taking atopy into account when using FeNO to tailor asthma medications is likely beneficial in reducing the number of children with severe exacerbations at the expense of increased ICS use. However, the strategy is unlikely beneficial for improving asthma control. A larger study is required to confirm or refute our findings. © 2014 Wiley Periodicals, Inc.

  15. Information exchange between control centres - theory and putting into practice of Tase.2; Informationsaustausch zwischen Leitstellen - Tase.2 in Theorie und Praxis

    Energy Technology Data Exchange (ETDEWEB)

    Kaib, W. [repas AEG Automation Systems GmbH, Bremen (Germany)

    1998-06-29

    After passing of the standards of the Inter-Control Center Protocol ICCP (Tase.2), first applications of this connection between control centers have been developed in Europe. The universal approach of Tase.2 allows the adaptation to most different tasks. This paper gives an overview and presents three applications of Tase.2. (orig.) [Deutsch] Nach der Verabschiedung der Normen ueber das Protokoll zum Informationsaustausch zwischen Leitstellen Tase.2/ICCP in Europa entstehen die ersten Anwendungen in Form von Leitstellenkopplungen. Der universelle Ansatz von Tase.2 ermoeglicht die Anpassung an unterschiedlichste Anforderungen. Der Verfasser gibt eine Uebersicht ueber Tase.2 und stellt drei Anwendungen vor. (orig.)

  16. KNMI Data Centre: Easy access for all

    Science.gov (United States)

    van de Vegte, John; Som de Cerff, Wim; Plieger, Maarten; de Vreede, Ernst; Sluiter, Raymond; Willem Noteboom, Jan; van der Neut, Ian; Verhoef, Hans; van Versendaal, Robert; van Binnendijk, Martin; Kalle, Henk; Knopper, Arthur; Spit, Jasper; Mastop, Joeri; Klos, Olaf; Calis, Gijs; Ha, Siu-Siu; van Moosel, Wim; Klein Ikkink, Henk-Jan; Tosun, Tuncay

    2013-04-01

    KNMI is the Dutch institute for weather, climate research and seismology. It disseminates weather information to the public at large, the government, aviation and the shipping industry in the interest of safety, the economy and a sustainable environment. To gain insight into long-term developments KNMI conducts research on climate change. Making the knowledge, data and information on hand at KNMI accessible is one core activity. A huge part of the KNMI information is from numerical models, insitu sensor networks and remote sensing satellites. This digital collection is mostly internal only available and is a collection of non searchable , non standardized file formats, lacking documentation and has no references to scientific publications. With the KNMI Data Centre (KDC) project these issues are tackled. In the project a user driven development approach with SCRUM was chosen to get maximum user involvement in a relative short development timeframe. Building on open standards and proven open source technology (which includes in-house developed software like ADAGUC WMS and Portal) resulted in a first release in December 2012 This presentation will focus on the aspects of KDC relating to its technical challenges, the development strategy and the initial usage results of the data centre.

  17. Topical tea tree oil effective in canine localised pruritic dermatitis--a multi-centre randomised double-blind controlled clinical trial in the veterinary practice.

    Science.gov (United States)

    Reichling, J; Fitzi, J; Hellmann, K; Wegener, T; Bucher, S; Saller, R

    2004-10-01

    Tea tree oil, a volatile oil, is well known for its broad antibacterial and antifungal activity. A standardised and stabilised 10% tea tree oil cream was tested against a commercial skin care cream (control cream) in the management of canine localised acute and chronic dermatitis. Fifty-seven dogs with clinical manifestations of mostly pruritic skin lesions or alterations, skin fold pyodermas and other forms of dermatitis, corroborated by predominantly positive fungal and bacterial skin isolates, were enrolled by seven practising veterinarians and randomly allocated to two study groups (28:29) and were treated twice daily with a blinded topical preparation. After 10 days of treatment, success rates of 71% for the tea tree oil cream and 41% for the control cream (over-all efficacy documented by the veterinary investigator) differed significantly (p = 0.04), favouring tea tree oil cream treatment. Accordingly on day 10, the tea tree oil cream caused significantly faster relief than the control cream (p = 0.04) for two common clinical dermatitis signs, pruritus (occurring in 84 % of dogs) and alopecia. Only one adverse event was reported in the tea tree oil group (suspected not to be causally related to the study drug) and none in the control cream group. The tested herbal cream appears to be a fast-acting safe alternative to conventional therapy for symptomatic treatment of canine localised dermatitis with pruritus.

  18. CMCC Data Distribution Centre

    Science.gov (United States)

    Aloisio, Giovanni; Fiore, Sandro; Negro, A.

    2010-05-01

    The CMCC Data Distribution Centre (DDC) is the primary entry point (web gateway) to the CMCC. It is a Data Grid Portal providing a ubiquitous and pervasive way to ease data publishing, climate metadata search, datasets discovery, metadata annotation, data access, data aggregation, sub-setting, etc. The grid portal security model includes the use of HTTPS protocol for secure communication with the client (based on X509v3 certificates that must be loaded into the browser) and secure cookies to establish and maintain user sessions. The CMCC DDC is now in a pre-production phase and it is currently used only by internal users (CMCC researchers and climate scientists). The most important component already available in the CMCC DDC is the Search Engine which allows users to perform, through web interfaces, distributed search and discovery activities by introducing one or more of the following search criteria: horizontal extent (which can be specified by interacting with a geographic map), vertical extent, temporal extent, keywords, topics, creation date, etc. By means of this page the user submits the first step of the query process on the metadata DB, then, she can choose one or more datasets retrieving and displaying the complete XML metadata description (from the browser). This way, the second step of the query process is carried out by accessing to a specific XML document of the metadata DB. Finally, through the web interface, the user can access to and download (partially or totally) the data stored on the storage device accessing to OPeNDAP servers and to other available grid storage interfaces. Requests concerning datasets stored in deep storage will be served asynchronously.

  19. The digital mapping of satellite images under no ground control and the distribution of landform, blue ice and meteorites in the Grove Mountains, Antarctica

    Institute of Scientific and Technical Information of China (English)

    孙家抦; 霍东民; 周军其; 孙朝辉

    2001-01-01

    The colorful satellite image maps with the scale of 1∶100 000 were made by processing the parameters-on-satellite under the condition of no data of field surveying. The purpose is to ensure the smooth performance of the choice of expedition route, navigation and research task before the Chinese National Antarctic Research Expedition (CHINARE) first made researches on the Grove Mountains. Moreover, on the basis of the visual interpretation of the satellite image, we preliminarily analyze and discuss the relief and landform, blue ice and meteorite distribution characteristics in the Grove Mountains. Key words Grove Mountains, parameters-on-satellite, satellite image, digital mapping, blue ice, meteorites distribution.

  20. The Effects of a Locally Developed mHealth Intervention on Delivery and Postnatal Care Utilization; A Prospective Controlled Evaluation among Health Centres in Ethiopia.

    Science.gov (United States)

    Shiferaw, Solomon; Spigt, Mark; Tekie, Michael; Abdullah, Muna; Fantahun, Mesganaw; Dinant, Geert-Jan

    2016-01-01

    Although there are studies showing that mobile phone solutions can improve health service delivery outcomes in the developed world, there is little empirical evidence that demonstrates the impact of mHealth interventions on key maternal health outcomes in low income settings. A non-randomized controlled study was conducted in the Amhara region, Ethiopia in 10 health facilities (5 intervention, 5 control) together serving around 250,000 people. Health workers in the intervention group received an android phone (3 phones per facility) loaded with an application that sends reminders for scheduled visits during antenatal care (ANC), delivery and postnatal care (PNC), and educational messages on dangers signs and common complaints during pregnancy. The intervention was developed at Addis Ababa University in Ethiopia. Primary outcomes were the percentage of women who had at least 4 ANC visits, institutional delivery and PNC visits at the health center after 12 months of implementation of the intervention. Overall 933 and 1037 women were included in the cross-sectional surveys at baseline and at follow-up respectively. In addition, the medical records of 1224 women who had at least one antenatal care visit were followed in the longitudinal study. Women who had their ANC visit in the intervention health centers were significantly more likely to deliver their baby in the same health center compared to the control group (43.1% versus 28.4%; Adjusted Odds Ratio (AOR): 1.98 (95%CI 1.53-2.55)). A significantly higher percentage of women who had ANC in the intervention group had PNC in the same health center compared to the control health centers (41.2% versus 21.1%: AOR: 2.77 (95%CI 2.12-3.61)). Our findings demonstrated that a locally customized mHealth application during ANC can significantly improve delivery and postnatal care service utilization possibly through positively influencing the behavior of health workers and their clients.

  1. The Effects of a Locally Developed mHealth Intervention on Delivery and Postnatal Care Utilization; A Prospective Controlled Evaluation among Health Centres in Ethiopia.

    Directory of Open Access Journals (Sweden)

    Solomon Shiferaw

    Full Text Available Although there are studies showing that mobile phone solutions can improve health service delivery outcomes in the developed world, there is little empirical evidence that demonstrates the impact of mHealth interventions on key maternal health outcomes in low income settings.A non-randomized controlled study was conducted in the Amhara region, Ethiopia in 10 health facilities (5 intervention, 5 control together serving around 250,000 people. Health workers in the intervention group received an android phone (3 phones per facility loaded with an application that sends reminders for scheduled visits during antenatal care (ANC, delivery and postnatal care (PNC, and educational messages on dangers signs and common complaints during pregnancy. The intervention was developed at Addis Ababa University in Ethiopia. Primary outcomes were the percentage of women who had at least 4 ANC visits, institutional delivery and PNC visits at the health center after 12 months of implementation of the intervention.Overall 933 and 1037 women were included in the cross-sectional surveys at baseline and at follow-up respectively. In addition, the medical records of 1224 women who had at least one antenatal care visit were followed in the longitudinal study. Women who had their ANC visit in the intervention health centers were significantly more likely to deliver their baby in the same health center compared to the control group (43.1% versus 28.4%; Adjusted Odds Ratio (AOR: 1.98 (95%CI 1.53-2.55. A significantly higher percentage of women who had ANC in the intervention group had PNC in the same health center compared to the control health centers (41.2% versus 21.1%: AOR: 2.77 (95%CI 2.12-3.61.Our findings demonstrated that a locally customized mHealth application during ANC can significantly improve delivery and postnatal care service utilization possibly through positively influencing the behavior of health workers and their clients.

  2. Assessing the risk of attack in the management of asthma: a review and proposal for revision of the current control-centred paradigm.

    Science.gov (United States)

    Blakey, John D; Woolnough, Kerry; Fellows, Jodie; Walker, Samantha; Thomas, Mike; Pavord, Ian D

    2013-09-01

    Asthma guidelines focus on day-to-day control of symptoms. However, asthma attacks remain common. They continue to cause mortality and considerable morbidity, and are a major financial burden to the UK National Health Service (NHS) and the wider community. Asthma attacks have chronic consequences, being associated with loss of lung function and significant psychological morbidity. In this article we argue that addressing daily symptom control is only one aspect of asthma treatment, and that there should be a more explicit focus on reducing the risk of asthma attacks. Management of future risk by general practitioners is already central to other conditions such as ischaemic heart disease and chronic renal impairment. We therefore propose a revised approach that separately considers the related domains of daily control and future risk of asthma attack. We believe this approach will have advantages over the current 'stepwise' approach to asthma management. It should encourage individualised treatment, including non-pharmacological measures, and thus may lead to more efficacious and less harmful management strategies. We speculate that this type of approach has the potential to reduce morbidity and healthcare costs related to asthma attacks.

  3. Dominance of ENSO-Like Variability in Controlling Tropical Ocean Surface Energy Fluxes in the Satellite Era

    Science.gov (United States)

    Robertson, F. R.; Miller, T. L.; Bosilovich, M. G.

    2008-01-01

    Ocean surface turbulent and radiative fluxes are critical links in the climate system since they mediate energy exchange between the two fluid systems (ocean and atmosphere) whose combined heat transport determines the basic character of Earth's climate. Moreover, interannual to decadal climate variability depends crucially on the nature of these exchange processes. For example, addressing the question of the degree to which the global hydrologic cycle is changing depends on our ability to observe and model these fluxes accurately. In this work we investigate the interannual to decadal variation of fluxes over the global tropics, especially the tropical oceans. Recent versions of satellite-derived fresh water flux estimates as well as some reanalyses (e.g. products from Remote Sensing Systems, the Woods Hole Oceanographic Institute, and Global Precipitation Climatology Project) suggest that increases in evaporation and precipitation over the past 20 years exceed those expected on the basis of climate model projected responses to greenhouse gas forcing. At the same time, it is well known that E1 Nino / Southern Oscillation behavior in the Pacific exhibits significant variability at scales longer than interannual. We examine here the degree to which surface fluxes attending these interannual to decadal fluctuations are related to ENSO. We examine consistency between these data sets and explore relationships between SST variations, flux changes and modulation of tropical Walker and Hadley circulations.

  4. Evaluating the effectiveness and cost-effectiveness of Dementia Care Mapping™ to enable person-centred care for people with dementia and their carers (DCM-EPIC) in care homes: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Surr, Claire A; Walwyn, Rebecca E A; Lilley-Kelly, Amanda; Cicero, Robert; Meads, David; Ballard, Clive; Burton, Kayleigh; Chenoweth, Lynn; Corbett, Anne; Creese, Byron; Downs, Murna; Farrin, Amanda J; Fossey, Jane; Garrod, Lucy; Graham, Elizabeth H; Griffiths, Alys; Holloway, Ivana; Jones, Sharon; Malik, Baber; Siddiqi, Najma; Robinson, Louise; Stokes, Graham; Wallace, Daphne

    2016-06-24

    Up to 90 % of people living with dementia in care homes experience one or more behaviours that staff may describe as challenging to support (BSC). Of these agitation is the most common and difficult to manage. The presence of agitation is associated with fewer visits from relatives, poorer quality of life and social isolation. It is recommended that agitation is treated through psychosocial interventions. Dementia Care Mapping™ (DCM™) is an established, widely used observational tool and practice development cycle, for ensuring a systematic approach to providing person-centred care. There is a body of practice-based literature and experience to suggests that DCM™ is potentially effective but limited robust evidence for its effectiveness, and no examination of its cost-effectiveness, as a UK health care intervention. Therefore, a definitive randomised controlled trial (RCT) of DCM™ in the UK is urgently needed. A pragmatic, multi-centre, cluster-randomised controlled trial of Dementia Care Mapping (DCM™) plus Usual Care (UC) versus UC alone, where UC is the normal care delivered within the care home following a minimum level of dementia awareness training. The trial will take place in residential, nursing and dementia-specialist care homes across West Yorkshire, Oxfordshire and London, with residents with dementia. A random sample of 50 care homes will be selected within which a minimum of 750 residents will be registered. Care homes will be randomised in an allocation ratio of 3:2 to receive either intervention or control. Outcome measures will be obtained at 6 and 16 months following randomisation. The primary outcome is agitation as measured by the Cohen-Mansfield Agitation Inventory, at 16 months post randomisation. Key secondary outcomes are other BSC and quality of life. There will be an integral cost-effectiveness analysis and a process evaluation. The protocol was refined following a pilot of trial procedures. Changes include replacement of a

  5. Ocean surveillance satellites

    Science.gov (United States)

    Laurent, D.

    Soviet and U.S. programs involving satellites for surveillance of ships and submarines are discussed, considering differences in approaches. The Soviet program began with the Cosmos 198 in 1967 and the latest, the Cosmos 1400 series, 15 m long and weighing 5 tons, carry radar for monitoring ships and a nuclear reactor for a power supply. Other Soviet spacecraft carrying passive microwave sensors and ion drives powered by solar panels have recently been detonated in orbit for unknown reasons. It has also been observed that the Soviet satellites are controlled in pairs, with sequential orbital changes for one following the other, and both satellites then overflying the same points. In contrast, U.S. surveillance satellites have been placed in higher orbits, thus placing greater demands on the capabilities of the on-board radar and camera systems. Project White Cloud and the Clipper Bow program are described, noting the continued operation of the White Cloud spacecraft, which are equipped to intercept radio signals from surface ships. Currently, the integrated tactical surveillance system program has completed its study and a decision is expected soon.

  6. Multipath/RFI/modulation study for DRSS-RFI problem: Voice coding and intelligibility testing for a satellite-based air traffic control system

    Science.gov (United States)

    Birch, J. N.; Getzin, N.

    1971-01-01

    Analog and digital voice coding techniques for application to an L-band satellite-basedair traffic control (ATC) system for over ocean deployment are examined. In addition to performance, the techniques are compared on the basis of cost, size, weight, power consumption, availability, reliability, and multiplexing features. Candidate systems are chosen on the bases of minimum required RF bandwidth and received carrier-to-noise density ratios. A detailed survey of automated and nonautomated intelligibility testing methods and devices is presented and comparisons given. Subjective evaluation of speech system by preference tests is considered. Conclusion and recommendations are developed regarding the selection of the voice system. Likewise, conclusions and recommendations are developed for the appropriate use of intelligibility tests, speech quality measurements, and preference tests with the framework of the proposed ATC system.

  7. Effectiveness and cost-effectiveness of body psychotherapy in the treatment of negative symptoms of schizophrenia – a multi-centre randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Priebe Stefan

    2013-01-01

    Full Text Available Abstract Background Negative symptoms of schizophrenia are frequently associated with poor long term outcomes. Established interventions have little, if any, positive effects on negative symptoms. Arts Therapies such as Body Psychotherapy (BPT have been suggested to reduce negative symptoms, but the existing evidence is limited. In a small exploratory trial a manualised form of group BPT led to significantly lower negative symptom levels both at the end of treatment and at 4 months follow-up as compared to supportive counseling. We designed a large multi-site trial to assess the effectiveness of a manualised BPT intervention in reducing negative symptoms, compared to an active control. Methods/Design In a randomised controlled trial, 256 schizophrenic outpatients with negative symptoms will be randomly allocated either to BPT or Pilates groups. In both conditions, patients will be offered two 90 minutes sessions per week in groups of about 8 patients over a period of 10 weeks. Outcomes are assessed at the end of treatment and at six months follow-up. The primary outcome is severity of negative symptoms, as measured by the Positive and Negative Symptom Scale (PANSS, whilst a range of secondary outcome measures include general psychopathology, social contacts, and quality of life. We will also assess the cost-effectiveness of the intervention. Discussion The study aims to evaluate the effectiveness of a promising form of group therapy which may help alleviate negative symptoms that are associated with unfavourable long-term outcomes and have so far been difficult to treat. If the trial is successful, it will add a new and effective option in the treatment of negative symptoms. Group BPT is manualised, might be attractive to many patients because of its unusual approach, and could potentially be rolled out to services at relatively little additional cost. Trial registration Current Controlled Trials ISRCTN84216587

  8. The tryptophan hydroxylase 1 (TPH1) gene, schizophrenia susceptibility, and suicidal behavior: a multi-centre case-control study and meta-analysis

    DEFF Research Database (Denmark)

    Saetre, Peter; Lundmark, Per; Wang, August;

    2010-01-01

    associated with schizophrenia. The minor allele (A) of this polymorphism (A218C) is also more frequent in patients who have attempted suicide and individuals who died by suicide, than in healthy control individuals. In an attempt to replicate previous findings, five single nucleotide polymorphisms (SNPs....../A779 locus increases the susceptibility of schizophrenia in Caucasian and Asian populations. In addition, the data at hand suggest that the locus contributes to the liability of psychiatric disorders characterized by elevated suicidal rates, rather than affecting suicidal behavior of individuals...

  9. Analysis of Satellite and Airborne Imagery for Detection of Water Hyacinth and Other Invasive Floating Macrophytes and Tracking of Aquatic Weed Control Efficacy

    Science.gov (United States)

    Potter, Christopher

    2016-01-01

    Waterways of the Sacramento San Joaquin Delta have recently become infested with invasive aquatic weeds such as floating water hyacinth (Eichhoria crassipes) and water primrose (Ludwigia peploides). These invasive plants cause many negative impacts, including, but not limited to: the blocking of waterways for commercial shipping and boating; clogging of irrigation screens, pumps and canals; and degradation of biological habitat through shading. Zhang et al. (1997, Ecological Applications, 7(3), 1039-1053) used NASA Landsat satellite imagery together with field calibration measurements to map physical and biological processes within marshlands of the San Francisco Bay. Live green biomass (LGB) and related variables were correlated with a simple vegetation index ratio of red and near infra-red bands from Landsat images. More recently, the percent (water area) cover of water hyacinth plotted against estimated LGB of emergent aquatic vegetation in the Delta from September 2014 Landsat imagery showed an 80 percent overall accuracy. For the past two years, we have partnered with the U. S. Department of Agriculture (USDA) and the Department of Plant Sciences, University of California at Davis to conduct new validation surveys of water hyacinth and water primrose coverage and LGB in Delta waterways. A plan is underway to transfer decision support tools developed at NASA's Ames Research Center based on Landsat satellite images to improve Delta-wide integrated management of floating aquatic weeds, while reducing chemical control costs. The main end-user for this application project will be the Division of Boating and Waterways (DBW) of the California Department of Parks and Recreation, who has the responsibility for chemical control of water hyacinth in the Delta.

  10. Minister unveils new nanotech centres

    Science.gov (United States)

    Dumé, Belle

    2009-06-01

    Three new nanotechnology research centres are to be set up in France as part of a €70m government plan to help French companies in the sector. Researchers at the new centres, which will be located in Grenoble, Saclay (near Paris) and Toulouse, will be encouraged to collaborate with industry to develop new nanotech-based products. Dubbed NANO-INNOV, the new plan includes €46m for two new buildings at Saclay, with the rest being used to buy new equipment at the three centres and to fund grant proposals from staff to the French National Research Agency (ANR).

  11. 25 years Nuclear Research Centre

    Energy Technology Data Exchange (ETDEWEB)

    Harde, R.

    1981-07-01

    On June 12, the Karlsruhe Nuclear Research Centre celebrated its 25th anniversary. The Centre was founded on July 19, 1956. The importance of this institution became apparent by the large number of prominent guests, at the head, the Federal President, Karl Carstens. Minister President Spaeth and the Federal Minister for Research and Technology, von Buelow, appreciated the achievements obtained by this big science centre of nuclear technology. The ceremony held in the State theatre of Baden-Wuerttemberg gave testimony of an impressing confession in favour of nuclear energy. Excerpts from the speech of the Chairman of the Managing Board, Prof. Harde, are quoted.

  12. The World Heritage Centr

    Directory of Open Access Journals (Sweden)

    Ayman G. Abdel Tawab

    2014-09-01

    Full Text Available New Gourna Village, which is located inside one of the World Heritage Sites in Egypt, has never been recognized as an element contributing to the site’s Outstanding Universal Value. The recognition of the village as a contributing element is reliant on the successful assessment of its authenticity and integrity. Responding to the dramatically declining integrity of the village, the World Heritage Centre has carried out an architectural study to guide the potential conservation works in the property. The study has recommended that a group of objectives and two approaches to the conservation of the village should be adopted. One of these two approaches has been concerned with the conservation of the village according to the architect’s original intentions and principles. The previous approach can be called the principles-based approach. The main aim of this study was to examine the agreement of the World Heritage Centre’s objectives and their proposed principles-based approach to the conservation of the village with the aim to improve its chance in meeting the conditions of authenticity and integrity. The study approached the previous aim by assessing, by means of a proposed methodology; the level of significance, authenticity and integrity of the property. Based on the previous assessment, a list of conservation interventions was proposed to improve the property’s chance in meeting the conditions of authenticity and integrity. Finally, the World Heritage Centre’s recommended approaches and objectives were examined against the previous proposed conservation interventions. The findings indicated the possibility to adopt the principles-based approach to the conservation of New Gourna Village, as well as the other World Heritage Centre’s objectives, without limiting the property’s chance in meeting the conditions of authenticity and integrity. The study recommends to carry out further studies that are concerned with the identification

  13. Stromal networking: cellular connections in the germinal centre.

    Science.gov (United States)

    Denton, Alice E; Linterman, Michelle A

    2017-03-17

    Secondary lymphoid organs are organized into distinct zones, governed by different types of mesenchymal stromal cells. These stromal cell subsets are critical for the generation of protective humoral immunity because they direct the migration of, and interaction between, multiple immune cell types to form the germinal centre. The germinal centre response generates long-lived antibody-secreting plasma cells and memory B cells which can provide long-term protection against re-infection. Stromal cell subsets mediate this response through control of immune cell trafficking, activation, localization and antigen access within the secondary lymphoid organ. Further, distinct populations of stromal cells underpin the delicate spatial organization of immune cells within the germinal centre. Because of this, the interactions between immune cells and stromal cells in secondary lymphoid organs are fundamental to the germinal centre response. Herein we review how this unique relationship leads to effective germinal centre responses.

  14. Surgical management and outcome of blunt major liver injuries: experience of damage control laparotomy with perihepatic packing in one trauma centre.

    Science.gov (United States)

    Lin, Being-Chuan; Fang, Jen-Feng; Chen, Ray-Jade; Wong, Yon-Cheong; Hsu, Yu-Pao

    2014-01-01

    This retrospective study aimed to assess the clinical experience and outcome of damage control laparotomy with perihepatic packing in the management of blunt major liver injuries. From January 1998 to December 2006, 58 patients of blunt major liver injury, American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) equal or greater than III, were operated with perihepatic packing at our institute. Demographic data, intra-operative findings, operative procedures, adjunctive managements and outcome were reviewed. To determine whether there was statistical difference between the survivor and non-survivor groups, data were compared by using Mann-Whitney U test for continuous variables, either Pearson's chi-square test or with Yates continuity correction for contingency tables, and results were considered statistically significant if p<0.05. Of the 58 patients, 20 (35%) were classified as AAST-OIS grade III, 24 (41%) as grade IV, and 14 (24%) as grade V. At laparotomy, depending on the severity of injuries, all 58 patients underwent various liver-related procedures and perihepatic packing. The more frequent liver-related procedures included debridement hepatectomy (n=21), hepatorrhaphy (n=19), selective hepatic artery ligation (n=11) and 7 patients required post-laparotomy hepatic transarterial embolization. Of the 58 patients, 28 survived and 30 died with a 52% mortality rate. Of the 30 deaths, uncontrolled liver bleeding in 24-h caused 25 deaths and delayed sepsis caused residual 5 deaths. The mortality rate versus OIS was grade III: 30% (6/20), grade IV: 54% (13/24), and grade V: 79% (11/14), respectively. On univariate analysis, the significant predictors of mortality were OIS grade (p=0.019), prolonged initial prothrombin time (PT) (p=0.004), active partial thromboplastin time (APTT) (p<0.0001) and decreased platelet count (p=0.005). The mortality rate of surgical blunt major liver injuries remains high even with perihepatic packing. Since

  15. Wi-Fi and Satellite-Based Location Techniques for Intelligent Agricultural Machinery Controlled by a Human Operator

    Directory of Open Access Journals (Sweden)

    Domagoj Drenjanac

    2014-10-01

    Full Text Available In the new agricultural scenarios, the interaction between autonomous tractors and a human operator is important when they jointly perform a task. Obtaining and exchanging accurate localization information between autonomous tractors and the human operator, working as a team, is a critical to maintaining safety, synchronization, and efficiency during the execution of a mission. An advanced localization system for both entities involved in the joint work, i.e., the autonomous tractors and the human operator, provides a basis for meeting the task requirements. In this paper, different localization techniques for a human operator and an autonomous tractor in a field environment were tested. First, we compared the localization performances of two global navigation satellite systems’ (GNSS receivers carried by the human operator: (1 an internal GNSS receiver built into a handheld device; and (2 an external DGNSS receiver with centimeter-level accuracy. To investigate autonomous tractor localization, a real-time kinematic (RTK-based localization system installed on autonomous tractor developed for agricultural applications was evaluated. Finally, a hybrid localization approach, which combines distance estimates obtained using a wireless scheme with the position of an autonomous tractor obtained using an RTK-GNSS system, is proposed. The hybrid solution is intended for user localization in unstructured environments in which the GNSS signal is obstructed. The hybrid localization approach has two components: (1 a localization algorithm based on the received signal strength indication (RSSI from the wireless environment; and (2 the acquisition of the tractor RTK coordinates when the human operator is near the tractor. In five RSSI tests, the best result achieved was an average localization error of 4 m. In tests of real-time position correction between rows, RMS error of 2.4 cm demonstrated that the passes were straight, as was desired for the

  16. Tethered satellite design

    Science.gov (United States)

    Manarini, G.

    1986-01-01

    The capability of the satellite to perform a variety of space operations to be accomplished from the shuttle is reviewed considering use of the satellite with man-in-loop and closed loop modes and deployment (toward or away from Earth, up to 100 km), stationkeeping, retrieval and control of the satellite. Scientific payloads are to be used to perform experiments and scientific investigation for applications such as magnetometry, electrodynamics, atmospheric science, chemical release, communications, plasmaphysics, dynamic environment, and power and thrust generation. The TSS-S will be reused for at least 3 missions after reconfiguration and refurbishment by changing the peculiar mission items such as thermal control, fixed boom for experiments, aerodynamic tail for yaw attitude control, external skin, experiments, and any other feature. The TSS-S is to be composed of three modules in order to allow independent integration of a single module and to facilitate the refurbishment and reconfiguration between flights. The three modules are service, auxiliary propulsion, and payload modules.

  17. The tryptophan hydroxylase 1 (TPH1) gene, schizophrenia susceptibility, and suicidal behavior: a multi-centre case-control study and meta-analysis

    DEFF Research Database (Denmark)

    Saetre, Peter; Lundmark, Per; Wang, August

    2010-01-01

    affected individuals having attempted suicide at least once and patients with no history of suicide attempts (P = 0.84). A systematic literature review and meta-analysis support the A218C polymorphism as a susceptibility locus for schizophrenia (odds ratio 1.17, 95% confidence interval 1......Serotonin (5-hydroxytryptamin; 5-HT) alternations has since long been suspected in the pathophysiology of schizophrenia. Tryptophan hydroxylase (tryptophan 5-monooxygenase; TPH) is the rate-limiting enzyme in the biosynthesis of 5-HT, and sequence variation in intron 6 of the TPH1 gene has been...... associated with schizophrenia. The minor allele (A) of this polymorphism (A218C) is also more frequent in patients who have attempted suicide and individuals who died by suicide, than in healthy control individuals. In an attempt to replicate previous findings, five single nucleotide polymorphisms (SNPs...

  18. Life- and person-centred help in Mecklenburg-Western Pomerania, Germany (DelpHi: study protocol for a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Thyrian Jochen

    2012-05-01

    Full Text Available Abstract Background The provision of appropriate medical and nursing care for people with dementia is a major challenge for the healthcare system in Germany. New models of healthcare provision need to be developed, tested and implemented on the population level. Trials in which collaborative care for dementia in the primary care setting were studied have demonstrated its effectiveness. These studies have been conducted in different healthcare systems, however, so it is unclear whether these results extend to the specific context of the German healthcare system. The objective of this population-based intervention trial in the primary care setting is to test the efficacy and efficiency of implementing a subsidiary support system on a population level for persons with dementia who live at home. Methods and study design The study was designed to assemble a general physician-based epidemiological cohort of people above the age of 70 who live at home (DelpHi cohort. These people are screened for eligibility to participate in a trial of dementia care management (DelpHi trial. The trial is a cluster-randomised, controlled intervention trial with two arms (intervention and control designed to test the efficacy and efficiency of implementing a subsidiary support system for persons with dementia who live at home. This subsidiary support system is initiated and coordinated by a dementia care manager: a nurse with dementia-specific qualifications who delivers the intervention according to a systematic, detailed protocol. The primary outcome is quality of life and healthcare for patients with dementia and their caregivers. This is a multidimensional outcome with a focus on four dimensions: (1 quality of life, (2 caregiver burden, (3 behavioural and psychological symptoms of dementia and (4 pharmacotherapy with an antidementia drug and prevention or suspension of potentially inappropriate medication. Secondary outcomes include the assessment of dementia

  19. RANDOMISED CONTROL STUDY OF USE OF PROGESTERONE V / S PLACEBO FOR MANAGEMENT OF SYMPTOMATIC PLACENTA PREVIA BEFORE 34 WEEKS OF GESTATION IN A TERTIARY CARE CENTRE

    Directory of Open Access Journals (Sweden)

    Shibram

    2015-04-01

    Full Text Available INTRODUCTI ON: APH complicates 3 - 5% of pregnancies and is a leading cause of perinatal and maternal mortality worldwide. Progesterone is essential in maintenance of pregnancy and helps in prolongation of pregnancy. Different trials have been done to show the efficacy and safety of progesterone in prevention of preterm birth but study related to use in expectant management of symptomatic placenta previa is very limited. AIMS AND OBJECTIVE: The objective of our study is to determine the effectiveness of intramascular 17 alpha hydroxy progesterone Caproate therapies vs. placebo in conservative management of patient with symptomatic placenta previa before 34 weeks of gestation. MATERIALS AND METHOD S: It is a randomized control study with 100 pregnant women attending Obstetric deptt. a t Nilratan Sircar Medical College and Hospital, Kolkata with symptomatic placenta previa having episode of warning haemorrhage before 34 weeks of gestation and fulfilling inclusion criteria were enrolled for the study in a two year period from January 2013 to December 2014. Statistical analysis was performed using student t - test and chai - square test where appropriate. RESULTS AND ANALYSIS: In our study prolongation of pregnancy in progesterone receiving group is statistically significant (p - value<0.001, significant difference were also found in gestational age at delivery ( p value of 0.0288, birth - weight (p - value of 0.0470. CON CLUSION: In this study use of 17 alpha hydroxy progesterone in expectant management of symptomatic placenta previa tends to be beneficial than placebo.

  20. Influence of inhomogeneous static magnetic field-exposure on patients with erosive gastritis: a randomized, self- and placebo-controlled, double-blind, single centre, pilot study.

    Science.gov (United States)

    Juhász, Márk; Nagy, Viktor L; Székely, Hajnal; Kocsis, Dorottya; Tulassay, Zsolt; László, János F

    2014-09-06

    This pilot study was devoted to the effect of static magnetic field (SMF)-exposure on erosive gastritis. The randomized, self- and placebo-controlled, double-blind, pilot study included 16 patients of the 2nd Department of Internal Medicine, Semmelweis University diagnosed with erosive gastritis. The instrumental analysis followed a qualitative (pre-intervention) assessment of the symptoms by the patient: lower heartburn (in the ventricle), upper heartburn (in the oesophagus), epigastric pain, regurgitation, bloating and dry cough. Medical diagnosis included a double-line upper panendoscopy followed by 30 min local inhomogeneous SMF-exposure intervention at the lower sternal region over the stomach with peak-to-peak magnetic induction of 3 mT and 30 mT m(-1) gradient at the target site. A qualitative (post-intervention) assessment of the same symptoms closed the examination. Sham- or SMF-exposure was used in a double-blind manner. The authors succeeded in justifying the clinically and statistically significant beneficial effect of the SMF- over sham-exposure on the symptoms of erosive gastritis, the average effect of inhibition was 56% by p = 0.001, n = 42 + 96. This pilot study was aimed to encourage gastroenterologists to test local, inhomogeneous SMF-exposure on erosive gastritis patients, so this intervention may become an evidence-based alternative or complementary method in the clinical use especially in cases when conventional therapy options are contraindicated. © 2014 The Author(s) Published by the Royal Society. All rights reserved.