WorldWideScience

Sample records for swarm constellation mapping

  1. 3-D electromagnetic induction studies using the Swarm constellation: Mapping conductivity anomalies in the Earth's mantle

    DEFF Research Database (Denmark)

    Kuvshinov, A.; Sabaka, T.; Olsen, Nils

    2006-01-01

    . For validation of the approach, 3 years of realistic synthetic data at Simulated orbits of the forthcoming Swarm constellation of 3 satellites have been used. To obtain the synthetic data for a given 3-D conductivity Earth's model a time-domain scheme has been applied which relies oil a Fourier transformation......-seated conductivity anomalies. Moreover, it has been demonstrated that these C-responses are successfully recovered from magnetic data collected by the proposed Swarm constellation of 3 satellites....

  2. 3-D electromagnetic induction studies using the Swarm constellation: Mapping conductivity anomalies in the Earth's mantle

    DEFF Research Database (Denmark)

    Kuvshinov, A.; Sabaka, T.; Olsen, Nils

    2006-01-01

    . For validation of the approach, 3 years of realistic synthetic data at Simulated orbits of the forthcoming Swarm constellation of 3 satellites have been used. To obtain the synthetic data for a given 3-D conductivity Earth's model a time-domain scheme has been applied which relies oil a Fourier transformation...... coefficients of the magnetic potential. From the coefficients, time series of the magnetic vertical component and of the horizontal divergence of the horizontal components are synthesized oil the grid and the C-responses are determined by means of signal processing of the corresponding time series...... of the inducing field, and oil a frequency domain forward modelling. The conductivity model consists of a thin Surface layer of realistic conductance and a 3-D mantle that incorporates a hypothetic deep regional anomaly beneath the Pacific Ocean plate. To establish the ability of the approach to capture...

  3. Level-2 product generation for the Swarm satellite constellation mission

    DEFF Research Database (Denmark)

    Olsen, Poul Erik Holmdahl; Tøffner-Clausen, Lars; Olsen, Nils

    In order to take advantage of the unique constellation aspect of ESA's Swarm constellation mission, considerably advanced data analysis tools have been developed. The Swarm ESL/SCARF (Satellite Constellation Application and Research Facility), a consortium of several research institutions, derives...

  4. Enhancing comprehensive inversions using the Swarm constellation

    DEFF Research Database (Denmark)

    Sabaka, T.J.; Olsen, Nils

    2006-01-01

    This paper reports on the findings of a simulation study designed to test various satellite configurations suggested for the upcoming Swarm magnetic mapping mission. The test is to see whether the mission objectives of recovering small-scale core secular variation (SV) and lithospheric magnetic...... to achieve proper signal separation. ne advantage of co-estimation over serial estimation of parameters is demonstrated by example. Synthetic data were calculated for a pool of six Swarm satellites from a model based heavily on the CM4 comprehensive model, but which has more small-scale lithospheric...

  5. SCARF - The Swarm Satellite Constellation Application and Research Facility

    DEFF Research Database (Denmark)

    Olsen, Nils

    2014-01-01

    Swarm, a three-satellite constellation to study the dynamics of the Earth's magnetic field and its interactions with the Earth system, has been launched in November 2013. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution, which...... will bring new insights into the Earth system by improving our understanding of the Earth's interior and environment. In order to take advantage of the unique constellation aspect of Swarm, considerably advanced data analysis tools have been developed. Scientific users will also benefit significantly from...... derived products, the so-called Level-2 products, that take into account the features of the constellation. The Swarm SCARF (Satellite Constellation Application and Research Facility), a consortium of several research institutions, has been established with the goal of deriving Level-2 products...

  6. The Swarm Satellite Constellation Application and Research Facility (SCARF) and Swarm data products

    DEFF Research Database (Denmark)

    Olsen, Nils; Friis-Christensen, Eigil; Floberghagen, R.

    2013-01-01

    Swarm, a three-satellite constellation to study the dynamics of the Earth's magnetic field and its interactions with the Earth system, is expected to be launched in late 2013. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution......, in order to gain new insights into the Earth system by improving our understanding of the Earth's interior and environment. In order to derive advanced models of the geomagnetic field (and other higher-level data products) it is necessary to take explicit advantage of the constellation aspect of Swarm....... The Swarm SCARF (Satellite Constellation Application and Research Facility) has been established with the goal of deriving Level-2 products by combination of data from the three satellites, and of the various instruments. The present paper describes the Swarm input data products (Level-1b and auxiliary data...

  7. Westward tilt of low-latitude plasma blobs as observed by the Swarm constellation

    DEFF Research Database (Denmark)

    Park, Jaeheung; Luehr, Hermann; Michaelis, Ingo

    2015-01-01

    In this study we investigate the three-dimensional structure of low-latitude plasma blobs using multi-instrument and multisatellite observations of the Swarm constellation. During the early commissioning phase the Swarm satellites were flying at the same altitude with zonal separation of about 0...

  8. A Model of the Earth's Magnetic Field From Two Year of Swarm Satellite Constellation Data

    DEFF Research Database (Denmark)

    Olsen, Nils; Finlay, Chris; Tøffner-Clausen, Lars

    More than two year of data from ESA's Swarm constellation mission are used to derive a model of the Earth’s magnetic field and its time variation (secular variation). The model describes contributions from the core and lithosphere as well as large-scale contributions from the magnetosphere (and its...... Earth-induced counterpart). We use data from geomagnetic quiet times and co-estimate the Euler angles describing the rotation between the vector magnetometer instrument frame and the North-East-Center (NEC) frame. In addition to the magnetic field observations provided by each of the three Swarm...... satellites and alongtrack first differences we include the East-west magnetic gradient information provided by the lower Swarm satellite pair, thereby explicitly taking advantage of the constellation aspect of Swarm. We assess the spatial and temporal model resolution that can be obtained from two years...

  9. Estimation of the magnetic field gradient tensor using the Swarm constellation

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Finlay, Chris; Olsen, Nils

    2014-01-01

    For the first time, part of the magnetic field gradient tensor is estimated in space by the Swarm mission. We investigate the possibility of a more complete estimation of the gradient tensor exploiting the Swarm constellation. The East-West gradients can be approximated by observations from...... the lower pair of Swarm satellites, whereas the North-South gradients can be approximated by the first differences in the along-track direction. As a preliminary test, here we will present an analysis of along track differences of CHAMP vector observations. These show considerably smaller standard...

  10. Determining polar ionospheric electrojet currents from Swarm satellite constellation magnetic data

    DEFF Research Database (Denmark)

    Aakjær, Cecilie Drost; Olsen, Nils; Finlay, Chris

    2016-01-01

    We determine the strength and location of the ionospheric currents responsible for the polar electrojets from magnetic data collected by the Swarm satellite constellation on an orbit-by-orbit basis. The ionospheric currents are modelled using a simple, yet robust, method by a series of line...

  11. The interhemispheric and F region dynamo currents revisited with the Swarm constellation

    DEFF Research Database (Denmark)

    Luehr, Hermann; Kervalishvili, Guram; Michaelis, Ingo

    2015-01-01

    Based on magnetic field data sampled by the Swarm satellite constellation it is possible for the first time to determine uniquely F region currents at low latitudes. Initial results are presented from the first 200days of formation flight (17 April to 5 November 2014). Detailed results have been...

  12. Swarm: A constellation to study the Earth's magnetic field

    DEFF Research Database (Denmark)

    Friis-Christensen, Eigil; Luhr, H.; Hulot, G.

    2006-01-01

    The Swarm mission was selected as the 5th mission in ESA's Earth Explorer Programme in 2004. The mission will provide the best ever survey of the geomagnetic field and its temporal evolution that will lead to new insights into the Earth system by improving our understanding of the Earth's interio......'s influence within the Earth system. In addition practical applications in many different areas, such as space weather, radiation hazards, navigation and resource management, will benefit from the Swarm concept....... field measurements, will provide the necessary observations that are required to separate and model the various Sources of the geomagnetic field. This results in it unique "view" inside the Earth from space to study the composition and processes of its interior. It also allows analysing the Sun...

  13. A Challenging Trio in Space 'Routine' Operations of the Swarm Satellite Constellation

    Science.gov (United States)

    Diekmann, Frank-Jurgen; Clerigo, Ignacio; Albini, Giuseppe; Maleville, Laurent; Neto, Alessandro; Patterson, David; Nino, Ana Piris; Sieg, Detlef

    2016-08-01

    Swarm is the first ESA Earth Observation Mission with three satellites flying in a semi-controlled constellation. The trio is operated from ESA's satellite control centre ESOC in Darmstadt, Germany. The Swarm Flight Operations Segment consists of the typical elements of a satellite control system at ESOC, but had to be carefully tailored for this innovative mission. The main challenge was the multi-satellite system of Swarm, which necessitated the development of a Mission Control System with a multi-domain functionality, both in hardware and software and covering real-time and backup domains. This was driven by the need for extreme flexibility for constellation operations and parallel activities.The three months of commissioning in 2014 were characterized by a very tight and dynamically changing schedule of activities. All operational issues could be solved during that time, including the challenging orbit acquisition phase to achieve the final constellation.Although the formal spacecraft commissioning phase was concluded in spring 2014, the investigations for some payload instruments continue even today. The Electrical Field Instruments are for instance still being tested in order to characterize and improve science data quality. Various test phases also became necessary for the Accelerometers on the Swarm satellites. In order to improve the performance of the GPS Receivers for better scientific exploitation and to minimize the failures due to loss of synchronization, a number of parameter changes were commanded via on-board patches.Finally, to minimize the impact on operations, a new strategy had to be implemented to handle single/multi bit errors in the on-board mass Memories, defining when to ignore and when to restore the memory via a re-initialisation.The poster presentation summarizes the Swarm specific ground segment elements of the FOS and explains some of the extended payload commissioning operations, turning Swarm into a most demanding and challenging

  14. The Swarm Initial Field Model – a Model of the Earth’s Magnetic Field for 2014 Determined From One Year of Swarm Satellite Constellation Data

    DEFF Research Database (Denmark)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent

    Almost one year of data from ESA's Swarm constellation mission are used to derive a model of the Earth’s magnetic field and its time variation (secular variation). The model describes contributions from the core and lithosphere as well as large-scale contributions from the magnetosphere (and its......) frame. In addition to the magnetic field observations provided by each of the three Swarm satellites we include the East-west magnetic gradient information provided by the lower Swarm satellite pair, thereby explicitly taking advantage of the constellation aspect of Swarm. We assess the spatial...... and temporal model resolution that can be obtained from one year of Swarm satellite data by comparison with other recent models that also include non-Swarm magnetic observations....

  15. A model of Earth’s magnetic field derived from 2 years of Swarm satellite constellation data

    DEFF Research Database (Denmark)

    Olsen, Nils; Finlay, Chris; Kotsiaros, Stavros

    2016-01-01

    More than 2 years of magnetic field data taken by the three-satellite constellation mission Swarm are used to derive a model of Earth’s magnetic field and its time variation. This model is called SIFMplus. In addition to the magnetic field observations provided by each of the three Swarm satellites......, explicit advantage is taken of the constellation aspect of Swarm by including East–West magnetic intensity and vector field gradient information from the lower satellite pair. Along-track differences of the magnetic intensity as well as of the vector components provide further information concerning...... dependence for n=7–15, demonstrates the possibility to determine high-quality field models from only 2 years of Swarm data, thanks to the unique constellation aspect of Swarm. To account for the magnetic signature caused by ionospheric electric currents at polar latitudes we co-estimate, together...

  16. Statistical analysis of geomagnetic field intensity differences between ASM and VFM instruments onboard Swarm constellation

    Science.gov (United States)

    De Michelis, Paola; Tozzi, Roberta; Consolini, Giuseppe

    2017-02-01

    From the very first measurements made by the magnetometers onboard Swarm satellites launched by European Space Agency (ESA) in late 2013, it emerged a discrepancy between scalar and vector measurements. An accurate analysis of this phenomenon brought to build an empirical model of the disturbance, highly correlated with the Sun incidence angle, and to correct vector data accordingly. The empirical model adopted by ESA results in a significant decrease in the amplitude of the disturbance affecting VFM measurements so greatly improving the vector magnetic data quality. This study is focused on the characterization of the difference between magnetic field intensity measured by the absolute scalar magnetometer (ASM) and that reconstructed using the vector field magnetometer (VFM) installed on Swarm constellation. Applying empirical mode decomposition method, we find the intrinsic mode functions (IMFs) associated with ASM-VFM total intensity differences obtained with data both uncorrected and corrected for the disturbance correlated with the Sun incidence angle. Surprisingly, no differences are found in the nature of the IMFs embedded in the analyzed signals, being these IMFs characterized by the same dominant periodicities before and after correction. The effect of correction manifests in the decrease in the energy associated with some IMFs contributing to corrected data. Some IMFs identified by analyzing the ASM-VFM intensity discrepancy are characterized by the same dominant periodicities of those obtained by analyzing the temperature fluctuations of the VFM electronic unit. Thus, the disturbance correlated with the Sun incidence angle could be still present in the corrected magnetic data. Furthermore, the ASM-VFM total intensity difference and the VFM electronic unit temperature display a maximal shared information with a time delay that depends on local time. Taken together, these findings may help to relate the features of the observed VFM-ASM total intensity

  17. Field-aligned currents' scale analysis performed with the Swarm constellation

    DEFF Research Database (Denmark)

    Lühr, Hermann; Park, Jaeheung; Gjerløv, Jesper Wittendorff

    2015-01-01

    We present a statistical study of the temporal- and spatial-scale characteristics of different field-aligned current (FAC) types derived with the Swarm satellite formation. We divide FACs into two classes: small-scale, up to some 10 km, which are carried predominantly by kinetic Alfve´n waves...

  18. Martian Swarm Exploration and Mapping Using Laser Slam

    Science.gov (United States)

    Nowak, S.; Krüger, T.; Matthaei, J.; Bestmann, U.

    2013-08-01

    In order to explore planet Mars in detail and search for extra-terrestrial life the observation from orbit is not sufficient. To realize complex exploration tasks the use of automatic operating robots with a robust fault-tolerant method of navigation, independent of any infrastructure is a possibility. This work includes a concept of rotary-wing Unmanned Aerial Vehicles (UAVs) and Unmanned Ground Vehicles (UGVs) for Martian exploration in a swarm. Besides the scenario of Martian surrounding, with a small number of distinctive landmarks, the challenge consists of a Simultaneous Localization and Mapping (SLAM) concept using laser data of all swarm members.

  19. MARTIAN SWARM EXPLORATION AND MAPPING USING LASER SLAM

    Directory of Open Access Journals (Sweden)

    S. Nowak

    2013-08-01

    Full Text Available In order to explore planet Mars in detail and search for extra-terrestrial life the observation from orbit is not sufficient. To realize complex exploration tasks the use of automatic operating robots with a robust fault-tolerant method of navigation, independent of any infrastructure is a possibility. This work includes a concept of rotary-wing Unmanned Aerial Vehicles (UAVs and Unmanned Ground Vehicles (UGVs for Martian exploration in a swarm. Besides the scenario of Martian surrounding, with a small number of distinctive landmarks, the challenge consists of a Simultaneous Localization and Mapping (SLAM concept using laser data of all swarm members.

  20. Swarm.

    Science.gov (United States)

    Petersen, Hugh

    2002-01-01

    Describes an eighth grade art project for which students created bug swarms on scratchboard. Explains that the project also teaches students about design principles, such as balance. Discusses how the students created their drawings. (CMK)

  1. Mapping the Constellation of Educational Marxism(s)

    Science.gov (United States)

    Lewis, Tyson E.

    2012-01-01

    In this paper, the author maps three radically different visions of Marxism in educational philosophy. Each "register" contains insights but also contradictions that cannot easily be resolved through internal modifications of the theory or through theoretical synthesis with other registers. The radical function of Marxist pedagogy is to create a…

  2. MAGNAS - Magnetic Nanoprobe SWARM

    DEFF Research Database (Denmark)

    Lubberstedt, H.; Koebel, D.; Hansen, Flemming

    2005-01-01

    This paper presents the Magnetic Nano-Probe Swarm mission utilising a constellation of several swarms of nano-satellites in order to acquire simultaneous measurements of the geomagnetic field resolving the local field gradients. The space segment comprises of up to 4 S/C swarms each consisting...... control and maintenance of the swarm constellation and serve as communication relay to the ground. The systems design relies on near-to-medium term technology....

  3. A scanning drift tube apparatus for spatiotemporal mapping of electron swarms

    Energy Technology Data Exchange (ETDEWEB)

    Korolov, I.; Vass, M.; Donkó, Z., E-mail: donko.zoltan@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Bastykova, N. Kh. [Institute of Experimental and Theoretical Physics, al-Farabi Kazakh National University, 96a Tole Bi, Almaty 050012 (Kazakhstan)

    2016-06-15

    A “scanning” drift tube apparatus, capable of mapping of the spatiotemporal evolution of electron swarms, developing between two plane electrodes under the effect of a homogeneous electric field, is presented. The electron swarms are initiated by photoelectron pulses and the temporal distributions of the electron flux are recorded while the electrode gap length (at a fixed electric field strength) is varied. Operation of the system is tested and verified with argon gas; the measured data are used for the evaluation of the electron bulk drift velocity. The experimental results for the space-time maps of the electron swarms — presented here for the first time — also allow clear observation of deviations from hydrodynamic transport. The swarm maps are also reproduced by particle simulations.

  4. Longitudinal Thin Structure of Equatorial Plasma Depletions Coincidently Observed by Swarm Constellation and all-Sky Imager

    Science.gov (United States)

    Xiong, Chao; Xu, Jiyao; Wu, Kun; Yuan, Wei

    2018-02-01

    The lower pair satellites of Swarm mission, flying side-by-side and separated by 1.4° in longitude (about 150 km), usually observed equatorial plasma depletions (EPDs) showing quite different structures, and sometime even only one satellite observed EPD. In this study, we provided 6-h continuous observations of EPDs on the night of 23-24 September 2014, from an all-sky imager located at Fuke (geographic:19.5°N,109.1°E), south of China. From the airglow images the EPDs were found with longitudinal extensions of about 50 km and all tilted from northwest to southeast direction. We further checked the in situ electron density simultaneously measured by the Swarm lower pair satellites and found the differences of Swarm in situ electron densities explained well by the longitudinally thin structure of EPDs observed from the all-sky imager. During later periods the bifurcation and merging were observed by the airglow images, and it was the first time to report both processes in the evolution of one EPD. The bifurcation was first observed at the higher-latitude part, and then observed at lower latitudes of EPD. The subbranches generated through bifurcation showed even thinner longitudinal extension of about 20-30 km, and later the subbranches started to merge with each other, forming a really complicated mesh of depleted regions.

  5. QAM to Circular Isomorphic Constellations

    OpenAIRE

    Kayhan, Farbod

    2016-01-01

    Employing high order constellations is inevitable in order to achieve higher spectral efficiency in satellite communication systems. In DVB-S2X standard, constellations with up to 256 points have been included. However, optimizing such high order constellations is a difficult task. In this paper we propose a very simple constellation design based on the radial map from QAM constellations to non-uniform APSK constellations. Our method provides a systematic way to generate a family of optimized...

  6. Changes in Earth's core-generated magnetic field, as observed by Swarm

    DEFF Research Database (Denmark)

    Finlay, Chris; Olsen, Nils; Gillet, Nicolas

    . In this contribution, we will present the core-generated magnetic field, and its recent time changes, as seen by ESA's Earth explorer mission Swarm. We will present a new time-dependent geomagnetic field model, called CHAOS-6, derived from satellite data collected by the Swarm constellation, as well as data from...... the previous missions CHAMP and Oersted together with ground observatory data. Advantage is taken of the constellation aspect of the Swarm mission by ingesting field differences along track and across track between the lower pair of Swarm satellites. Evaluating the global field model at the outer boundary...... of the source region, the core-mantle boundary, we present maps of the detailed structure of the geodynamo, and how this is presently evolving. Both the trend (secular variation) and accelerations in the field changes since the launch of the Swarm mission will be presented. Assuming that field changes...

  7. Coarse-grained variables for particle-based models: diffusion maps and animal swarming simulations

    Science.gov (United States)

    Liu, Ping; Safford, Hannah R.; Couzin, Iain D.; Kevrekidis, Ioannis G.

    2014-12-01

    As microscopic (e.g. atomistic, stochastic, agent-based, particle-based) simulations become increasingly prevalent in the modeling of complex systems, so does the need to systematically coarse-grain the information they provide. Before even starting to formulate relevant coarse-grained equations, we need to determine the right macroscopic observables—the right variables in terms of which emergent behavior will be described. This paper illustrates the use of data mining (and, in particular, diffusion maps, a nonlinear manifold learning technique) in coarse-graining the dynamics of a particle-based model of animal swarming. Our computational data-driven coarse-graining approach extracts two coarse (collective) variables from the detailed particle-based simulations, and helps formulate a low-dimensional stochastic differential equation in terms of these two collective variables; this allows the efficient quantification of the interplay of "informed" and "naive" individuals in the collective swarm dynamics. We also present a brief exploration of swarm breakup and use data-mining in an attempt to identify useful predictors for it. In our discussion of the scope and limitations of the approach we focus on the key step of selecting an informative metric, allowing us to usefully compare different particle swarm configurations.

  8. The Swarm Magnetometry Package

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Jørgensen, John Leif; Friis-Christensen, Eigil

    2008-01-01

    The Swarm mission under the ESA's Living Planet Programme is planned for launch in 2010 and consists of a constellation of three satellites at LEO. The prime objective of Swarm is to measure the geomagnetic field with unprecedented accuracy in space and time. The magnetometry package consists...

  9. NASAs EDSN Aims to Overcome the Operational Challenges of CubeSat Constellations and Demonstrate an Economical Swarm of 8 CubeSats Useful for Space Science Investigations

    Science.gov (United States)

    Smith, Harrison Brodsky; Hu, Steven Hung Kee; Cockrell, James J.

    2013-01-01

    Operators of a constellation of CubeSats have to confront a number of daunting challenges that can be cost prohibitive, or operationally prohibitive, to missions that could otherwise be enabled by a satellite constellation. Challenges including operations complexity, intersatellite communication, intersatellite navigation, and time sharing tasks between satellites are all complicated by operating with the usual CubeSat size, power, and budget constraints. EDSN pioneers innovative solutions to these problems as they are presented on the nano-scale satellite platform.

  10. Hysteresis compensation of the Prandtl-Ishlinskii model for piezoelectric actuators using modified particle swarm optimization with chaotic map.

    Science.gov (United States)

    Long, Zhili; Wang, Rui; Fang, Jiwen; Dai, Xufei; Li, Zuohua

    2017-07-01

    Piezoelectric actuators invariably exhibit hysteresis nonlinearities that tend to become significant under the open-loop condition and could cause oscillations and errors in nanometer-positioning tasks. Chaotic map modified particle swarm optimization (MPSO) is proposed and implemented to identify the Prandtl-Ishlinskii model for piezoelectric actuators. Hysteresis compensation is attained through application of an inverse Prandtl-Ishlinskii model, in which the parameters are formulated based on the original model with chaotic map MPSO. To strengthen the diversity and improve the searching ergodicity of the swarm, an initial method of adaptive inertia weight based on a chaotic map is proposed. To compare and prove that the swarm's convergence occurs before stochastic initialization and to attain an optimal particle swarm optimization algorithm, the parameters of a proportional-integral-derivative controller are searched using self-tuning, and the simulated results are used to verify the search effectiveness of chaotic map MPSO. The results show that chaotic map MPSO is superior to its competitors for identifying the Prandtl-Ishlinskii model and that the inverse Prandtl-Ishlinskii model can provide hysteresis compensation under different conditions in a simple and effective manner.

  11. A novel chaotic particle swarm optimization approach using Henon map and implicit filtering local search for economic load dispatch

    International Nuclear Information System (INIS)

    Coelho, Leandro dos Santos; Mariani, Viviana Cocco

    2009-01-01

    Particle swarm optimization (PSO) is a population-based swarm intelligence algorithm driven by the simulation of a social psychological metaphor instead of the survival of the fittest individual. Based on the chaotic systems theory, this paper proposed a novel chaotic PSO combined with an implicit filtering (IF) local search method to solve economic dispatch problems. Since chaotic mapping enjoys certainty, ergodicity and the stochastic property, the proposed PSO introduces chaos mapping using Henon map sequences which increases its convergence rate and resulting precision. The chaotic PSO approach is used to produce good potential solutions, and the IF is used to fine-tune of final solution of PSO. The hybrid methodology is validated for a test system consisting of 13 thermal units whose incremental fuel cost function takes into account the valve-point loading effects. Simulation results are promising and show the effectiveness of the proposed approach.

  12. A Wandering Robot : Self-localization and Mapping of Swarm Robots

    OpenAIRE

    竹下 聡亮; 髙田 宗樹; 平田 隆幸

    2015-01-01

    Swarm intelligence has been attracted much attention of researchers in various fields. A swarm robot is one of theresearch fields of the swarm intelligence. In the study of the swarm robots, a number of small robots are used. Althoughindividual robot ability is not so high, a colony of robots can achieve a complex task with co-operative work. The antsearches feeding area, and carries food to the nest with marking by pheromone. Other ants trace the pheromone and goto the feeding area. Many ant...

  13. Short-term cascaded hydroelectric system scheduling based on chaotic particle swarm optimization using improved logistic map

    Science.gov (United States)

    He, Yaoyao; Yang, Shanlin; Xu, Qifa

    2013-07-01

    In order to solve the model of short-term cascaded hydroelectric system scheduling, a novel chaotic particle swarm optimization (CPSO) algorithm using improved logistic map is introduced, which uses the water discharge as the decision variables combined with the death penalty function. According to the principle of maximum power generation, the proposed approach makes use of the ergodicity, symmetry and stochastic property of improved logistic chaotic map for enhancing the performance of particle swarm optimization (PSO) algorithm. The new hybrid method has been examined and tested on two test functions and a practical cascaded hydroelectric system. The experimental results show that the effectiveness and robustness of the proposed CPSO algorithm in comparison with other traditional algorithms.

  14. Platform Constellations

    DEFF Research Database (Denmark)

    Staykova, Kalina Stefanova; Damsgaard, Jan

    2016-01-01

    This research paper presents an initial attempt to introduce and explain the emergence of new phenomenon, which we refer to as platform constellations. Functioning as highly modular systems, the platform constellations are collections of highly connected platforms which co-exist in parallel...... and as such allow us to study platforms not only as separate entities, but also to investigate the relationship between several platforms offered and governed by one and the same platform provider. By investigating two case studies of indigenous platform constellations formed around the hugely popular instant...

  15. The constellation of dietary factors in adolescent acne: a semantic connectivity map approach.

    Science.gov (United States)

    Grossi, E; Cazzaniga, S; Crotti, S; Naldi, L; Di Landro, A; Ingordo, V; Cusano, F; Atzori, L; Tripodi Cutrì, F; Musumeci, M L; Pezzarossa, E; Bettoli, V; Caproni, M; Bonci, A

    2016-01-01

    Different lifestyle and dietetic factors have been linked with the onset and severity of acne. To assess the complex interconnection between dietetic variables and acne. This was a reanalysis of data from a case-control study by using a semantic connectivity map approach. 563 subjects, aged 10-24 years, involved in a case-control study of acne between March 2009 and February 2010, were considered in this study. The analysis evaluated the link between a moderate to severe acne and anthropometric variables, family history and dietetic factors. Analyses were conducted by relying on an artificial adaptive system, the Auto Semantic Connectivity Map (AutoCM). The AutoCM map showed that moderate-severe acne was closely associated with family history of acne in first degree relatives, obesity (BMI ≥ 30), and high consumption of milk, in particular skim milk, cheese/yogurt, sweets/cakes, chocolate, and a low consumption of fish, and limited intake of fruits/vegetables. Our analyses confirm the link between several dietetic items and acne. When providing care, dermatologists should also be aware of the complex interconnection between dietetic factors and acne. © 2014 European Academy of Dermatology and Venereology.

  16. Frontier constellations

    DEFF Research Database (Denmark)

    Eilenberg, Michael

    2014-01-01

    expansion, population resettlement and securitization, and the confluence of these dynamic processes creates special frontier constellations. Through the case of the Indonesian-Malaysian borderlands, I explore how processes of frontier colonization through agricultural expansion have been a recurrent...

  17. The Earth Gravitational Observatory (EGO): Nanosat Constellations For Advanced Gravity Mapping

    Science.gov (United States)

    Yunck, T.; Saltman, A.; Bettadpur, S. V.; Nerem, R. S.; Abel, J.

    2017-12-01

    The trend to nanosats for space-based remote sensing is transforming system architectures: fleets of "cellular" craft scanning Earth with exceptional precision and economy. GeoOptics Inc has been selected by NASA to develop a vision for that transition with an initial focus on advanced gravity field mapping. Building on our spaceborne GNSS technology we introduce innovations that will improve gravity mapping roughly tenfold over previous missions at a fraction of the cost. The power of EGO is realized in its N-satellite form where all satellites in a cluster receive dual-frequency crosslinks from all other satellites, yielding N(N-1)/2 independent measurements. Twelve "cells" thus yield 66 independent links. Because the cells form a 2D arc with spacings ranging from 200 km to 3,000 km, EGO senses a wider range of gravity wavelengths and offers greater geometrical observing strength. The benefits are two-fold: Improved time resolution enables observation of sub-seasonal processes, as from hydro-meteorological phenomena; improved measurement quality enhances all gravity solutions. For the GRACE mission, key limitations arise from such spacecraft factors as long-term accelerometer error, attitude knowledge and thermal stability, which are largely independent from cell to cell. Data from a dozen cells reduces their impact by 3x, by the "root-n" averaging effect. Multi-cell closures improve on this further. The many closure paths among 12 cells provide strong constraints to correct for observed range changes not compatible with a gravity source, including accelerometer errors in measuring non-conservative forces. Perhaps more significantly from a science standpoint, system-level estimates with data from diverse orbits can attack the many scientifically limiting sources of temporal aliasing.

  18. Tracking and mapping of spatiotemporal quantities using unicellular swarm intelligence visualisation of invisible hazardous substances using unicellular swarm intelligence

    CERN Document Server

    Oyekan, John Oluwagbemiga

    2016-01-01

    The book discusses new algorithms capable of searching for, tracking, mapping and providing a visualization of invisible substances. It reports on the realization of a bacterium-inspired robotic controller that can be used by an agent to search for any environmental spatial function such as temperature or pollution. Using the parameters of a mathematical model, the book shows that it is possible to control the exploration, exploitation and sensitivity of the agent. This feature sets the work apart from the usual method of applying the bacterium behavior to robotic agents. The book also discusses how a computationally tractable multi-agent robotic controller was developed and used to track as well as provide a visual map of a spatio-temporal distribution of a substance. On the one hand, this book provides biologists and ecologists with a basis to perform simulations related to how individual organisms respond to spatio-temporal factors in their environment as well as predict and analyze the behavior of organis...

  19. The constellation observing Atlas

    CERN Document Server

    Privett, Grant

    2013-01-01

    Designed for anyone who wishes to learn the constellations or observe the best and brightest deep sky objects and double stars, this book contains an alphabetical list of constellations complete with star maps, historical background, and highlights of deep sky objects. Each entry contains position and physical information on enough stars to support astronomers in star-hopping, swinging the telescope from star to star to star to arrive at a faint target. It provides a carefully selected list of accessible and rewarding deep sky objects. Full-color maps show the constellations, with star types (spectral and physical) indicated by the colors used on the map. Extended objects such as galaxies and nebulae are shown with the approximate apparent size in the sky. With unmatched thoroughness and accessibility, this is a constellation atlas that makes the ideal companion to a night's telescope viewing, for novices and expert amateur astronomers alike. Easy to navigate and refer to, it is the key that unlocks the do...

  20. Swarm Science objectives and challenges

    DEFF Research Database (Denmark)

    Friis-Christensen, Eigil; Lühr, Hermann; Hulot, Gauthier

    Swarm is the fifth Earth Explorer mission in ESA’s Living Planet Programme to be launched in 2009. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution. The innovative constellation concept and a unique set of dedicated instrume......Swarm is the fifth Earth Explorer mission in ESA’s Living Planet Programme to be launched in 2009. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution. The innovative constellation concept and a unique set of dedicated...... instruments will provide the necessary observations that are required to separate and model the various sources of the geomagnetic field. This will provide new insights into the Earth system by improving our understanding of the Earth’s interior and Sun-Earth connection processes....

  1. A method to derive maps of ionospheric conductances, currents, and convection from the Swarm multisatellite mission

    DEFF Research Database (Denmark)

    Amm, O.; Vanhamäki, H.; Kauristie, K.

    2015-01-01

    The European Space Agency (ESA) Swarm spacecraft mission is the first multisatellite ionospheric mission with two low-orbiting spacecraft that are flying in parallel at a distance of ~100–140 km, thus allowing derivation of spatial gradients of ionospheric parameters not only along the orbits......, currents, and electric field in the area between the trajectories of the two lower spacecraft, and even to some extent outside of it. This technique is based on Spherical Elementary Current Systems. We present test cases of modeled situations from which we calculate virtual Swarm data and show...

  2. Visual Analysis of Swarm and Geomagnetic Model Data

    Science.gov (United States)

    Santillan Pedrosa, Daniel; Triebnig, Gerhard

    2016-08-01

    ESA Swarm data is available for anyone to use via the virtual research platform "VirES for Swarm" (http://vires.services). A highly interactive data manipulation and retrieval interface is provided for the magnetic products of the European Space Agency (ESA) Swarm constellation mission. It includes tools for studying various Earth magnetic models and for comparing them to the Swarm satellite measurements and given solar activity levels.

  3. Towards improved knowledge of geology and global thermal regime from Swarm satellites magnetic gradient observations

    DEFF Research Database (Denmark)

    Ravat, Dhananjay; Olsen, Nils; Sabaka, Terence

    ., 2015, in review). Despite having global set of observations from POGO, Magsat, Ørsted, CHAMP, and Swarm satellites (altitude > 400 km), preservation of intermediate wavelengths from about 100 to 375 km proves challenging (known as the “spectral gap”). Since the gradients of magnetic field have higher...... spatial resolution than the fields themselves, they are helpful in improving the coverage in the spectral gap. East-West and North-South (along orbit) gradients from Swarm magnetic field satellites provide an opportunity to examine the improvement in the anomaly coverage in the spectral gap and its effect...... Anomaly Map compilation (ca. 2002), the original compilation corrected with satellite-altitude data sets, and Swarm constellation gradient corrected fields over the U.S. Using this U.S. study as a test, we examine the possibility of improving the spectral coverage in many regions of the world where...

  4. Modeling dynamic swarms

    KAUST Repository

    Ghanem, Bernard

    2013-01-01

    This paper proposes the problem of modeling video sequences of dynamic swarms (DSs). We define a DS as a large layout of stochastically repetitive spatial configurations of dynamic objects (swarm elements) whose motions exhibit local spatiotemporal interdependency and stationarity, i.e., the motions are similar in any small spatiotemporal neighborhood. Examples of DS abound in nature, e.g., herds of animals and flocks of birds. To capture the local spatiotemporal properties of the DS, we present a probabilistic model that learns both the spatial layout of swarm elements (based on low-level image segmentation) and their joint dynamics that are modeled as linear transformations. To this end, a spatiotemporal neighborhood is associated with each swarm element, in which local stationarity is enforced both spatially and temporally. We assume that the prior on the swarm dynamics is distributed according to an MRF in both space and time. Embedding this model in a MAP framework, we iterate between learning the spatial layout of the swarm and its dynamics. We learn the swarm transformations using ICM, which iterates between estimating these transformations and updating their distribution in the spatiotemporal neighborhoods. We demonstrate the validity of our method by conducting experiments on real and synthetic video sequences. Real sequences of birds, geese, robot swarms, and pedestrians evaluate the applicability of our model to real world data. © 2012 Elsevier Inc. All rights reserved.

  5. Big Data: A Parallel Particle Swarm Optimization-Back-Propagation Neural Network Algorithm Based on MapReduce.

    Science.gov (United States)

    Cao, Jianfang; Cui, Hongyan; Shi, Hao; Jiao, Lijuan

    2016-01-01

    A back-propagation (BP) neural network can solve complicated random nonlinear mapping problems; therefore, it can be applied to a wide range of problems. However, as the sample size increases, the time required to train BP neural networks becomes lengthy. Moreover, the classification accuracy decreases as well. To improve the classification accuracy and runtime efficiency of the BP neural network algorithm, we proposed a parallel design and realization method for a particle swarm optimization (PSO)-optimized BP neural network based on MapReduce on the Hadoop platform using both the PSO algorithm and a parallel design. The PSO algorithm was used to optimize the BP neural network's initial weights and thresholds and improve the accuracy of the classification algorithm. The MapReduce parallel programming model was utilized to achieve parallel processing of the BP algorithm, thereby solving the problems of hardware and communication overhead when the BP neural network addresses big data. Datasets on 5 different scales were constructed using the scene image library from the SUN Database. The classification accuracy of the parallel PSO-BP neural network algorithm is approximately 92%, and the system efficiency is approximately 0.85, which presents obvious advantages when processing big data. The algorithm proposed in this study demonstrated both higher classification accuracy and improved time efficiency, which represents a significant improvement obtained from applying parallel processing to an intelligent algorithm on big data.

  6. An initial ULF wave index derived from 2 years of Swarm observations

    Science.gov (United States)

    Papadimitriou, Constantinos; Balasis, Georgios; Daglis, Ioannis A.; Giannakis, Omiros

    2018-03-01

    The ongoing Swarm satellite mission provides an opportunity for better knowledge of the near-Earth electromagnetic environment. Herein, we use a new methodological approach for the detection and classification of ultra low-frequency (ULF) wave events observed by Swarm based on an existing time-frequency analysis (TFA) tool and utilizing a state-of-the-art high-resolution magnetic field model and Swarm Level 2 products (i.e., field-aligned currents - FACs - and the Ionospheric Bubble Index - IBI). We present maps of the dependence of ULF wave power with magnetic latitude and magnetic local time (MLT) as well as geographic latitude and longitude from the three satellites at their different locations in low-Earth orbit (LEO) for a period spanning 2 years after the constellation's final configuration. We show that the inclusion of the Swarm single-spacecraft FAC product in our analysis eliminates all the wave activity at high altitudes, which is physically unrealistic. Moreover, we derive a Swarm orbit-by-orbit Pc3 wave (20-100 MHz) index for the topside ionosphere and compare its values with the corresponding variations of solar wind variables and geomagnetic activity indices. This is the first attempt, to our knowledge, to derive a ULF wave index from LEO satellite data. The technique can be potentially used to define a new Level 2 product from the mission, the Swarm ULF wave index, which would be suitable for space weather applications.

  7. Detecting unstable periodic orbits of nonlinear mappings by a novel quantum-behaved particle swarm optimization non-Lyapunov way

    International Nuclear Information System (INIS)

    Gao Fei; Gao Hongrui; Li Zhuoqiu; Tong Hengqing; Lee, Ju-Jang

    2009-01-01

    It is well known that set of unstable periodic orbits (UPOs) can be thought of as the skeleton for the dynamics. However, detecting UPOs of nonlinear map is one of the most challenging problems of nonlinear science in both numerical computations and experimental measures. In this paper, a new method is proposed to detect the UPOs in a non-Lyapunov way. Firstly three special techniques are added to quantum-behaved particle swarm optimization (QPSO), a novel mbest particle, contracting the searching space self-adaptively and boundaries restriction (NCB), then the new method NCB-QPSO is proposed. It can maintain an effective search mechanism with fine equilibrium between exploitation and exploration. Secondly, the problems of detecting the UPOs are converted into a non-negative functions' minimization through a proper translation in a non-Lyapunov way. Thirdly the simulations to 6 benchmark optimization problems and different high order UPOs of 5 classic nonlinear maps are done by the proposed method. And the results show that NCB-QPSO is a successful method in detecting the UPOs, and it has the advantages of fast convergence, high precision and robustness.

  8. Optical Intersatellite Communications for CubeSat Swarms, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The growing interest in CubeSat swarm and constellation systems by NASA, the Department of Defense and commercial ventures has created a need for self-managed...

  9. SWARM - An earth Observation Mission investigating Geospace

    DEFF Research Database (Denmark)

    Friis-Christensen, Eigil; Lühr, H.; Knudsen, D.

    2008-01-01

    The Swarm mission was selected as the 5th mission in ESA's Earth Explorer Programme in 2004. This mission aims at measuring the Earth's magnetic field with unprecedented accuracy. This will be done by a constellation of three satellites, where two will fly at lower altitude, measuring the gradient...... of the Swarm science objectives, the mission concept, the scientific instrumentation, and the expected contribution to the ILWS programme will be summarized. (C) 2007 Published by Elsevier Ltd on behalf of COSPAR....

  10. Using a Combined Platform of Swarm Intelligence Algorithms and GIS to Provide Land Suitability Maps for Locating Cardiac Rehabilitation Defibrillators.

    Science.gov (United States)

    Kaffash-Charandabi, Neda; Sadeghi-Niaraki, Abolghasem; Park, Dong-Kyun

    2015-08-01

    Cardiac arrest is a condition in which the heart is completely stopped and is not pumping any blood. Although most cardiac arrest cases are reported from homes or hospitals, about 20% occur in public areas. Therefore, these areas need to be investigated in terms of cardiac arrest incidence so that places of high incidence can be identified and cardiac rehabilitation defibrillators installed there. In order to investigate a study area in Petersburg, Pennsylvania State, and to determine appropriate places for installing defibrillators with 5-year period data, swarm intelligence algorithms were used. Moreover, the location of the defibrillators was determined based on the following five evaluation criteria: land use, altitude of the area, economic conditions, distance from hospitals and approximate areas of reported cases of cardiac arrest for public places that were created in geospatial information system (GIS). The A-P HADEL algorithm results were more precise about 27.36%. The validation results indicated a wider coverage of real values and the verification results confirmed the faster and more exact optimization of the cost function in the PSO method. The study findings emphasize the necessity of applying optimal optimization methods along with GIS and precise selection of criteria in the selection of optimal locations for installing medical facilities because the selected algorithm and criteria dramatically affect the final responses. Meanwhile, providing land suitability maps for installing facilities across hot and risky spots has the potential to save many lives.

  11. Swarm Products and Space Weather Applications

    DEFF Research Database (Denmark)

    Stolle, Claudia; Olsen, Nils; Martini, Daniel

    The Swarm satellite constellation mission provides high precision magnetic field data and models and other observations that enable us to explore near Earth space for example in terms of in situ electron density and electric fields. On board GPS observables can be used for sounding ionospheric...... and plasmaspheric electron content and GPS and accelerometer data are used to derive information on thermospheric density.Continuous data sets from LEO satellites, such as Swarm, and often combined with ground observations have been useful in developing empirical models of the temporal occurrence and local...... in aeronomy and space weather. We will emphasize results from the Swarm mission....

  12. [Application of small remote sensing satellite constellations for environmental hazards in wetland landscape mapping: taking Liaohe Delta, Liaoning Province of Northeast China as a case].

    Science.gov (United States)

    Yang, Yuan-Zheng; Chang, Yu; Hu, Yuan-Man; Liu, Miao; Li, Yue-Hui

    2011-06-01

    To timely and accurately acquire the spatial distribution pattern of wetlands is of significance for the dynamic monitoring, conservation, and sustainable utilization of wetlands. The small remote sensing satellite constellations A/B stars (HJ-1A/1B stars) for environmental hazards were launched by China for monitoring terrestrial resources, which could provide a new data source of remote sensing image acquisition for retrieving wetland types. Taking Liaohe Delta as a case, this paper compared the accuracy of wetland classification map and the area of each wetland type retrieved from CCD data (HJ CCD data) and TM5 data, and validated and explored the applicability and the applied potential of HJ CCD data in wetland resources dynamic monitoring. The results showed that HJ CCD data could completely replace Landsat TM5 data in feature extraction and remote sensing classification. In real-time monitoring, due to its 2 days of data acquisition cycle, HJ CCD data had the priority to Landsat TM5 data (16 days of data acquisition cycle).

  13. Swarm Data Processing and First Scientific Results

    DEFF Research Database (Denmark)

    Olsen, Nils

    2014-01-01

    Swarm, a three-satellite constellation to study the dynamics of the Earth's magnetic field and its interactions with the Earth system, has been launched in November 2013. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution, which...... will bring new insights into the Earth system by improving our understanding of the Earth's interior and environment. Each of the three Swarm satellites provides high-precision and high-resolution measurements of the strength, direction and variation of the magnetic field, complemented by precise navigation......, accelerometer, plasma and electric field measurements. These observations will be distributed by ESA as Level-1b data, which are the calibrated and formatted time series of e.g. the magnetic field measurements taken by each of the three Swarm satellites. The talks presents a first scientific validation of Swarm...

  14. Elastic and inelastic collisions of swarms

    Science.gov (United States)

    Armbruster, Dieter; Martin, Stephan; Thatcher, Andrea

    2017-04-01

    Scattering interactions of swarms in potentials that are generated by an attraction-repulsion model are studied. In free space, swarms in this model form a well-defined steady state describing the translation of a stable formation of the particles whose shape depends on the interaction potential. Thus, the collision between a swarm and a boundary or between two swarms can be treated as (quasi)-particle scattering. Such scattering experiments result in internal excitations of the swarm or in bound states, respectively. In addition, varying a parameter linked to the relative importance of damping and potential forces drives transitions between elastic and inelastic scattering of the particles. By tracking the swarm's center of mass, a refraction rule is derived via simulations relating the incoming and outgoing directions of a swarm hitting the wall. Iterating the map derived from the refraction law allows us to predict and understand the dynamics and bifurcations of swarms in square boxes and in channels.

  15. The Swarm Initial Field Model for the 2014 geomagnetic field

    DEFF Research Database (Denmark)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent

    2015-01-01

    Data from the first year of ESA's Swarm constellation mission are used to derive the Swarm Initial Field Model (SIFM), a new model of the Earth's magnetic field and its time variation. In addition to the conventional magnetic field observations provided by each of the three Swarm satellites...... agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for East...

  16. Projects as value constellations

    DEFF Research Database (Denmark)

    Laursen, Markus

    Creating value has been outlined as very central to projects applying the organizational perspective to projects. It has been suggested that value is created in value constellations or project networks, where actors work together to create value. However, research on the value creation process...... in value constellations is scarce, and through an exploratory study of two project networks in a cultural setting we investigate how value is created in value constellations. We outline how each project may be a distinct type of value constellation, one project creates value for the partners of the network...... as a consortium, and the project creates value primarily for others as a facilitator....

  17. Geomagnetism mission concepts after Swarm

    International Nuclear Information System (INIS)

    Michael Purucker; Sabaka, T.J.; Richard Holme

    2009-01-01

    Complete text of publication follows. While planning for the ESA Swarm mission has been a primary focus of geomagnetism over the past decade, the long time lags necessary for satellite missions dictate that planning for the next mission begin even before the launch of Swarm. Swarm will measure, for the first time, the E-W gradient of the magnetic field. In 2006, NASA launched a minisatellite magnetometer constellation mission (ST-5) to test technologies and software. The ST-5 constellation made the first along-track gradient measurements. One of the concepts under consideration for missions after Swarm is to systematically measure spatial gradients. The radial gradient could be measured using either an 'uncontrolled' fleet of satellites at different altitudes and local times, or by two or more satellites in a cartwheel configuration. Small-scale static features (degrees > 13) of the core field remain unknown because of their overlap with the crustal field, but they are of critical importance in core flow modeling. To what extent can small-scale features of the core field be separated from longer-wavelength crustal fields using radial gradients? We discuss this question in the context of a model study in which we attempt to recover separate core and crustal fields. The long wavelength crustal field model input is based on the seismic 3SMAC model, updated using MF-6. The core field model input is based on CHAOS-2. We will discuss the extent to which such a separation is ill-posed, and dependent on details of the parameterization. We will also discuss the extent to which such a separation is affected by the presence of annihilators.

  18. Towards diagnostic tools for analysing Swarm data through model retrievals

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Plank, Gernot; Haagmans, R.

    The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal dependency, and to gain new insights into improving our knowledge of the Earth’s interior and climate. The Swarm concept consists of a constellation of three satellites in three different...... polar orbits between 300 and 550 km altitude. Goal of the current study is to build tools and to analyze datasets, in order to allow a fast diagnosis of the Swarm system performance in orbit during the commission phase and operations of the spacecraft. The effects on the reconstruction of the magnetic...... to test the influence of ionospheric residual signal or the impact of data selection on the lithospheric retrieval. Initially, the study considers one satellite and emphasises on the lithospheric field reconstruction, but in a second step it is extended to a realistic Swarm constellation of three...

  19. The Swarm Initial Field Model for the 2014 Geomagnetic Field

    Science.gov (United States)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent; Finlay, Christopher C.; Beggan, Ciaran; Chulliat, Arnaud; Sabaka, Terence J.; Floberghagen, Rune; Friis-Christensen, Eigil; Haagmans, Roger

    2015-01-01

    Data from the first year of ESA's Swarm constellation mission are used to derive the Swarm Initial Field Model (SIFM), a new model of the Earth's magnetic field and its time variation. In addition to the conventional magnetic field observations provided by each of the three Swarm satellites, explicit advantage is taken of the constellation aspect by including east-west magnetic intensity gradient information from the lower satellite pair. Along-track differences in magnetic intensity provide further information concerning the north-south gradient. The SIFM static field shows excellent agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for east-west intensity differences between the lower satellite pair being only 0.12 nT.

  20. SATELLITE CONSTELLATION DESIGN PARAMETER

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. SATELLITE CONSTELLATION DESIGN PARAMETER. 1. ORBIT CHARACTERISTICS. ORBITAL HEIGHT >= 20,000 KM. LONGER VISIBILITY; ORBITAL PERIOD. PERTURBATIONS(MINIMUM). SOLAR RADIATION PRESSURE (IMPACTS ECCENTRICITY); LUNI ...

  1. 3-Dimensional Necklace Flower Constellations

    Science.gov (United States)

    Arnas, David; Casanova, Daniel; Tresaco, Eva; Mortari, Daniele

    2017-12-01

    A new approach in satellite constellation design is presented in this paper, taking as a base the 3D Lattice Flower Constellation Theory and introducing the necklace problem in its formulation. This creates a further generalization of the Flower Constellation Theory, increasing the possibilities of constellation distribution while maintaining the characteristic symmetries of the original theory in the design.

  2. Mapping 3D plasma structure in the solar wind with the L1 constellation: joint observations from Wind, ACE, DSCOVR, and SoHO

    Science.gov (United States)

    Stevens, M. L.; Kasper, J. C.; Case, A. W.; Korreck, K. E.; Szabo, A.; Biesecker, D. A.; Prchlik, J.

    2017-12-01

    At this moment in time, four observatories with similar instrumentation- Wind, ACE, DSCOVR, and SoHO- are stationed directly upstream of the Earth and making continuous observations. They are separated by drift-time baselines of seconds to minutes, timescales on which MHD instabilities in the solar wind are known to grow and evolve, and spatial baselines of tens to 200 earth radii, length scales relevant to the Earth's magnetosphere. By comparing measurements of matched solar wind structures from the four vantage points, the form of structures and associated dynamics on these scales is illuminated. Our targets include shocks and MHD discontinuities, stream fronts, locii of reconnection and exhaust flow boundary layers, plasmoids, and solitary structures born of nonlinear instability. We use the tetrahedral quality factors and other conventions adopted for Cluster to identify periods where the WADS constellation is suitably non-degenerate and arranged in such a way as to enable specific types of spatial, temporal, or spatiotemporal inferences. We present here an overview of the geometries accessible to the L1 constellation and timing-based and plasma-based observations of solar wind structures from 2016-17. We discuss the unique potential of the constellation approach for space physics and space weather forecasting at 1 AU.

  3. Uncharted constellations asterisms, single-source and rebrands

    CERN Document Server

    Barentine, John C

    2016-01-01

    This book compiles an array of interesting constellations that fell by the wayside before the IAU established the modern canon of constellations. That decision left out lesser known ones whose history is nevertheless interesting, but at last author John Barentine is giving them their due. This book is a companion to "The Alternate Constellations", highlighting the more obscure configurations.  The 16 constellations found in this volume fall into one or more of three broad categories: asterims, such as the Big Dipper in Ursa Major; single-sourced constellations introduced on surviving charts by a cartographer perhaps currying the favor of sponsors; and re-brands, new figures meant to displace existing constellations, often for an ideological reason. All of them reveal something unique about the development of humanity's map of the sky. .

  4. Drone Swarms

    Science.gov (United States)

    2017-05-25

    accessed December 20, 2016, http://nationalinterest.org/ blog /the-buzz/swarming-mini-drones-inside- the-pentagons-plan-overwhelm-16135. 43 United States Air...2014, accessed January 26, 2017, http://www.popsci.com/ blog -network/eastern- arsenal/chinas-new-military-robots-pack-more-robots-inside-starcraft...January 21, 2016, accessed February 2, 2017, http://nationalinterest.org/ blog /the-buzz/america-vs-russia- the-race-underwater-spy-drones-14981. 19

  5. Aquarius-Pisces Constellation Boundary Update

    Science.gov (United States)

    Durst, Steve

    2017-06-01

    Observation, mapping and study of Galaxy Stars has provided humanity direction, foundation, clarity and understanding through the ages.Human civilization advances itself using increasing intelligence and knowledge to develop tools and know how, the science of constellation star maps included: All that has been created by humanity, is to serve humanity.When people continue to use constellation star maps that no longer serve people effectively, the maps are updated, as is now the Aquarius-Pisces Constellation Boundary Update (APCBU), which marks 2000 as the year the Sun is in Aquarius at the vernal equinox.The 21st Century APCBU accounts for and incorporates science factors of precession, relativity and galacticity for professional astronomers, and social imperatives of increasing freedom, liberation and egalitarian culture for the 7.5 billion people of Earth.Twenty years into this first century of a new millennium and a new age is an effective time for an APCBU of such elegant simplicity that it changes less than 0.1% of the area of the IAU 1930 official constellation map, which marks 2597 about the year the Sun is in Aquarius at the time of the vernal equinox.The 21st Century APCBU results provide clarity and direction for humanity's next 2,000 years, if not 10,000 or 12,000 years, and advance the official astronomy / science start of the Aquarius Age -- long anticipated, desired, and imperative, especially in America -- by some 600 years.How much attention is increasingly focused on this region of the sky -- such as the recent discovery of 7 Earth-like worlds orbiting the Trappist-1 star in the Aquarius constellation -- will be an epochal 21st Century phenomenon of human science, society, and starlife.

  6. Migraine comorbidity constellations.

    Science.gov (United States)

    Tietjen, Gretchen E; Herial, Nabeel A; Hardgrove, Jacqueline; Utley, Christine; White, Leah

    2007-06-01

    To identify distinct constellations of comorbid disorders occurring in migraineurs, and to examine differences in demographics, headache profiles, and psychosocial features between the comorbidity constellations. This is a retrospective electronic chart review of consecutive new female outpatients diagnosed with migraine (n = 223) using International Classification of Headache Disorders (ICHD)-II criteria. Questionnaire collected information on comorbid diagnoses, current depression, somatic symptoms, psychosocial stressors, and antidepressant use, social and abuse history. Cluster analysis, based on nonheadache disorders, was performed and differences between the resulting groups were examined. We identified 3 groups. Group 1 (n = 55) was defined by hypertension, hyperlipidemia, diabetes mellitus, and hypothyroidism; Group 2 (n = 83) by depression, anxiety, and fibromyalgia; Group 3 (n = 85) by the absence of defining comorbidities. Group 1 had more males (22% vs 5% vs 12%, P constellations, with differing headache and psychosocial profiles, suggesting heterogeneity of genetic and environmental factors. This may have implications for diagnosis and disease management.

  7. Sensor Webs to Constellations

    Science.gov (United States)

    Cole, M.

    2017-12-01

    Advanced technology plays a key role in enabling future Earth-observing missions needed for global monitoring and climate research. Rapid progress over the past decade and anticipated for the coming decades have diminished the size of some satellites while increasing the amount of data and required pace of integration and analysis. Sensor web developments provide correlations to constellations of smallsats. Reviewing current advances in sensor webs and requirements for constellations will improve planning, operations, and data management for future architectures of multiple satellites with a common mission goal.

  8. Constellations-driven innovation

    DEFF Research Database (Denmark)

    Hansbøl, Mikala

    2011-01-01

    a particularly useful point of departure for engaging in researching innovation and didactic design of digital teaching and learning instruments such as the Theme Board that are programmed and serviced 'in the sky'. I call this approach: constellation-driven innovations....

  9. The Family Constellation Scale.

    Science.gov (United States)

    Lemire, David

    The Family Constellation Scale (FC Scale) is an instrument that assesses perceived birth order in families. It can be used in counseling to help initiate conversations about various traits and assumptions that tend to characterize first-born, middle-born children, youngest-born, and only children. It provides both counselors and clients insights…

  10. Macrosecuritization and Security Constellations

    DEFF Research Database (Denmark)

    Buzan, Barry; Wæver, Ole

    2009-01-01

    the middle and system levels, and asks whether there is not more of substance there than the existing Copenhagen school analyses suggests. It revisits the under-discussed concept of security constellations in Copenhagen school theory, and adds to it the idea of macrosecuritizations as ways of getting...

  11. A particle swarm optimized kernel-based clustering method for crop mapping from multi-temporal polarimetric L-band SAR observations

    Science.gov (United States)

    Tamiminia, Haifa; Homayouni, Saeid; McNairn, Heather; Safari, Abdoreza

    2017-06-01

    Polarimetric Synthetic Aperture Radar (PolSAR) data, thanks to their specific characteristics such as high resolution, weather and daylight independence, have become a valuable source of information for environment monitoring and management. The discrimination capability of observations acquired by these sensors can be used for land cover classification and mapping. The aim of this paper is to propose an optimized kernel-based C-means clustering algorithm for agriculture crop mapping from multi-temporal PolSAR data. Firstly, several polarimetric features are extracted from preprocessed data. These features are linear polarization intensities, and several statistical and physical based decompositions such as Cloude-Pottier, Freeman-Durden and Yamaguchi techniques. Then, the kernelized version of hard and fuzzy C-means clustering algorithms are applied to these polarimetric features in order to identify crop types. The kernel function, unlike the conventional partitioning clustering algorithms, simplifies the non-spherical and non-linearly patterns of data structure, to be clustered easily. In addition, in order to enhance the results, Particle Swarm Optimization (PSO) algorithm is used to tune the kernel parameters, cluster centers and to optimize features selection. The efficiency of this method was evaluated by using multi-temporal UAVSAR L-band images acquired over an agricultural area near Winnipeg, Manitoba, Canada, during June and July in 2012. The results demonstrate more accurate crop maps using the proposed method when compared to the classical approaches, (e.g. 12% improvement in general). In addition, when the optimization technique is used, greater improvement is observed in crop classification, e.g. 5% in overall. Furthermore, a strong relationship between Freeman-Durden volume scattering component, which is related to canopy structure, and phenological growth stages is observed.

  12. Landslide Susceptibility Mapping Based on Particle Swarm Optimization of Multiple Kernel Relevance Vector Machines: Case of a Low Hill Area in Sichuan Province, China

    Directory of Open Access Journals (Sweden)

    Yongliang Lin

    2016-10-01

    Full Text Available In this paper, we propose a multiple kernel relevance vector machine (RVM method based on the adaptive cloud particle swarm optimization (PSO algorithm to map landslide susceptibility in the low hill area of Sichuan Province, China. In the multi-kernel structure, the kernel selection problem can be solved by adjusting the kernel weight, which determines the single kernel contribution of the final kernel mapping. The weights and parameters of the multi-kernel function were optimized using the PSO algorithm. In addition, the convergence speed of the PSO algorithm was increased using cloud theory. To ensure the stability of the prediction model, the result of a five-fold cross-validation method was used as the fitness of the PSO algorithm. To verify the results, receiver operating characteristic curves (ROC and landslide dot density (LDD were used. The results show that the model that used a heterogeneous kernel (a combination of two different kernel functions had a larger area under the ROC curve (0.7616 and a lower prediction error ratio (0.28% than did the other types of kernel models employed in this study. In addition, both the sum of two high susceptibility zone LDDs (6.71/100 km2 and the sum of two low susceptibility zone LDDs (0.82/100 km2 demonstrated that the landslide susceptibility map based on the heterogeneous kernel model was closest to the historical landslide distribution. In conclusion, the results obtained in this study can provide very useful information for disaster prevention and land-use planning in the study area.

  13. The elusive constellations of poverty.

    Science.gov (United States)

    Breugelmans, Seger M; Plantinga, Arnoud; Zeelenberg, Marcel; Poluektova, Olga; Efremova, Maria

    2017-01-01

    Pepper & Nettle describe possible processes underlying what they call a behavioral constellation of deprivation (BCD). Although we are certain about the application of evolutionary models to our understanding of poverty, we are less certain about the utility of behavioral constellations. The empirical record on poverty-related behaviors is much more divergent and broad than such constellations suggest.

  14. CM5, a pre-Swarm comprehensive geomagnetic field model derived from over 12 yr of CHAMP, Ørsted, SAC-C and observatory data

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Olsen, Nils; Tyler, Robert H.

    2015-01-01

    A comprehensive magnetic field model named CM5 has been derived from CHAMP, Orsted and SAC-C satellite and observatory hourly-means data from 2000 August to 2013 January using the Swarm Level-2 Comprehensive Inversion (CI) algorithm. Swarm is a recently launched constellation of three satellites...... to map the Earth's magnetic field. The CI technique includes several interesting features such as the bias mitigation scheme known as Selective Infinite Variance Weighting (SIVW), a new treatment for attitude error in satellite vector measurements, and the inclusion of 3-D conductivity for ionospheric...... induction. SIVW has allowed for a much improved lithospheric field recovery over CM4 by exploiting CHAMP along-track difference data yielding resolution levels up to spherical harmonic degree 107, and has allowed for the successful extraction of the oceanic M2 tidal magnetic field from quiet, nightside data...

  15. Constellation Commodities Studies Summary

    Science.gov (United States)

    Dirschka, Eric

    2011-01-01

    Constellation program was NASA's long-term program for space exploration. The goal of the commodities studies was to solicit industry expertise in production, storage, and transportation required for future use and to improve efficiency and life cycle cost over legacy methods. Objectives were to consolidate KSC, CCAFS and other requirements; extract available industry expertise; identify commercial opportunities; and establish synergy with State of Florida partnerships. Study results are reviewed.

  16. Robot Swarms

    Science.gov (United States)

    Morring, Frank, Jr.

    2005-01-01

    Engineers and interns at this NASA field center are building the prototype of a robotic rover that could go where no wheeled rover has gone before-into the dark cold craters at the lunar poles and across the Moon s rugged highlands-like a walking tetrahedron. With NASA pushing to meet President Bush's new exploration objectives, the robots taking shape here today could be on the Moon in a decade. In the longer term, the concept could lead to shape-shifting robot swarms designed to explore distant planetary surfaces in advance of humans. "If you look at all of NASA s projections of the future, anyone s projections of the space program, they re all rigid-body architecture," says Steven Curtis, principal investigator on the effort. "This is not rigid-body. The whole key here is flexibility and reconfigurability with a capital R."

  17. Swarm intelligence.

    Science.gov (United States)

    Chambers, David W

    2011-01-01

    The standard view of how things work is that an outside force impacts a group of individuals and causes outcomes they are interested in. The outside force may not affect all individuals to the same extent, but we can summarize the effect by taking the average. Effective influence is thought to come from the top, not from the group that is being led. The alternative considered here is that a substantial degree of intelligence resided in the individuals or elements that someone wants to study or change. And these elements of the system interact with each other. This phenomenon goes by many names, but will be called swarm intelligence here. There are many cases where simple rules followed at the local level trump or outperform understanding or control from above. Five examples will be given: (a) ethics; (b) the progression of periodontal diseases; (b) dental continuing education; (c) leadership from within; and (d) the wisdom of group decision making.

  18. Swarm Verification

    Science.gov (United States)

    Holzmann, Gerard J.; Joshi, Rajeev; Groce, Alex

    2008-01-01

    Reportedly, supercomputer designer Seymour Cray once said that he would sooner use two strong oxen to plow a field than a thousand chickens. Although this is undoubtedly wise when it comes to plowing a field, it is not so clear for other types of tasks. Model checking problems are of the proverbial "search the needle in a haystack" type. Such problems can often be parallelized easily. Alas, none of the usual divide and conquer methods can be used to parallelize the working of a model checker. Given that it has become easier than ever to gain access to large numbers of computers to perform even routine tasks it is becoming more and more attractive to find alternate ways to use these resources to speed up model checking tasks. This paper describes one such method, called swarm verification.

  19. Characteristics of Swarm Seismicity in Northern California

    Science.gov (United States)

    Chiorini, S.; Lekic, V.

    2017-12-01

    Seismic swarms are characterized by an anomalously large number of earthquakes compared to the background rate of seismicity that are tightly clustered in space (typically, one to tens of kilometers) and time (typically, days to weeks). However, why and how swarms occur is poorly understood, partly because of the difficulty of identifying the range of swarm behaviors within large seismic catalogs. Previous studies have found that swarms, compared to other earthquake sequences, appear to be more common in extensional (Vidale & Shearer, 2006) and volcanic settings (Hayashi & Morita, 2003). In addition, swarms more commonly exhibit migration patterns, consistent with either fluid diffusion (Chen & Shearer, 2011; Chen et al., 2012) or aseismic creep (Lohman & McGuire, 2007), and are preferentially found in areas of enhanced heat flow (Enescu, 2009; Zaliapin & Ben Zion, 2016). While the swarm seismicity of Southern California has been studied extensively, that of Northern California has not been systematically documented and characterized. We employed two complementary methods of swarm identification: the approach of Vidale and Shearer (2006; henceforth VS2006) based on a priori threshold distances and timings of quakes, and the spatio-temporal distance metric proposed by Zaliapin et al. (2008; henceforth Z2008) in order to build a complete catalog of swarm seismicity in Northern California spanning 1984-2016 (Waldhauser & Schaff, 2008). Once filtered for aftershocks, the catalog allows us to describe the main features of swarm seismicity in Northern California, including spatial distribution, association or lack thereof with known faults and volcanic systems, and seismically quiescent regions. We then apply a robust technique to characterize the morphology of swarms, leading to subsets of swarms that are oriented either vertically or horizontally in space. When mapped, vertical swarms show a significant association with volcanic regions, and horizontal swarms with

  20. Swarm Intelligence systems

    International Nuclear Information System (INIS)

    Beni, G.

    1994-01-01

    We review the characteristics of Swarm Intelligence and discuss systems exhibiting it. The recently developed mathematical description of Swarm behavior is also reviewed and discussed. The self-organization of Swarms is described as the reconfiguring asynchronously and conservatively of a distribution. Swarm reconfigurations are based on producing distributions that are solutions to systems of linear equations. Conservation and asynchronicity are related, respectively, to the global and local nature of the Swarm problem. The conditions for the convergence of the Swarm algorithm are presented. The important point is that, under very general conditions, the Swarm reconfigures in a time which is independent of the size of the Swarm. This fact implies that a centralized controller can never reconfigure as fast as a Swarm provided the size of the Swarm is large enough. This result is related to the unpredictability of the Swarm, a basic property of Swarm Intelligence. Finally, the conditions under which Swarm algorithms become of practical importance are discussed and examples given. (author)

  1. CEOS precipitation constellation

    Science.gov (United States)

    Neeck, Steven P.; Oki, Riko

    2007-10-01

    The outcomes of the 19th Committee on Earth Observing Satellites (CEOS) Plenary held in London in November 2005, recognized that the CEOS Implementation Plan for Space-Based Observations for Global Earth Observation System of Systems (GEOSS) should: - identify the supply of space-based observations required to satisfy the requirements expressed by the 10-year implementation plan for GEOSS; and - propose an innovative process whereby the many disparate types of Earth observing programs funded by CEOS Member agencies might contribute to the supply of the required observations. The CEOS Task Force charged with drafting the CEOS Implementation Plan for Space-Based Observations for GEOSS focused its early efforts on the creation of a 'new planning process' which would satisfy the various criteria demanded by member space agencies, and which would hopefully encourage a new phase of specificity and focus in the multi-lateral co-operation efforts undertaken by space agencies under the CEOS umbrella - resulting in improved engagement of all CEOS Members and real implementation results. The CEOS Constellations is the title given to this new process, and four pilot studies have been initiated in order to pioneer and test the concept. The Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) were selected as the lead agencies for the study of the development of a CEOS Precipitation Constellation with the support of other CEOS space agency and user community participants. The goals, approach, and anticipated outcomes for the study will be discussed.

  2. Asterism and constellation: Terminological dilemmas

    Directory of Open Access Journals (Sweden)

    Zorica Prnjat

    2017-04-01

    Full Text Available In contemporary astronomical literature, there is no uniform definition of the term asterism. This inconsistency is the consequence of differences between the traditional understanding of the term constellation, from the standpoint of the naked eye astronomy, and its contemporary understanding from the standpoint of the International Astronomical Union. A traditional constellation is a recognizable star configuration with a well-established name, whereas the International Astronomical Union defines a constellation as an exactly defined sector of the cosmic space that belongs to a particular traditional constellation. Asterism is a lower rank term in comparison to constellation, and as such it may not denote a whole traditional constellation, as these terms would become synonymous and parts of constellations would become “asterisms of asterisms“. Similarly, asterism cannot define a macro configuration composed of the brightest stars in more constellations, thus, the Summer Triangle and other sky polygons are not asterisms. Therefore, asterisms are neither constellations nor sky polygons, but the third - easily recognizable parts of traditional constellations with historically well-established names, including separate groups of smaller stars that belong to star clusters (autonomous asterisms. Forms and names of asterisms may or may not be consistent with the parent constellation, and accordingly asterisms can be divided into compatible and incompatible. If asterisms have outlived the exact division of the celestial sphere and remained irreplaceable celestial landmarks in the naked eye astronomy, then it is high time for the International Astronomical Union to agree on the definition of asterism and to compile their official list.

  3. The elusive constellations of poverty

    NARCIS (Netherlands)

    Breugelmans, S.M.; Plantinga, A.; Zeelenberg, M.; Poluektova, Olga; Efremova, Maria

    2018-01-01

    Pepper & Nettle describe possible processes underlying what they call a behavioral constellation of deprivation (BCD). Although we are certain about the application of evolutionary models to our understanding of poverty, we are less certain about the utility of behavioral constellations. The

  4. The Magnetospheric Multiscale Constellation

    Science.gov (United States)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  5. Quick look tools for magnetic field retrievals from Swarm satellite data

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Plank, Gernot; Haagmans, Roger

    The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal dependency, and to gain new insights into improving our knowledge of the Earth’s interior and climate. The Swarm concept consists of a constellation of three satellites in three different...... near polar orbits between 300 and 550 km altitude. Goal of the current study is to achieve a fast diagnosis of the Swarm system performance in orbit during commission phase and operations of the spacecraft. With the help of a specially developed software package datasets are analyzed in terms...... we consider one satellite. As a second step, the study is extended to the gradient approach which uses the more realistic Swarm constellation of two flying side­by­side satellites. As a result, the lithospheric field is reconstructed with better quality by magnetic field gradient data. Monthly...

  6. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

    2014-01-01

    Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

  7. Constellations and their relationship with categories

    OpenAIRE

    Gould, Victoria; Stokes, Tim

    2015-01-01

    Constellations are partial algebras that are one-sided generalisations of categories. It has previously been shown that the category of inductive constellations is isomorphic to the category of left restriction semigroups. Here we consider constellations in full generality, giving many examples. We characterise those small constellations that are isomorphic to constellations of partial functions. We examine in detail the relationship between constellations and categories, showing the latter t...

  8. Simultaneous field-aligned currents at Swarm and Cluster satellites

    DEFF Research Database (Denmark)

    Dunlop, M. W.; Yang, J. Y.; Yang, Y. Y.

    2015-01-01

    altitude) orbits using a particular Swarm and Cluster conjunction. The Cluster signatures are interpreted and ordered through joint mapping of the ground/magnetospheric footprints and estimation of the auroral zone boundaries (taken as indication of the boundaries of Region 1 and Region 2 currents). We...... find clear evidence of both small-scale and large-scale FACs and clear matching of the behavior and structure of the large-scale currents at both Cluster and Swarm. The methodology is made possible through the joint operations of Cluster and Swarm, which contain, in the first several months of Swarm...

  9. Particle Swarm Optimization

    Science.gov (United States)

    Venter, Gerhard; Sobieszczanski-Sobieski Jaroslaw

    2002-01-01

    The purpose of this paper is to show how the search algorithm known as particle swarm optimization performs. Here, particle swarm optimization is applied to structural design problems, but the method has a much wider range of possible applications. The paper's new contributions are improvements to the particle swarm optimization algorithm and conclusions and recommendations as to the utility of the algorithm, Results of numerical experiments for both continuous and discrete applications are presented in the paper. The results indicate that the particle swarm optimization algorithm does locate the constrained minimum design in continuous applications with very good precision, albeit at a much higher computational cost than that of a typical gradient based optimizer. However, the true potential of particle swarm optimization is primarily in applications with discrete and/or discontinuous functions and variables. Additionally, particle swarm optimization has the potential of efficient computation with very large numbers of concurrently operating processors.

  10. 2D Necklace Flower Constellations

    Science.gov (United States)

    Arnas, David; Casanova, Daniel; Tresaco, Eva

    2018-01-01

    The 2D Necklace Flower Constellation theory is a new design framework based on the 2D Lattice Flower Constellations that allows to expand the possibilities of design while maintaining the number of satellites in the configuration. The methodology presented is a generalization of the 2D Lattice design, where the concept of necklace is introduced in the formulation. This allows to assess the problem of building a constellation in orbit, or the study of the reconfiguration possibilities in a constellation. Moreover, this work includes three counting theorems that allow to know beforehand the number of possible configurations that the theory can provide. This new formulation is especially suited for design and optimization techniques.

  11. Swarm Level 2 Comprehensive Inversion, 2016 Production

    DEFF Research Database (Denmark)

    Tøffner-Clausen, Lars; Sabaka, Terence; Olsen, Nils

    In the framework of the ESA Earth Observation Magnetic Mapping Mission Swarm, the Expert Support Laboratories (ESL) provides high quality Level 2 Products describing a.o. the magnetic fields of the Earth. This poster provides details of the Level 2 Products from the Comprehensive Inversion chain...

  12. Swarm Utilisation Analysis: LEO satellite observations for the ESA's SSA Space Weather network

    Science.gov (United States)

    Kervalishvili, Guram; Stolle, Claudia; Rauberg, Jan; Olsen, Nils; Vennerstrøm, Susanne; Gullikstad Johnsen, Magnar; Hall, Chris

    2017-04-01

    ESA's (European Space Agency) constellation mission Swarm was successfully launched on 22 November 2013. The three satellites achieved their final constellation on 17 April 2014 and since then Swarm-A and Swarm-C orbiting the Earth at about 470 km (flying side-by-side) and Swarm-B at about 520 km altitude. Each of Swarm satellite carries instruments with high precision to measure magnetic and electric fields, neutral and plasma densities, and TEC (Total Electron Content) for which a dual frequency GPS receiver is used. SUA (Swarm Utilisation Analysis) is a project of the ESA's SSA (Space Situational Awareness) SWE (Space Weather) program. Within this framework GFZ (German Research Centre for Geosciences, Potsdam, Germany) and DTU (National Space Institute, Kongens Lyngby, Denmark) have developed two new Swarm products ROT (Rate Of change of TEC) and PEJ (Location and intensity level of Polar Electrojets), respectively. ROT is derived as the first time derivative from the Swarm measurements of TEC at 1 Hz sampling. ROT is highly relevant for users in navigation and communications: strong plasma gradients cause GPS signal degradation or even loss of GPS signal. Also, ROT is a relevant space weather asset irrespective of geomagnetic activity, e.g., high amplitude values of ROT occur during all geomagnetic conditions. PEJ is derived from the Swarm measurements of the magnetic field strength at 1 Hz sampling. PEJ has a high-level importance for power grid companies since the polar electrojet is a major cause for ground-induced currents. ROT and PEJ together with five existing Swarm products TEC, electron density, IBI (Ionospheric Bubble Index), FAC (Field-Aligned Current), and vector magnetic field build the SUA service prototype. This prototype will be integrated into ESA's SSA Space Weather network as a federated service and will be available soon from ESA's SSA SWE Ionospheric Weather and Geomagnetic Conditions Expert Service Centres (ESCs).

  13. CM5, a Pre-Swarm Comprehensive Geomagnetic Field Model Derived from Over 12 Yr of CHAMP, Orsted, SAC-C and Observatory Data

    Science.gov (United States)

    Sabaka, Terence J.; Olsen, Nils; Tyler, Robert H.; Kuvshinov, Alexey

    2014-01-01

    A comprehensive magnetic field model named CM5 has been derived from CHAMP, Ørsted and SAC-C satellite and observatory hourly-means data from 2000 August to 2013 January using the Swarm Level-2 Comprehensive Inversion (CI) algorithm. Swarm is a recently launched constellation of three satellites to map the Earth's magnetic field. The CI technique includes several interesting features such as the bias mitigation scheme known as Selective Infinite Variance Weighting (SIVW), a new treatment for attitude error in satellite vector measurements, and the inclusion of 3-D conductivity for ionospheric induction. SIVW has allowed for a much improved lithospheric field recovery over CM4 by exploiting CHAMP along-track difference data yielding resolution levels up to spherical harmonic degree 107, and has allowed for the successful extraction of the oceanic M2 tidal magnetic field from quiet, nightside data. The 3-D induction now captures anomalous Solar-quiet features in coastal observatory daily records. CM5 provides a satisfactory, continuous description of the major magnetic fields in the near-Earth region over this time span, and its lithospheric, ionospheric and oceanic M2 tidal constituents may be used as validation tools for future Swarm Level-2 products coming from the CI algorithm and other dedicated product algorithms.

  14. A Two Teraflop Swarm

    Directory of Open Access Journals (Sweden)

    Simon Jones

    2018-02-01

    Full Text Available We introduce the Xpuck swarm, a research platform with an aggregate raw processing power in excess of two teraflops. The swarm uses 16 e-puck robots augmented with custom hardware that uses the substantial CPU and GPU processing power available from modern mobile system-on-chip devices. The augmented robots, called Xpucks, have at least an order of magnitude greater performance than previous swarm robotics platforms. The platform enables new experiments that require high individual robot computation and multiple robots. Uses include online evolution or learning of swarm controllers, simulation for answering what-if questions about possible actions, distributed super-computing for mobile platforms, and real-world applications of swarm robotics that requires image processing, or SLAM. The teraflop swarm could also be used to explore swarming in nature by providing platforms with similar computational power as simple insects. We demonstrate the computational capability of the swarm by implementing a fast physics-based robot simulator and using this within a distributed island model evolutionary system, all hosted on the Xpucks.

  15. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    The introgression of modern humans (Homo sapiens) with Neanderthals 40,000 YBP after a half-million years of separation, may have led to the best example of a hybrid swarm on earth. Modern trade and transportation in support of the human hybrids has continued to introduce additional species, genotyp...

  16. Swarm GPS Receiver Performance under the Influence of Ionospheric Scintillation

    Science.gov (United States)

    Ren, Le; Schön, Steffen

    2016-04-01

    The Swarm mission launched on 22 November 2013 is ESA's first constellation of satellites to study the dynamics of the Earth's magnetic field and its interaction with the Earth system. This mission consists of three identical satellites in near-polar orbits , two flying almost side-by-side at an initial altitude of 460 km, the third flying in a higher orbit of about 530 km. Each satellite is equipped with a high precision 8-channels dual-frequency receiver for the precise orbit determination, which is also the essential fundament in order to take full advantage of the data information provided by this constellation, e.g. for the recovery of gravity field. The quality of the final orbit determination depends on the observation data from the receivers. In this contribution, we will analyze the performance of the Swarm on-board receivers, especially under the influence of ionospheric scintillation caused by ionospheric irregularities. This is a prerequisite for high quality satellite positioning as well as a sound study of the ionosphere. Ionospheric scintillation can lead to the phase disturbances, cycle slips or even loss of signal tracking. The RINEX observation data from Swarm Level 1b products are used to analyze the Swarm receiver performance. We will demonstrate the signal strength, code and phase noise, different linear combinations (geometry free, ionosphere free), as well as GDOP values for the 3 Swarm satellites. The first results show that the observation data are severely disturbed and the signals could be lost around the geomagnetic equator and geomagnetic poles where the ionosphere is active. The results also show that the receivers are more stable in those areas after the update in October 2015.

  17. Optimizing coverage and revisit time in sparse military satellite constellations a comparison of traditional approaches and genetic algorithms

    OpenAIRE

    Parish, Jason A.

    2004-01-01

    Sparse military satellite constellations were designed using two methods: a traditional approach and a genetic algorithm. One of the traditional constellation designs was the Discoverer II space based radar. Discoverer II was an 8 plane, 24 satellite, Low Earth Orbit (LEO), Walker constellation designed to provide high-range resolution ground moving target indication (HRR-GMTI), synthetic aperture radar (SAR) imaging and high resolution digital terrain mapping. The traditional method designed...

  18. Use of the Comprehensive Inversion method for Swarm satellite data analysis

    DEFF Research Database (Denmark)

    Sabaka, T. J.; Tøffner-Clausen, Lars; Olsen, Nils

    2013-01-01

    An advanced algorithm, known as the “Comprehensive Inversion” (CI), is presented for the analysis of Swarm measurements to generate a consistent set of Level-2 data products to be delivered by the Swarm “Satellite Constellation Application and Research Facility” (SCARF) to the European Space Agency...... of gradient information from the low-altitude Swarm satellite pair to determine small-scale lithospheric fields, and an improvement in the treatment of attitude error due to noise in star-tracking systems over previously established methods. The advanced CI algorithm is validated by applying it to synthetic...... data from a full simulation of the Swarm mission, where it is found to significantly exceed all mandatory and most target accuracy requirements....

  19. Swarm-based medicine.

    Science.gov (United States)

    Putora, Paul Martin; Oldenburg, Jan

    2013-09-19

    Occasionally, medical decisions have to be taken in the absence of evidence-based guidelines. Other sources can be drawn upon to fill in the gaps, including experience and intuition. Authorities or experts, with their knowledge and experience, may provide further input--known as "eminence-based medicine". Due to the Internet and digital media, interactions among physicians now take place at a higher rate than ever before. With the rising number of interconnected individuals and their communication capabilities, the medical community is obtaining the properties of a swarm. The way individual physicians act depends on other physicians; medical societies act based on their members. Swarm behavior might facilitate the generation and distribution of knowledge as an unconscious process. As such, "swarm-based medicine" may add a further source of information to the classical approaches of evidence- and eminence-based medicine. How to integrate swarm-based medicine into practice is left to the individual physician, but even this decision will be influenced by the swarm.

  20. Multispacecraft current estimates at swarm

    DEFF Research Database (Denmark)

    Dunlop, M. W.; Yang, Y.-Y.; Yang, J.-Y.

    2015-01-01

    During the first several months of the three-spacecraft Swarm mission all three spacecraft camerepeatedly into close alignment, providing an ideal opportunity for validating the proposed dual-spacecraftmethod for estimating current density from the Swarm magnetic field data. Two of the Swarm...

  1. Development of Constellation-X optics technologies at MSFC

    Science.gov (United States)

    O'Dell, Stephen L.; Jones, William D.; Ramsey, Brian D.; Engelhaupt, Darell E.; Smith, Winfred S.; Cohen, Lester M.; Van Speybroeck, Leon P.

    2000-07-01

    The Constellation X-ray Mission is the next major x-ray- astronomy mission in the NASA Space Science road map. As a follow-on to the Chandra X-ray Observatory--nee, the Advanced X-ray Astrophysics Facility--Constellation X will provide high-throughput, high-resolution spectroscopy to probe the gravitational field, kinematics, temperature, density, composition and ionization state of cosmic sources. The Constellation-X observatory system comprises four separate satellites, each with one large Spectroscopy X-ray Telescope (SXT, with a pixelated microcalorimeter and a reflection-grating-CCD spectrometer) and three smaller Hard X-ray Telescopes (HXTs, with pixelated hard-x-ray detectors). Essential to the success of Constellation X is the development of large (1.6-m-diameter), lightweight optics for the SXT mirror assembly. With the Smithsonian Astrophysical Observatory, teams led by NASA's Marshall Space Flight Center, by NASA's Goddard Space Flight Center, and by Italy's Osservatorio Astronomico di Brera are currently developing competing mirror techniques for lightweight SXT optics, toward achieving the required system-level half-power diameter--better than 15 arcsec.

  2. Particle Swarm Optimization Toolbox

    Science.gov (United States)

    Grant, Michael J.

    2010-01-01

    The Particle Swarm Optimization Toolbox is a library of evolutionary optimization tools developed in the MATLAB environment. The algorithms contained in the library include a genetic algorithm (GA), a single-objective particle swarm optimizer (SOPSO), and a multi-objective particle swarm optimizer (MOPSO). Development focused on both the SOPSO and MOPSO. A GA was included mainly for comparison purposes, and the particle swarm optimizers appeared to perform better for a wide variety of optimization problems. All algorithms are capable of performing unconstrained and constrained optimization. The particle swarm optimizers are capable of performing single and multi-objective optimization. The SOPSO and MOPSO algorithms are based on swarming theory and bird-flocking patterns to search the trade space for the optimal solution or optimal trade in competing objectives. The MOPSO generates Pareto fronts for objectives that are in competition. A GA, based on Darwin evolutionary theory, is also included in the library. The GA consists of individuals that form a population in the design space. The population mates to form offspring at new locations in the design space. These offspring contain traits from both of the parents. The algorithm is based on this combination of traits from parents to hopefully provide an improved solution than either of the original parents. As the algorithm progresses, individuals that hold these optimal traits will emerge as the optimal solutions. Due to the generic design of all optimization algorithms, each algorithm interfaces with a user-supplied objective function. This function serves as a "black-box" to the optimizers in which the only purpose of this function is to evaluate solutions provided by the optimizers. Hence, the user-supplied function can be numerical simulations, analytical functions, etc., since the specific detail of this function is of no concern to the optimizer. These algorithms were originally developed to support entry

  3. Swarm algorithms with chaotic jumps for optimization of multimodal functions

    Science.gov (United States)

    Krohling, Renato A.; Mendel, Eduardo; Campos, Mauro

    2011-11-01

    In this article, the use of some well-known versions of particle swarm optimization (PSO) namely the canonical PSO, the bare bones PSO (BBPSO) and the fully informed particle swarm (FIPS) is investigated on multimodal optimization problems. A hybrid approach which consists of swarm algorithms combined with a jump strategy in order to escape from local optima is developed and tested. The jump strategy is based on the chaotic logistic map. The hybrid algorithm was tested for all three versions of PSO and simulation results show that the addition of the jump strategy improves the performance of swarm algorithms for most of the investigated optimization problems. Comparison with the off-the-shelf PSO with local topology (l best model) has also been performed and indicates the superior performance of the standard PSO with chaotic jump over the standard both using local topology (l best model).

  4. Family constellation and psychosexual disturbances.

    Science.gov (United States)

    Lidberg, L

    1976-08-01

    In patients with psychosexual disturbances (impotence and ejaculatio praecox) the family constellation during childhood and the patients' occupations were compared with the Swedish population census. The parents of the patients were older, and the patients were more often the only son or the only child. A greater percentage of the patients had technical or office administrative professions than the inhabitants in Stockholm. The findings are discussed with references to a supposed focus on achievement in the upbringing of the oldest or only son. Focus on achievement may cause emotional restraint and subsequently psychosexual disturbances.

  5. A Novel Distributed Quantum-Behaved Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Yangyang Li

    2017-01-01

    Full Text Available Quantum-behaved particle swarm optimization (QPSO is an improved version of particle swarm optimization (PSO and has shown superior performance on many optimization problems. But for now, it may not always satisfy the situations. Nowadays, problems become larger and more complex, and most serial optimization algorithms cannot deal with the problem or need plenty of computing cost. Fortunately, as an effective model in dealing with problems with big data which need huge computation, MapReduce has been widely used in many areas. In this paper, we implement QPSO on MapReduce model and propose MapReduce quantum-behaved particle swarm optimization (MRQPSO which achieves parallel and distributed QPSO. Comparisons are made between MRQPSO and QPSO on some test problems and nonlinear equation systems. The results show that MRQPSO could complete computing task with less time. Meanwhile, from the view of optimization performance, MRQPSO outperforms QPSO in many cases.

  6. Optimal Maintenance for Stochastically Degrading Staellite Constellations

    National Research Council Canada - National Science Library

    Cook, Timothy J

    2005-01-01

    .... Previous work has developed a methodology to compute an optimal replacement policy for a satellite constellation in which satellites were viewed as binary entities, either operational or failed...

  7. Stochastic Capability Models for Degrading Satellite Constellations

    National Research Council Canada - National Science Library

    Gulyas, Cole W

    2005-01-01

    This thesis proposes and analyzes a new measure of functional capability for satellite constellations that incorporates the instantaneous availability and mission effectiveness of individual satellites...

  8. АSTERISM AND CONSTELLATION: TERMINOLOGICAL DILEMMAS

    Directory of Open Access Journals (Sweden)

    Zorica Prnjat

    2017-04-01

    Full Text Available In contemporary astronomical literature, there is no uniform definition of the term asterism. This inconsistency is the consequence of differences between traditional understanding of the term constellation, from the standpoint of the naked eye astronomy, and its contemporary understanding from the standpoint of the International Astronomical Union. A traditional constellation is a recognizable star configuration with a well-established name, whereas the International Astronomical Union defines a constellation as an exactly defined sector of the cosmic space that belongs to a particular traditional constellation. Asterism is a lower rank term in comparison to constellation, and as such it may not denote a whole traditional constellation, as these terms would become synonymous and parts of constellations would become “asterisms of asterisms“. Similarly, asterism cannot define a macro configuration composed of the brightest stars in more constellations, thus, the Summer Triangle and other sky polygons are not asterisms. Therefore, asterisms are neither constellations nor sky polygons, but the third – easily recognizable parts of traditional constellations with historically well-established names, including separate groups of smaller stars that belong to star clusters (autonomous asterisms. Forms and names of asterisms may or may not be consistent with the parent constellation, and accordingly asterisms can be divided into compatible and incompatible. If asterisms have outlived the exact division of the celestial sphere and remained irreplaceable celestial landmarks in the naked eye astronomy, it is high time for the International Astronomical Union to agree on the definition of asterism and to compile their official list.

  9. Glowworm swarm optimization theory, algorithms, and applications

    CERN Document Server

    Kaipa, Krishnanand N

    2017-01-01

    This book provides a comprehensive account of the glowworm swarm optimization (GSO) algorithm, including details of the underlying ideas, theoretical foundations, algorithm development, various applications, and MATLAB programs for the basic GSO algorithm. It also discusses several research problems at different levels of sophistication that can be attempted by interested researchers. The generality of the GSO algorithm is evident in its application to diverse problems ranging from optimization to robotics. Examples include computation of multiple optima, annual crop planning, cooperative exploration, distributed search, multiple source localization, contaminant boundary mapping, wireless sensor networks, clustering, knapsack, numerical integration, solving fixed point equations, solving systems of nonlinear equations, and engineering design optimization. The book is a valuable resource for researchers as well as graduate and undergraduate students in the area of swarm intelligence and computational intellige...

  10. The Solar system.Stars and constellations

    Science.gov (United States)

    Horia Minda, Octavian

    2017-04-01

    It is important for students to understand what is in our Solar System. The Students need to know that there are other things besides the Earth, Sun and Moon in the solar sky. The students will learn about the other eight planets and a few other celestial objects like stars and constellations. Constellations are useful because they can help people to recognize stars in the sky. By looking for patterns, the stars and locations can be much easier to spot. The constellations had uses in ancient times. They were used to help keep track of the calendar. This was very important so that people knew when to plant and harvest crops. Another important use for constellations was navigation. By finding Ursa Minor it is fairly easy to spot the North Star (Polaris). Using the height of the North Star in the sky, navigators could figure out their latitude helping ships to travel across the oceans. Objective: 1. The students will be introduced to the origin of the stars they see at night. 2. They will learn that there are groups of stars called constellations. The students will individually create their own constellations. They will be given the chance to tell the class a small story explaining their constellation. Evaluation of Children: The children will be evaluated through the creation of their constellations and ability to work in groups on the computers.

  11. Constellations: A New Paradigm for Earth Observations

    Science.gov (United States)

    Kelly, Angelita C.; Volz, Stephen M.; Yuhas, Cheryl L.; Case, Warren F.

    2009-01-01

    The last decade has seen a significant increase in the number and the capabilities of remote sensing satellites launched by the international community. A relatively new approach has been the launching of satellites into heterogeneous constellations. Constellations provide the scientists a capability to acquire science data, not only from specific instruments on a single satellite, but also from instruments on other satellites that fly in the same orbit. Initial results from the A-Train (especially following the CALIPSO/CloudSat launch) attest to the tremendous scientific value of constellation flying. This paper provides a history of the constellations (particularly the A-Train) and how the A-Train mission design was driven by science requirements. The A-Train has presented operational challenges which had not previously been encountered. Operations planning had to address not only how the satellites of each constellation operate safely together, but also how the two constellations fly in the same orbits without interfering with each other when commands are uplinked or data are downlinked to their respective ground stations. This paper discusses the benefits of joining an on-orbit constellation. When compared to a single, large satellite, a constellation infrastructure offers more than just the opportunities for coincidental science observations. For example, constellations reduce risks by distributing observing instruments among numerous satellites; in contrast, a failed launch or a system failure in a single satellite would lead to loss of all observations. Constellations allow for more focused, less complex satellites. Constellations distribute the development, testing, and operations costs among various agencies and organizations for example, the Morning and Afternoon Constellations involve several agencies within the U.S. and in other countries. Lastly, this paper addresses the need to plan for the long-term evolution of a constellation. Agencies need to have

  12. Swarming Overlay Construction Strategies

    OpenAIRE

    Al Hamra, Anwar; Liogkas, Nikitas; Legout, Arnaud; Barakat, Chadi

    2009-01-01

    International audience; Swarming peer-to-peer systems play an increasingly instrumental role in Internet content distribution. It is therefore important to better understand how these systems behave in practice. Recent research efforts have looked at various protocol parameters and have measured how they affect system performance and robustness. However, the importance of the strategy based on which peers establish connections has been largely overlooked. This work utilizes extensive simulati...

  13. Swarm robotics and minimalism

    Science.gov (United States)

    Sharkey, Amanda J. C.

    2007-09-01

    Swarm Robotics (SR) is closely related to Swarm Intelligence, and both were initially inspired by studies of social insects. Their guiding principles are based on their biological inspiration and take the form of an emphasis on decentralized local control and communication. Earlier studies went a step further in emphasizing the use of simple reactive robots that only communicate indirectly through the environment. More recently SR studies have moved beyond these constraints to explore the use of non-reactive robots that communicate directly, and that can learn and represent their environment. There is no clear agreement in the literature about how far such extensions of the original principles could go. Should there be any limitations on the individual abilities of the robots used in SR studies? Should knowledge of the capabilities of social insects lead to constraints on the capabilities of individual robots in SR studies? There is a lack of explicit discussion of such questions, and researchers have adopted a variety of constraints for a variety of reasons. A simple taxonomy of swarm robotics is presented here with the aim of addressing and clarifying these questions. The taxonomy distinguishes subareas of SR based on the emphases and justifications for minimalism and individual simplicity.

  14. A Parallel Particle Swarm Optimizer

    National Research Council Canada - National Science Library

    Schutte, J. F; Fregly, B .J; Haftka, R. T; George, A. D

    2003-01-01

    .... Motivated by a computationally demanding biomechanical system identification problem, we introduce a parallel implementation of a stochastic population based global optimizer, the Particle Swarm...

  15. Utilizing field-aligned current profiles derived from Swarm to estimate the peak emission height of 630 nm auroral arcs: a comparison of methods and discussion of associated error estimates in the ASI data.

    Science.gov (United States)

    Gillies, D. M.; Knudsen, D. J.; Donovan, E.; Jackel, B. J.; Gillies, R.; Spanswick, E.

    2017-12-01

    We compare field-aligned currents (FACs) measured by the Swarm constellation of satellites with the location of red-line (630 nm) auroral arcs observed by all-sky imagers (ASIs) to derive a characteristic emission height for the optical emissions. In our 10 events we find that an altitude of 200 km applied to the ASI maps gives optimal agreement between the two observations. We also compare the new FAC method against the traditional triangulation method using pairs of all-sky imagers (ASIs), and against electron density profiles obtained from the Resolute Bay Incoherent Scatter Radar-Canadian radar (RISR-C), both of which are consistent with a characteristic emission height of 200 km. We also present the spatial error associated with georeferencing REdline Geospace Observatory (REGO) and THEMIS all-sky imagers (ASIs) and how it applies to altitude projections of the mapped image. Utilizing this error we validate the estimated altitude of redline aurora using two methods: triangulation between ASIs and field-aligned current profiles derived from magnetometers on-board the Swarm satellites.

  16. Space Weather opportunities from the Swarm mission including near real time applications

    DEFF Research Database (Denmark)

    Stolle, Claudia; Floberghagen, Rune; Luehr, Hermann

    2013-01-01

    observations of the solar and interplanetary conditions. New opportunities lie in the implementation of in-situ observations of the ionosphere and upper atmosphere onboard low Earth orbiting (LEO) satellites. The multi-satellite mission Swarm is equipped with several instruments which will observe...... electromagnetic and atmospheric parameters of the near Earth space environment. Taking advantage of the multi-disciplinary measurements and the mission constellation different Swarm products have been defined or demonstrate great potential for further development of novel space weather products. Examples...... these products in timely manner will add significant value in monitoring present space weather and helping to predict the evolution of several magnetic and ionospheric events. Swarm will be a demonstrator mission for the valuable application of LEO satellite observations for space weather monitoring tools....

  17. Rate-adaptive Constellation Shaping for Near-capacity Achieving Turbo Coded BICM

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Forchhammer, Søren; Larsen, Knud J.

    2014-01-01

    In this paper the problem of constellation shaping is considered. Mapping functions are designed for a many- to-one signal shaping strategy, combined with a turbo coded Bit-interleaved Coded Modulation (BICM), based on symmetric Huffman codes with binary reflected Gray-like properties. An algorithm...... quality estimation. Gains of more than 1dB are observed for high SNR compared to conventional turbo coded BICM, and it is shown that the mapping functions designed here significantly outperform current state of the art Turbo- Trellis Coded Modulation and other existing constellation shaping methods...

  18. Earthquake swarms in South America

    Science.gov (United States)

    Holtkamp, S. G.; Pritchard, M. E.; Lohman, R. B.

    2011-10-01

    We searched for earthquake swarms in South America between 1973 and 2009 using the global Preliminary Determination of Epicenters (PDE) catalogue. Seismicity rates vary greatly over the South American continent, so we employ a manual search approach that aims to be insensitive to spatial and temporal scales or to the number of earthquakes in a potential swarm. We identify 29 possible swarms involving 5-180 earthquakes each (with total swarm moment magnitudes between 4.7 and 6.9) within a range of tectonic and volcanic locations. Some of the earthquake swarms on the subduction megathrust occur as foreshocks and delineate the limits of main shock rupture propagation for large earthquakes, including the 2010 Mw 8.8 Maule, Chile and 2007 Mw 8.1 Pisco, Peru earthquakes. Also, subduction megathrust swarms commonly occur at the location of subduction of aseismic ridges, including areas of long-standing seismic gaps in Peru and Ecuador. The magnitude-frequency relationship of swarms we observe appears to agree with previously determined magnitude-frequency scaling for swarms in Japan. We examine geodetic data covering five of the swarms to search for an aseismic component. Only two of these swarms (at Copiapó, Chile, in 2006 and near Ticsani Volcano, Peru, in 2005) have suitable satellite-based Interferometric Synthetic Aperture Radar (InSAR) observations. We invert the InSAR geodetic signal and find that the ground deformation associated with these swarms does not require a significant component of aseismic fault slip or magmatic intrusion. Three swarms in the vicinity of the volcanic arc in southern Peru appear to be triggered by the Mw= 8.5 2001 Peru earthquake, but predicted static Coulomb stress changes due to the main shock were very small at the swarm locations, suggesting that dynamic triggering processes may have had a role in their occurrence. Although we identified few swarms in volcanic regions, we suggest that particularly large volcanic swarms (those that

  19. Provider collaboration: cohesion, constellations, and shared patients.

    Science.gov (United States)

    Mandl, Kenneth D; Olson, Karen L; Mines, Daniel; Liu, Chunfu; Tian, Fang

    2014-11-01

    There is a natural assumption that quality and efficiency are optimized when providers consistently work together and share patients. Diversity in composition and recurrence of groups that provide face-to-face care to the same patients has not previously been studied. Claims data enable identification of the constellation of providers caring for a single patient. To indirectly measure teamwork and provider collaboration, we measure recurrence of provider constellations and cohesion among providers. Retrospective analysis of commercial healthcare claims from a single insurer. Patients with claims for office visits and their outpatient providers. To maximize capture of provider panels, the cohort was drawn from the four regions with the highest plan coverage. Regional outpatient provider networks were constructed with providers as nodes and number of shared patients as links. Measures of cohesion and stability of provider constellations derived from the networks of providers to quantify patient sharing. For 10,325 providers and their 521,145 patients, there were 2,641,933 collaborative provider pairs sharing at least one patient. Fifty-four percent only shared a single patient, and 19 % shared two. Of 15,449,835 unique collaborative triads, 92 % shared one patient, 5 % shared two, and 0.2 % shared ten or more. Patient constellations had a median of four providers. Any precise constellation recurred rarely-89 % with exactly two providers shared just one patient and only 4 % shared over two; 97 % of constellations with exactly three providers shared just one patient. Four percent of constellations with 2+ providers were not at all cohesive, sharing only the hub patient. In the remaining constellations, a median of 93 % of provider pairs shared at least one additional patient beyond the hub patient. Stunning variability in the constellations of providers caring for patients may challenge underlying assumptions about the current state of teamwork in healthcare.

  20. BRITE-Constellation Science Operations

    Science.gov (United States)

    Kuschnig, R.

    2017-09-01

    BRITE-Constellation is a nanosatellite mission designed for stellar astrophysical research in collaboration between Austria, Canada and Poland. A fleet of six spacecrafts was funded, built and launched, two from each country, all designed to perform precise time-series photometry of the brightest stars in the sky. While the spacecrafts have the same basic design, three satellites host an instrument sensitive in a red bandpass, the others, for a blue wavelength range. From the six satellites launched, five are operational. The sixth one did not separate from the upper stage of the rocket and remains idle. The first pair, the Austrian satellites, started to collect science measurements with their wide field (˜24°) cameras in early December 2013. Since then, more than 340 stars were observed during 16 campaigns, the majority for more than 100 days (up to 168 days) continuously. In total, more than 2.1 million measurements have been collected so far. Originally, the limiting magnitude for target stars was set to \\mag(V)=4. However, even stars as faint as \\mag(V)=6.5 have been observed with sufficient precision. This is a review of science operations conducted during the past 3.5 years.

  1. The 50 Constellation Priority Sites

    Science.gov (United States)

    Noble, S.; Joosten, K.; Eppler, D.; Gruener, J.; Mendell, W.; French, R.; Plescia, J.; Spudis, P.; Wargo, M.; Robinson, M.; hide

    2009-01-01

    The Constellation program (CxP) has developed a list of 50 sites of interest on the Moon which will be targeted by the LRO narrow angle camera. The list has also been provided to the M team to supplement their targeting list. This list does not represent a "site selection" process; rather the goal was to find "representative" sites and terrains to understand the range of possible surface conditions for human lunar exploration to aid engineering design and operational planning. The list compilers leveraged heavily on past site selection work (e.g. Geoscience and a Lunar Base Workshop - 1988, Site Selection Strategy for a Lunar Outpost - 1990, Exploration Systems Architecture Study (ESAS) - 2005). Considerations included scientific, resource utilization, and operational merits, and a desire to span lunar terrain types. The targets have been organized into two "tiers" of 25 sites each to provide a relative priority ranking in the event of mutual interference. A LEAG SAT (special action team) was established to validate and recommend modifications to the list. This SAT was chaired by Dr. Paul Lucey. They provided their final results to CxP in May. Dr. Wendell Mendell will organize an on-going analysis of the data as they come down to ensure data quality and determine if and when a site has sufficient data to be retired from the list. The list was compiled using the best available data, however, it is understood that with the flood of new lunar data, minor modifications or adjustments may be required.

  2. EOS Terra: Mission Status Constellation MOWG

    Science.gov (United States)

    Mantziaras, Dimitrios

    2016-01-01

    This EOS Terra Mission Status Constellation MOWG will discuss mission summary; spacecraft subsystems summary, recent and planned activities; inclination adjust maneuvers, conjunction history, propellant usage and lifetime estimate; and end of mission plan.

  3. Odyssey between the constellations and neuromedicine.

    Science.gov (United States)

    Lee, Kung-Shing; Lin, Chih-Lin; Chuang, Chih-Lung; Hwang, Shiuh-Lin; Howng, Shen-Long; Lieu, Ann-Shung

    2006-01-01

    The constellations have some connections with neuromedicine. As neurosurgeons, we can learn something from the night sky. Medical terms or descriptions are generously used from mythology or celestial lore. Neurosurgeons spend so much time on their professional careers that they may ignore something wonderful which is worthy of their attention. The puzzling issues between the constellations and neuromedicine can be exciting. Imagination allows neurosurgery to make great strides and progression. With that same imagination we can take an odyssey!

  4. Components of Swarm Intelligence

    Energy Technology Data Exchange (ETDEWEB)

    David Bruemmer; Donald Dudenhoeffer; Matthew Anderson; Mark McKay

    2004-03-01

    This paper discusses the successes and failures over the past three years as efforts at the Idaho National Engineering and Environmental Laboratory (INEEL) have developed and evaluated robot behaviors that promote the emergence of swarm intelligence. Using a team of 12 small robots with the ability to respond to light and sound, the INEEL has investigated the fundamental advantages of swarm behavior as well as the limitations of this approach. The paper discusses the ways in which biology has inspired this work and the ways in which adherence to the biological model has proven to be both a benefit and hindrance to developing a fieldable system. The paper outlines how a hierarchical command and control structure can be imposed in order to permit human control at a level of group abstraction and discusses experimental results that show how group performance scales as different numbers of robots are utilized. Lastly, the paper outlines the applications for which the resulting capabilities have been applied and demonstrated.

  5. A Mapping Method Applied to the IT Solutions Procurement Guide of IN/SLTI/ MPOG 04/2014 Normative Instruction and Models Constellation CMMI-ACQ, CMMI-DEV and CMMI-SVC

    Directory of Open Access Journals (Sweden)

    PLÁCIDO DA SILVA, L. S.

    2016-12-01

    Full Text Available Several initiatives have emerged in the search for improvement of software processes in recent years. These initiatives are usually guided by Standards, Models and Quality Standards, aiming to establish best practices to guide the definition of processes and support the assessment of the maturity and capacity of organizations in the development of software products and provision of IT services. Despite the emergence of several initiatives, when the topic refers to the processes of contracting information technology (IT solutions by the Brazilian Federal Public Administration (APF, its application in the context of organizations has obstacles, such as the complexity of the processes and oversight of federal government agencies. In order to overcome these obstacles, the Court of Audit of the Union (TCU recommended the preparation of the SLTI/MPOG 04/2014 Normative Instruction, containing guidelines for the process of contracting IT Solutions. This work defines a Mapping Method between IN/SLTI/MPOG 04/2014 and APF's IT Solutions Procurement Guide (GCSTI, with the objective of identifying the maturity and adherence of GCSTI to CMMI-ACQ, CMMI -DEV and CMMI-SVC. This work defines a Mapping Method between IN / SLTI / MPOG 04/2014 and its processes defined in the APF IT Solutions Procurement Guide (GCSTI, with the objective of identifying the maturity and adherence of the GCSTI to the Models CMMI-ACQ, CMMI-DEV and CMMI-SVC and bringing as benefits a systematized and structured methodology to apply and map models, norms and standards of any nature. As a result of this research, the mapping method created allowed the mapping between the CMMI and GSTI models of IN / SLTI / PMO 04/2014, and the method could be applied in any other mapping, from which the processes were oriented to the same Structure and had similar objectives.

  6. Book Review: Photo-Guide to the Constellations: A Self-Teaching Guide to Finding Your Way Around the Heavens (Copyright 1998, Springer; London)

    Science.gov (United States)

    Marigza, R. N., Jr.

    2009-06-01

    Chris Kitchin's Photo-Guide to the Constellations is part of the Practical Astronomy Series that is edited by Patrick Moore. The guide provides photos and sketches of the constellations along with the background on the history of the constellation, derivation of its name, descriptions and a list of deepsky objects that can be found. Each photo in the book is backed up with a map of the targeted area in the sky, making it somewhat like an atlas of constellations. The book also provides a brief description of the planets.

  7. Tectonic setting of the Wooded Island earthquake swarm, eastern Washington

    Science.gov (United States)

    Blakely, Richard J.; Sherrod, Brian L.; Weaver, Craig S.; Rohay, Alan C.; Wells, Ray E.

    2012-01-01

    Magnetic anomalies provide insights into the tectonic implications of a swarm of ~1500 shallow (~1 km deep) earthquakes that occurred in 2009 on the Hanford site,Washington. Epicenters were concentrated in a 2 km2 area nearWooded Island in the Columbia River. The largest earthquake (M 3.0) had first motions consistent with slip on a northwest-striking reverse fault. The swarm was accompanied by 35 mm of vertical surface deformation, seen in satellite interferometry (InSAR), interpreted to be caused by ~50 mm of slip on a northwest-striking reverse fault and associated bedding-plane fault in the underlying Columbia River Basalt Group (CRBG). A magnetic anomaly over exposed CRBG at Yakima Ridge 40 km northwest of Wooded Island extends southeastward beyond the ridge to the Columbia River, suggesting that the Yakima Ridge anticline and its associated thrust fault extend southeastward in the subsurface. In map view, the concealed anticline passes through the earthquake swarm and lies parallel to reverse faults determined from first motions and InSAR data. A forward model of the magnetic anomaly near Wooded Island is consistent with uplift of concealed CRBG, with the top surface swarm and the thrust and bedding-plane faults modeled from interferometry all fall within the northeastern limb of the faulted anticline. Although fluids may be responsible for triggering the Wooded Island earthquake swarm, the seismic and aseismic deformation are consistent with regional-scale tectonic compression across the concealed Yakima Ridge anticline.

  8. EXIT Chart Analysis of Iterative Demodulation and Decoding of MPSK Constellations with Signal Space Diversity

    NARCIS (Netherlands)

    Weber, J.H.; Kiyani, N.F.

    2008-01-01

    Bit interleaved coded modulation (BICM) schemes have been shown to increase the diversity order. This paper studies the extension of such schemes with iterative demodulation and decoding (ID) using error correcting codes coupled with rotated MPSK signal constellations with different symbol mappings

  9. Quantum Behaved Particle Swarm Optimization Algorithm Based on Artificial Fish Swarm

    OpenAIRE

    Yumin, Dong; Li, Zhao

    2014-01-01

    Quantum behaved particle swarm algorithm is a new intelligent optimization algorithm; the algorithm has less parameters and is easily implemented. In view of the existing quantum behaved particle swarm optimization algorithm for the premature convergence problem, put forward a quantum particle swarm optimization algorithm based on artificial fish swarm. The new algorithm based on quantum behaved particle swarm algorithm, introducing the swarm and following activities, meanwhile using the a...

  10. Visualization of Biosurfactant Film Flow in a Bacillus subtilis Swarm Colony on an Agar Plate.

    Science.gov (United States)

    Kim, Kyunghoon; Kim, Jung Kyung

    2015-08-26

    Collective bacterial dynamics plays a crucial role in colony development. Although many research groups have studied the behavior of fluidic swarm colonies, the detailed mechanics of its motion remains elusive. Here, we developed a visualization method using submicron fluorescent beads for investigating the flow field in a thin layer of fluid that covers a Bacillus subtilis swarm colony growing on an agar plate. The beads were initially embedded in the agar plate and subsequently distributed spontaneously at the upper surface of the expanding colony. We conducted long-term live cell imaging of the B. subtilis colony using the fluorescent tracers, and obtained high-resolution velocity maps of microscale vortices in the swarm colony using particle image velocimetry. A distinct periodic fluctuation in the average speed and vorticity of flow in swarm colony was observed at the inner region of the colony, and correlated with the switch between bacterial swarming and growth phases. At the advancing edge of the colony, both the magnitudes of velocity and vorticity of flow in swarm colony were inversely correlated with the spreading speed of the swarm edge. The advanced imaging tool developed in this study would facilitate further understanding of the effect of micro vortices in swarm colony on the collective dynamics of bacteria.

  11. Visualization of Biosurfactant Film Flow in a Bacillus subtilis Swarm Colony on an Agar Plate

    Directory of Open Access Journals (Sweden)

    Kyunghoon Kim

    2015-08-01

    Full Text Available Collective bacterial dynamics plays a crucial role in colony development. Although many research groups have studied the behavior of fluidic swarm colonies, the detailed mechanics of its motion remains elusive. Here, we developed a visualization method using submicron fluorescent beads for investigating the flow field in a thin layer of fluid that covers a Bacillus subtilis swarm colony growing on an agar plate. The beads were initially embedded in the agar plate and subsequently distributed spontaneously at the upper surface of the expanding colony. We conducted long-term live cell imaging of the B. subtilis colony using the fluorescent tracers, and obtained high-resolution velocity maps of microscale vortices in the swarm colony using particle image velocimetry. A distinct periodic fluctuation in the average speed and vorticity of flow in swarm colony was observed at the inner region of the colony, and correlated with the switch between bacterial swarming and growth phases. At the advancing edge of the colony, both the magnitudes of velocity and vorticity of flow in swarm colony were inversely correlated with the spreading speed of the swarm edge. The advanced imaging tool developed in this study would facilitate further understanding of the effect of micro vortices in swarm colony on the collective dynamics of bacteria.

  12. Station keeping strategies for constellations of satellites

    Science.gov (United States)

    Lamy, Alain; Pascal, Stephane

    Communication systems based on constellations of satellite deployed in Low Earth Orbits (LEO) constitute a great number of new space projects. The objectives of these missions are generally expressed in term of global properties: coverage (global or related to specific areas), simultaneous satellite visibilities with ground stations, maximum waiting time. The quality of the service provided by the mission is defined by statistical measurements of these properties (probability of having one satellite in visibility from any point more than 0.8 for example) that must be guaranteed during the mission life-time by adequate station keeping strategies. Immediate solutions for station keeping of constellation are either non-controlled orbits (simple but with uncertain results) or independent orbit control for each satellite (with respect to a nominal orbit). This latter solution is reliable and well known but may overload control stations; so it is necessary to find better strategies, in term of cost (reduction of Delta V or ground segment load), adapted to constellations. Thus, the aim of this paper is to study the feasibility of a global station keeping strategy. Provided that the perturbations affecting each satellite are of the same magnitude (as it is the case for Walker constellations for example), the constellation geometry degrade gracefully as well as its statistical properties. Consequently, the strategy consistes in controlling relative positions of the satellites instead of keeping each satellite in its absolute window. If one takes into account operational station keeping scenarios.

  13. Chaos embedded particle swarm optimization algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Alatas, Bilal [Firat University, Department of Computer Engineering, 23119 Elazig (Turkey)], E-mail: balatas@firat.edu.tr; Akin, Erhan [Firat University, Department of Computer Engineering, 23119 Elazig (Turkey)], E-mail: eakin@firat.edu.tr; Ozer, A. Bedri [Firat University, Department of Computer Engineering, 23119 Elazig (Turkey)], E-mail: bozer@firat.edu.tr

    2009-05-30

    This paper proposes new particle swarm optimization (PSO) methods that use chaotic maps for parameter adaptation. This has been done by using of chaotic number generators each time a random number is needed by the classical PSO algorithm. Twelve chaos-embedded PSO methods have been proposed and eight chaotic maps have been analyzed in the benchmark functions. It has been detected that coupling emergent results in different areas, like those of PSO and complex dynamics, can improve the quality of results in some optimization problems. It has been also shown that, some of the proposed methods have somewhat increased the solution quality, that is in some cases they improved the global searching capability by escaping the local solutions.

  14. Chaos embedded particle swarm optimization algorithms

    International Nuclear Information System (INIS)

    Alatas, Bilal; Akin, Erhan; Ozer, A. Bedri

    2009-01-01

    This paper proposes new particle swarm optimization (PSO) methods that use chaotic maps for parameter adaptation. This has been done by using of chaotic number generators each time a random number is needed by the classical PSO algorithm. Twelve chaos-embedded PSO methods have been proposed and eight chaotic maps have been analyzed in the benchmark functions. It has been detected that coupling emergent results in different areas, like those of PSO and complex dynamics, can improve the quality of results in some optimization problems. It has been also shown that, some of the proposed methods have somewhat increased the solution quality, that is in some cases they improved the global searching capability by escaping the local solutions.

  15. Methods and apparatuses for signaling with geometric constellations

    Science.gov (United States)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2012-01-01

    Communication systems are described that use signal constellations, which have unequally spaced (i.e. geometrically shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes d.sub.min, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

  16. Orbit and Gravity Field Solutions from Swarm GPS Observations - First Result

    Science.gov (United States)

    Jaeggi, A.; Dahle, C.; Arnold, D.; Bock, H.; Flechtner, F.

    2014-12-01

    Although ESA's Earth Explorer Mission Swarm is primarily dedicated to measure the Earth's magnetic field, it may also serve as a gravity field mission. Equipped with GPS receivers, accelerometers, star-tracker assemblies and laser retro-reflectors, the three Swarm satellites are potentially capable to be used as a high-low satellite-to-satellite tracking (hl-SST) observing system, following the missions CHAMP (first single-satellite hl-SST mission), GRACE (twin-satellite mission with additional ultra-precise low-low SST and GOCE (single-satellite mission additionally equipped with a gradiometer). GRACE, dedicated to measure the time-variability of the gravity field, is the only mission still in orbit, but its lifetime will likely end before launch of its follow-on mission GRACE-FO in August 2017 primarily due to aging of the onboard batteries after meanwhile more than 12 years of operation. Swarm is probably a good candidate to provide time-variable gravity field solutions and to close a potential gap between GRACE and GRACE-FO. Consisting of three satellites, Swarm also offers to use inter-satellite GPS-derived baselines as additional observations. However, as of today it is not clear if such information will substantially improve the gravity field solutions. Nevertheless, the properties of the Swarm constellation with two lower satellites flying in a pendulum-like orbit and a slightly differently inclined third satellite at higher altitude still represent a unique observing system raising expectations at least compared to CHAMP derived time-variable gravity field solutions. Whatever processing method will be applied for Swarm gravity field recovery, its success strongly depends on the quality of the Swarm Level 1b data as well as the quality of the derived Swarm orbits. With first Level 1b data sets available since mid of May 2014 (excluding accelerometer data), first results for Swarm orbits and baselines, as well as Swarm gravity field solutions are presented

  17. A Swarm of Ancient Stars

    Science.gov (United States)

    2010-12-01

    We know of about 150 of the rich collections of old stars called globular clusters that orbit our galaxy, the Milky Way. This sharp new image of Messier 107, captured by the Wide Field Imager on the 2.2-metre telescope at ESO's La Silla Observatory in Chile, displays the structure of one such globular cluster in exquisite detail. Studying these stellar swarms has revealed much about the history of our galaxy and how stars evolve. The globular cluster Messier 107, also known as NGC 6171, is a compact and ancient family of stars that lies about 21 000 light-years away. Messier 107 is a bustling metropolis: thousands of stars in globular clusters like this one are concentrated into a space that is only about twenty times the distance between our Sun and its nearest stellar neighbour, Alpha Centauri, across. A significant number of these stars have already evolved into red giants, one of the last stages of a star's life, and have a yellowish colour in this image. Globular clusters are among the oldest objects in the Universe. And since the stars within a globular cluster formed from the same cloud of interstellar matter at roughly the same time - typically over 10 billion years ago - they are all low-mass stars, as lightweights burn their hydrogen fuel supply much more slowly than stellar behemoths. Globular clusters formed during the earliest stages in the formation of their host galaxies and therefore studying these objects can give significant insights into how galaxies, and their component stars, evolve. Messier 107 has undergone intensive observations, being one of the 160 stellar fields that was selected for the Pre-FLAMES Survey - a preliminary survey conducted between 1999 and 2002 using the 2.2-metre telescope at ESO's La Silla Observatory in Chile, to find suitable stars for follow-up observations with the VLT's spectroscopic instrument FLAMES [1]. Using FLAMES, it is possible to observe up to 130 targets at the same time, making it particularly well suited

  18. A New Constellation Configuration Scheme for Communicating Architecture in Cislunar Space

    Directory of Open Access Journals (Sweden)

    Ming Xu

    2013-01-01

    Full Text Available A new constellation configuration is proposed to provide near-constant communications between any two points in the cislunar space. Four satellites were allocated on some natural orbits near points by a multiple shooting corrector numerically. The revisiting intervals between the successive revisits on specified points by the constellation are demonstrated both on the geographical maps of the Earth and the Moon, with a consideration of equatorial inclinations with respect to the Earth-Moon orbital plane. Moreover, the coverage periodicity on the Moon is induced by Metonic cycle of 19 years. Cost analysis on stationkeeping and launching is implemented for this constellation in detail. Finally, some aspects about communications, such as satellite links, delays, ground stations, and communication devices, are surveyed preliminarily.

  19. International Earth Science Constellation (ESC) Introduction

    Science.gov (United States)

    Guit, William J.; Machado, Michael J.

    2016-01-01

    This is the Welcome and Introduction presentation for the International Earth Science Constellation (ESC) Mission Operations Working Group (MOWG) meeting held in Albuquerque NM from September 27-29. It contains an org chart, charter, history, significant topics to be discussed, AquaAura 2017 inclination adjust maneuver calendar, a-train long range plans, upcoming events, and action items.

  20. Screening Donors for Rare Antigen Constellations.

    Science.gov (United States)

    Wagner, Franz F

    2009-01-01

    SCREENING BLOOD DONORS FOR RARE ANTIGEN CONSTELLATIONS HAS BEEN IMPLEMENTED USING SIMPLE PCR METHODS: PCR with enzyme digestion has been used to type donor cohorts for Dombrock antigens, and PCR with sequence-specific priming to identify donors negative for antigens of high frequency. The advantages and disadvantages of the methods as well as their current state is discussed.

  1. Exploring Database Improvements for GPM Constellation Precipitation Retrievals

    Science.gov (United States)

    Ringerud, S.; Kidd, C.; Skofronick Jackson, G.

    2017-12-01

    The Global Precipitation Measurement Mission (GPM) offers an unprecedented opportunity for understanding and mapping of liquid and frozen precipitation on a global scale. GPM mission development of physically based retrieval algorithms, for application consistently across the constellation radiometers, relies on combined active-passive retrievals from the GPM core satellite as a transfer standard. Radiative transfer modeling is then utilized to compute a priori databases at the frequency and footprint geometry of each individual radiometer. The Goddard Profiling Algorithm (GPROF) performs constellation retrievals across the GPM databases in a Bayesian framework, constraining searches using model data on a pixel-by-pixel basis. This work explores how the retrieval might be enhanced with additional information available within the brightness temperature observations themselves. In order to better exploit available information content, model water vapor is replaced with retrieved water vapor. Rather than treating each footprint as a 1D profile alone in space, information regarding Tb variability in the horizontal is added as well as variability in the time dimension. This additional information is tested and evaluated for retrieval improvement in the context of the Bayesian retrieval scheme. Retrieval differences are presented as a function of precipitation and surface type for evaluation of where the added information proves most effective.

  2. Small Satellite Constellations for Geospace Sciences

    Science.gov (United States)

    Spence, H. E.

    2016-12-01

    The recent National Academy of Sciences Solar and Space Physics Decadal Survey (DS) identified community-consensus science priorities for the decade spanning 2013 - 2022. In this talk, we discuss the ways by which small satellite constellations are already and may soon accelerate progress toward achieving many of these science targets. The DS outlined four overarching science goals: (1) determine the origins of the Sun's activity and predict the variations in the space environment; (2) determine the dynamics and coupling of Earth's magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs; (3) determine the interaction of the Sun with the solar system and the interstellar medium; and, (4) discover and characterize fundamental processes that occur both within the heliosphere and throughout the universe. These DS science goals provide the context for key science challenges in the three connected parts of the system that encompass all of solar and space physics, herein referred to as geospace: the Sun and heliosphere; the coupled solar wind-magnetosphere system; and, the coupled atmosphere-ionosphere-magnetosphere system. The DS further presented the role that small satellites play in resolving many of these science challenges, with a particular emphasis on the role that constellations of small satellites will play. While once considered by many as being "futuristic" or even "unrealizable", constellations of small satellites are already making important contributions to geospace science and with the promise for more to come. Using the DS as a guidepost, in this presentation, we outline representative small satellite constellation missions alread underway, some in development, and others notionally proposed over the next several years that employ small satellite constellations to tackle large science imperatives. Finally, we give examples of key small satellite technologies in development that will potentially enable great scientific

  3. A Modified Particle Swarm Optimization Algorithm

    OpenAIRE

    Jie He; Hui Guo

    2013-01-01

    In optimizing the particle swarm optimization (PSO) that inevitable existence problem of prematurity and the local convergence, this paper base on this aspects is put forward a kind of modified particle swarm optimization algorithm, take the gradient descent method (BP algorithm) as a particle swarm operator embedded in particle swarm algorithm, and at the same time use to attenuation wall (Damping) approach to make fly off the search area of the particles of size remain unchanged and avoid t...

  4. On low complexity detection for QAM isomorphic constellations

    OpenAIRE

    Kayhan, Farbod

    2017-01-01

    Despite of the known gap from the Shannon's capacity, several standards are still employing QAM or star shape constellations, mainly due to the existing low complexity detectors. In this paper, we investigate the low complexity detection for a family of QAM isomorphic constellations. These constellations are known to perform very close to the peak-power limited capacity, outperforming the DVB-S2X standard constellations. The proposed strategy is to first remap the received signals to the QAM ...

  5. Swarm Satellites : Design, Characteristics and Applications

    NARCIS (Netherlands)

    Engelen, S.

    2016-01-01

    Satellite swarms are a novelty, yet promise to deliver unprecedented robustness and data-collection efficiency. They are so new in fact that even the definition of what a satellite swarm is is disputable, and consequently, the term "swarm" is used for practically any type of distributed space

  6. Particle Swarm Optimization with Double Learning Patterns.

    Science.gov (United States)

    Shen, Yuanxia; Wei, Linna; Zeng, Chuanhua; Chen, Jian

    2016-01-01

    Particle Swarm Optimization (PSO) is an effective tool in solving optimization problems. However, PSO usually suffers from the premature convergence due to the quick losing of the swarm diversity. In this paper, we first analyze the motion behavior of the swarm based on the probability characteristic of learning parameters. Then a PSO with double learning patterns (PSO-DLP) is developed, which employs the master swarm and the slave swarm with different learning patterns to achieve a trade-off between the convergence speed and the swarm diversity. The particles in the master swarm and the slave swarm are encouraged to explore search for keeping the swarm diversity and to learn from the global best particle for refining a promising solution, respectively. When the evolutionary states of two swarms interact, an interaction mechanism is enabled. This mechanism can help the slave swarm in jumping out of the local optima and improve the convergence precision of the master swarm. The proposed PSO-DLP is evaluated on 20 benchmark functions, including rotated multimodal and complex shifted problems. The simulation results and statistical analysis show that PSO-DLP obtains a promising performance and outperforms eight PSO variants.

  7. Tectonic setting of the Wooded Island earthquake swarm, eastern Washington

    Science.gov (United States)

    Blakely, Richard J.; Sherrod, Brian L.; Weaver, Craig S.; Rohay, Alan C.; Wells, Ray E.

    2012-01-01

    Magnetic anomalies provide insights into the tectonic implications of a swarm of ~1500 shallow (~1 km deep) earthquakes that occurred in 2009 on the Hanford site,Washington. Epicenters were concentrated in a 2 km2 area nearWooded Island in the Columbia River. The largest earthquake (M 3.0) had first motions consistent with slip on a northwest-striking reverse fault. The swarm was accompanied by 35 mm of vertical surface deformation, seen in satellite interferometry (InSAR), interpreted to be caused by ~50 mm of slip on a northwest-striking reverse fault and associated bedding-plane fault in the underlying Columbia River Basalt Group (CRBG). A magnetic anomaly over exposed CRBG at Yakima Ridge 40 km northwest of Wooded Island extends southeastward beyond the ridge to the Columbia River, suggesting that the Yakima Ridge anticline and its associated thrust fault extend southeastward in the subsurface. In map view, the concealed anticline passes through the earthquake swarm and lies parallel to reverse faults determined from first motions and InSAR data. A forward model of the magnetic anomaly near Wooded Island is consistent with uplift of concealed CRBG, with the top surface plane faults modeled from interferometry all fall within the northeastern limb of the faulted anticline. Although fluids may be responsible for triggering the Wooded Island earthquake swarm, the seismic and aseismic deformation are consistent with regional-scale tectonic compression across the concealed Yakima Ridge anticline.

  8. Binary Cockroach Swarm Optimization for Combinatorial Optimization Problem

    Directory of Open Access Journals (Sweden)

    Ibidun Christiana Obagbuwa

    2016-09-01

    Full Text Available The Cockroach Swarm Optimization (CSO algorithm is inspired by cockroach social behavior. It is a simple and efficient meta-heuristic algorithm and has been applied to solve global optimization problems successfully. The original CSO algorithm and its variants operate mainly in continuous search space and cannot solve binary-coded optimization problems directly. Many optimization problems have their decision variables in binary. Binary Cockroach Swarm Optimization (BCSO is proposed in this paper to tackle such problems and was evaluated on the popular Traveling Salesman Problem (TSP, which is considered to be an NP-hard Combinatorial Optimization Problem (COP. A transfer function was employed to map a continuous search space CSO to binary search space. The performance of the proposed algorithm was tested firstly on benchmark functions through simulation studies and compared with the performance of existing binary particle swarm optimization and continuous space versions of CSO. The proposed BCSO was adapted to TSP and applied to a set of benchmark instances of symmetric TSP from the TSP library. The results of the proposed Binary Cockroach Swarm Optimization (BCSO algorithm on TSP were compared to other meta-heuristic algorithms.

  9. Observatory data and the Swarm mission

    DEFF Research Database (Denmark)

    Macmillan, S.; Olsen, Nils

    2013-01-01

    The ESA Swarm mission to identify and measure very accurately the different magnetic signals that arise in the Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere, which together form the magnetic field around the Earth, has increased interest in magnetic data collected on the surface...... of the Earth at observatories. The scientific use of Swarm data and Swarm-derived products is greatly enhanced by combination with observatory data and indices. As part of the Swarm Level-2 data activities plans are in place to distribute such ground-based data along with the Swarm data as auxiliary data...

  10. Family constellation factors and parent suicide potential.

    Science.gov (United States)

    Wenz, F V

    1982-05-01

    This study assessed if, in fact, family constellation was one of the multiple etiological factors of parent suicide potential. Durkheim's proposition was examined, that married men and women, and especially women, are protected against suicide risk in direct proportion to the number of children they have. The sample consisted of 145 families, comprising 243 parents and 392 children under age 18, which form the subject of this study. A partial correlation approach was taken. Family size and density were significantly related to parent suicide potential. The effects of the family constellation factors were sex-specific. For married women, and to a lesser extent for married men, suicide potential declined with the number of children and density. Sibling spacing proved not significant in predicting parent suicide potential. The findings were discussed in terms of the social integration hypothesis, marital status, sex roles, and depression.

  11. Constellation design with geometric and probabilistic shaping

    Science.gov (United States)

    Zhang, Shaoliang; Yaman, Fatih

    2018-02-01

    A systematic study, including theory, simulation and experiments, is carried out to review the generalized pairwise optimization algorithm for designing optimized constellation. In order to verify its effectiveness, the algorithm is applied in three testing cases: 2-dimensional 8 quadrature amplitude modulation (QAM), 4-dimensional set-partitioning QAM, and probabilistic-shaped (PS) 32QAM. The results suggest that geometric shaping can work together with PS to further bridge the gap toward the Shannon limit.

  12. NASA's Constellation Program: Milestones Towards the Frontier

    Science.gov (United States)

    Hanley, Jeffrey M.; Thomas, Lawrence D.; Rhatigan, Jennifer L.; Boatright, Tony J.

    2009-01-01

    This slide presentation reviews the status and progress made in the Constellation Program's work towards the goal of lunar and Martian exploration flights. It includes views of the various components of the program, and reviews the status of the engine tests, and the development of the Ares I-X towards test launch, the Orion Crew Module, the launch abort system, and the ground operations facilities.

  13. Gold rush - A swarm dynamics in games

    Science.gov (United States)

    Zelinka, Ivan; Bukacek, Michal

    2017-07-01

    This paper is focused on swarm intelligence techniques and its practical use in computer games. The aim is to show how a swarm dynamics can be generated by multiplayer game, then recorded, analyzed and eventually controlled. In this paper we also discuss possibility to use swarm intelligence instead of game players. Based on our previous experiments two games, using swarm algorithms are mentioned briefly here. The first one is strategy game StarCraft: Brood War, and TicTacToe in which SOMA algorithm has also take a role of player against human player. Open research reported here has shown potential benefit of swarm computation in the field of strategy games and players strategy based on swarm behavior record and analysis. We propose new game called Gold Rush as an experimental environment for human or artificial swarm behavior and consequent analysis.

  14. Epidemic Synchronization in Robotic Swarms

    DEFF Research Database (Denmark)

    Schiøler, Henrik; Nielsen, Jens Frederik Dalsgaard; Ngo, Trung Dung

    2009-01-01

    Clock synchronization in swarms of networked mobile robots is studied in a probabilistic, epidemic framework. In this setting communication and synchonization is considered to be a randomized process, taking place at unplanned instants of geographical rendezvous between robots. In combination...... as an infinite-dimensional optimal controlproblem. Illustrative numerical examples are given and commented....

  15. Hybrid chaotic ant swarm optimization

    International Nuclear Information System (INIS)

    Li Yuying; Wen Qiaoyan; Li Lixiang; Peng Haipeng

    2009-01-01

    Chaotic ant swarm optimization (CASO) is a powerful chaos search algorithm that is used to find the global optimum solution in search space. However, the CASO algorithm has some disadvantages, such as lower solution precision and longer computational time, when solving complex optimization problems. To resolve these problems, an improved CASO, called hybrid chaotic swarm optimization (HCASO), is proposed in this paper. The new algorithm introduces preselection operator and discrete recombination operator into the CASO; meanwhile it replaces the best position found by own and its neighbors' ants with the best position found by preselection operator and discrete recombination operator in evolution equation. Through testing five benchmark functions with large dimensionality, the experimental results show the new method enhances the solution accuracy and stability greatly, as well as reduces the computational time and computer memory significantly when compared to the CASO. In addition, we observe the results can become better with swarm size increasing from the sensitivity study to swarm size. And we gain some relations between problem dimensions and swam size according to scalability study.

  16. behaved particle swarm optimization (QPSO)

    African Journals Online (AJOL)

    Administrator

    2011-06-13

    Jun 13, 2011 ... popular OLS. Thus, QPSO-RBF estimator was more favorable to the control and fault diagnosis of the fermentation process, and consequently, it increased the yield of fermentation. Key words: Soft-sensing model, quantum-behaved particle swarm optimization algorithm, neural network. INTRODUCTION.

  17. Insular species swarm goes underground

    DEFF Research Database (Denmark)

    P. S. Reboleira, Ana Sofia; Enghoff, Henrik

    2014-01-01

    -group, an insular species swarm distributed in the archipelagos of Madeira and the Canary Islands. We discuss the differences between the new species and their relatives and present information on the subterranean environment of Madeira. An updated overview of the subterranean biodiversity of millipedes...

  18. Automating Trend Analysis for Spacecraft Constellations

    Science.gov (United States)

    Davis, George; Cooter, Miranda; Updike, Clark; Carey, Everett; Mackey, Jennifer; Rykowski, Timothy; Powers, Edward I. (Technical Monitor)

    2001-01-01

    Spacecraft trend analysis is a vital mission operations function performed by satellite controllers and engineers, who perform detailed analyses of engineering telemetry data to diagnose subsystem faults and to detect trends that may potentially lead to degraded subsystem performance or failure in the future. It is this latter function that is of greatest importance, for careful trending can often predict or detect events that may lead to a spacecraft's entry into safe-hold. Early prediction and detection of such events could result in the avoidance of, or rapid return to service from, spacecraft safing, which not only results in reduced recovery costs but also in a higher overall level of service for the satellite system. Contemporary spacecraft trending activities are manually intensive and are primarily performed diagnostically after a fault occurs, rather than proactively to predict its occurrence. They also tend to rely on information systems and software that are oudated when compared to current technologies. When coupled with the fact that flight operations teams often have limited resources, proactive trending opportunities are limited, and detailed trend analysis is often reserved for critical responses to safe holds or other on-orbit events such as maneuvers. While the contemporary trend analysis approach has sufficed for current single-spacecraft operations, it will be unfeasible for NASA's planned and proposed space science constellations. Missions such as the Dynamics, Reconnection and Configuration Observatory (DRACO), for example, are planning to launch as many as 100 'nanospacecraft' to form a homogenous constellation. A simple extrapolation of resources and manpower based on single-spacecraft operations suggests that trending for such a large spacecraft fleet will be unmanageable, unwieldy, and cost-prohibitive. It is therefore imperative that an approach to automating the spacecraft trend analysis function be studied, developed, and applied to

  19. Constellation modulation - an approach to increase spectral efficiency.

    Science.gov (United States)

    Dash, Soumya Sunder; Pythoud, Frederic; Hillerkuss, David; Baeuerle, Benedikt; Josten, Arne; Leuchtmann, Pascal; Leuthold, Juerg

    2017-07-10

    Constellation modulation (CM) is introduced as a new degree of freedom to increase the spectral efficiency and to further approach the Shannon limit. Constellation modulation is the art of encoding information not only in the symbols within a constellation but also by encoding information by selecting a constellation from a set of constellations that are switched from time to time. The set of constellations is not limited to sets of partitions from a given constellation but can e.g., be obtained from an existing constellation by applying geometrical transformations such as rotations, translations, scaling, or even more abstract transformations. The architecture of the transmitter and the receiver allows for constellation modulation to be used on top of existing modulations with little penalties on the bit-error ratio (BER) or on the required signal-to-noise ratio (SNR). The spectral bandwidth used by this modulation scheme is identical to the original modulation. Simulations demonstrate a particular advantage of the scheme for low SNR situations. So, for instance, it is demonstrated by simulation that a spectral efficiency increases by up to 33% and 20% can be obtained at a BER of 10 -3 and 2×10 -2 for a regular BPSK modulation format, respectively. Applying constellation modulation, we derive a most power efficient 4D-CM-BPSK modulation format that provides a spectral efficiency of 0.7 bit/s/Hz for an SNR of 0.2 dB at a BER of 2 × 10 -2 .

  20. A quantum particle swarm optimizer with chaotic mutation operator

    International Nuclear Information System (INIS)

    Coelho, Leandro dos Santos

    2008-01-01

    Particle swarm optimization (PSO) is a population-based swarm intelligence algorithm that shares many similarities with evolutionary computation techniques. However, the PSO is driven by the simulation of a social psychological metaphor motivated by collective behaviors of bird and other social organisms instead of the survival of the fittest individual. Inspired by the classical PSO method and quantum mechanics theories, this work presents a novel Quantum-behaved PSO (QPSO) using chaotic mutation operator. The application of chaotic sequences based on chaotic Zaslavskii map instead of random sequences in QPSO is a powerful strategy to diversify the QPSO population and improve the QPSO's performance in preventing premature convergence to local minima. The simulation results demonstrate good performance of the QPSO in solving a well-studied continuous optimization problem of mechanical engineering design

  1. Global Lithospheric Apparent Susceptibility Distribution Converted from Geomagnetic Models by CHAMP and Swarm Satellite Magnetic Measurements

    Science.gov (United States)

    Du, Jinsong; Chen, Chao; Xiong, Xiong; Li, Yongdong; Liang, Qing

    2016-04-01

    Recently, because of continually accumulated magnetic measurements by CHAMP satellite and Swarm constellation of three satellites and well developed methodologies and techniques of data processing and geomagnetic field modeling etc., global lithospheric magnetic anomaly field models become more and more reliable. This makes the quantitative interpretation of lithospheric magnetic anomaly field possible for having an insight into large-scale magnetic structures in the crust and uppermost mantle. Many different approaches have been utilized to understand the magnetized sources, such as forward, inversion, statistics, correlation analysis, Euler deconvolution, signal transformations etc. Among all quantitative interpretation methods, the directly converting a magnetic anomaly map into a magnetic susceptibility anomaly map proposed by Arkani-Hamed & Strangway (1985) is, we think, the most fast quantitative interpretation tool for global studies. We just call this method AS85 hereinafter for short. Although Gubbins et al. (2011) provided a formula to directly calculate the apparent magnetic vector distribution, the AS85 method introduced constraints of magnetized direction and thus corresponding results are expected to be more robust especially in world-wide continents. Therefore, in this study, we first improved the AS85 method further considering non-axial dipolar inducing field using formulae by Nolte & Siebert (1987), initial model or priori information for starting coefficients in the apparent susceptibility conversion, hidden longest-wavelength components of lithospheric magnetic field and field contaminations from global oceanic remanent magnetization. Then, we used the vertically integrated susceptibility model by Hemant & Maus (2005) and vertically integrated remanent magnetization model by Masterton et al. (2013) to test the validity of our improved method. Subsequently, we applied the conversion method to geomagnetic field models by CHAMP and Swarm satellite

  2. An immune-inspired swarm aggregation algorithm for self-healing swarm robotic systems.

    Science.gov (United States)

    Timmis, J; Ismail, A R; Bjerknes, J D; Winfield, A F T

    2016-08-01

    Swarm robotics is concerned with the decentralised coordination of multiple robots having only limited communication and interaction abilities. Although fault tolerance and robustness to individual robot failures have often been used to justify the use of swarm robotic systems, recent studies have shown that swarm robotic systems are susceptible to certain types of failure. In this paper we propose an approach to self-healing swarm robotic systems and take inspiration from the process of granuloma formation, a process of containment and repair found in the immune system. We use a case study of a swarm performing team work where previous works have demonstrated that partially failed robots have the most detrimental effect on overall swarm behaviour. We have developed an immune inspired approach that permits the recovery from certain failure modes during operation of the swarm, overcoming issues that effect swarm behaviour associated with partially failed robots. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. The power of inexpensive satellite constellations

    Science.gov (United States)

    Dyrud, Lars P.; La Tour, Rose; Swartz, William H.; Nag, Sreeja; Lorentz, Steven R.; Hilker, Thomas; Wiscombe, Warren J.; Papadakis, Stergios J.

    2014-06-01

    Two thematic drivers are motivating the science community towards constellations of small satellites, the revelation that many next generation system science questions are uniquely addressed with sufficient numbers of simultaneous space based measurements, and the realization that space is historically expensive, and in an environment of constrained costs, we must innovate to ―do more with less‖. We present analysis that answers many of the key questions surrounding constellations of scientific satellites, including research that resulted from the GEOScan community based effort originally intended as hosted payloads on Iridium NEXT. We present analysis that answers the question how many satellites does global system science require? Perhaps serendipitously, the analyses show that many of the key science questions independently converge towards similar results, i.e. that approximately 60+ satellites are needed for transformative, as opposed to incremental capability in system science. The current challenge is how to effectively transition products from design to mass production for space based instruments and vehicles. Ideally, the lesson learned from past designs and builds of various space products should pave the way toward a better manufacturing plan that utilizes just a fraction of the prototype`s cost. Using the commercial products industry implementations of mass customization as an example, we will discuss about the benefits of standardization in design requirements for space instruments and vehicles. For example, the instruments (payloads) are designed to have standardized elements, components, or modules that interchangeably work together within a linkage system. We conclude with a discussion on implementation plans and the new paradigms for community and international cooperation enabled by small satellite constellations.

  4. Interactions of the space debris environment with mega constellations-Using the example of the OneWeb constellation

    Science.gov (United States)

    Radtke, Jonas; Kebschull, Christopher; Stoll, Enrico

    2017-02-01

    Recently, several announcements have been published to deploy satellite constellations into Low Earth Orbit (LEO) containing several hundred to thousands of rather small sized objects. The purpose of these constellations is to provide a worldwide internet coverage, even to the remotest areas. Examples of these mega-constellations are one from SpaceX, which is announced to comprise of about 4000 satellites, the Norwegian STEAM network, which is told to contain 4257 satellites, and the OneWeb constellation, which forms one of the smaller constellations with 720 satellites. As example constellation, OneWeb has been chosen. From all announced constellation, OneWeb by far delivered most information, both in regards to constellation design and their plans to encounter space debris issues, which is the reason why it has been chosen for these analyses. In this paper, at first an overview of the planned OneWeb constellation setup is given. From this description, a mission life-cycle is deduced, splitting the complete orbital lifetime of the satellites into four phases. Following, using ESA-MASTER, for each of the mission phases the flux on both single constellations satellites and the complete constellation are performed and the collision probabilities are derived. The focus in this analysis is set on catastrophic collisions. This analysis is then varied parametrically for different operational altitudes of the constellation as well as different lifetimes with different assumptions for the success of post mission disposal (PMD). Following the to-be-expected mean number of collision avoidance manoeuvres during all active mission phases is performed using ARES from ESA's DRAMA tool suite. The same variations as during the flux analysis are considered. Lastly the characteristics of hypothetical OneWeb satellite fragmentation clouds, calculated using the NASA Breakup model, are described and the impact of collision clouds from OneWeb satellites on the constellation itself is

  5. Trade-space Analysis for Constellations

    Science.gov (United States)

    Le Moigne, J.; Dabney, P.; de Weck, O. L.; Foreman, V.; Grogan, P.; Holland, M. P.; Hughes, S. P.; Nag, S.

    2016-12-01

    Traditionally, space missions have relied on relatively large and monolithic satellites, but in the past few years, under a changing technological and economic environment, including instrument and spacecraft miniaturization, scalable launchers, secondary launches as well as hosted payloads, there is growing interest in implementing future NASA missions as Distributed Spacecraft Missions (DSM). The objective of our project is to provide a framework that facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori Science goals. In this first version of our Trade-space Analysis Tool for Constellations (TAT-C), we are investigating questions such as: "How many spacecraft should be included in the constellation? Which design has the best cost/risk value?" The main goals of TAT-C are to: Handle multiple spacecraft sharing a mission objective, from SmallSats up through flagships, Explore the variables trade space for pre-defined science, cost and risk goals, and pre-defined metrics Optimize cost and performance across multiple instruments and platforms vs. one at a time. This paper describes the overall architecture of TAT-C including: a User Interface (UI) interacting with multiple users - scientists, missions designers or program managers; an Executive Driver gathering requirements from UI, then formulating Trade-space Search Requests for the Trade-space Search Iterator first with inputs from the Knowledge Base, then, in collaboration with the Orbit & Coverage, Reduction & Metrics, and Cost& Risk modules, generating multiple potential architectures and their associated characteristics. TAT-C leverages the use of the Goddard Mission Analysis Tool (GMAT) to compute coverage and ancillary data, streamlining the computations by modeling orbits in a way that balances accuracy and performance. TAT-C current version includes uniform Walker constellations as well as Ad-Hoc constellations, and its cost model represents an aggregate model

  6. Constellation pharmacology: a new paradigm for drug discovery.

    Science.gov (United States)

    Teichert, Russell W; Schmidt, Eric W; Olivera, Baldomero M

    2015-01-01

    Constellation pharmacology is a cell-based high-content phenotypic-screening platform that utilizes subtype-selective pharmacological agents to elucidate the cell-specific combinations (constellations) of key signaling proteins that define specific cell types. Heterogeneous populations of native cells, in which the different individual cell types have been identified and characterized, are the foundation for this screening platform. Constellation pharmacology is useful for screening small molecules or for deconvoluting complex mixtures of biologically active natural products. This platform has been used to purify natural products and discover their molecular mechanisms. In the ongoing development of constellation pharmacology, there is a positive feedback loop between the pharmacological characterization of cell types and screening for new drug candidates. As constellation pharmacology is used to discover compounds with novel targeting-selectivity profiles, those new compounds then further help to elucidate the constellations of specific cell types, thereby increasing the content of this high-content platform.

  7. Guidebook to the Constellations Telescopic Sights, Tales, and Myths

    CERN Document Server

    Simpson, Phil

    2012-01-01

    This handbook is a guide to exploring the night sky and its wonderful telescopic sights. All eighty-eight officially recognized constellations in both hemispheres are presented in natural groups, related by their origin and location. The author, a former astronomy instructor and planetarium director, has for over thirty-five years, researched myths from all over the world to identify the most memorable stories which link multiple constellations in a single story. Thus, the interested observer may discover that it will be easier to use already known constellations to locate and remember new constellations. The author has found that showing each constellation figure with a simple line drawing is helpful for remembering each constellation. He includes photographs of many of the brighter celestial objects, as well as many accompanying drawings which illustrate how the telescopic views differ from the photographs. One way to use this handbook, which is useful to beginners as well as experienced astronomers, is to ...

  8. Swarm analysis by using transport equations

    International Nuclear Information System (INIS)

    Dote, Toshihiko.

    1985-01-01

    As the basis of weak ionization plasma phenomena, the motion, i.e. swarm, of charged particles in the gas is analyzed by use of the transport equations, from which basic nature of the swarm is discussed. The present report is an overview of the studies made in the past several years. Described are principally the most basic aspects concerning behaviors of the electrons and positive ions, that is, the basic equations and their significance, characteristics of the behaviors of the electron and positive ion swarms as revealed by solving the equations, and various characteristics of the swarm parameters. Contents are: Maxwell-Boltzmann's transport equations, behavior of the electron swarm, energy loss of the electrons, and behavior of the positive ion swarm. (Mori, K.)

  9. Time-delayed autosynchronous swarm control.

    Science.gov (United States)

    Biggs, James D; Bennet, Derek J; Dadzie, S Kokou

    2012-01-01

    In this paper a general Morse potential model of self-propelling particles is considered in the presence of a time-delayed term and a spring potential. It is shown that the emergent swarm behavior is dependent on the delay term and weights of the time-delayed function, which can be set to induce a stationary swarm, a rotating swarm with uniform translation, and a rotating swarm with a stationary center of mass. An analysis of the mean field equations shows that without a spring potential the motion of the center of mass is determined explicitly by a multivalued function. For a nonzero spring potential the swarm converges to a vortex formation about a stationary center of mass, except at discrete bifurcation points where the center of mass will periodically trace an ellipse. The analytical results defining the behavior of the center of mass are shown to correspond with the numerical swarm simulations.

  10. Extracting Ocean-Generated Tidal Magnetic Signals from Swarm Data through Satellite Gradiometry

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Tyler, Robert H.; Olsen, Nils

    2016-01-01

    Ocean-generated magnetic field models of the Principal Lunar, M2, and the Larger Lunar elliptic, N2, semi-diurnal tidal constituents were estimated through a “Comprehensive Inversion" of the first 20.5 months of magnetic measurements from ESA's Swarm satellite constellation mission. While the con...... of ocean electrodynamic properties at temporal resolutions of one to two years, which may have important implications for the inference of ocean temperature and salinity.......Ocean-generated magnetic field models of the Principal Lunar, M2, and the Larger Lunar elliptic, N2, semi-diurnal tidal constituents were estimated through a “Comprehensive Inversion" of the first 20.5 months of magnetic measurements from ESA's Swarm satellite constellation mission. While......, but over a shorter interval, at higher altitude, and during more magnetically disturbed conditions. Recovered N2 contains non-oceanic signal, but is highly correlated with theoretical models in regions of maximum oceanic amplitude. Thus, satellite magnetic gradiometry may eventually enable the monitoring...

  11. Open Sourcing Social Change: Inside the Constellation Model

    Directory of Open Access Journals (Sweden)

    Tonya Surman

    2008-09-01

    Full Text Available The constellation model was developed by and for the Canadian Partnership for Children's Health and the Environment. The model offers an innovative approach to organizing collaborative efforts in the social mission sector and shares various elements of the open source model. It emphasizes self-organizing and concrete action within a network of partner organizations working on a common issue. Constellations are self-organizing action teams that operate within the broader strategic vision of a partnership. These constellations are outwardly focused, placing their attention on creating value for those in the external environment rather than on the partnership itself. While serious effort is invested into core partnership governance and management, most of the energy is devoted to the decision making, resources and collaborative effort required to create social value. The constellations drive and define the partnership. The constellation model emerged from a deep understanding of the power of networks and peer production. Leadership rotates fluidly amongst partners, with each partner having the freedom to head up a constellation and to participate in constellations that carry out activities that are of more peripheral interest. The Internet provided the platform, the partner network enabled the expertise to align itself, and the goal of reducing chemical exposure in children kept the energy flowing. Building on seven years of experience, this article provides an overview of the constellation model, discusses the results from the CPCHE, and identifies similarities and differences between the constellation and open source models.

  12. Dynamics and Controls of Swarms of Femtosatellites

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed research activity is focused on the development of fuel and computationally efficient guidance and control algorithms for spacecraft swarms. The...

  13. Time Optimal Reachability Analysis Using Swarm Verification

    DEFF Research Database (Denmark)

    Zhang, Zhengkui; Nielsen, Brian; Larsen, Kim Guldstrand

    2016-01-01

    and planning problems, response time optimization etc. We propose swarm verification to accelerate time optimal reachability using the real-time model-checker Uppaal. In swarm verification, a large number of model checker instances execute in parallel on a computer cluster using different, typically randomized...... search strategies. We develop four swarm algorithms and evaluate them with four models in terms scalability, and time- and memory consumption. Three of these cooperate by exchanging costs of intermediate solutions to prune the search using a branch-and-bound approach. Our results show that swarm...

  14. Interacting Brownian Swarms: Some Analytical Results

    Directory of Open Access Journals (Sweden)

    Guillaume Sartoretti

    2016-01-01

    Full Text Available We consider the dynamics of swarms of scalar Brownian agents subject to local imitation mechanisms implemented using mutual rank-based interactions. For appropriate values of the underlying control parameters, the swarm propagates tightly and the distances separating successive agents are iid exponential random variables. Implicitly, the implementation of rank-based mutual interactions, requires that agents have infinite interaction ranges. Using the probabilistic size of the swarm’s support, we analytically estimate the critical interaction range below that flocked swarms cannot survive. In the second part of the paper, we consider the interactions between two flocked swarms of Brownian agents with finite interaction ranges. Both swarms travel with different barycentric velocities, and agents from both swarms indifferently interact with each other. For appropriate initial configurations, both swarms eventually collide (i.e., all agents interact. Depending on the values of the control parameters, one of the following patterns emerges after collision: (i Both swarms remain essentially flocked, or (ii the swarms become ultimately quasi-free and recover their nominal barycentric speeds. We derive a set of analytical flocking conditions based on the generalized rank-based Brownian motion. An extensive set of numerical simulations corroborates our analytical findings.

  15. Hyperspectral Cubesat Constellation for Natural Hazard Response

    Science.gov (United States)

    Mandl, Daniel; Crum, Gary; Ly, Vuong; Handy, Matthew; Huemmrich, Karl F.; Ong, Lawrence; Holt, Ben; Maharaja, Rishabh

    2016-01-01

    The authors on this paper are team members of the Earth Observing 1 (E0-1) mission which has flown an imaging spectrometer (hyperspectral) instrument called Hyperion for the past 15+ years. The satellite is able to image any spot on Earth in the nadir looking direction every 16 days and with slewing, of the satellite for up to a 23 degree view angle, any spot on the Earth can be imaged approximately every 2 to 3 days. EO-1 has been used to track many natural hazards such as wildfires, volcanoes and floods. An enhanced capability that has been sought is the ability to image natural hazards in a daily time series for space-based imaging spectrometers. The Hyperion cannot provide this capability on EO-1 with the present polar orbit. However, a constellation of cubesats, each with the same imaging spectrometer, positioned strategically can be used to provide daily coverage or even diurnal coverage, cost-effectively. This paper sought to design a cubesat constellation mission that would accomplish this goal and then to articulate the key tradeoffs.

  16. The GANDER constellation for maritime dissaster mitigation

    Science.gov (United States)

    da Silva Curiel, R. A.; Jolly, G.; Zheng, Y.

    1999-09-01

    The development of sea state monitoring from polar-orbiting satellites has recently moved away from the concept of single, multi-sensor platform such as ERS-2, Topex/Poseidon or ENVISAT towards the design of a system that would allow frequent updates from a constellation of small satellites equipped with special-purpose radar altimeters. This new system, called GANDER for Global Altimeter Network Designed to Evaluate Risk, has attracted significant support from a number of important customer segments including the military. This paper details the design of an altimeter for a Surrey small satellite, and illustrates the major system trade-offs that need to be made. Critical to the viability of the mission will be the development of a radar altimeter capable of operating successfully on a small satellite bus, within a limited volume and power budget. The mission design presents a number of key technological challenges, in order to permit a physically small antenna to be employed, and to minimise the pulse power. This can be achieved by advanced techniques, such as the delay Doppler altimeter concept, which emphasises the needs for high-speed on-board signal processing, phase linearity and pulse-to-pulse phase coherency. The system design for the GANDER constellation is also described, illustrating how it not only offers a means for maritime disaster mitigation, but also can reduce shipping cost and time.

  17. South Atlantic Anomaly evolution by means of Swarm data

    Science.gov (United States)

    Pavon-Carrasco, F. Javier; Qamili, Enkelejda; De Santis, Angelo

    2015-04-01

    The study of the South Atlantic Anomaly (SAA) is an important challenge nowadays not only for the geomagnetic and paleomagnetic community, but also for other areas focused on the Earth Observation. This large magnetic anomaly is characterized by values of geomagnetic field intensity around 30% lower than expected for those latitudes and covers a large area in the South Atlantic Ocean between Southwest Brazil and South Africa. This great depression of the geomagnetic field strength at the Earth's surface has an internal deep origin: it is caused by a prominent patch of reversed polarity flux in the outer core. Since the Earth's magnetic field has an important protective role for the all geosphere because it deflects a large part of the solar radiation that would otherwise reach the Earth's surface, a large increase of the SAA could have dramatic consequences for human health and technologies. In the last three decades, an almost constant monitoring of the SAA has been carried out using satellite data showing a clear picture of the behaviour and evolution of the SAA, which area is growing alarmingly during the most recent years at the Earth's surface and at the core mantle boundary. In this context, the ESA Swarm mission (constituted by a constellation of three satellites in near-polar low orbits at two different altitudes) is providing detailed measurements of the intensity and directional elements of the geomagnetic field with high-precision and resolution never reached in the former space missions. This work aims to analyse in detail in space and time the SAA from the Earth's surface up to the satellite altitude. In order to carry out this study, comprehensive geomagnetic models at regional and global scale will be performed using the dataset provided by the Swarm satellites and all the available ground data. This kind of study is crucial to understand the evolution of the Earth's magnetic field in this area, and to possibly predict its future behaviour.

  18. Identifying Interacting Genetic Variations by Fish-Swarm Logic Regression

    Directory of Open Access Journals (Sweden)

    Xuanping Zhang

    2013-01-01

    Full Text Available Understanding associations between genotypes and complex traits is a fundamental problem in human genetics. A major open problem in mapping phenotypes is that of identifying a set of interacting genetic variants, which might contribute to complex traits. Logic regression (LR is a powerful multivariant association tool. Several LR-based approaches have been successfully applied to different datasets. However, these approaches are not adequate with regard to accuracy and efficiency. In this paper, we propose a new LR-based approach, called fish-swarm logic regression (FSLR, which improves the logic regression process by incorporating swarm optimization. In our approach, a school of fish agents are conducted in parallel. Each fish agent holds a regression model, while the school searches for better models through various preset behaviors. A swarm algorithm improves the accuracy and the efficiency by speeding up the convergence and preventing it from dropping into local optimums. We apply our approach on a real screening dataset and a series of simulation scenarios. Compared to three existing LR-based approaches, our approach outperforms them by having lower type I and type II error rates, being able to identify more preset causal sites, and performing at faster speeds.

  19. Swarm: Recent Progress in Analysis of the Sun Induced Magnetic Disturbance

    DEFF Research Database (Denmark)

    Tøffner-Clausen, Lars; Lesur, Vincent; Brauer, Peter

    The ESA Earth Observation Magnetic Mission Swarm carries high precision vector and scalar magnetometers. Careful analyses have revealed s smaller, Sun driven magnetic disturbance of the vector magnetometer. This disturbance have been imperically mapped and corrected since mid 2015. This work...

  20. Signal Constellations for Multilevel Coded Modulation with Sparse Graph Codes

    NARCIS (Netherlands)

    Cronie, H.S.

    2005-01-01

    A method to combine error-correction coding and spectral efficient modulation for transmission over channels with Gaussian noise is presented. The method of modulation leads to a signal constellation in which the constellation symbols have a nonuniform distribution. This gives a so-called shape gain

  1. Equal distribution of satellite constellations on circular target orbits

    NARCIS (Netherlands)

    Vos, E.; Scherpen, J.M.A.; van der Schaft, A. J.

    2014-01-01

    This paper addresses the problem of equal distribution of satellite constellations on circular target orbits. The control goal is to make the constellation converge to a circular target orbit, while spatially distributing the satellites at equal inter-satellite distances. The solution is defined in

  2. Consumer Perceptions of Service Constellations : Implications for Service Innovation

    NARCIS (Netherlands)

    van Riel, A.C.R.; Calabretta, G.; Driessen, P.H.; Hillebrand, B.; Humphreys, A.; Krafft, M.; Beckers, S.F.M.

    2013-01-01

    Purpose - The purpose of this paper is to investigate how the service constellation perspective affects innovation strategies and potentially contributes to the innovation literature, proposing a research agenda. Design/methodology/approach - By analyzing the notion of a service constellation, the

  3. Development of Constellation's Launch Control System

    Science.gov (United States)

    Lougheed, Kirk D.; Peaden, Cary J.

    2010-01-01

    The paper focuses on the National Aeronautics and Space Administration (NASA) Constellation Program's Launch Control System (LCS) development effort at Kennedy Space Center (KSC). It provides a brief history of some preceding efforts to provide launch control and ground processing systems for other NASA programs, and some lessons learned from those experiences. It then provides high level descriptions of the LCS mission, objectives, organization, architecture, and progress. It discusses some of our development tenets, including our use of standards based design and use of off-the-shelf products whenever possible, incremental development cycles, and highly reliable, available, and supportable enterprise class system servers. It concludes with some new lessons learned and our plans for the future.

  4. 3rd international swarm seminar. Proceedings

    International Nuclear Information System (INIS)

    Lindinger, W.; Villinger, H.; Federer, W.

    1983-01-01

    47 papers on various problems of ion physics have been presented. The session headings are 1) recombination and electron attachment 2) transport of electrons in gases and liquids 3) swarm studies on collisions of metastable and on collisions of Rydberg atoms 4) ion neutral-interactions 5) ion transport in gases 6) applied aspects of swarm studies. (G.Q.)

  5. Osmotic pressure in a bacterial swarm.

    Science.gov (United States)

    Ping, Liyan; Wu, Yilin; Hosu, Basarab G; Tang, Jay X; Berg, Howard C

    2014-08-19

    Using Escherichia coli as a model organism, we studied how water is recruited by a bacterial swarm. A previous analysis of trajectories of small air bubbles revealed a stream of fluid flowing in a clockwise direction ahead of the swarm. A companion study suggested that water moves out of the agar into the swarm in a narrow region centered ∼ 30 μm from the leading edge of the swarm and then back into the agar (at a smaller rate) in a region centered ∼ 120 μm back from the leading edge. Presumably, these flows are driven by changes in osmolarity. Here, we utilized green/red fluorescent liposomes as reporters of osmolarity to verify this hypothesis. The stream of fluid that flows in front of the swarm contains osmolytes. Two distinct regions are observed inside the swarm near its leading edge: an outer high-osmolarity band (∼ 30 mOsm higher than the agar baseline) and an inner low-osmolarity band (isotonic or slightly hypotonic to the agar baseline). This profile supports the fluid-flow model derived from the drift of air bubbles and provides new (to our knowledge) insights into water maintenance in bacterial swarms. High osmotic pressure at the leading edge of the swarm extracts water from the underlying agar and promotes motility. The osmolyte is of high molecular weight and probably is lipopolysaccharide. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  6. Cubesat Constellation Design for Air Traffic Monitoring

    Science.gov (United States)

    Nag, Sreeja; Rios, Joseph Lucio; Gerhardt, David; Pham, Camvu

    2015-01-01

    Suitably equipped global and local air traffic can be tracked. The tracking information may then be used for control from ground-based stations by receiving the Automatic Dependent Surveillance-Broadcast (ADS-B) signal. The ADS-B signal, emitted from the aircraft's Mode-S transponder, is currently tracked by terrestrial based receivers but not over remote oceans or sparsely populated regions such as Alaska or the Pacific Ocean. Lack of real-time aircraft time/location information in remote areas significantly hinders optimal planning and control because bigger "safety bubbles" (lateral and vertical separation) are required around the aircraft until they reach radar-controlled airspace. Moreover, it presents a search-and-rescue bottleneck. Aircraft in distress, e.g. Air France AF449 that crashed in 2009, take days to be located or cannot be located at all, e.g. Malaysia Airlines MH370 in 2014. In this paper, we describe a tool for designing a constellation of small satellites which demonstrates, through high-fidelity modeling based on simulated air traffic data, the value of space-based ADS-B monitoring and provides recommendations for cost-efficient deployment of a constellation of small satellites to increase safety and situational awareness in the currently poorly-served surveillance area of Alaska. Air traffic data has been obtained from the Future ATM Concepts Evaluation Tool (FACET), developed at NASA Ames Research Center, simulated over the Alaskan airspace over a period of one day. The simulation is driven by MATLAB with satellites propagated and coverage calculated using AGI's Satellite ToolKit(STK10).

  7. Optimal Design of Satellite Constellation Korean Peninsula Regions

    Directory of Open Access Journals (Sweden)

    Nam-Kyun Kim

    2008-06-01

    Full Text Available Designing satellite constellations providing partial coverage of certain regions becomes more important as small low-altitude satellites receives an increasing attention due to its cost-effectiveness analysis. Generally, Walker's method is a standard constellation method for global coverage but not effective for partial coverage. The purpose of this study is to design optimal constellation of satellites for effective observation in Korean peninsula regions. In this study, a new constellation design method is presented for partial coverage, using direct control of satellites' orbital elements. And also, a ground repeating circular orbit is considered for each satellite's orbit with the Earth oblateness effect. As the results, at least four satellites are required to observe the Korean peninsula regions effectively when minimum elevation angle is assumed as 12 degrees. The results from new method are better than those from the best Walker method. The proposed algorithm will be useful to design satellite constellation missions of Korea in future.

  8. Night sky a field guide to the constellations

    CERN Document Server

    Poppele, Jonathan

    2009-01-01

    Stargazing is among the most peaceful and inspiring outdoor activities. Night Sky, the award-winning book by Jonathan Poppele, makes it more fun than ever! Take a simple approach to finding 62 constellations by focusing on one constellation at a time, instead of attempting to study dizzying charts. Start with the easy-to-find constellations during each season and work toward the more difficult ones. Better yet, you'll learn how to locate any constellation in relation to the Big Dipper, the North Star and the top of the sky. With two ways to locate each constellation, you'll know where in the sky to look and what to look for! Along the way, you'll be introduced to mythology, facts and tidbits, as well as details about the planets, solar system and more! As an added bonus, the book comes with a red-light flashlight for night reading.

  9. Stellar aberration correction and thermoelastic compensation of Swarm μASC attitude observations: A comment to the Express Letter “Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements”, by Stefan Maus

    DEFF Research Database (Denmark)

    Herceg, M.; Jørgensen, P. S.; Jørgensen, J. L.

    2017-01-01

    The Swarm constellation of three satellites measures the magnetic signal of the Earth using both a Vector Field Magnetometer and an Absolute Scalar Magnetometer. A Micro Advanced Stellar Compass (μASC) mounted on a common, supposedly stable, optical bench precisely determines its inertial attitude...... to be caused by thermal gradient sensitivity of the optical bench system, opposing the underlying assumption of perfect platform stability. The results after applying thermal corrections show significant decrease in root mean square, with Inter Boresight Angle of thermally corrected data being nearly flat...

  10. Design and control of swarm dynamics

    CERN Document Server

    Bouffanais, Roland

    2016-01-01

    The book is about the key elements required for designing, building and controlling effective artificial swarms comprised of multiple moving physical agents. Therefore this book presents the fundamentals of each of those key elements in the particular frame of dynamic swarming, specifically exposing the profound connections between these elements and establish some general design principles for swarming behaviors. This scientific endeavor requires an inter-disciplinary approach: biomimetic inspiration from ethology and ecology, study of social information flow, analysis of temporal and adaptive signaling network of interaction, considerations of control of networked real-time systems, and lastly, elements of complex adaptive dynamical systems. This book offers a completely new perspective on the scientific understanding of dynamic collective behaviors thanks to its multi-disciplinary approach and its focus on artificial swarm of physical agents. Two of the key problems in understanding the emergence of swarm ...

  11. Particle swarm genetic algorithm and its application

    International Nuclear Information System (INIS)

    Liu Chengxiang; Yan Changxiang; Wang Jianjun; Liu Zhenhai

    2012-01-01

    To solve the problems of slow convergence speed and tendency to fall into the local optimum of the standard particle swarm optimization while dealing with nonlinear constraint optimization problem, a particle swarm genetic algorithm is designed. The proposed algorithm adopts feasibility principle handles constraint conditions and avoids the difficulty of penalty function method in selecting punishment factor, generates initial feasible group randomly, which accelerates particle swarm convergence speed, and introduces genetic algorithm crossover and mutation strategy to avoid particle swarm falls into the local optimum Through the optimization calculation of the typical test functions, the results show that particle swarm genetic algorithm has better optimized performance. The algorithm is applied in nuclear power plant optimization, and the optimization results are significantly. (authors)

  12. Swarm controlled emergence for ant clustering

    DEFF Research Database (Denmark)

    Scheidler, Alexander; Merkle, Daniel; Middendorf, Martin

    2013-01-01

    Purpose: Swarm controlled emergence is proposed as an approach to control emergent effects in (artificial) swarms. The method involves the introduction of specific control agents into the swarm systems. Control agents behave similar to the normal agents and do not directly influence the behavior...... of the normal agents. The specific design of the control agents depends on the particular swarm system considered. The aim of this paper is to apply the method to ant clustering. Ant clustering, as an emergent effect, can be observed in nature and has inspired the design of several technical systems, e.......g. moving robots, and clustering algorithms. Design/methodology/approach: Different types of control agents for that ant clustering model are designed by introducing slight changes to the behavioural rules of the normal agents. The clustering behaviour of the resulting swarms is investigated by extensive...

  13. Towards CHAOS-5 - How can Swarm contribute?

    DEFF Research Database (Denmark)

    Finlay, Chris; Olsen, Nils; Tøffner-Clausen, Lars

    2014-01-01

    The launch of ESA's satellite trio Swarm in November 2013 opens an exciting new chapter in the observation and monitoring of Earth's magnetic field from space. We report preliminary results from an extension of the CHAOS series of geomagnetic field models to include both scalar and vector field...... observations from the three Swarm satellites, along with the most recent quasi-definitive ground observatory data. The fit of this new update CHAOS field model to the Swarm observations will be presented in detail providing useful insight the initial Swarm data. Enhancements of the CHAOS modelling scheme...... include a 1 minute time resolution for the RC index and anisotropic weighting of vector field data depending on quasi-dipole latitude. We shall also report on the perspective given by the initial Swarm data on rapid field changes currently taking place in the Atlantic sector....

  14. Swarms, swarming and entanglements of fungal hyphae and of plant roots

    Science.gov (United States)

    Barlow, Peter W.; Fisahn, Joachim

    2013-01-01

    There has been recent interest in the possibility that plant roots can show oriented collective motion, or swarming behavior. We examine the evidence supportive of root swarming and we also present new observations on this topic. Seven criteria are proposed for the definition of a swarm, whose application can help identify putative swarming behavior in plants. Examples where these criteria are fulfilled, at many levels of organization, are presented in relation to plant roots and root systems, as well as to the root-like mycelial cords (rhizomorphs) of fungi. The ideas of both an “active” swarming, directed by a signal which imposes a common vector on swarm element aggregation, and a “passive” swarming, where aggregation results from external constraint, are introduced. Active swarming is a pattern of cooperative behavior peculiar to the sporophyte generation of vascular plants and is the antithesis of the competitive behavior shown by the gametophyte generation of such plants, where passive swarming may be found. Fungal mycelial cords could serve as a model example of swarming in a multi-cellular, non-animal system. PMID:24255743

  15. Cooperative Control of Swarms of Unmanned Aerial Vehicles

    NARCIS (Netherlands)

    De Vries, E.; Subbarao, K.

    2011-01-01

    Potential function based swarm control is a technique using artificial potential functions to generate steering commands resulting in swarming behavior. This means that the vehicles in the swarm autonomously take care of flying in formation, resulting in steering the swarm, instead of all the

  16. Updating the CHAOS series of field models using Swarm data and resulting candidate models for IGRF-12

    DEFF Research Database (Denmark)

    Finlay, Chris; Olsen, Nils; Tøffner-Clausen, Lars

    Ten months of data from ESA's Swarm mission, together with recent ground observatory monthly means, are used to update the CHAOS series of geomagnetic field models with a focus on time-changes of the core field. As for previous CHAOS field models quiet-time, night-side, data selection criteria......th order spline representation with knot points spaced at 0.5 year intervals. The resulting field model is able to consistently fit data from six independent low Earth orbit satellites: Oersted, CHAMP, SAC-C and the three Swarm satellites. As an example, we present comparisons of the excellent model...... fit obtained to both the Swarm data and the CHAMP data. The new model also provides a good description of observatory secular variation, capturing rapid field evolution events during the past decade. Maps of the core surface field and its secular variation can already be extracted in the Swarm-era. We...

  17. On the capability of SWARM for estimating time-variable gravity fields and mass variations

    Science.gov (United States)

    Reubelt, Tilo; Baur, Oliver; Weigelt, Matthias; Sneeuw, Nico

    2013-04-01

    Recently, the implementation of the GRACE Follow-On mission has been approved. However, this successor of GRACE is planned to become operational in 2017 at the earliest. In order to fill the impending gap of 3-4 years between GRACE and GRACE-FO, the capability of the magnetic field mission SWARM as a gap filler for time-variable gravity field determination has to be investigated. Since the three SWARM satellites, where two of them fly on a pendulum formation, are equipped with high-quality GPS receivers and accelerometers, orbit analysis from high-low Satellite-to-Satellite Tracking (hl-SST) can be applied for geopotential recovery. As data analysis from CHAMP and GRACE has shown, the detection of annual gravity signals and gravity trends from hl-SST is possible for long-wavelength features corresponding to a Gaussian radius of 1000 km, although the accuracy of a low-low SST mission like GRACE cannot be reached. However, since SWARM is a three-satellite constellation and might provide GPS data of higher quality compared to previous missions, improved gravity field recovery can be expected. We present detailed closed-loop simulation studies for a 5 years period based on time-variable gravity caused by mass changes in the hydrosphere, cryosphere and solid Earth. Models for these variations are used to simulate the SWARM satellite orbits. We recover time-variable gravity from orbit analysis adopting the acceleration approach. Finally, we convert time-variable gravity to mass change in order to compare with the a priori model input.

  18. The precursory earthquake swarm in Greece

    Directory of Open Access Journals (Sweden)

    D. Rhoades

    2000-06-01

    Full Text Available The Hellenic subduction region displays the same precursory swarm phenomenon as has been found in comparable regions of New Zealand and Japan. In the earthquake catalogue of the Aristotle University of Thessaloniki, 10 past sequences of precursory swarms and related major mainshock events have been identified. These correlate, in respect of location, magnitude and time, with the 9 sequences previously identified in New Zealand, and 9 in Japan, bringing the total of sequences to 28, and the totals of related events (allowing for clustering to 56 precursory swarms and 42 mainshock events. The results add strength to the hypothesis that swarms are long-range predictors of mainshock events. A close similarity between the swarm and aftershock magnitudes in a given sequence is also confirmed in Greece, supporting the proposal that swarms are an integral part of the seismogenic process in subduction regions. Further, the modelling of swarms as part of an overall increase in seismicity, the onset of which marks the onset of seismogenesis, is well illustrated from past sequences in Greece. Formal tests are being carried out in Greece, in parallel with New Zealand and Japan, to ascertain the performance of the hypothesis as a basis for long-range synoptic forecasting.

  19. Chaos Quantum-Behaved Cat Swarm Optimization Algorithm and Its Application in the PV MPPT

    Directory of Open Access Journals (Sweden)

    Xiaohua Nie

    2017-01-01

    Full Text Available Cat Swarm Optimization (CSO algorithm was put forward in 2006. Despite a faster convergence speed compared with Particle Swarm Optimization (PSO algorithm, the application of CSO is greatly limited by the drawback of “premature convergence,” that is, the possibility of trapping in local optimum when dealing with nonlinear optimization problem with a large number of local extreme values. In order to surmount the shortcomings of CSO, Chaos Quantum-behaved Cat Swarm Optimization (CQCSO algorithm is proposed in this paper. Firstly, Quantum-behaved Cat Swarm Optimization (QCSO algorithm improves the accuracy of the CSO algorithm, because it is easy to fall into the local optimum in the later stage. Chaos Quantum-behaved Cat Swarm Optimization (CQCSO algorithm is proposed by introducing tent map for jumping out of local optimum in this paper. Secondly, CQCSO has been applied in the simulation of five different test functions, showing higher accuracy and less time consumption than CSO and QCSO. Finally, photovoltaic MPPT model and experimental platform are established and global maximum power point tracking control strategy is achieved by CQCSO algorithm, the effectiveness and efficiency of which have been verified by both simulation and experiment.

  20. Chaos Quantum-Behaved Cat Swarm Optimization Algorithm and Its Application in the PV MPPT.

    Science.gov (United States)

    Nie, Xiaohua; Wang, Wei; Nie, Haoyao

    2017-01-01

    Cat Swarm Optimization (CSO) algorithm was put forward in 2006. Despite a faster convergence speed compared with Particle Swarm Optimization (PSO) algorithm, the application of CSO is greatly limited by the drawback of "premature convergence," that is, the possibility of trapping in local optimum when dealing with nonlinear optimization problem with a large number of local extreme values. In order to surmount the shortcomings of CSO, Chaos Quantum-behaved Cat Swarm Optimization (CQCSO) algorithm is proposed in this paper. Firstly, Quantum-behaved Cat Swarm Optimization (QCSO) algorithm improves the accuracy of the CSO algorithm, because it is easy to fall into the local optimum in the later stage. Chaos Quantum-behaved Cat Swarm Optimization (CQCSO) algorithm is proposed by introducing tent map for jumping out of local optimum in this paper. Secondly, CQCSO has been applied in the simulation of five different test functions, showing higher accuracy and less time consumption than CSO and QCSO. Finally, photovoltaic MPPT model and experimental platform are established and global maximum power point tracking control strategy is achieved by CQCSO algorithm, the effectiveness and efficiency of which have been verified by both simulation and experiment.

  1. Physiological processes related to the bee swarming

    Directory of Open Access Journals (Sweden)

    Jiří Svoboda

    2010-01-01

    Full Text Available One of the essential genetically subjected behaviours of a bee-colony is swarming. However, in the time of queen breeding and technical approach to colony division, swarming constitutes a problem in the effectiveness of controlled beekeeping and subsequently in decreasing of the attainable economic profits. The intensity of swarming is a polyfactorial phenomenon whose characteristic feature is seasonality (the availability of breed, course of weather so the swarming intensity is different in particular years. This study is connected with the research carried out at the Department of Zoo­lo­gy, Fisheries, Hydrobiology and Apiculture at Mendel University in Brno. The experiment focused on the relationship between the swarming and biological state of bee-colony was realized in three seasons of the period 2003–2005. Experimental bee-colonies were stimulated to the swarming fever by zoo-technical practices, at the same time the biological status of given bee-colony was observed. Within the process of marking of newly emerged workers there was observed their number continuously during the particular season. The samples of 3- and 4-week-old workers were instrumental to the analysis of the development of their hypopharyngeal glands. The study has proved that a bee-colonies building higher number of queen cells are likely expected to be in swarming fever, b 3-week-old workers have hypopharyngeal glands in higher stage of development than 4-week-old workers, c higher stage of swarming fever is closely correlated with higher stage of de­ve­lop­ment of hypopharyngeal glands. These facts can contribute to the comprehension of the reason and relationships of the swarming.

  2. Optimal Constellation Design for Orbital Munitions Delivery System

    National Research Council Canada - National Science Library

    Anderson, Jason

    2004-01-01

    Rather than delivering conventional munitions through the airspace of uncooperative nations, a constellation of space-stored weapons could potentially target any point on the Earth and arrive within...

  3. SmallSat Constellation Inter-satellite Link System Simulator

    Data.gov (United States)

    National Aeronautics and Space Administration — Goddard Space Flight Center Distributed Space Mission (DSM) seeks to design and develop the technologies required to achieve the mission goals.  For a constellation...

  4. Swarming and the Future of Conflict

    National Research Council Canada - National Science Library

    Arquilla, John

    2000-01-01

    Swarming is seemingly amorphous, but it is a deliberately structured, coordinated, strategic way to strike from all directions, by means of a sustainable pulsing of force and/or fire, close-in as well...

  5. Locating multiple optima using particle swarm optimization

    CSIR Research Space (South Africa)

    Brits, R

    2007-01-01

    Full Text Available Many scientific and engineering applications require optimization methods to find more than one solution to multimodal optimization problems. This paper presents a new particle swarm optimization (PSO) technique to locate and refine multiple...

  6. Study of particle swarm optimization particle trajectories

    CSIR Research Space (South Africa)

    Van den Bergh, F

    2006-01-01

    Full Text Available Particle swarm optimization (PSO) has shown to be an efficient, robust and simple optimization algorithm. Most of the PSO studies are empirical, with only a few theoretical analyses that concentrate on understanding particle trajectories...

  7. Particle swarm optimisation classical and quantum perspectives

    CERN Document Server

    Sun, Jun; Wu, Xiao-Jun

    2016-01-01

    IntroductionOptimisation Problems and Optimisation MethodsRandom Search TechniquesMetaheuristic MethodsSwarm IntelligenceParticle Swarm OptimisationOverviewMotivationsPSO Algorithm: Basic Concepts and the ProcedureParadigm: How to Use PSO to Solve Optimisation ProblemsSome Harder Examples Some Variants of Particle Swarm Optimisation Why Does the PSO Algorithm Need to Be Improved? Inertia and Constriction-Acceleration Techniques for PSOLocal Best ModelProbabilistic AlgorithmsOther Variants of PSO Quantum-Behaved Particle Swarm Optimisation OverviewMotivation: From Classical Dynamics to Quantum MechanicsQuantum Model: Fundamentals of QPSOQPSO AlgorithmSome Essential ApplicationsSome Variants of QPSOSummary Advanced Topics Behaviour Analysis of Individual ParticlesConvergence Analysis of the AlgorithmTime Complexity and Rate of ConvergenceParameter Selection and PerformanceSummaryIndustrial Applications Inverse Problems for Partial Differential EquationsInverse Problems for Non-Linear Dynamical SystemsOptimal De...

  8. PARTICLE SWARM OPTIMIZATION BASED OF THE MAXIMUM ...

    African Journals Online (AJOL)

    2010-06-30

    Jun 30, 2010 ... PARTICLE SWARM OPTIMIZATION BASED OF THE MAXIMUM. PHOTOVOLTAIC POWER TRACTIOQG UNDER DIFFERENT CONDITIONS. Y. Labbi*, D. Ben Attous and H. Sarhoud. Department of Electrotechnics, Faculty of Electrical Engineering El-Oued University. Center, Algeria. Received: 01 ...

  9. A REVIEW OF SWARMING UNMANNED AERIAL VEHICLES

    Directory of Open Access Journals (Sweden)

    CORNEA Mihai

    2016-11-01

    Full Text Available This paper in if fact an overview of state of the art in mobile multi-robot systems as an initial part of our research in implementing a system based on swarm robotics concepts to be used in natural disaster search and rescue missions. The system is to be composed of a group of drones that can detect survivor mobile cell signals and exhibit some other features as well. This paper surveys the swarm robotics research landscape to provide a theoretical background to the implementation and help determine the techniques available to create the system. The Particle swarm optimization (PSO and Glowworm swarm optimization (GSO algorithms are briefly described and there is also insight into Bird flocking behavior and the model behind it

  10. Open Sourcing Social Change: Inside the Constellation Model

    OpenAIRE

    Tonya Surman; Mark Surman

    2008-01-01

    The constellation model was developed by and for the Canadian Partnership for Children's Health and the Environment. The model offers an innovative approach to organizing collaborative efforts in the social mission sector and shares various elements of the open source model. It emphasizes self-organizing and concrete action within a network of partner organizations working on a common issue. Constellations are self-organizing action teams that operate within the broader strategic vision of a ...

  11. Locally Diverse Constellations from the Special Orthogonal Group

    OpenAIRE

    Karpuk, David; Hollanti, Camilla

    2015-01-01

    To optimize rotated multidimensional constellations over a single-input single-output Rayleigh fading channel, a family of rotation matrices is constructed for all dimensions which are a power of 2. This family is a one-parameter subgroup of the group of rotation matrices, and is located using a gradient descent scheme on this Lie group. The parameter defining the family is chosen to optimize the cutoff rate of the constellation. The optimal rotation parameter is computed explicitly for low s...

  12. Gene expression in Pseudomonas aeruginosa swarming motility

    Directory of Open Access Journals (Sweden)

    Déziel Eric

    2010-10-01

    Full Text Available Abstract Background The bacterium Pseudomonas aeruginosa is capable of three types of motilities: swimming, twitching and swarming. The latter is characterized by a fast and coordinated group movement over a semi-solid surface resulting from intercellular interactions and morphological differentiation. A striking feature of swarming motility is the complex fractal-like patterns displayed by migrating bacteria while they move away from their inoculation point. This type of group behaviour is still poorly understood and its characterization provides important information on bacterial structured communities such as biofilms. Using GeneChip® Affymetrix microarrays, we obtained the transcriptomic profiles of both bacterial populations located at the tip of migrating tendrils and swarm center of swarming colonies and compared these profiles to that of a bacterial control population grown on the same media but solidified to not allow swarming motility. Results Microarray raw data were corrected for background noise with the RMA algorithm and quantile normalized. Differentially expressed genes between the three conditions were selected using a threshold of 1.5 log2-fold, which gave a total of 378 selected genes (6.3% of the predicted open reading frames of strain PA14. Major shifts in gene expression patterns are observed in each growth conditions, highlighting the presence of distinct bacterial subpopulations within a swarming colony (tendril tips vs. swarm center. Unexpectedly, microarrays expression data reveal that a minority of genes are up-regulated in tendril tip populations. Among them, we found energy metabolism, ribosomal protein and transport of small molecules related genes. On the other hand, many well-known virulence factors genes were globally repressed in tendril tip cells. Swarm center cells are distinct and appear to be under oxidative and copper stress responses. Conclusions Results reported in this study show that, as opposed to

  13. Particle ''swarm'' dynamics in triboelectric systems

    International Nuclear Information System (INIS)

    Vinay, Stephen J.; Jhon, Myung S.

    2001-01-01

    Using state-of-the-art flow/particle visualization and animation techniques, the time-dependent statistical distributions of charged-particle ''swarms'' exposed to external fields (both electrostatic and flow) are examined. We found that interparticle interaction and drag forces mainly influenced swarm dispersion in a Lagrangian reference frame, whereas the average particle trajectory was affected primarily by the external electric and flow fields

  14. The Swarm Computing Approach to Business Intelligence

    Directory of Open Access Journals (Sweden)

    Schumann Andrew

    2015-07-01

    Full Text Available We have proposed to use some features of swarm behaviours in modelling business processes. Due to these features we deal with a propagation of business processes in all accessible directions. This propagation is involved into our formalization instead of communicating sequential processes. As a result, we have constructed a business process diagram language based on the swarm behavior and an extension of that language in the form of reflexive management language.

  15. BRITE Constellation: data processing and photometry

    Science.gov (United States)

    Popowicz, A.; Pigulski, A.; Bernacki, K.; Kuschnig, R.; Pablo, H.; Ramiaramanantsoa, T.; Zocłońska, E.; Baade, D.; Handler, G.; Moffat, A. F. J.; Wade, G. A.; Neiner, C.; Rucinski, S. M.; Weiss, W. W.; Koudelka, O.; Orleański, P.; Schwarzenberg-Czerny, A.; Zwintz, K.

    2017-09-01

    Context. The BRIght Target Explorer (BRITE) mission is a pioneering space project aimed at the long-term photometric monitoring of the brightest stars in the sky by means of a constellation of nanosatellites. Its main advantage is high photometric accuracy and time coverage which are inaccessible from the ground. Its main drawback is the lack of cooling of the CCD detectors and the absence of good shielding that would protect them from energetic particles. Aims: The main aim of this paper is the presentation of procedures used to obtain high-precision photometry from a series of images acquired by the BRITE satellites in two modes of observing, stare and chopping. The other aim is a comparison of the photometry obtained with two different pipelines and a comparison of the real scatter with expectations. Methods: We developed two pipelines corresponding to the two modes of observing. They are based on aperture photometry with a constant aperture, circular for stare mode of observing and thresholded for chopping mode. Impulsive noise is a serious problem for observations made in the stare mode of observing and therefore in the pipeline developed for observations made in this mode, hot pixels are replaced using the information from shifted images in a series obtained during a single orbit of a satellite. In the other pipeline, the hot pixel replacement is not required because the photometry is made in difference images. Results: The assessment of the performance of both pipelines is presented. It is based on two comparisons, which use data from six runs of the UniBRITE satellite: (I) comparison of photometry obtained by both pipelines on the same data, which were partly affected by charge transfer inefficiency (CTI), (II) comparison of real scatter with theoretical expectations. It is shown that for CTI-affected observations, the chopping pipeline provides much better photometry than the other pipeline. For other observations, the results are comparable only for data

  16. Heterogeneous architecture to process swarm optimization algorithms

    Directory of Open Access Journals (Sweden)

    Maria A. Dávila-Guzmán

    2014-01-01

    Full Text Available Since few years ago, the parallel processing has been embedded in personal computers by including co-processing units as the graphics processing units resulting in a heterogeneous platform. This paper presents the implementation of swarm algorithms on this platform to solve several functions from optimization problems, where they highlight their inherent parallel processing and distributed control features. In the swarm algorithms, each individual and dimension problem are parallelized by the granularity of the processing system which also offer low communication latency between individuals through the embedded processing. To evaluate the potential of swarm algorithms on graphics processing units we have implemented two of them: the particle swarm optimization algorithm and the bacterial foraging optimization algorithm. The algorithms’ performance is measured using the acceleration where they are contrasted between a typical sequential processing platform and the NVIDIA GeForce GTX480 heterogeneous platform; the results show that the particle swarm algorithm obtained up to 36.82x and the bacterial foraging swarm algorithm obtained up to 9.26x. Finally, the effect to increase the size of the population is evaluated where we show both the dispersion and the quality of the solutions are decreased despite of high acceleration performance since the initial distribution of the individuals can converge to local optimal solution.

  17. 75 FR 2163 - Constellation Energy; Notice of Docketing of Special Nuclear Material License SNM-2505 Amendment...

    Science.gov (United States)

    2010-01-14

    ... COMMISSION Constellation Energy; Notice of Docketing of Special Nuclear Material License SNM-2505 Amendment... June 15, 2009, from Constellation Energy (Constellation) to amend its Special Nuclear Material License... will remain the same for this action. An NRC review, documented in a letter to Constellation dated July...

  18. A self-adaptive chaotic particle swarm algorithm for short term hydroelectric system scheduling in deregulated environment

    International Nuclear Information System (INIS)

    Jiang Chuanwen; Bompard, Etorre

    2005-01-01

    This paper proposes a short term hydroelectric plant dispatch model based on the rule of maximizing the benefit. For the optimal dispatch model, which is a large scale nonlinear planning problem with multi-constraints and multi-variables, this paper proposes a novel self-adaptive chaotic particle swarm optimization algorithm to solve the short term generation scheduling of a hydro-system better in a deregulated environment. Since chaotic mapping enjoys certainty, ergodicity and the stochastic property, the proposed approach introduces chaos mapping and an adaptive scaling term into the particle swarm optimization algorithm, which increases its convergence rate and resulting precision. The new method has been examined and tested on a practical hydro-system. The results are promising and show the effectiveness and robustness of the proposed approach in comparison with the traditional particle swarm optimization algorithm

  19. Intelligent micro-spacecraft constellation for the geomagnetic storm forecasts

    Science.gov (United States)

    Veselovsky, I.; Yakovchouk, O.

    Two micro-spacecraft constellation with solar sails partially compensating the solar gravity allow their placement in the points along the Sun-Earth line behind the standard L1 point i e further out from the Earth and closer to the Sun The distances of the placement from the Earth and the base distances between such satellites depend on the ratios of their mass to the sail area It can be selected in the way needed for the warning of the coronal mass ejection arrival several or many hours before the upcoming geomagnetic storm Measurements of the magnetic field vector are necessary and sufficient for this purpose on each spacecraft No plasma measurements are needed for this purpose which makes the weight of spacecraft minimal The sail can be used also as a solar panel an antenna oriented on the Earth for the radio transmission and device for obtaining a stable mechanical orientation of the spacecraft axis along the Sun-Earth line Time delays and known base distances between satellites allow the solar wind velocity measurements with a sufficient accuracy for the warning of the coronal mass ejection arrival to the Earth Sky maps obtained with micro photo cameras and processed on board can give the accurate spacecraft orientation needed for the determination of the crucial quantity magnetic field vector orientation Together with measured magnetic field strength and the solar wind velocity on can obtain information for the robust forecast of geomagnetic storms The key element of the project is the intelligent on board programming needed for

  20. On Formal Specification of Emergent Behaviours in Swarm Robotic Systems

    Directory of Open Access Journals (Sweden)

    Clare Dixon

    2008-11-01

    Full Text Available It is a characteristic of swarm robotics that specifying overall emergent swarm behaviours in terms of the low-level behaviours of individual robots is very difficult. Yet if swarm robotics is to make the transition from the laboratory to real-world engineering realisation we need such specifications. This paper explores the use of temporal logic to formally specify, and possibly also prove, the emergent behaviours of a robotic swarm. The paper makes use of a simplified wireless connected swarm as a case study with which to illustrate the approach. Such a formal approach could be an important step toward a disciplined design methodology for swarm robotics.

  1. On Formal Specification of Emergent Behaviours in Swarm Robotic Systems

    Directory of Open Access Journals (Sweden)

    Alan FT Winfield

    2005-12-01

    Full Text Available It is a characteristic of swarm robotics that specifying overall emergent swarm behaviours in terms of the low-level behaviours of individual robots is very difficult. Yet if swarm robotics is to make the transition from the laboratory to real-world engineering realisation we need such specifications. This paper explores the use of temporal logic to formally specify, and possibly also prove, the emergent behaviours of a robotic swarm. The paper makes use of a simplified wireless connected swarm as a case study with which to illustrate the approach. Such a formal approach could be an important step toward a disciplined design methodology for swarm robotics.

  2. Merging the fields of swarm robotics and new media: Perceiving swarm robotics as new media

    Directory of Open Access Journals (Sweden)

    Monika O. Ivanova

    2014-06-01

    Full Text Available The aim of this paper is to provide evidence that swarm robotic systems can be perceived as new media objects. A thorough description of the five principles of new media proposed by Lev Manovich in “The Language of New Media” is presented. This is complemented by a state of the art on swarm robotics with an in-depth comparison of the characteristics of both fields. Also presented are examples of swarm robotics used in new media installations in order to illustrate the cutting-edge applications of robotics and artificial intelligence achieved through the unity of bothfields. The hypothesis of this research is that a novel point of view would be introduced by examining the field of swarm robotics through the scope of new media, which would benefit thework of both new media and swarm robotic researchers.

  3. The impact of GPS receiver modifications and ionospheric activity on Swarm baseline determination

    Science.gov (United States)

    Mao, X.; Visser, P. N. A. M.; van den IJssel, J.

    2018-05-01

    The European Space Agency (ESA) Swarm mission is a satellite constellation launched on 22 November 2013 aiming at observing the Earth geomagnetic field and its temporal variations. The three identical satellites are equipped with high-precision dual-frequency Global Positioning System (GPS) receivers, which make the constellation an ideal test bed for baseline determination. From October 2014 to August 2016, a number of GPS receiver modifications and a new GPS Receiver Independent Exchange Format (RINEX) converter were implemented. Moreover, the on-board GPS receiver performance has been influenced by the ionospheric scintillations. The impact of these factors is assessed for baseline determination of the pendulum formation flying Swarm-A and -C satellites. In total 30 months of data - from 15 July 2014 to the end of 2016 - is analyzed. The assessment includes analysis of observation residuals, success rate of GPS carrier phase ambiguity fixing, a consistency check between the so-called kinematic and reduced-dynamic baseline solution, and validations of orbits by comparing with Satellite Laser Ranging (SLR) observations. External baseline solutions from The German Space Operations Center (GSOC) and Astronomisches Institut - Universität Bern (AIUB) are also included in the comparison. Results indicate that the GPS receiver modifications and RINEX converter changes are effective to improve the baseline determination. This research eventually shows a consistency level of 9.3/4.9/3.0 mm between kinematic and reduced-dynamic baselines in the radial/along-track/cross-track directions. On average 98.3% of the epochs have kinematic solutions. Consistency between TU Delft and external reduced-dynamic baseline solutions is at a level of 1 mm level in all directions.

  4. Streamlining the Design Tradespace for Earth Imaging Constellations

    Science.gov (United States)

    Nag, Sreeja; Hughes, Steven P.; Le Moigne, Jacqueline J.

    2016-01-01

    Satellite constellations and Distributed Spacecraft Mission (DSM) architectures offer unique benefits to Earth observation scientists and unique challenges to cost estimators. The Cost and Risk (CR) module of the Tradespace Analysis Tool for Constellations (TAT-C) being developed by NASA Goddard seeks to address some of these challenges by providing a new approach to cost modeling, which aggregates existing Cost Estimating Relationships (CER) from respected sources, cost estimating best practices, and data from existing and proposed satellite designs. Cost estimation through this tool is approached from two perspectives: parametric cost estimating relationships and analogous cost estimation techniques. The dual approach utilized within the TAT-C CR module is intended to address prevailing concerns regarding early design stage cost estimates, and offer increased transparency and fidelity by offering two preliminary perspectives on mission cost. This work outlines the existing cost model, details assumptions built into the model, and explains what measures have been taken to address the particular challenges of constellation cost estimating. The risk estimation portion of the TAT-C CR module is still in development and will be presented in future work. The cost estimate produced by the CR module is not intended to be an exact mission valuation, but rather a comparative tool to assist in the exploration of the constellation design tradespace. Previous work has noted that estimating the cost of satellite constellations is difficult given that no comprehensive model for constellation cost estimation has yet been developed, and as such, quantitative assessment of multiple spacecraft missions has many remaining areas of uncertainty. By incorporating well-established CERs with preliminary approaches to approaching these uncertainties, the CR module offers more complete approach to constellation costing than has previously been available to mission architects or Earth

  5. Collective motion of predictive swarms.

    Directory of Open Access Journals (Sweden)

    Nathaniel Rupprecht

    Full Text Available Theoretical models of populations and swarms typically start with the assumption that the motion of agents is governed by the local stimuli. However, an intelligent agent, with some understanding of the laws that govern its habitat, can anticipate the future, and make predictions to gather resources more efficiently. Here we study a specific model of this kind, where agents aim to maximize their consumption of a diffusing resource, by attempting to predict the future of a resource field and the actions of other agents. Once the agents make a prediction, they are attracted to move towards regions that have, and will have, denser resources. We find that the further the agents attempt to see into the future, the more their attempts at prediction fail, and the less resources they consume. We also study the case where predictive agents compete against non-predictive agents and find the predictors perform better than the non-predictors only when their relative numbers are very small. We conclude that predictivity pays off either when the predictors do not see too far into the future or the number of predictors is small.

  6. PWR power distribution flattening using Quantum Particle Swarm intelligence

    International Nuclear Information System (INIS)

    Jamalipour, M.; Gharib, M.; Sayareh, R.; Khoshahval, F.

    2013-01-01

    Highlights: ► Quantum Particle Swarm Optimization (QPSO) is applied to ICFMO. ► A differential mutation operator is added to enhance QPSO performance (QPSO-DM). ► PSO, QPSO and QPSO-DM are tested on Bushehr Nuclear Power Plant (BNPP). ► It is observed that QPSO-DM is comparable to PSO and QPSO on ICFMO. - Abstract: In-core fuel management optimization (ICFMO) is one of the most challenging concepts of nuclear engineering. Most of the strategies implemented for optimizing fuel loading pattern in nuclear power reactors are based on maximizing core multiplication factor in order to extract maximum energy and reducing power peaking factor from a predetermined value to maintain fuel integrity. In this investigation a new method using Quantum Particle Swarm Optimization (QPSO) algorithm has been developed in order to flatten power density distribution in WWER-1000 Bushehr Nuclear Power Plant (BNPP) and thereby provide a better safety margin. The result and convergence of this method show that QPSO performs very well and is comparable to PSO. Furthermore, an operator has been added to QPSO as a mutation operator. This algorithm, called QPSO-DM, shows a better performance on ICFMO than PSO and QPSO. MATLAB software was used to map PSO, QPSO and QPSO-DM for loading pattern optimization. Multi-group constants generated by WIMS for different fuel configurations were fed into CITATION to obtain the power density distribution

  7. P-adic valued models of swarm behaviour

    Science.gov (United States)

    Schumann, Andrew

    2017-07-01

    The swarm behaviour can be fully determined by attractants (food pieces) which change the directions of swarm propagation. If we assume that at each time step the swarm can find out not more than p - 1 attractants, then the swarm behaviour can be coded by p-adic integers. The main task of any swarm is to logistically optimize the road system connecting the reachable attractants. In the meanwhile, the transporting network of the swarm has loops (circles) and permanently changes, e.g. the swarm occupies some attractants and leaves the others. However, this complex dynamics can be effectively coded by p-adic integers. This allows us to represent the swarm behaviour as a calculation on p-adic valued strings.

  8. Self-organized sorting limits behavioral variability in swarms.

    Science.gov (United States)

    Copenhagen, Katherine; Quint, David A; Gopinathan, Ajay

    2016-08-23

    Swarming is a phenomenon where collective motion arises from simple local interactions between typically identical individuals. Here, we investigate the effects of variability in behavior among the agents in finite swarms with both alignment and cohesive interactions. We show that swarming is abolished above a critical fraction of non-aligners who do not participate in alignment. In certain regimes, however, swarms above the critical threshold can dynamically reorganize and sort out excess non-aligners to maintain the average fraction close to the critical value. This persists even in swarms with a distribution of alignment interactions, suggesting a simple, robust and efficient mechanism that allows heterogeneously mixed populations to naturally regulate their composition and remain in a collective swarming state or even differentiate among behavioral phenotypes. We show that, for evolving swarms, this self-organized sorting behavior can couple to the evolutionary dynamics leading to new evolutionarily stable equilibrium populations set by the physical swarm parameters.

  9. Dark Energy, Dark Matter and Science with Constellation-X

    Science.gov (United States)

    Cardiff, Ann Hornschemeier

    2005-01-01

    Constellation-X, with more than 100 times the collecting area of any previous spectroscopic mission operating in the 0.25-40 keV bandpass, will enable highthroughput, high spectral resolution studies of sources ranging from the most luminous accreting supermassive black holes in the Universe to the disks around young stars where planets form. This talk will review the updated Constellation-X science case, released in booklet form during summer 2005. The science areas where Constellation-X will have major impact include the exploration of the space-time geometry of black holes spanning nine orders of magnitude in mass and the nature of the dark energy and dark matter which govern the expansion and ultimate fate of the Universe. Constellation-X will also explore processes referred to as "cosmic feedback" whereby mechanical energy, radiation, and chemical elements from star formation and black holes are returned to interstellar and intergalactic medium, profoundly affecting the development of structure in the Universe, and will also probe all the important life cycles of matter, from stellar and planetary birth to stellar death via supernova to stellar endpoints in the form of accreting binaries and supernova remnants. This talk will touch upon all these areas, with particular emphasis on Constellation-X's role in the study of Dark Energy.

  10. Prehistory of Zodiac Dating: Three Strata of Upper Paleolithic Constellations

    Science.gov (United States)

    Gurshtein, Alex A.

    A pattern of archaic proto-constellations is extracted from Aratus' "The Phaenomena" didactic poem list according to a size criterion elaborated earlier, and their symbolism is analyzed. As a result of this approach three celestial symbolical strata are discovered to be probably a reflection of the symbols for the Lower, the Middle and the Upper Worlds; the Under-World creatures have a water character, the Middle World ones are mostly anthropomorphic and flying beings are for the Upper World. The strata excerpted from Aratus' sky seems to be in agreement with the well-known Babylonian division into three god pathways for Ea (Enki), Anu and Enlil. There is a possibility of dating the pattern discovered because of precession's strong influence as far back as 16 thousand years, the result being supported by the comparison of different star group mean sizes. The archaic constellation pattern under consideration is a reasonable background of symbolical meanings for the first Zodiacal generation quartet (7.5 thousand years old) examined by the author previously. The enormous size of the Argo constellation (Ship of Argo and his Argonauts) as well as the large sizes of other southern constellations are explained as due to the existence of an accumulation zone near the South celestial pole. Some extra correlations between the reconstruction proposed and cultural data available are discussed. The paper is the second part of the investigation "On the Origin of the Zodiacal constellations" published in Vistas in Astronomy, vol.36, pp.171-190, 1993.

  11. Swarm behavioral sorting based on robotic hardware variation

    OpenAIRE

    Shang, Beining; Crowder, Richard; Zauner, Klaus-Peter

    2014-01-01

    Swarm robotic systems can offer advantages of robustness, flexibility and scalability, just like social insects. One of the issues that researchers are facing is the hardware variation when implementing real robotic swarms. Identical software cannot guarantee identical behaviors among all robots due to hardware differences between swarm members. We propose a novel approach for sorting swarm robots according to their hardware differences. This method is based on the large number of interaction...

  12. Extracting Ocean-Generated Tidal Magnetic Signals from Swarm Data Through Satellite Gradiometry

    Science.gov (United States)

    Sabaka, Terence J.; Tyler, Robert H.; Olsen, Nils

    2016-01-01

    Ocean-generated magnetic field models of the Principal Lunar, M2, and the Larger Lunar elliptic, N2, semidiurnal tidal constituents were estimated through a "Comprehensive Inversion" of the first 20.5 months of magnetic measurements from European Space Agency's (ESA) Swarm satellite constellation mission. While the constellation provides important north-south along-track gradiometry information, it is the unique low-spacecraft pair that allows for east-west cross-track gradiometry. This latter type is crucial in delivering an M2 estimate of similar quality with that derived from over 10 years of CHAMP satellite data but over a shorter interval, at higher altitude, and during more magnetically disturbed conditions. Recovered N2 contains nonoceanic signal but is highly correlated with theoretical models in regions of maximum oceanic amplitude. Thus, satellite magnetic gradiometry may eventually enable the monitoring of ocean electrodynamic properties at temporal resolutions of 1 to 2 years, which may have important implications for the inference of ocean temperature and salinity.

  13. Code Single Point Positioning Using Nominal GNSS Constellations (Future Perception)

    Science.gov (United States)

    Farah, A. M. A.

    Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry, science, military, transportation and recreation & sports. Two systems are currently in operation, namely GPS (the USA Global Positioning System) and GLONASS (the Russian GLObal NAvigation Satellite System), and a third is planned, the European satellite navigation system GALILEO. The potential performance improvements achievable through combining these systems could be significant and expectations are high. The need is inevitable to explore the future of positioning from different nominal constellations. In this research paper, Bernese 5.0 software could be modified to simulate and process GNSS observations from three different constellations (GPS, GLONASS and Galileo) using different combinations. This study presents results of code single point positioning for five stations using the three constellations and different combinations.

  14. Optimal swarm formation for odor plume finding.

    Science.gov (United States)

    Marjovi, Ali; Marques, Lino

    2014-12-01

    This paper presents an analytical approach to the problem of odor plume finding by a network of swarm robotic gas sensors, and finds an optimal configuration for them, given a set of assumptions. Considering cross-wind movement for the swarm, we found that the best spatial formation of robots in finding odor plumes is diagonal line configuration with equal distance between each pair of neighboring robots. We show that the distance between neighboring pairs in the line topology depends mainly on the wind speed and the environmental conditions, whereas, the number of robots and the swarm's crosswind movement distance do not show significant impact on optimal configurations. These solutions were analyzed and verified by simulations and experimentally validated in a reduced scale realistic environment using a set of mobile robots.

  15. Emergent dynamics of laboratory insect swarms.

    Science.gov (United States)

    Kelley, Douglas H; Ouellette, Nicholas T

    2013-01-01

    Collective animal behaviour occurs at nearly every biological size scale, from single-celled organisms to the largest animals on earth. It has long been known that models with simple interaction rules can reproduce qualitative features of this complex behaviour. But determining whether these models accurately capture the biology requires data from real animals, which has historically been difficult to obtain. Here, we report three-dimensional, time-resolved measurements of the positions, velocities, and accelerations of individual insects in laboratory swarms of the midge Chironomus riparius. Even though the swarms do not show an overall polarisation, we find statistical evidence for local clusters of correlated motion. We also show that the swarms display an effective large-scale potential that keeps individuals bound together, and we characterize the shape of this potential. Our results provide quantitative data against which the emergent characteristics of animal aggregation models can be benchmarked.

  16. Swarm analysis by using transport equations, 1

    International Nuclear Information System (INIS)

    Dote, Toshihiko; Shimada, Masatoshi

    1980-01-01

    By evolving Maxwell-Boltzmann transport equations, various quantities on swarm of charged particles have been analyzed. Although this treatment is properly general, and common transport equations for charged particles ought to be given, in particular, equations only for electrons were presented here. The relation between the random energy and the drift energy was first derived and the general expression of the electron velocity was deduced too. For a simple example, one dimensional steady-state electron swarm in a uniform medium was treated. Electron swarm characteristics numerically calculated in He, Ne or Ar exhibited some interesting properties, which were physically clearly elucidated. These results were also compared with several data already published. Agreements between them were qualitatively rather well in detailed structures. (author)

  17. Novelty-driven Particle Swarm Optimization

    DEFF Research Database (Denmark)

    Galvao, Diana; Lehman, Joel Anthony; Urbano, Paulo

    2015-01-01

    Particle Swarm Optimization (PSO) is a well-known population-based optimization algorithm. Most often it is applied to optimize objective-based fitness functions that reward progress towards a desired objective or behavior. As a result, search increasingly focuses on higher-fitness areas. However......, in problems with many local optima, such focus often leads to premature convergence that precludes reaching the intended objective. To remedy this problem in certain types of domains, this paper introduces Novelty-driven Particle Swarm Optimization (NdPSO), which is motivated by the novelty search algorithm...... in genetic programming, this paper implements NdPSO as an extension of the grammatical swarm method, which combines PSO with genetic programming. The resulting NdPSO implementation is tested in three different domains representative of those in which it might provide advantage over objective-driven PSO...

  18. Dependency of geodynamic parameters on the GNSS constellation

    Science.gov (United States)

    Scaramuzza, Stefano; Dach, Rolf; Beutler, Gerhard; Arnold, Daniel; Sušnik, Andreja; Jäggi, Adrian

    2018-01-01

    Significant differences in time series of geodynamic parameters determined with different Global Navigation Satellite Systems (GNSS) exist and are only partially explained. We study whether the different number of orbital planes within a particular GNSS contributes to the observed differences by analyzing time series of geocenter coordinates (GCCs) and pole coordinates estimated from several real and virtual GNSS constellations: GPS, GLONASS, a combined GPS/GLONASS constellation, and two virtual GPS sub-systems, which are obtained by splitting up the original GPS constellation into two groups of three orbital planes each. The computed constellation-specific GCCs and pole coordinates are analyzed for systematic differences, and their spectral behavior and formal errors are inspected. We show that the number of orbital planes barely influences the geocenter estimates. GLONASS' larger inclination and formal errors of the orbits seem to be the main reason for the initially observed differences. A smaller number of orbital planes may lead, however, to degradations in the estimates of the pole coordinates. A clear signal at three cycles per year is visible in the spectra of the differences between our estimates of the pole coordinates and the corresponding IERS 08 C04 values. Combinations of two 3-plane systems, even with similar ascending nodes, reduce this signal. The understanding of the relation between the satellite constellations and the resulting geodynamic parameters is important, because the GNSS currently under development, such as the European Galileo and the medium Earth orbit constellation of the Chinese BeiDou system, also consist of only three orbital planes.

  19. Empirically characteristic analysis of chaotic PID controlling particle swarm optimization.

    Science.gov (United States)

    Yan, Danping; Lu, Yongzhong; Zhou, Min; Chen, Shiping; Levy, David

    2017-01-01

    Since chaos systems generally have the intrinsic properties of sensitivity to initial conditions, topological mixing and density of periodic orbits, they may tactfully use the chaotic ergodic orbits to achieve the global optimum or their better approximation to given cost functions with high probability. During the past decade, they have increasingly received much attention from academic community and industry society throughout the world. To improve the performance of particle swarm optimization (PSO), we herein propose a chaotic proportional integral derivative (PID) controlling PSO algorithm by the hybridization of chaotic logistic dynamics and hierarchical inertia weight. The hierarchical inertia weight coefficients are determined in accordance with the present fitness values of the local best positions so as to adaptively expand the particles' search space. Moreover, the chaotic logistic map is not only used in the substitution of the two random parameters affecting the convergence behavior, but also used in the chaotic local search for the global best position so as to easily avoid the particles' premature behaviors via the whole search space. Thereafter, the convergent analysis of chaotic PID controlling PSO is under deep investigation. Empirical simulation results demonstrate that compared with other several chaotic PSO algorithms like chaotic PSO with the logistic map, chaotic PSO with the tent map and chaotic catfish PSO with the logistic map, chaotic PID controlling PSO exhibits much better search efficiency and quality when solving the optimization problems. Additionally, the parameter estimation of a nonlinear dynamic system also further clarifies its superiority to chaotic catfish PSO, genetic algorithm (GA) and PSO.

  20. The Swarm End-to-End mission simulator study: A demonstration of separating the various contributions to Earth's magnetic field using synthetic data

    DEFF Research Database (Denmark)

    Olsen, Nils; Haagmans, R.; Sabaka, T.J.

    2006-01-01

    Swarm, a satellite constellation to measure Earth's magnetic field with unpreceded accuracy, has been selected by ESA for launch in 2009. The mission will provide the best ever survey of the geomagnetic field and its temporal evolution, in order to gain new insights into the Earth system...... to the science objectives of Swarm. In order to be able to use realistic parameters of the Earth's environment, the mission simulation starts at January 1, 1997 and lasts until re-entry of the lower satellites five years later. Synthetic magnetic field values were generated for all relevant contributions...... to Earth's magnetic field: core and lithospheric fields, fields due to currents in the ionosphere and magnetosphere, due to their secondary, induced, currents in the oceans, lithosphere and mantle, and fields due to currents coupling the ionosphere and magnetosphere. Several independent methods were...

  1. Bacterial Swarming: social behaviour or hydrodynamics?

    Science.gov (United States)

    Vermant, Jan

    2010-03-01

    Bacterial swarming of colonies is typically described as a social phenomenon between bacteria, whereby groups of bacteria collectively move atop solid surfaces. This multicellular behavior, during which the organized bacterial populations are embedded in an extracellular slime layer, is connected to important features such as biofilm formation and virulence. Despite the possible intricate quorum sensing mechanisms that regulate swarming, several physico-chemical phenomena may play a role in the dynamics of swarming and biofilm formation. Especially the striking fingering patterns formed by some swarmer colonies on relatively soft sub phases have attracted the attention as they could be the signatures of an instability. Recently, a parallel has been drawn between the swarming patterns and the spreading of viscous drops under the influence of a surfactant, which lead to similar patterns [1]. Starting from the observation that several of the molecules, essential in swarming systems, are strong biosurfactants, the possibility of flows driven by gradients in surface tension, has been proposed. This Marangoni flows are known to lead to these characteristic patterns. For Rhizobium etli not only the pattern formation, but also the experimentally observed spreading speed has been shown to be consistent with the one expected for Marangoni flows for the surface pressures, thickness, and viscosities that have been observed [2]. We will present an experimental study of swarming colonies of the bacteria Pseudomonas aeruginosa, the pattern formation, the surfactant gradients and height profiles in comparison with predictions of a thin film hydrodynamic model.[4pt] [1] Matar O.K. and Troian S., Phys. Fluids 11 : 3232 (1999)[0pt] [2] Daniels, R et al., PNAS, 103 (40): 14965-14970 (2006)

  2. Swarms of UAVs and fighter aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Trahan, M.W.; Wagner, J.S.; Stantz, K.M.; Gray, P.C.; Robinett, R.

    1998-11-01

    This paper describes a method of modeling swarms of UAVs and/or fighter aircraft using particle simulation concepts. Recent investigations into the use of genetic algorithms to design neural networks for the control of autonomous vehicles (i.e., robots) led to the examination of methods of simulating large collections of robots. This paper describes the successful implementation of a model of swarm dynamics using particle simulation concepts. Several examples of the complex behaviors achieved in a target/interceptor scenario are presented.

  3. Swarm field dynamics and functional morphogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Millonas, M.M. [Los Alamos National Lab., NM (United States)]|[Santa Fe Inst., NM (United States)

    1993-02-01

    A class of models with application to swarm behavior as well as many other types of complex systems is studied with an emphasis on analytic techniques and results. Special attention is given to the role played by fluctuations in determining the behavior of such systems. In particular it is suggested that such fluctuations may play an active role, and not just the usual passive one, in the organization of structure in the vicinity of a non-equilibrium phase transition. One model, that of an ant swarm, is analyzed in more detail as an illustration of these ideas.

  4. Software Engineering and Swarm-Based Systems

    Science.gov (United States)

    Hinchey, Michael G.; Sterritt, Roy; Pena, Joaquin; Rouff, Christopher A.

    2006-01-01

    We discuss two software engineering aspects in the development of complex swarm-based systems. NASA researchers have been investigating various possible concept missions that would greatly advance future space exploration capabilities. The concept mission that we have focused on exploits the principles of autonomic computing as well as being based on the use of intelligent swarms, whereby a (potentially large) number of similar spacecraft collaborate to achieve mission goals. The intent is that such systems not only can be sent to explore remote and harsh environments but also are endowed with greater degrees of protection and longevity to achieve mission goals.

  5. Methods and Apparatuses for Signaling with Geometric Constellations in a Raleigh Fading Channel

    Science.gov (United States)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2017-01-01

    Communication systems are described that use signal constellations, which have unequally spaced (i.e. `geometrically` shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR, over the Raleigh fading channel. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes d.sub.min, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

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

    Science.gov (United States)

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

    2013-01-01

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

  7. Swarm formation control utilizing elliptical surfaces and limiting functions.

    Science.gov (United States)

    Barnes, Laura E; Fields, Mary Anne; Valavanis, Kimon P

    2009-12-01

    In this paper, we present a strategy for organizing swarms of unmanned vehicles into a formation by utilizing artificial potential fields that were generated from normal and sigmoid functions. These functions construct the surface on which swarm members travel, controlling the overall swarm geometry and the individual member spacing. Nonlinear limiting functions are defined to provide tighter swarm control by modifying and adjusting a set of control variables that force the swarm to behave according to set constraints, formation, and member spacing. The artificial potential functions and limiting functions are combined to control swarm formation, orientation, and swarm movement as a whole. Parameters are chosen based on desired formation and user-defined constraints. This approach is computationally efficient and scales well to different swarm sizes, to heterogeneous systems, and to both centralized and decentralized swarm models. Simulation results are presented for a swarm of 10 and 40 robots that follow circle, ellipse, and wedge formations. Experimental results are included to demonstrate the applicability of the approach on a swarm of four custom-built unmanned ground vehicles (UGVs).

  8. Implementasi Prilaku Berkelompok Pada Swarm Robots Menggunakan Teknik Logika Fuzzy-Particle Swarm Optimization

    OpenAIRE

    Nurmaini, Siti

    2013-01-01

    Dalam paper ini dijelaskan teknik komunikasi swarm robot untuk mencapai suatu target yang telah ditentukan. Pada percobaan ini digunakan 3 robot sederhana yang identik dengan 3 sensor infra-red, sensor kompas dan X-Bee. Untuk mencapai target dan menentukan posisi dari masing-masing robot digunakan sebuah sensor kamera dengan metode deteksi perbedaan warna. Swarm robot dan sensor kamera terhubung dengan komputer yang berfungsi sebagai pusat informasi dan penyim...

  9. Complex emergent dynamics of anisotropic swarms: Convergence vs oscillation

    International Nuclear Information System (INIS)

    Chu Tianguang; Wang Long; Chen Tongwen; Mu Shumei

    2006-01-01

    This paper considers an anisotropic swarm model with a simple attraction and repulsion function. It is shown that the members of a reciprocal swarm will aggregate and eventually form a cohesive cluster of finite size around the swarm center. Moreover, the swarm system is also completely stable, i.e., every solution converges to the set of equilibrium points of the system. These results are also valid for a class of non-reciprocal swarms under the detailed balance condition on coupling weights. For general non-reciprocal swarms, numerical simulations are worked out to demonstrate more complex oscillatory motions in the systems. The study provides further insight into the effect of the interaction pattern on the collective behavior of a swarm system

  10. DNA-assisted swarm control in a biomolecular motor system.

    Science.gov (United States)

    Keya, Jakia Jannat; Suzuki, Ryuhei; Kabir, Arif Md Rashedul; Inoue, Daisuke; Asanuma, Hiroyuki; Sada, Kazuki; Hess, Henry; Kuzuya, Akinori; Kakugo, Akira

    2018-01-31

    In nature, swarming behavior has evolved repeatedly among motile organisms because it confers a variety of beneficial emergent properties. These include improved information gathering, protection from predators, and resource utilization. Some organisms, e.g., locusts, switch between solitary and swarm behavior in response to external stimuli. Aspects of swarming behavior have been demonstrated for motile supramolecular systems composed of biomolecular motors and cytoskeletal filaments, where cross-linkers induce large scale organization. The capabilities of such supramolecular systems may be further extended if the swarming behavior can be programmed and controlled. Here, we demonstrate that the swarming of DNA-functionalized microtubules (MTs) propelled by surface-adhered kinesin motors can be programmed and reversibly regulated by DNA signals. Emergent swarm behavior, such as translational and circular motion, can be selected by tuning the MT stiffness. Photoresponsive DNA containing azobenzene groups enables switching between solitary and swarm behavior in response to stimulation with visible or ultraviolet light.

  11. Video Games, Identity, and the Constellation of Information

    Science.gov (United States)

    Martin, Crystle

    2012-01-01

    This article explores the identity of youth in relation to the information sources they choose in the constellation of information of video games, using the massively multiplayer online game "World of Warcraft" as an example. From this study, several identities are recognized that are combinations of the participants skill and level in the game,…

  12. Regional positioning using a low Earth orbit satellite constellation

    Science.gov (United States)

    Shtark, Tomer; Gurfil, Pini

    2018-02-01

    Global and regional satellite navigation systems are constellations orbiting the Earth and transmitting radio signals for determining position and velocity of users around the globe. The state-of-the-art navigation satellite systems are located in medium Earth orbits and geosynchronous Earth orbits and are characterized by high launching, building and maintenance costs. For applications that require only regional coverage, the continuous and global coverage that existing systems provide may be unnecessary. Thus, a nano-satellites-based regional navigation satellite system in Low Earth Orbit (LEO), with significantly reduced launching, building and maintenance costs, can be considered. Thus, this paper is aimed at developing a LEO constellation optimization and design method, using genetic algorithms and gradient-based optimization. The preliminary results of this study include 268 LEO constellations, aimed at regional navigation in an approximately 1000 km × 1000 km area centered at the geographic coordinates [30, 30] degrees. The constellations performance is examined using simulations, and the figures of merit include total coverage time, revisit time, and geometric dilution of precision (GDOP) percentiles. The GDOP is a quantity that determines the positioning solution accuracy and solely depends on the spatial geometry of the satellites. Whereas the optimization method takes into account only the Earth's second zonal harmonic coefficient, the simulations include the Earth's gravitational field with zonal and tesseral harmonics up to degree 10 and order 10, Solar radiation pressure, drag, and the lunisolar gravitational perturbation.

  13. EOS Terra Terra Constellation Exit/Future Maneuver Plans Update

    Science.gov (United States)

    Mantziaras, Dimitrios

    2016-01-01

    This EOS Terra Constellation Exit/Future Maneuver Plans Update presentation will discuss brief history of Terra EOM work; lifetime fuel estimates; baseline vs. proposed plan origin; resultant exit orbit; baseline vs. proposed exit plan; long term orbit altitude; revised lifetime proposal and fallback options.

  14. Human Activity Recognition Using Hierarchically-Mined Feature Constellations

    NARCIS (Netherlands)

    Oikonomopoulos, A.; Pantic, Maja

    In this paper we address the problem of human activity modelling and recognition by means of a hierarchical representation of mined dense spatiotemporal features. At each level of the hierarchy, the proposed method selects feature constellations that are increasingly discriminative and

  15. The new aesthetic and art : constellations of the postdigital

    NARCIS (Netherlands)

    Contreras-Koterbay, Scott; Mirocha, Łukas; Rasch, M.D.; Roestenburg, N.C.H.F.

    2016-01-01

    The New Aesthetic and Art: Constellations of the Postdigital is an interdisciplinary analysis focusing on new digital phenomena at the intersections of theory and contemporary art. Asserting the unique character of New Aesthetic objects, Contreras-Koterbay and Mirocha trace the origins of the New

  16. An integrated hyperspectral and SAR satellite constellation for environment monitoring

    Science.gov (United States)

    Wang, Jinnian; Ren, Fuhu; Xie, Chou; An, Jun; Tong, Zhanbo

    2017-09-01

    A fully-integrated, Hyperspectral optical and SAR (Synthetic Aperture Radar) constellation of small earth observation satellites will be deployed over multiple launches from last December to next five years. The Constellation is expected to comprise a minimum of 16 satellites (8 SAR and 8 optical ) flying in two orbital planes, with each plane consisting of four satellite pairs, equally-spaced around the orbit plane. Each pair of satellites will consist of a hyperspectral/mutispectral optical satellite and a high-resolution SAR satellite (X-band) flying in tandem. The constellation is expected to offer a number of innovative capabilities for environment monitoring. As a pre-launch experiment, two hyperspectral earth observation minisatellites, Spark 01 and 02 were launched as secondary payloads together with Tansat in December 2016 on a CZ-2D rocket. The satellites feature a wide-range hyperspectral imager. The ground resolution is 50 m, covering spectral range from visible to near infrared (420 nm - 1000 nm) and a swath width of 100km. The imager has an average spectral resolution of 5 nm with 148 channels, and a single satellite could obtain hyperspectral imagery with 2.5 million km2 per day, for global coverage every 16 days. This paper describes the potential applications of constellation image in environment monitoring.

  17. Temporal Probabilistic Constellation Shaping for WDM Optical Communication Systems

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Forchhammer, Søren

    2016-01-01

    Finite state machine sources transmitting QPSK are studied as input to WDM optical fiber systems with ideal distributed Raman amplification. The probabilities of successive constellation symbols are shaped for nonlinear transmission and gains of around 500km (5-10%) are demonstrated...

  18. Distributed leadership in health care teams: Constellation role distribution and leadership practices.

    Science.gov (United States)

    Chreim, Samia; MacNaughton, Kate

    2016-01-01

    Recent literature has been critical of research that adopts a narrow focus on single leaders and on leadership attributes and has called for attention to leadership that is distributed among individuals and to practices in which leaders engage. We conducted a study of health care teams where we attended to role distribution among leadership constellation members and to loose or tight coupling practices between leaders and the remainder of the team. This focus provides insights into how leadership can be practiced and structured to enhance team functioning. A qualitative, multicase study of four teams was conducted. Data collection involved 44 interviews with almost all the members of the teams and 18 team meeting observations. Thematic analysis was conducted by the two authors. Leadership constellations can give rise to leadership role overlaps and gaps that may create ambiguity within teams, ambiguity is diminished if the leaders can agree on which leader assumes ultimate authority in an area, the presence of more leaders does not necessarily entail more comprehensive fulfillment of team needs, and teams' needs for tight or loose leadership practices are influenced by contextual factors that we elaborate. (a) It is important to recognize areas of overlap and gaps in leadership roles and to provide clarity about role boundaries to avoid ambiguity. Role mapping exercises and open discussions should be considered. (b) Attempting to spread formal leadership responsibilities informally among individuals is not always a workable strategy for addressing team needs. (c) Organizations need to examine critically the allocation of resources to leadership activities.

  19. Tectonic stress regime in the 2003-2004 and 2012-2015 earthquake swarms in the Ubaye Valley, French Alps

    Science.gov (United States)

    Fojtíková, Lucia; Vavryčuk, Václav

    2018-02-01

    We study two earthquake swarms that occurred in the Ubaye Valley, French Alps within the past decade: the 2003-2004 earthquake swarm with the strongest shock of magnitude ML = 2.7, and the 2012-2015 earthquake swarm with the strongest shock of magnitude ML = 4.8. The 2003-2004 seismic activity clustered along a 9-km-long rupture zone at depth between 3 and 8 km. The 2012-2015 activity occurred a few kilometres to the northwest from the previous one. We applied the iterative joint inversion for stress and fault orientations developed by Vavryčuk (2014) to focal mechanisms of 74 events of the 2003-2004 swarm and of 13 strongest events of the 2012-2015 swarm. The retrieved stress regime is consistent for both seismic activities. The σ 3 principal axis is nearly horizontal with azimuth of 103°. The σ 1 and σ 2 principal axes are inclined and their stress magnitudes are similar. The active faults are optimally oriented for shear faulting with respect to tectonic stress and differ from major fault systems known from geological mapping in the region. The estimated low value of friction coefficient at the faults 0.2-0.3 supports an idea of seismic activity triggered or strongly affected by presence of fluids.

  20. Collective behaviors of two-component swarms.

    Science.gov (United States)

    You, Sang Koo; Kwon, Dae Hyuk; Park, Yong-ik; Kim, Sun Myong; Chung, Myung-Hoon; Kim, Chul Koo

    2009-12-07

    We present a particle-based simulation study on two-component swarms where there exist two different types of groups in a swarm. Effects of different parameters between the two groups are studied systematically based on Langevin's equation. It is shown that the mass difference can introduce a protective behavior for the lighter members of the swarm in a vortex state. When the self-propelling strength is allowed to differ between two groups, it is observed that the swarm becomes spatially segregated and finally separated into two components at a certain critical value. We also investigate effects of different preferences for shelters on their collective decision making. In particular, it is found that the probability of selecting a shelter from the other varies sigmoidally as a function of the number ratio. The model is shown to describe the dynamics of the shelter choosing process of the cockroach-robot mixed group satisfactorily. It raises the possibility that the present model can be applied to the problems of pest control and fishing using robots and decoys.

  1. Selectively-informed particle swarm optimization.

    Science.gov (United States)

    Gao, Yang; Du, Wenbo; Yan, Gang

    2015-03-19

    Particle swarm optimization (PSO) is a nature-inspired algorithm that has shown outstanding performance in solving many realistic problems. In the original PSO and most of its variants all particles are treated equally, overlooking the impact of structural heterogeneity on individual behavior. Here we employ complex networks to represent the population structure of swarms and propose a selectively-informed PSO (SIPSO), in which the particles choose different learning strategies based on their connections: a densely-connected hub particle gets full information from all of its neighbors while a non-hub particle with few connections can only follow a single yet best-performed neighbor. Extensive numerical experiments on widely-used benchmark functions show that our SIPSO algorithm remarkably outperforms the PSO and its existing variants in success rate, solution quality, and convergence speed. We also explore the evolution process from a microscopic point of view, leading to the discovery of different roles that the particles play in optimization. The hub particles guide the optimization process towards correct directions while the non-hub particles maintain the necessary population diversity, resulting in the optimum overall performance of SIPSO. These findings deepen our understanding of swarm intelligence and may shed light on the underlying mechanism of information exchange in natural swarm and flocking behaviors.

  2. Bubble Swarm Rise Velocity in Fluidized Beds.

    Czech Academy of Sciences Publication Activity Database

    Punčochář, Miroslav; Růžička, Marek; Šimčík, Miroslav

    2016-01-01

    Roč. 152, OCT 2 (2016), s. 84-94 ISSN 0009-2509 R&D Projects: GA ČR(CZ) GA15-05534S Institutional support: RVO:67985858 Keywords : bubbling fluidized bed * gas-solid * bubble swarm velocity Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.895, year: 2016

  3. On the reliability of spacecraft swarms

    NARCIS (Netherlands)

    Engelen, S.; Gill, E.K.A.; Verhoeven, C.J.M.

    2012-01-01

    Satellite swarms, consisting of a large number of identical, miniaturized and simple satellites, are claimed to provide an implementation for specific space missions which require high reliability. However, a consistent model of how reliability and availability on mission level is linked to cost-

  4. Structural preconditions of West Bohemia earthquake swarms

    Czech Academy of Sciences Publication Activity Database

    Novotný, Miroslav; Špičák, Aleš; Weinlich, F. H.

    2013-01-01

    Roč. 34, č. 4 (2013), s. 491-519 ISSN 0169-3298 R&D Projects: GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : West Bohemia earthquake swarm s * depth-recursive refraction tomography * CEL09 refraction profile Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 5.112, year: 2013

  5. Improvements of the Swarm Accelerometer Data Processing

    DEFF Research Database (Denmark)

    Siemes, Christian; Grunwaldt, Ludwig; Peresty, Radek

    The Swarm satellites were launched on 22 November 2013 and carry accelerometers and GPS receivers as part of their scientific payload. The GPS receivers are not only used for locating the position and time of the magnetic measurements, but also for determining non-gravitational forces like drag...

  6. Data distribution in the OLFAR satellite swarm

    NARCIS (Netherlands)

    Budianu, A.; Willink-Castro, T.J.; Engelen, S.; Rajan, R.T.; Rajan, Raj; Smith, D.M.P.; Meijerink, Arjan; Bentum, Marinus Jan

    2013-01-01

    The Orbiting Low Frequency Antennas for Radio Astronomy (OLFAR) project aims to develop a radio telescope for very low frequencies (below 30 MHz) by using a swarm of 50 or more nano-satellites. Spread in a 100-km diameter cloud, the satellites will form a very large aperture capable of sensing the

  7. 75 FR 53688 - Constellation Mystic Power, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2010-09-01

    ...-000] Constellation Mystic Power, LLC; Supplemental Notice That Initial Market-Based Rate Filing... the above-referenced proceeding of Constellation Mystic Power, LLC's application for market-based rate...

  8. Human Systems Integration in Practice: Constellation Lessons Learned

    Science.gov (United States)

    Zumbado, Jennifer Rochlis

    2012-01-01

    NASA's Constellation program provided a unique testbed for Human Systems Integration (HSI) as a fundamental element of the Systems Engineering process. Constellation was the first major program to have HSI mandated by NASA's Human Rating document. Proper HSI is critical to the success of any project that relies on humans to function as operators, maintainers, or controllers of a system. HSI improves mission, system and human performance, significantly reduces lifecycle costs, lowers risk and minimizes re-design. Successful HSI begins with sufficient project schedule dedicated to the generation of human systems requirements, but is by no means solely a requirements management process. A top-down systems engineering process that recognizes throughout the organization, human factors as a technical discipline equal to traditional engineering disciplines with authority for the overall system. This partners with a bottoms-up mechanism for human-centered design and technical issue resolution. The Constellation Human Systems Integration Group (HSIG) was a part of the Systems Engineering and Integration (SE&I) organization within the program office, and existed alongside similar groups such as Flight Performance, Environments & Constraints, and Integrated Loads, Structures and Mechanisms. While the HSIG successfully managed, via influence leadership, a down-and-in Community of Practice to facilitate technical integration and issue resolution, it lacked parallel top-down authority to drive integrated design. This presentation will discuss how HSI was applied to Constellation, the lessons learned and best practices it revealed, and recommendations to future NASA program and project managers. This presentation will discuss how Human Systems Integration (HSI) was applied to NASA's Constellation program, the lessons learned and best practices it revealed, and recommendations to future NASA program and project managers on how to accomplish this critical function.

  9. VISTA - A Constellation for Real Time Regional Imaging

    Science.gov (United States)

    Meerman, Max; Boland, Lee; da Silva Curiel, Alex; Sweeting, Martin, , Sir

    2002-01-01

    The role of satellites in medium and high-resolution reconnaissance of the Earth's surface has been well demonstrated in recent years through missions such as Landsat, SPOT, IKONOS, ImageSat and Quickbird. The market for such data products is well served and likely to become more competitive with further very-high-resolution missions. Whereas commercial markets have concentrated on enhancing resolution, the small satellite sector has concentrated on reducing the cost of data products, and the development of systems providing niche services. One such EO requirement that can be well met by smaller satellites is the need for higher temporal resolution, as this typically requires a large number of satellites to operate as a constellation - thus far financially impractical using conventional EO satellites. Surrey is currently engaged in building its first constellation that will provide daily global coverage at moderate resolution (32-metre GSD and 600km swath) in three spectral bands. Targeted at providing timely quick-look data products for disaster mitigation and monitoring, the constellation comprises 7 satellites in a single orbital plane. Each satellite has a wide swath so that successive satellites progressively cover the entire globe in a single day. The Vista constellation takes this concept a step further, and is proposed for applications requiring near-continuous surveillance of regional activity. By introducing a multiple plane constellation of small Earth observation satellites, it is possible to monitor continuously selected regions anywhere on the globe. The paper describes the system trades and outlines the scope of the performance that could be obtained from such a system. A cost model illustrates that the balance between launch and space segment costs must be reached by considering suitable replacement strategies, and that the system is highly sensitive to requirement creep. Finally, it is shown that the use of cost effective, small satellites leads to

  10. The Development and Delivery of On-Demand RADARSAT Constellation Mission Ground Deformation Products Based on Advanced Insar Technology

    Science.gov (United States)

    Samsonov, S. V.; Feng, W.

    2017-12-01

    InSAR-based mapping of surface deformation (displacement) has proven valuable to a variety of geoscience applications within NRCan. Conventional approaches to InSAR analysis require significant expert intervention to separate useful signal from noise and are not suited to the address the opportunities and challenges presented by the large multi-temporal SAR datasets provided by future radar constellations. The Canada Centre for Mapping and Earth Observation (CCMEO) develops, in support of NRCAN and Government of Canada priorities a framework for automatic generation of standard and advanced deformation products based on Interferometric Synthetic Aperture Radar (InSAR) technology from RADARSAT Constellation Mission (RCM) Synthetic Aperture Radar data. We utilize existing processing algorithms that are currently used for processing RADARSAT-2 data and adapt them to RCM specifications. In addition we develop novel advanced processing algorithms that address large data sets made possible by the satellites' rapid revisit cycle and expand InSAR functionality to regional and national scales across a wide range of time scales. Through automation the system makes it possible to extend the mapping of surface deformation to non-SAR experts. The architecture is scalable and expandable to serve large number of clients and simultaneously address multiple application areas including: natural and anthropogenic hazards, natural resource development, permafrost and glacier monitoring, coastal and environmental change and wetlands mapping.

  11. 78 FR 32385 - Exelon Generation Company, LLC; CER Generation II, LLC; Constellation Mystic Power, LLC...

    Science.gov (United States)

    2013-05-30

    ... Generation Company, LLC; CER Generation II, LLC; Constellation Mystic Power, LLC; Constellation NewEnergy, Inc.; Constellation Power Source Generation, Inc.; Criterion Power Partners, LLC; Notice of Petition...) Rules of Practice and Procedure, 18 CFR 385.207, Exelon Generation Company, LLC, CER Generation II, LLC...

  12. A Bio-Inspired Approach to Task Assignment of Swarm Robots in 3-D Dynamic Environments.

    Science.gov (United States)

    Xin Yi; Anmin Zhu; Yang, Simon X; Chaomin Luo

    2017-04-01

    Intending to mimic the operating mechanism of biological neural systems, a self organizing map-based approach to task assignment of a swarm of robots in 3-D dynamic environments is proposed in this paper. This approach integrates the advantages and characteristics of biological neural systems. It is capable of dynamically planning the paths of a swarm of robots in 3-D environments under uncertain situations, such as when some robots are presented in or broken down or when more than one robot is needed for some special task locations. A Bezier path optimizing algorithm and a parameter adjusting algorithm are integrated in this paper. It is capable of reducing the complexity of the robot navigation control and limiting the number of convergence iterations. The simulation results with different environments demonstrate the effectiveness of the proposed approach.

  13. Exploring the Architectural Tradespace of Severe Weather Monitoring Nanosatellite Constellations

    Science.gov (United States)

    Hitomi, N.; Selva, D.; Blackwell, W. J.

    2014-12-01

    MicroMAS-1, a 3U nanosatellite developed by MIT/LL, MIT/SSL, and University of Massachusetts, was launched on July 13, 2014 and is scheduled for deployment from the International Space Station in September. The development of MicroMAS motivates an architectural analysis of a constellation of nanosatellites with the goal of drastically reducing the cost of observing severe storms compared with current monolithic missions such as the Precision and All-Weather Temperature and Humidity (PATH) mission from the NASA Decadal Survey. Our goal is to evolve the instrument capability on weather monitoring nanosatellites to achieve higher performance and better satisfy stakeholder needs. Clear definitions of performance requirements are critical in the conceptual design phase when much of the project's lifecycle cost and performance will be fixed. Ability to perform trade studies and optimization of performance needs with instrument capability will enable design teams to focus on key technologies that will introduce high value and high return on investment. In this work, we approach the significant trades and trends of constellations for monitoring severe storms by applying our rule-based decision support tool. We examine a subset of stakeholder groups listed in the OSCAR online database (e.g., weather, climate) that would benefit from severe storm weather data and their respective observation requirements (e.g. spatial resolution, accuracy). We use ten parameters in our analysis, including atmospheric temperature, humidity, and precipitation. We compare the performance and cost of thousands of different possible constellations. The constellations support hyperspectral sounders that cover different portions of the millimeter-wave spectrum (50-60 GHz, 118GHz, 183GHz) in different orbits, and the performance results are compared against those of the monolithic PATH mission. Our preliminary results indicate that constellations using the hyperspectral millimeter wave sounders can

  14. A chaotic quantum-behaved particle swarm approach applied to optimization of heat exchangers

    International Nuclear Information System (INIS)

    Mariani, Viviana Cocco; Klassen Duck, Anderson Rodrigo; Guerra, Fabio Alessandro; Santos Coelho, Leandro dos; Rao, Ravipudi Venkata

    2012-01-01

    Particle swarm optimization (PSO) method is a population-based optimization technique of swarm intelligence field in which each solution called “particle” flies around in a multidimensional problem search space. During the flight, every particle adjusts its position according to its own experience, as well as the experience of neighboring particles, using the best position encountered by itself and its neighbors. In this paper, a new quantum particle swarm optimization (QPSO) approach combined with Zaslavskii chaotic map sequences (QPSOZ) to shell and tube heat exchanger optimization is presented based on the minimization from economic view point. The results obtained in this paper for two case studies using the proposed QPSOZ approach, are compared with those obtained by using genetic algorithm, PSO and classical QPSO showing the best performance of QPSOZ. In order to verify the capability of the proposed method, two case studies are also presented showing that significant cost reductions are feasible with respect to traditionally designed exchangers. Referring to the literature test cases, reduction of capital investment up to 20% and 6% for the first and second cases, respectively, were obtained. Therefore, the annual pumping cost decreased markedly 72% and 75%, with an overall decrease of total cost up to 30% and 27%, respectively, for the cases 1 and 2, respectively, showing the improvement potential of the proposed method, QPSOZ. - Highlights: ► Shell and tube heat exchanger is minimized from economic view point. ► A new quantum particle swarm optimization (QPSO) combined with Zaslavskii chaotic map sequences (QPSOZ) is proposed. ► Reduction of capital investment up to 20% and 6% for the first and second cases was obtained. ► Annual pumping cost decreased 72% and 75%, with an overall decrease of total cost up to 30% and 27% using QPSOZ.

  15. Rannyaya istoriya Mesopotamskikh sozvezdij (k probleme proiskhozhdeniya sozvezdij) %t The early history of Mesopotamian constellations (to the problem of the constellations origin

    Science.gov (United States)

    Kurtik, G. E.

    This paper considers the early written and iconographic sources of the end of the 4th-beginning of the 2nd millennia B.C. which can shed light on the problem of the origin of Mesopotamian constellations. We were interested, first of all, with two questions: (1) whether it is possible to make a conclusion on the basis of the sources that the constellations were already distinguished in Mesopotamia in the appropriate period, and, if-yes, (2) what constellation or group of constellations is there the question about? In most cases the conclusion turns out to be either negative or uncertain because the sources allow ambiguous, sometimes opposite senses, interpretations.

  16. Methodology and method and appartus for signaling with capacity optimized constellations

    Science.gov (United States)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2012-01-01

    Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel.

  17. Methodology and Method and Apparatus for Signaling with Capacity Optimized Constellations

    Science.gov (United States)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2017-01-01

    Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel.

  18. Stellar aberration correction and thermoelastic compensation of Swarm μASC attitude observationsA comment to the Express Letter "Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements", by Stefan Maus

    Science.gov (United States)

    Herceg, M.; Jørgensen, P. S.; Jørgensen, J. L.

    2017-11-01

    The Swarm constellation of three satellites measures the magnetic signal of the Earth using both a Vector Field Magnetometer and an Absolute Scalar Magnetometer. A Micro Advanced Stellar Compass (μASC) mounted on a common, supposedly stable, optical bench precisely determines its inertial attitude. However, comparison of the Inter Boresight Angle shows a relative attitude variation between the μASC Camera Head Units. These misalignments between Camera Head Units and a geomagnetic reference frame cannot be explained by incorrect aberration correction (as theorized by Maus). Herceg et al. found them to be caused by thermal gradient sensitivity of the optical bench system, opposing the underlying assumption of perfect platform stability. The results after applying thermal corrections show significant decrease in root mean square, with Inter Boresight Angle of thermally corrected data being nearly flat and clean from any variation caused by thermoelastic effects.

  19. Hidden topological constellations and polyvalent charges in chiral nematic droplets.

    Science.gov (United States)

    Posnjak, Gregor; Čopar, Simon; Muševič, Igor

    2017-02-21

    Topology has an increasingly important role in the physics of condensed matter, quantum systems, material science, photonics and biology, with spectacular realizations of topological concepts in liquid crystals. Here we report on long-lived hidden topological states in thermally quenched, chiral nematic droplets, formed from string-like, triangular and polyhedral constellations of monovalent and polyvalent singular point defects. These topological defects are regularly packed into a spherical liquid volume and stabilized by the elastic energy barrier due to the helical structure and confinement of the liquid crystal in the micro-sphere. We observe, for the first time, topological three-dimensional point defects of the quantized hedgehog charge q=-2, -3. These higher-charge defects act as ideal polyvalent artificial atoms, binding the defects into polyhedral constellations representing topological molecules.

  20. Scaling and spatial complementarity of tectonic earthquake swarms

    KAUST Repository

    Passarelli, Luigi

    2017-11-10

    Tectonic earthquake swarms (TES) often coincide with aseismic slip and sometimes precede damaging earthquakes. In spite of recent progress in understanding the significance and properties of TES at plate boundaries, their mechanics and scaling are still largely uncertain. Here we evaluate several TES that occurred during the past 20 years on a transform plate boundary in North Iceland. We show that the swarms complement each other spatially with later swarms discouraged from fault segments activated by earlier swarms, which suggests efficient strain release and aseismic slip. The fault area illuminated by earthquakes during swarms may be more representative of the total moment release than the cumulative moment of the swarm earthquakes. We use these findings and other published results from a variety of tectonic settings to discuss general scaling properties for TES. The results indicate that the importance of TES in releasing tectonic strain at plate boundaries may have been underestimated.

  1. Navigation Constellation Design Using a Multi-Objective Genetic Algorithm

    Science.gov (United States)

    2015-03-26

    objective functions for each individual in the GA population. The combination of the MINSGA and STK was given the term CODEC meaning Constellation...Optimal Design by Evolutionary Computation. Five different test cases were used to establish the performance of CODEC . The first test case is called...Inclination Characterization, which determines the inclination range for a Walker 5/5/1 configuration. CODEC correctly identified the region between

  2. Integration of 5G Technologies in LEO Mega-Constellations

    OpenAIRE

    Guidotti, Alessandro; Vanelli-Coralli, Alessandro; Kodheli, Oltjon; Colavolpe, Giulio; Foggi, Tommaso

    2017-01-01

    3GPP is finalising the first release of the 5G New Radio physical layer. To cope with the demanding 5G requirements on global connectivity and large throughput, Satellite Communications might be a valuable resource to extend and complement terrestrial networks. In this context, we introduce an integrated architecture for 5G-based LEO mega-constellations and assess the impact of large Doppler shifts and delays on both the 5G waveform and the PHY/MAC layer procedures.

  3. Family constellation and creativity: firstborn predominance among classical music composers.

    Science.gov (United States)

    Schubert, D S; Wagner, M E; Schubert, H J

    1977-01-01

    Biographies of classical musci composers were examined for family constellation information. Usable data were found for 80 composers. Firstborns, especially only children, were found significantly more frequently than in a sample of creative writers studied by Bliss. Increased frequency of firstborns was also suggested in a study of musical performers by Raychaudhuri. Classical musci composition was seen as an ability more similar to usual academic pursuits than creative writing.

  4. Integration of Satellites in 5G through LEO Constellations

    OpenAIRE

    Kodheli, Oltjon; Guidotti, Alessandro; Vanelli-Coralli, Alessandro

    2017-01-01

    The standardization of 5G systems is entering in its critical phase, with 3GPP that will publish the PHY standard by June 2017. In order to meet the demanding 5G requirements both in terms of large throughput and global connectivity, Satellite Communications provide a valuable resource to extend and complement terrestrial networks. In this context, we consider a heterogeneous architecture in which a LEO mega-constellation satellite system provides backhaul connectivity to terrestrial 5G Relay...

  5. LTE-based Satellite Communications in LEO Mega-Constellations

    OpenAIRE

    Guidotti, A.; Vanelli-Coralli, A.; Foggi, T.; Colavolpe, G.; Caus, M.; Bas, J.; Cioni, S.; Modenini, A.

    2017-01-01

    The integration of satellite and terrestrial networks is a promising solution for extending broadband coverage to areas not connected to a terrestrial infrastructure, as also demonstrated by recent commercial and standardisation endeavours. However, the large delays and Doppler shifts over the satellite channel pose severe technical challenges to traditional terrestrial systems, as LTE or 5G. In this paper, two architectures are proposed for a LEO mega-constellation realising a satellite-enab...

  6. Hand Gesture Recognition Using Particle Swarm Movement

    Directory of Open Access Journals (Sweden)

    Clementine Nyirarugira

    2016-01-01

    Full Text Available We present a gesture recognition method derived from particle swarm movement for free-air hand gesture recognition. Online gesture recognition remains a difficult problem due to uncertainty in vision-based gesture boundary detection methods. We suggest an automated process of segmenting meaningful gesture trajectories based on particle swarm movement. A subgesture detection and reasoning method is incorporated in the proposed recognizer to avoid premature gesture spotting. Evaluation of the proposed method shows promising recognition results: 97.6% on preisolated gestures, 94.9% on stream gestures with assistive boundary indicators, and 94.2% for blind gesture spotting on digit gesture vocabulary. The proposed recognizer requires fewer computation resources; thus it is a good candidate for real-time applications.

  7. Macroscopic definition of distributed swarm morphogenesis

    Science.gov (United States)

    Aznar, Fidel; Pujol, Mar; Rizo, Ramón

    2012-12-01

    In this paper, we present a system that will be able to obtain microscopic assembly behaviours for a robotic swarm to achieve an assembly target (macroscopic model). It will be designed taking into consideration the essential features of a self-assembling system needed to be implemented in a real robotic swarm. This system is composed of a typology of generative languages PD0L, and an algorithm for generating individual rules to be processed by the robots. The assembly process will be performed in a distributed manner, and will be also designed to require minimal communication capabilities between robots. Both the expressive capacities of language and the rule generation algorithm will be demonstrated by evaluating their performance with a core set of test morphologies widely used in self-assembly tasks. Furthermore, we compare the assembly time and the number of messages required between a classic controller (centralised) and our distributed approach.

  8. Swarm-based algorithm for phase unwrapping.

    Science.gov (United States)

    da Silva Maciel, Lucas; Albertazzi, Armando G

    2014-08-20

    A novel algorithm for phase unwrapping based on swarm intelligence is proposed. The algorithm was designed based on three main goals: maximum coverage of reliable information, focused effort for better efficiency, and reliable unwrapping. Experiments were performed, and a new agent was designed to follow a simple set of five rules in order to collectively achieve these goals. These rules consist of random walking for unwrapping and searching, ambiguity evaluation by comparing unwrapped regions, and a replication behavior responsible for the good distribution of agents throughout the image. The results were comparable with the results from established methods. The swarm-based algorithm was able to suppress ambiguities better than the flood-fill algorithm without relying on lengthy processing times. In addition, future developments such as parallel processing and better-quality evaluation present great potential for the proposed method.

  9. Thermoregulation and adaptation in honeybee swarms

    Science.gov (United States)

    Ocko, Samuel; Mahadevan, L.

    2012-11-01

    Swarming is an essential part of honeybee behavior, wherein thousands of bees cling onto each other to form a dense cluster that is exposed to the environment for up to several days. This cluster has the ability to maintain its core temperature actively without a central controller raising the question of mechanism. Inspired by experimental observations, we treat the swarm cluster as an active porous structure with a variable metabolism that needs to adjust to outside conditions to control heat loss and regulate its core temperature. Using a continuum model that takes the form of a set of advection-diffusion equations for heat transfer in a mobile porous medium, we show that effective thermoregulation can result from the collective behavior of individual bees in the cluster.

  10. Diffusion tensor in electron swarm transport

    International Nuclear Information System (INIS)

    Makabe, T.; Mori, T.

    1983-01-01

    Expression for the diffusion tensor of the electron (or light ion) swarm is presented from the higher-order expansion of the velocity distribution in the Boltzmann equation in hydrodynamic stage. Derived diffusion coefficients for the transverse and longitudinal directions include the additional terms representative of the curvature effect under the action of an electric field with the usual-two-term expressions. Numerical analysis is given for the electron swarm in model gases having the momentum transfer cross section Qsub(m)(epsilon)=Q 0 epsilon sup(beta) (β=0, 1/2, 1) using the present theory. As the result, appreciable degree of discrepancy appears between the transverse diffusion coefficient defined here and the conventional expression with increasing of β in Qsub(m). (Author)

  11. Intelligent Mobile Olfaction of Swarm Robots

    Directory of Open Access Journals (Sweden)

    Siti Nurmaini

    2013-06-01

    Full Text Available This work presents intelligent mobile olfaction design and experimental results of intelligent swarm robots to detection a gas/odour source in an indoor environment by using multi agent based on hybrid algorithm. We examine the problem for deciding when, how and where the gas/odour sensor should be activated. Simple form of cooperation between Interval Type-2 Fuzzy Logic and Particle Swarm Optimization (IT2FL-PSO algorithm is implemented in the olfaction strategies. The real experiments performed on smaller five mobile robots equipped with dynamic gas/odour sensor TGS2600 and three infra-red sensors. The results show that single robot-based olfaction system with 5 behaviors capable for searching source of a simulated chemical leak in unknown environment and flooking behavior can be done by 3 robots to find the source of gas/odour.

  12. Small-scale field-aligned currents caused by tropical cyclones as observed by the SWARM satellites above the ionosphere

    Science.gov (United States)

    Aoyama, T.; Iyemori, T.; Nakanishi, K.

    2014-12-01

    We present case studies of small-scale magnetic fluctuations above typhoons, hurricanes and cyclones as observed by the swarm constellation. It is reported lately that AGWs(atmospheric gravity waves) generated by meteorological phenomena in the troposphere such as typhoons and tornadoes, large earthquakes and volcanic eruptions propagate to the mesosphere and thermosphere. We observe them in various forms(e.g. airglows, ionospheric disturbances and TEC variations). We are proposing the following model. AGWs caused by atmospheric disturbances in the troposphere propagate to the ionospheric E-layer, drive dynamo action and generate field-aligned currents. The satellites observe magnetic fluctuations above the ionosphere. In this presentation, we focus on cases of tropical cyclone(hurricanes in North America, typhoons in North-West Pacific).

  13. Kinematic Precise Point Positioning Using Multi-Constellation Global Navigation Satellite System (GNSS Observations

    Directory of Open Access Journals (Sweden)

    Xidong Yu

    2017-01-01

    Full Text Available Multi-constellation global navigation satellite systems (GNSSs are expected to enhance the capability of precise point positioning (PPP by improving the positioning accuracy and reducing the convergence time because more satellites will be available. This paper discusses the performance of multi-constellation kinematic PPP based on a multi-constellation kinematic PPP model, Kalman filter and stochastic models. The experimental dataset was collected from the receivers on a vehicle and processed using self-developed software. A comparison of the multi-constellation kinematic PPP and real-time kinematic (RTK results revealed that the availability, positioning accuracy and convergence performance of the multi-constellation kinematic PPP were all better than those of both global positioning system (GPS-based PPP and dual-constellation PPP. Multi-constellation kinematic PPP can provide a positioning service with centimetre-level accuracy for dynamic users.

  14. Determination of Earth outgoing radiation using a constellation of satellites

    Science.gov (United States)

    Gristey, Jake; Chiu, Christine; Gurney, Robert; Han, Shin-Chan; Morcrette, Cyril

    2017-04-01

    The outgoing radiation fluxes at the top of the atmosphere, referred to as Earth outgoing radiation (EOR), constitute a vital component of the Earth's energy budget. This EOR exhibits strong diurnal signatures and is inherently connected to the rapidly evolving scene from which the radiation originates, so our ability to accurately monitor EOR with sufficient temporal resolution and spatial coverage is crucial for weather and climate studies. Despite vast improvements in satellite observations in recent decades, achieving these criteria remains challenging from current measurements. A technology revolution in small satellites and sensor miniaturisation has created a new and exciting opportunity for a novel, viable and sustainable observation strategy from a constellation of satellites, capable of providing both global coverage and high temporal resolution simultaneously. To explore the potential of a constellation approach for observing EOR we perform a series of theoretical simulation experiments. Using the results from these simulation experiments, we will demonstrate a baseline constellation configuration capable of accurately monitoring global EOR at unprecedented temporal resolution. We will also show whether it is possible to reveal synoptic scale, fast evolving phenomena by applying a deconvolution technique to the simulated measurements. The ability to observe and understand the relationship between these phenomena and changes in EOR is of fundamental importance in constraining future warming of our climate system.

  15. Optimal Orbit Design for the Magnetospheric Imaging Constellation

    Science.gov (United States)

    Hughes, Steven P.; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    The Magnetospheric Imaging Constellation (MagIC) is a NASA space science concept to study the Earth's Magnetosphere. The concept proposes to apply tomography techniques using an array of spacecraft to obtain three dimensional images of the Earth's magnetosphere. This paper presents an optimal orbit design to ensure that the constellation is in the desired region of the magnetosphere for maximum time. The solution is found using a steepest descent optimization algorithm that takes into account perturbations from the non-spherical Earth, drag, Sun, Moon and other significant bodies. The solution also satisfies constraints on maximum eclipse duration and geometry constraints to allow an adequate GPS navigation solution. We present three solutions depending upon the epoch of the primary science: vernal equinox, summer solstice, and a third midway between the vernal equinox and summer solstice. Orbit insertion is also considered. All spacecraft are assumed to be launched on a single vehicle into a nominal orbit and the (Delta)V's to achieve the nominal orbit are presented. After insertion into the nominal orbit, each spacecraft undergoes a phasing maneuver to place it in the appropriate position with respect to the rest of the constellation. We present a minimum fuel approach to maneuver each spacecraft from the nominal orbit into the desired final orbit.

  16. Learning Curve for Teaching Constellations in a Planetarium

    Science.gov (United States)

    Hintz, Eric G.; Smith, N.; Moody, J. W.; Stephens, D. C.; Joner, M. D.; Hintz, M.; Lawler, J.; Jones, M.; Bench, N.

    2014-01-01

    As part of a larger project we have examined how students learn constellations in a planetarium environment. Students in our introductory descriptive astronomy class were given a 50 object quiz before any instruction. This quiz includes 30 constellations, 17 bright stars, two star clusters, and the Orion Nebula. In addition we gathered a small set of demographic information. After the initial quiz we tracked student scores through the semester to see how long it took for them to learn all 50 objects. We also plan to give a follow-up constellation quiz to students who have previously taken the quiz to test for retention. This will cover a time line for 6 months up to 4 years. We will present our early results from this study. This data will also be used as a baseline for a study of Head Mounted Displays to teach a deaf audience in a planetarium. This work is partially supported by funding from the National Science Foundation grant IIS-1124548 and the Sorenson Foundation.

  17. Survey of Methods and Algorithms of Robot Swarm Aggregation

    Science.gov (United States)

    E Shlyakhov, N.; Vatamaniuk, I. V.; Ronzhin, A. L.

    2017-01-01

    The paper considers the problem of swarm aggregation of autonomous robots with the use of three methods based on the analogy of the behavior of biological objects. The algorithms substantiating the requirements for hardware realization of sensor, computer and network resources and propulsion devices are presented. Techniques for efficiency estimation of swarm aggregation via space-time characteristics are described. The developed model of the robot swarm reconfiguration into a predetermined three-dimensional shape is presented.

  18. A Game Theoretic Approach to Swarm Robotics

    Directory of Open Access Journals (Sweden)

    S. N. Givigi

    2006-01-01

    Full Text Available In this article, we discuss some techniques for achieving swarm intelligent robots through the use of traits of personality. Traits of personality are characteristics of each robot that, altogether, define the robot's behaviours. We discuss the use of evolutionary psychology to select a set of traits of personality that will evolve due to a learning process based on reinforcement learning. The use of Game Theory is introduced, and some simulations showing its potential are reported.

  19. A Review of Particle Swarm Optimization

    Science.gov (United States)

    Jain, N. K.; Nangia, Uma; Jain, Jyoti

    2018-03-01

    This paper presents an overview of the research progress in Particle Swarm Optimization (PSO) during 1995-2017. Fifty two papers have been reviewed. They have been categorized into nine categories based on various aspects. This technique has attracted many researchers because of its simplicity which led to many improvements and modifications of the basic PSO. Some researchers carried out the hybridization of PSO with other evolutionary techniques. This paper discusses the progress of PSO, its improvements, modifications and applications.

  20. PARTICLE SWARM OPTIMIZATION- EVOLUTION, OVERVIEW AND APPLICATIONS

    OpenAIRE

    Dr.R.Umarani,; V.Selvi

    2010-01-01

    The present work interprets on Particle Swarm Optimization and simple software agents so called particles, move in the explore breathing space of an optimization problem. The position of a particle represents a solution to the optimization problem at hand. Each particle searches for better positions in the search space by changing its velocity according to rules originally inspired by behavioral models of bird flocking. The outlines of the paper explicate the overview, evolution, applications...

  1. Galactic Building Blocks Seen Swarming Around Andromeda

    Science.gov (United States)

    2004-02-01

    Green Bank, WV - A team of astronomers using the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) has made the first conclusive detection of what appear to be the leftover building blocks of galaxy formation -- neutral hydrogen clouds -- swarming around the Andromeda Galaxy, the nearest large spiral galaxy to the Milky Way. This discovery may help scientists understand the structure and evolution of the Milky Way and all spiral galaxies. It also may help explain why certain young stars in mature galaxies are surprisingly bereft of the heavy elements that their contemporaries contain. Andromeda Galaxy This image depicts several long-sought galactic "building blocks" in orbit of the Andromeda Galaxy (M31). The newfound hydrogen clouds are depicted in a shade of orange (GBT), while gas that comprises the massive hydrogen disk of Andromeda is shown at high-resolution in blue (Westerbork Sythesis Radio Telescope). CREDIT: NRAO/AUI/NSF, WSRT (Click on Image for Larger Version) "Giant galaxies, like Andromeda and our own Milky Way, are thought to form through repeated mergers with smaller galaxies and through the accretion of vast numbers of even lower mass 'clouds' -- dark objects that lack stars and even are too small to call galaxies," said David A. Thilker of the Johns Hopkins University in Baltimore, Maryland. "Theoretical studies predict that this process of galactic growth continues today, but astronomers have been unable to detect the expected low mass 'building blocks' falling into nearby galaxies, until now." Thilker's research is published in the Astrophysical Journal Letters. Other contributors include: Robert Braun of the Netherlands Foundation for Research in Astronomy; Rene A.M. Walterbos of New Mexico State University; Edvige Corbelli of the Osservatorio Astrofisico di Arcetri in Italy; Felix J. Lockman and Ronald Maddalena of the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia; and Edward Murphy of the

  2. Foraging behavior analysis of swarm robotics system

    Directory of Open Access Journals (Sweden)

    Sakthivelmurugan E.

    2018-01-01

    Full Text Available Swarm robotics is a number of small robots that are synchronically works together to accomplish a given task. Swarm robotics faces many problems in performing a given task. The problems are pattern formation, aggregation, Chain formation, self-assembly, coordinated movement, hole avoidance, foraging and self-deployment. Foraging is most essential part in swarm robotics. Foraging is the task to discover the item and get back into the shell. The researchers conducted foraging experiments with random-movement of robots and they have end up with unique solutions. Most of the researchers have conducted experiments using the circular arena. The shell is placed at the centre of the arena and environment boundary is well known. In this study, an attempt is made to different strategic movements like straight line approach, parallel line approach, divider approach, expanding square approach, and parallel sweep approach. All these approaches are to be simulated by using player/stage open-source simulation software based on C and C++ programming language in Linux operating system. Finally statistical comparison will be done with task completion time of all these strategies using ANOVA to identify the significant searching strategy.

  3. Empirically characteristic analysis of chaotic PID controlling particle swarm optimization

    Science.gov (United States)

    Yan, Danping; Lu, Yongzhong; Zhou, Min; Chen, Shiping; Levy, David

    2017-01-01

    Since chaos systems generally have the intrinsic properties of sensitivity to initial conditions, topological mixing and density of periodic orbits, they may tactfully use the chaotic ergodic orbits to achieve the global optimum or their better approximation to given cost functions with high probability. During the past decade, they have increasingly received much attention from academic community and industry society throughout the world. To improve the performance of particle swarm optimization (PSO), we herein propose a chaotic proportional integral derivative (PID) controlling PSO algorithm by the hybridization of chaotic logistic dynamics and hierarchical inertia weight. The hierarchical inertia weight coefficients are determined in accordance with the present fitness values of the local best positions so as to adaptively expand the particles’ search space. Moreover, the chaotic logistic map is not only used in the substitution of the two random parameters affecting the convergence behavior, but also used in the chaotic local search for the global best position so as to easily avoid the particles’ premature behaviors via the whole search space. Thereafter, the convergent analysis of chaotic PID controlling PSO is under deep investigation. Empirical simulation results demonstrate that compared with other several chaotic PSO algorithms like chaotic PSO with the logistic map, chaotic PSO with the tent map and chaotic catfish PSO with the logistic map, chaotic PID controlling PSO exhibits much better search efficiency and quality when solving the optimization problems. Additionally, the parameter estimation of a nonlinear dynamic system also further clarifies its superiority to chaotic catfish PSO, genetic algorithm (GA) and PSO. PMID:28472050

  4. Empirically characteristic analysis of chaotic PID controlling particle swarm optimization.

    Directory of Open Access Journals (Sweden)

    Danping Yan

    Full Text Available Since chaos systems generally have the intrinsic properties of sensitivity to initial conditions, topological mixing and density of periodic orbits, they may tactfully use the chaotic ergodic orbits to achieve the global optimum or their better approximation to given cost functions with high probability. During the past decade, they have increasingly received much attention from academic community and industry society throughout the world. To improve the performance of particle swarm optimization (PSO, we herein propose a chaotic proportional integral derivative (PID controlling PSO algorithm by the hybridization of chaotic logistic dynamics and hierarchical inertia weight. The hierarchical inertia weight coefficients are determined in accordance with the present fitness values of the local best positions so as to adaptively expand the particles' search space. Moreover, the chaotic logistic map is not only used in the substitution of the two random parameters affecting the convergence behavior, but also used in the chaotic local search for the global best position so as to easily avoid the particles' premature behaviors via the whole search space. Thereafter, the convergent analysis of chaotic PID controlling PSO is under deep investigation. Empirical simulation results demonstrate that compared with other several chaotic PSO algorithms like chaotic PSO with the logistic map, chaotic PSO with the tent map and chaotic catfish PSO with the logistic map, chaotic PID controlling PSO exhibits much better search efficiency and quality when solving the optimization problems. Additionally, the parameter estimation of a nonlinear dynamic system also further clarifies its superiority to chaotic catfish PSO, genetic algorithm (GA and PSO.

  5. A Swarm Optimization Genetic Algorithm Based on Quantum-Behaved Particle Swarm Optimization.

    Science.gov (United States)

    Sun, Tao; Xu, Ming-Hai

    2017-01-01

    Quantum-behaved particle swarm optimization (QPSO) algorithm is a variant of the traditional particle swarm optimization (PSO). The QPSO that was originally developed for continuous search spaces outperforms the traditional PSO in search ability. This paper analyzes the main factors that impact the search ability of QPSO and converts the particle movement formula to the mutation condition by introducing the rejection region, thus proposing a new binary algorithm, named swarm optimization genetic algorithm (SOGA), because it is more like genetic algorithm (GA) than PSO in form. SOGA has crossover and mutation operator as GA but does not need to set the crossover and mutation probability, so it has fewer parameters to control. The proposed algorithm was tested with several nonlinear high-dimension functions in the binary search space, and the results were compared with those from BPSO, BQPSO, and GA. The experimental results show that SOGA is distinctly superior to the other three algorithms in terms of solution accuracy and convergence.

  6. Collective motion with anticipation: Flocking, spinning, and swarming

    Science.gov (United States)

    Morin, Alexandre; Caussin, Jean-Baptiste; Eloy, Christophe; Bartolo, Denis

    2015-01-01

    We investigate the collective dynamics of self-propelled particles able to probe and anticipate the orientation of their neighbors. We show that a simple anticipation strategy hinders the emergence of homogeneous flocking patterns. Yet anticipation promotes two other forms of self-organization: collective spinning and swarming. In the spinning phase, all particles follow synchronous circular orbits, while in the swarming phase, the population condensates into a single compact swarm that cruises coherently without requiring any cohesive interactions. We quantitatively characterize and rationalize these phases of polar active matter and discuss potential applications to the design of swarming robots.

  7. DISCUS: Distributed Intelligent Swarm Control & Utilization System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SSCI and University of Washington (Prof. Behcet Acikmese) propose to develop, integrate and test an innovative Distributed Intelligent Swarm Control &...

  8. Collective motion of a class of social foraging swarms

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bo [Intelligent Control Laboratory, Center for Systems and Control, Department of Industrial Engineering and Management, College of Engineering, Peking University, Beijing 100871 (China)], E-mail: boliu@mech.pku.edu.cn; Chu Tianguang [Intelligent Control Laboratory, Center for Systems and Control, Department of Industrial Engineering and Management, College of Engineering, Peking University, Beijing 100871 (China)], E-mail: chutg@pku.edu.cn; Wang Long; Wang Zhanfeng [Intelligent Control Laboratory, Center for Systems and Control, Department of Industrial Engineering and Management, College of Engineering, Peking University, Beijing 100871 (China)

    2008-10-15

    This paper considers a class of social foraging swarms with a nutrient profile (or an attractant/repellent) and an attraction-repulsion coupling function, which is chosen to guarantee collision avoidance between individuals. The paper also studies non-identical interaction ability or efficiency among different swarm individuals for different profiles. The swarm behavior is a result of a balance between inter-individual interplays as well as the interplays of the swarm individuals (agents) with their environment. It is proved that the individuals of a quasi-reciprocal swarm will aggregate and eventually form a cohesive cluster of finite size for different profiles. It is also shown that the swarm system is completely stable, that is, every solution converges to the set of equilibrium points of the system. Moreover, all the swarm individuals will converge to more favorable areas of the profile under certain conditions. For general non-reciprocal swarms, numerical simulations show that more complex self-organized rotation may occur in the swarms.

  9. Collective motion of a class of social foraging swarms

    International Nuclear Information System (INIS)

    Liu Bo; Chu Tianguang; Wang Long; Wang Zhanfeng

    2008-01-01

    This paper considers a class of social foraging swarms with a nutrient profile (or an attractant/repellent) and an attraction-repulsion coupling function, which is chosen to guarantee collision avoidance between individuals. The paper also studies non-identical interaction ability or efficiency among different swarm individuals for different profiles. The swarm behavior is a result of a balance between inter-individual interplays as well as the interplays of the swarm individuals (agents) with their environment. It is proved that the individuals of a quasi-reciprocal swarm will aggregate and eventually form a cohesive cluster of finite size for different profiles. It is also shown that the swarm system is completely stable, that is, every solution converges to the set of equilibrium points of the system. Moreover, all the swarm individuals will converge to more favorable areas of the profile under certain conditions. For general non-reciprocal swarms, numerical simulations show that more complex self-organized rotation may occur in the swarms

  10. Details of microearthquake swarms in the Columbia basin, Washington

    International Nuclear Information System (INIS)

    Malone, S.D.; Rothe, G.H.; Smith, S.W.

    1975-01-01

    Three microearthquake swarms in the Columbia River basin of eastern Washington were studied by means of a small portable seismic network. Earthquakes in this area typically occur in swarms, concentrated both temporally and spatially. One unusual characteristic of the three swarms studied was the shallow focal depths of all events. Most events located had depths less than 1 km; none were deeper than 2 km. Composite focal mechanism solutions indicate that more than one fault surface is active in any one swarm. All events had some thrust component with the axis of maximum compression oriented roughly in a north-south direction. (auth)

  11. Collective motion with anticipation: flocking, spinning, and swarming.

    Science.gov (United States)

    Morin, Alexandre; Caussin, Jean-Baptiste; Eloy, Christophe; Bartolo, Denis

    2015-01-01

    We investigate the collective dynamics of self-propelled particles able to probe and anticipate the orientation of their neighbors. We show that a simple anticipation strategy hinders the emergence of homogeneous flocking patterns. Yet anticipation promotes two other forms of self-organization: collective spinning and swarming. In the spinning phase, all particles follow synchronous circular orbits, while in the swarming phase, the population condensates into a single compact swarm that cruises coherently without requiring any cohesive interactions. We quantitatively characterize and rationalize these phases of polar active matter and discuss potential applications to the design of swarming robots.

  12. Multiple Genome Constellations of Similar and Distinct Influenza A Viruses Co-Circulate in Pigs During Epidemic Events.

    Science.gov (United States)

    Diaz, Andres; Marthaler, Douglas; Corzo, Cesar; Muñoz-Zanzi, Claudia; Sreevatsan, Srinand; Culhane, Marie; Torremorell, Montserrat

    2017-09-19

    Swine play a key role in the ecology and transmission of influenza A viruses (IAVs) between species. However, the epidemiology and diversity of swine IAVs is not completely understood. In this cohort study, we sampled on a weekly basis 132 3-week old pigs for 15 weeks. We found two overlapping epidemic events of infection in which most pigs (98.4%) tested PCR positive for IAVs. The prevalence rate of infection ranged between 0 and 86% per week and the incidence density ranged between 0 and 71 cases per 100 pigs-week. Three distinct influenza viral groups (VGs) replicating as a "swarm" of viruses were identified (swine H1-gamma, H1-beta, and H3-cluster-IV IAVs) and co-circulated at different proportions over time suggesting differential allele fitness. Furthermore, using deep genome sequencing 13 distinct viral genome constellations were differentiated. Moreover, 78% of the pigs had recurrent infections with IAVs closely related to each other or IAVs clearly distinct. Our results demonstrated the molecular complexity of swine IAVs during natural infection of pigs in which novel strains of IAVs with zoonotic and pandemic potential can emerge. These are key findings to design better health interventions to reduce the transmission of swine IAVs and minimize the public health risk.

  13. Scheduling algorithms for rapid imaging using agile Cubesat constellations

    Science.gov (United States)

    Nag, Sreeja; Li, Alan S.; Merrick, James H.

    2018-02-01

    Distributed Space Missions such as formation flight and constellations, are being recognized as important Earth Observation solutions to increase measurement samples over space and time. Cubesats are increasing in size (27U, ∼40 kg in development) with increasing capabilities to host imager payloads. Given the precise attitude control systems emerging in the commercial market, Cubesats now have the ability to slew and capture images within short notice. We propose a modular framework that combines orbital mechanics, attitude control and scheduling optimization to plan the time-varying, full-body orientation of agile Cubesats in a constellation such that they maximize the number of observed images and observation time, within the constraints of Cubesat hardware specifications. The attitude control strategy combines bang-bang and PD control, with constraints such as power consumption, response time, and stability factored into the optimality computations and a possible extension to PID control to account for disturbances. Schedule optimization is performed using dynamic programming with two levels of heuristics, verified and improved upon using mixed integer linear programming. The automated scheduler is expected to run on ground station resources and the resultant schedules uplinked to the satellites for execution, however it can be adapted for onboard scheduling, contingent on Cubesat hardware and software upgrades. The framework is generalizable over small steerable spacecraft, sensor specifications, imaging objectives and regions of interest, and is demonstrated using multiple 20 kg satellites in Low Earth Orbit for two case studies - rapid imaging of Landsat's land and coastal images and extended imaging of global, warm water coral reefs. The proposed algorithm captures up to 161% more Landsat images than nadir-pointing sensors with the same field of view, on a 2-satellite constellation over a 12-h simulation. Integer programming was able to verify that

  14. Autonomous Scheduling Requirements for Agile Cubesat Constellations in Earth Observation

    Science.gov (United States)

    Nag, S.; Li, A. S. X.; Kumar, S.

    2017-12-01

    Distributed Space Missions such as formation flight and constellations, are being recognized as important Earth Observation solutions to increase measurement samples over space and time. Cubesats are increasing in size (27U, 40 kg) with increasing capabilities to host imager payloads. Given the precise attitude control systems emerging commercially, Cubesats now have the ability to slew and capture images within short notice. Prior literature has demonstrated a modular framework that combines orbital mechanics, attitude control and scheduling optimization to plan the time-varying orientation of agile Cubesats in a constellation such that they maximize the number of observed images, within the constraints of hardware specs. Schedule optimization is performed on the ground autonomously, using dynamic programming with two levels of heuristics, verified and improved upon using mixed integer linear programming. Our algorithm-in-the-loop simulation applied to Landsat's use case, captured up to 161% more Landsat images than nadir-pointing sensors with the same field of view, on a 2-satellite constellation over a 12-hour simulation. In this paper, we will derive the requirements for the above algorithm to run onboard small satellites such that the constellation can make time-sensitive decisions to slew and capture images autonomously, without ground support. We will apply the above autonomous algorithm to a time critical use case - monitoring of precipitation and subsequent effects on floods, landslides and soil moisture, as quantified by the NASA Unified Weather Research and Forecasting Model. Since the latency between these event occurrences is quite low, they make a strong case for autonomous decisions among satellites in a constellation. The algorithm can be implemented in the Plan Execution Interchange Language - NASA's open source technology for automation, used to operate the International Space Station and LADEE's in flight software - enabling a controller

  15. A simple formula for the series of constellations and quasi-constellations with boundaries

    OpenAIRE

    Collet, Gwendal; Fusy, Eric

    2014-01-01

    International audience; We obtain a very simple formula for the generating function of bipartite (resp. quasi-bipartite) planar maps with boundaries (holes) of prescribed lengths, which generalizes certain expressions obtained by Eynard in a book to appear. The formula is derived from a bijection due to Bouttier, Di Francesco and Guitter combined with a process (reminiscent of a construction of Pitman) of aggregating connected components of a forest into a single tree. The formula naturally e...

  16. A comparative analysis of chaotic particle swarm optimizations for detecting single nucleotide polymorphism barcodes.

    Science.gov (United States)

    Chuang, Li-Yeh; Moi, Sin-Hua; Lin, Yu-Da; Yang, Cheng-Hong

    2016-10-01

    Evolutionary algorithms could overcome the computational limitations for the statistical evaluation of large datasets for high-order single nucleotide polymorphism (SNP) barcodes. Previous studies have proposed several chaotic particle swarm optimization (CPSO) methods to detect SNP barcodes for disease analysis (e.g., for breast cancer and chronic diseases). This work evaluated additional chaotic maps combined with the particle swarm optimization (PSO) method to detect SNP barcodes using a high-dimensional dataset. Nine chaotic maps were used to improve PSO method results and compared the searching ability amongst all CPSO methods. The XOR and ZZ disease models were used to compare all chaotic maps combined with PSO method. Efficacy evaluations of CPSO methods were based on statistical values from the chi-square test (χ 2 ). The results showed that chaotic maps could improve the searching ability of PSO method when population are trapped in the local optimum. The minor allele frequency (MAF) indicated that, amongst all CPSO methods, the numbers of SNPs, sample size, and the highest χ 2 value in all datasets were found in the Sinai chaotic map combined with PSO method. We used the simple linear regression results of the gbest values in all generations to compare the all methods. Sinai chaotic map combined with PSO method provided the highest β values (β≥0.32 in XOR disease model and β≥0.04 in ZZ disease model) and the significant p-value (p-value<0.001 in both the XOR and ZZ disease models). The Sinai chaotic map was found to effectively enhance the fitness values (χ 2 ) of PSO method, indicating that the Sinai chaotic map combined with PSO method is more effective at detecting potential SNP barcodes in both the XOR and ZZ disease models. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. A hybrid search algorithm for swarm robots searching in an unknown environment.

    Science.gov (United States)

    Li, Shoutao; Li, Lina; Lee, Gordon; Zhang, Hao

    2014-01-01

    This paper proposes a novel method to improve the efficiency of a swarm of robots searching in an unknown environment. The approach focuses on the process of feeding and individual coordination characteristics inspired by the foraging behavior in nature. A predatory strategy was used for searching; hence, this hybrid approach integrated a random search technique with a dynamic particle swarm optimization (DPSO) search algorithm. If a search robot could not find any target information, it used a random search algorithm for a global search. If the robot found any target information in a region, the DPSO search algorithm was used for a local search. This particle swarm optimization search algorithm is dynamic as all the parameters in the algorithm are refreshed synchronously through a communication mechanism until the robots find the target position, after which, the robots fall back to a random searching mode. Thus, in this searching strategy, the robots alternated between two searching algorithms until the whole area was covered. During the searching process, the robots used a local communication mechanism to share map information and DPSO parameters to reduce the communication burden and overcome hardware limitations. If the search area is very large, search efficiency may be greatly reduced if only one robot searches an entire region given the limited resources available and time constraints. In this research we divided the entire search area into several subregions, selected a target utility function to determine which subregion should be initially searched and thereby reduced the residence time of the target to improve search efficiency.

  18. The upper surface of an Escherichia coli swarm is stationary.

    Science.gov (United States)

    Zhang, Rongjing; Turner, Linda; Berg, Howard C

    2010-01-05

    When grown in a rich medium on agar, many bacteria elongate, produce more flagella, and swim in a thin film of fluid over the agar surface in swirling packs. Cells that spread in this way are said to swarm. The agar is a solid gel, with pores smaller than the bacteria, so the swarm/agar interface is fixed. Here we show, in experiments with Escherichia coli, that the swarm/air interface also is fixed. We deposited MgO smoke particles on the top surface of an E. coli swarm near its advancing edge, where cells move in a single layer, and then followed the motion of the particles by dark-field microscopy and the motion of the underlying cells by phase-contrast microscopy. Remarkably, the smoke particles remained fixed (diffusing only a few micrometers) while the swarming cells streamed past underneath. The diffusion coefficients of the smoke particles were smaller over the virgin agar ahead of the swarm than over the swarm itself. Changes between these two modes of behavior were evident within 10-20 microm of the swarm edge, indicating an increase in depth of the fluid in advance of the swarm. The only plausible way that the swarm/air interface can be fixed is that it is covered by a surfactant monolayer pinned at its edges. When a swarm is exposed to air, such a monolayer can markedly reduce water loss. When cells invade tissue, the ability to move rapidly between closely opposed fixed surfaces is a useful trait.

  19. From organized internal traffic to collective navigation of bacterial swarms

    International Nuclear Information System (INIS)

    Ariel, Gil; Shklarsh, Adi; Kalisman, Oren; Ben-Jacob, Eshel; Ingham, Colin

    2013-01-01

    Bacterial swarming resulting in collective navigation over surfaces provides a valuable example of cooperative colonization of new territories. The social bacterium Paenibacillus vortex exhibits successful and diverse swarming strategies. When grown on hard agar surfaces with peptone, P. vortex develops complex colonies of vortices (rotating bacterial aggregates). In contrast, during growth on Mueller–Hinton broth gelled into a soft agar surface, a new strategy of multi-level organization is revealed: the colonies are organized into a special network of swarms (or ‘snakes’ of a fraction of millimeter in width) with intricate internal traffic. More specifically, cell movement is organized in two or three lanes of bacteria traveling between the back and the front of the swarm. This special form of cellular logistics suggests new methods in which bacteria can share resources and risk while searching for food or migrating into new territories. While the vortices-based organization on hard agar surfaces has been modeled before, here, we introduce a new multi-agent bacterial swarming model devised to capture the swarms-based organization on soft surfaces. We test two putative generic mechanisms that may underlie the observed swarming logistics: (i) chemo-activated taxis in response to chemical cues and (ii) special align-and-push interactions between the bacteria and the boundary of the layer of lubricant collectively generated by the swarming bacteria. Using realistic parameters, the model captures the observed phenomena with semi-quantitative agreement in terms of the velocity as well as the dynamics of the swarm and its envelope. This agreement implies that the bacteria interactions with the swarm boundary play a crucial role in mediating the interplay between the collective movement of the swarm and the internal traffic dynamics. (paper)

  20. Nanosatellite constellation deployment using on-board magnetic torquer interaction with space plasma

    Science.gov (United States)

    Park, Ji Hyun; Matsuzawa, Shinji; Inamori, Takaya; Jeung, In-Seuck

    2018-04-01

    One of the advantages that drive nanosatellite development is the potential of multi-point observation through constellation operation. However, constellation deployment of nanosatellites has been a challenge, as thruster operations for orbit maneuver were limited due to mass, volume, and power. Recently, a de-orbiting mechanism using magnetic torquer interaction with space plasma has been introduced, so-called plasma drag. As no additional hardware nor propellant is required, plasma drag has the potential in being used as constellation deployment method. In this research, a novel constellation deployment method using plasma drag is proposed. Orbit decay rate of the satellites in a constellation is controlled using plasma drag in order to achieve a desired phase angle and phase angle rate. A simplified 1D problem is formulated for an elementary analysis of the constellation deployment time. Numerical simulations are further performed for analytical analysis assessment and sensitivity analysis. Analytical analysis and numerical simulation results both agree that the constellation deployment time is proportional to the inverse square root of magnetic moment, the square root of desired phase angle and the square root of satellite mass. CubeSats ranging from 1 to 3 U (1-3 kg nanosatellites) are examined in order to investigate the feasibility of plasma drag constellation on nanosatellite systems. The feasibility analysis results show that plasma drag constellation is feasible on CubeSats, which open up the possibility of CubeSat constellation missions.

  1. Registration of Vehicle-Borne Point Clouds and Panoramic Images Based on Sensor Constellations.

    Science.gov (United States)

    Yao, Lianbi; Wu, Hangbin; Li, Yayun; Meng, Bin; Qian, Jinfei; Liu, Chun; Fan, Hongchao

    2017-04-11

    A mobile mapping system (MMS) is usually utilized to collect environmental data on and around urban roads. Laser scanners and panoramic cameras are the main sensors of an MMS. This paper presents a new method for the registration of the point clouds and panoramic images based on sensor constellation. After the sensor constellation was analyzed, a feature point, the intersection of the connecting line between the global positioning system (GPS) antenna and the panoramic camera with a horizontal plane, was utilized to separate the point clouds into blocks. The blocks for the central and sideward laser scanners were extracted with the segmentation feature points. Then, the point clouds located in the blocks were separated from the original point clouds. Each point in the blocks was used to find the accurate corresponding pixel in the relative panoramic images via a collinear function, and the position and orientation relationship amongst different sensors. A search strategy is proposed for the correspondence of laser scanners and lenses of panoramic cameras to reduce calculation complexity and improve efficiency. Four cases of different urban road types were selected to verify the efficiency and accuracy of the proposed method. Results indicate that most of the point clouds (with an average of 99.7%) were successfully registered with the panoramic images with great efficiency. Geometric evaluation results indicate that horizontal accuracy was approximately 0.10-0.20 m, and vertical accuracy was approximately 0.01-0.02 m for all cases. Finally, the main factors that affect registration accuracy, including time synchronization amongst different sensors, system positioning and vehicle speed, are discussed.

  2. BRITE-Constellation: Nanosatellites for precision photometry of bright stars

    Science.gov (United States)

    Weiss, W. W.; Moffat, A. F. J.; Schwarzenberg-Czerny, A.; Koudelka, O. F.; Grant, C. C.; Zee, R. E.; Kuschnig, R.; Mochnacki, St.; Rucinski, S. M.; Matthews, J. M.; Orleański, P.; Pamyatnykh, A. A.; Pigulski, A.; Alves, J.; Guedel, M.; Handler, G.; Wade, G. A.; Scholtz, A. L.; Scholtz

    2014-02-01

    BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, brightness and temperature variations of stars brighter than V ~ 4, with precision and time coverage not possible from the ground. The current mission design consists of three pairs of 7 kg nanosats (hence ``Constellation'') from Austria, Canada and Poland carrying optical telescopes (3 cm aperture) and CCDs. One instrument in each pair is equipped with a blue filter; the other, a red filter. The first two nanosats (funded by Austria) are UniBRITE, designed and built by UTIAS-SFL (University of Toronto Institute for Aerospace Studies-Space Flight Laboratory) and its twin, BRITE-Austria, built by the Technical University Graz (TUG) with support of UTIAS-SFL. They were launched on 25 February 2013 by the Indian Space Agency, under contract to the Canadian Space Agency. Each BRITE instrument has a wide field of view (~ 24 degrees), so up to 15 bright stars can be observed simultaneously in 32 × 32 sub-rasters. Photometry (with reduced precision but thorough time sampling) of additional fainter targets will be possible through on-board data processing. A critical technical element of the BRITE mission is the three-axis attitude control system to stabilize a nanosat with very low inertia. The pointing stability is better than 1.5 arcminutes rms, a significant advance by UTIAS-SFL over any previous nanosatellite. BRITE-Constellation will primarily measure p- and g-mode pulsations to probe the interiors and ages of stars through asteroseismology. The BRITE sample of many of the brightest stars in the night sky is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases (cool giants and AGB stars). The Hertzsprung-Russell diagram for stars brighter than mag V=4 from which the BRITE-Constellation sample

  3. Agent-Based Simulation and Analysis of a Defensive UAV Swarm Against an Enemy UAV Swarm

    Science.gov (United States)

    2011-06-01

    energy options” [10]. The research of swarm robotics derives much of its inspiration from natural systems. Social insects are known to coordinate their...Monterey, California 9. CPT. Francisco J. Hederra Direccion de Investigacion , Programas y Desarrollo de la Armada Armada de Chile CHILE 10. CAPT Jeffrey Kline, USN(ret.) Naval Postgraduate School Monterey, California 91

  4. Markerless human motion tracking using hierarchical multi-swarm cooperative particle swarm optimization.

    Science.gov (United States)

    Saini, Sanjay; Zakaria, Nordin; Rambli, Dayang Rohaya Awang; Sulaiman, Suziah

    2015-01-01

    The high-dimensional search space involved in markerless full-body articulated human motion tracking from multiple-views video sequences has led to a number of solutions based on metaheuristics, the most recent form of which is Particle Swarm Optimization (PSO). However, the classical PSO suffers from premature convergence and it is trapped easily into local optima, significantly affecting the tracking accuracy. To overcome these drawbacks, we have developed a method for the problem based on Hierarchical Multi-Swarm Cooperative Particle Swarm Optimization (H-MCPSO). The tracking problem is formulated as a non-linear 34-dimensional function optimization problem where the fitness function quantifies the difference between the observed image and a projection of the model configuration. Both the silhouette and edge likelihoods are used in the fitness function. Experiments using Brown and HumanEva-II dataset demonstrated that H-MCPSO performance is better than two leading alternative approaches-Annealed Particle Filter (APF) and Hierarchical Particle Swarm Optimization (HPSO). Further, the proposed tracking method is capable of automatic initialization and self-recovery from temporary tracking failures. Comprehensive experimental results are presented to support the claims.

  5. A new hybrid teaching–learning particle swarm optimization ...

    Indian Academy of Sciences (India)

    This paper proposes a novel hybrid teaching–learning particle swarm optimization (HTLPSO) algorithm, which merges two established nature-inspired algorithms, namely, optimization based on teaching–learning (TLBO) and particle swarm optimization (PSO). The HTLPSO merges the best half of population obtained after ...

  6. Issues concerning reproductive isolation in a rice hybrid swarm ...

    African Journals Online (AJOL)

    The study reveals post-zygotic mechanism involving segregational as well as developmental hybrid sterility to be the major isolating mechanism involved the reproductive isolation existing among the parent populations in the swarm. Hybridization and introgression have played significant roles in creating this hybrid swarm ...

  7. Validation of Swarm accelerometer data by modelled nongravitational forces

    Science.gov (United States)

    Bezděk, Aleš; Sebera, Josef; Klokočník, Jaroslav

    2017-05-01

    Swarm is a three-satellite mission of the European Space Agency, in orbit since November 2013, whose main objective is the study of the Earth's magnetic field from space. As part of other scientific payload, each Swarm satellite is equipped with an accelerometer that measures the nongravitational forces (e.g. atmospheric drag and radiation pressure). Since the mission beginning, the Swarm onboard accelerometer observations have been facing a problem of much higher temperature influence than it had been anticipated in the pre-launch tests. In our paper, we use the a posteriori computed models of physical nongravitational forces acting on each satellite for external validation of the accelerometer measurements. To reduce the high temperature dependence, we apply a simple and straightforward method of linear temperature correction. The most successful application of this approach is for the along-track component of the accelerometer data, where the signal magnitude is strongest. The best performing accelerometer is that of the Swarm C satellite, the accelerometer of Swarm A displays more temperature dependence and noise, the noisiest accelerometer data set is provided by Swarm B. We analyzed the occurrence of anomalous periods in the along-track accelerometer component of Swarm A and Swarm C, when the number of accelerometer hardware anomalies is peaking. Over the time interval from June 2014 to December 2015, we found a correlation between these anomalous periods and the minima in the time-varying part of the modelled nongravitational signal.

  8. Swarming behaviour and mass occurrences in the world's largest ...

    African Journals Online (AJOL)

    The first records of mass occurrences (swarming behaviour) in giant pill - millipedes, order Sphaerotheriida, are reported from Madagascar. Swarming behaviour in the order Sphaerotheriida seems to be restricted to a single of more than sixty described Malagasy species, Zoosphaerium neptunus (Butler, 1872), which is the ...

  9. Improved cuckoo search with particle swarm optimization for ...

    Indian Academy of Sciences (India)

    Content based image retrieval (CBIR); image compression; partial recurrent neural network (PRNN); particle swarm optimization (PSO); HAARwavelet; Cuckoo Search ... are NP hard, a hybrid Particle Swarm Optimization (PSO) – Cuckoo Search algorithm (CS) is proposed to optimize the learning rate of the neural network.

  10. UAV Swarm Behavior Modeling for Early Exposure of Failure Modes

    Science.gov (United States)

    2016-09-01

    Figure 6. Swarm vs. Swarm Event Trace Graph .......................................................10 Figure 7. PACOM Crimson Viper 2010 Exercise ...method for modeling behaviors of the software, hardware, business processes, and other parts of the system. The event grammar models the behavior as a...ability to represent events in various patterns. Table 1 describes the various patterns in both natural language and MP event grammar . These

  11. Solving Unconstrained Global Optimization Problems via Hybrid Swarm Intelligence Approaches

    OpenAIRE

    Wu, Jui-Yu

    2013-01-01

    Stochastic global optimization (SGO) algorithms such as the particle swarm optimization (PSO) approach have become popular for solving unconstrained global optimization (UGO) problems. The PSO approach, which belongs to the swarm intelligence domain, does not require gradient information, enabling it to overcome this limitation of traditional nonlinear programming methods. Unfortunately, PSO algorithm implementation and performance depend on several parameters, such as cognitive parameter, so...

  12. An Ecological Approach to the Supervisory Control of UAV Swarms

    NARCIS (Netherlands)

    Fuchs, C.; Borst, C.; De Croon, G.C.H.E.; Van Paassen, M.M.; Mulder, M.

    2014-01-01

    This research employs ecological interface design to improve the human machine interface of an existing ground control station for the supervisory control of UAV swarms. As a case study, a general ground surveillance mission with four UAVs is envisioned. An analysis of the swarming work domain is

  13. Global gene expression profile for swarming Bacillus cereus bacteria.

    Science.gov (United States)

    Salvetti, Sara; Faegri, Karoline; Ghelardi, Emilia; Kolstø, Anne-Brit; Senesi, Sonia

    2011-08-01

    Bacillus cereus can use swarming to move over and colonize solid surfaces in different environments. This kind of motility is a collective behavior accompanied by the production of long and hyperflagellate swarm cells. In this study, the genome-wide transcriptional response of B. cereus ATCC 14579 during swarming was analyzed. Swarming was shown to trigger the differential expression (>2-fold change) of 118 genes. Downregulated genes included those required for basic cellular metabolism. In accordance with the hyperflagellate phenotype of the swarm cell, genes encoding flagellin were overexpressed. Some genes associated with K(+) transport, phBC6A51 phage genes, and the binding component of the enterotoxin hemolysin BL (HBL) were also induced. Quantitative reverse transcription-PCR (qRT-PCR) experiments indicated an almost 2-fold upregulation of the entire hbl operon during swarming. Finally, BC1435 and BC1436, orthologs of liaI-liaH that are known to be involved in the resistance of Bacillus subtilis to daptomycin, were upregulated under swarming conditions. Accordingly, phenotypic assays showed reduced susceptibility of swarming B. cereus cells to daptomycin, and P(spac)-induced hyper-expression of these genes in liquid medium highlighted the role of BC1435 and BC1436 in the response of B. cereus to daptomycin.

  14. A persistent homology approach to collective behavior in insect swarms

    Science.gov (United States)

    Sinhuber, Michael; Ouellette, Nicholas T.

    Various animals from birds and fish to insects tend to form aggregates, displaying self-organized collective swarming behavior. Due to their frequent occurrence in nature and their implications for engineered, collective systems, these systems have been investigated and modeled thoroughly for decades. Common approaches range from modeling them with coupled differential equations on the individual level up to continuum approaches. We present an alternative, topology-based approach for describing swarming behavior at the macroscale rather than the microscale. We study laboratory swarms of Chironomus riparius, a flying, non-biting midge. To obtain the time-resolved three-dimensional trajectories of individual insects, we use a multi-camera stereoimaging and particle-tracking setup. To investigate the swarming behavior in a topological sense, we employ a persistent homology approach to identify persisting structures and features in the insect swarm that elude a direct, ensemble-averaging approach. We are able to identify features of sub-clusters in the swarm that show behavior distinct from that of the remaining swarm members. The coexistence of sub-swarms with different features resembles some non-biological systems such as active colloids or even thermodynamic systems.

  15. Swarming modulatory effects of some amino acids on Proteus ...

    African Journals Online (AJOL)

    Swarming motility, a multicellular behaviour characterized by periodic concentric growth on solid media has severally been reported as a constraint in the clinical investigation of mixed-culture infections involving Proteus and as a requirement for virulence. While media are being formulated to restrain swarming in this ...

  16. Improved cuckoo search with particle swarm optimization for ...

    Indian Academy of Sciences (India)

    work are NP hard, a hybrid Particle Swarm Optimization (PSO) – Cuckoo Search algorithm (CS) is proposed to optimize the learning rate of the neural network. Keywords. Content based image retrieval (CBIR); image compression; partial recurrent neural network (PRNN); particle swarm optimization (PSO); HAAR wavelet;.

  17. Trade-Space Analysis Tool for Constellations (TAT-C)

    Science.gov (United States)

    Le Moigne, Jacqueline; Dabney, Philip; de Weck, Olivier; Foreman, Veronica; Grogan, Paul; Holland, Matthew; Hughes, Steven; Nag, Sreeja

    2016-01-01

    Traditionally, space missions have relied on relatively large and monolithic satellites, but in the past few years, under a changing technological and economic environment, including instrument and spacecraft miniaturization, scalable launchers, secondary launches as well as hosted payloads, there is growing interest in implementing future NASA missions as Distributed Spacecraft Missions (DSM). The objective of our project is to provide a framework that facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori Science goals. In this first version of our Trade-space Analysis Tool for Constellations (TAT-C), we are investigating questions such as: How many spacecraft should be included in the constellation? Which design has the best costrisk value? The main goals of TAT-C are to: Handle multiple spacecraft sharing a mission objective, from SmallSats up through flagships, Explore the variables trade space for pre-defined science, cost and risk goals, and pre-defined metrics Optimize cost and performance across multiple instruments and platforms vs. one at a time.This paper describes the overall architecture of TAT-C including: a User Interface (UI) interacting with multiple users - scientists, missions designers or program managers; an Executive Driver gathering requirements from UI, then formulating Trade-space Search Requests for the Trade-space Search Iterator first with inputs from the Knowledge Base, then, in collaboration with the Orbit Coverage, Reduction Metrics, and Cost Risk modules, generating multiple potential architectures and their associated characteristics. TAT-C leverages the use of the Goddard Mission Analysis Tool (GMAT) to compute coverage and ancillary data, streamlining the computations by modeling orbits in a way that balances accuracy and performance.TAT-C current version includes uniform Walker constellations as well as Ad-Hoc constellations, and its cost model represents an aggregate model consisting of

  18. CubeSat constellations for disaster management in remote areas

    Science.gov (United States)

    Santilli, Giancarlo; Vendittozzi, Cristian; Cappelletti, Chantal; Battistini, Simone; Gessini, Paolo

    2018-04-01

    In recent years, CubeSats have considerably extended their range of possible applications, from a low cost means to train students and young researchers in space related activities up to possible complementary solutions to larger missions. Increasingly popular, whereas CubeSats are still not a solution for all types of missions, they offer the possibility of performing ambitious scientific experiments. Especially worth considering is the possibility of performing Distributed Space Missions, in which CubeSat systems can be used to increase observation sampling rates and resolutions, as well as to perform tasks that a single satellite is unable to handle. The cost of access to space for traditional Earth Observation (EO) missions is still quite high. Efficient architecture design would allow reducing mission costs by employing CubeSat systems, while maintaining a level of performance that, for some applications, could be close to that provided by larger platforms, and decreasing the time needed to design and deploy a fully functional constellation. For these reasons many countries, including developing nations, agencies and organizations are looking to CubeSat platforms to access space cheaply with, potentially, tens of remote sensing satellites. During disaster management, real-time, fast and continuous information broadcast is a fundamental requirement. In this sense, a constellation of small satellites can considerably decrease the revisit time (defined as the time elapsed between two consecutive observations of the same point on Earth by a satellite) over remote areas, by increasing the number of spacecraft properly distributed in orbit. This allows collecting as much data as possible for the use by Disaster Management Centers. This paper describes the characteristics of a constellation of CubeSats built to enable access over the most remote regions of Brazil, supporting an integrated system for mitigating environmental disasters in an attempt to prevent the

  19. Effect of Cell Aspect Ratio on Swarming Bacteria

    Science.gov (United States)

    Ilkanaiv, Bella; Kearns, Daniel B.; Ariel, Gil; Be'er, Avraham

    2017-04-01

    Swarming bacteria collectively migrate on surfaces using flagella, forming dynamic whirls and jets that consist of millions of individuals. Because some swarming bacteria elongate prior to actual motion, cell aspect ratio may play a significant role in the collective dynamics. Extensive research on self-propelled rodlike particles confirms that elongation promotes alignment, strongly affecting the dynamics. Here, we study experimentally the collective dynamics of variants of swarming Bacillus subtilis that differ in length. We show that the swarming statistics depends on the aspect ratio in a critical, fundamental fashion not predicted by theory. The fastest motion was obtained for the wild-type and variants that are similar in length. However, shorter and longer cells exhibit anomalous, non-Gaussian statistics and nonexponential decay of the autocorrelation function, indicating lower collective motility. These results suggest that the robust mechanisms to maintain aspect ratios may be important for efficient swarming motility. Wild-type cells are optimal in this sense.

  20. Benefits of collective intelligence: Swarm intelligent foraging, an ethnographic research

    Directory of Open Access Journals (Sweden)

    Sivave Mashingaidze

    2014-12-01

    Full Text Available Wisdom of crowds; bees, colonies of ants, schools of fish, flocks of birds, and fireflies flashing synchronously are all examples of highly coordinated behaviors that emerge from collective, decentralized intelligence. This article is an ethnographic study of swarm intelligence foraging of swarms and the benefits derived from collective decision making. The author used using secondary data analysis to look at the benefits of swarm intelligence in decision making to achieve intended goals. Concepts like combined decision making and consensus were discussed and four principles of swarm intelligence were also discussed viz; coordination, cooperation, deliberation and collaboration. The research found out that collective decision making in swarms is the touchstone of achieving their goals. The research further recommended corporate to adopt collective intelligence for business sustainability.

  1. Formations of Robotic Swarm: An Artificial Force Based Approach

    Directory of Open Access Journals (Sweden)

    Samitha W. Ekanayake

    2009-03-01

    Full Text Available Cooperative control of multiple mobile robots is an attractive and challenging problem which has drawn considerable attention in the recent past. This paper introduces a scalable decentralized control algorithm to navigate a group of mobile robots (swarm into a predefined shape in 2D space. The proposed architecture uses artificial forces to control mobile agents into the shape and spread them inside the shape while avoiding inter- member collisions. The theoretical analysis of the swarm behavior describes the motion of the complete swarm and individual members in relevant situations. We use computer simulated case studies to verify the theoretical assertions and to demonstrate the robustness of the swarm under external disturbances such as death of agents, change of shape etc. Also the performance of the proposed distributed swarm control architecture was investigated in the presence of realistic implementation issues such as localization errors, communication range limitations, boundedness of forces etc.

  2. Formations of Robotic Swarm: An Artificial Force Based Approach

    Directory of Open Access Journals (Sweden)

    Samitha W. Ekanayake

    2010-09-01

    Full Text Available Cooperative control of multiple mobile robots is an attractive and challenging problem which has drawn considerable attention in the recent past. This paper introduces a scalable decentralized control algorithm to navigate a group of mobile robots (swarm into a predefined shape in 2D space. The proposed architecture uses artificial forces to control mobile agents into the shape and spread them inside the shape while avoiding inter- member collisions. The theoretical analysis of the swarm behavior describes the motion of the complete swarm and individual members in relevant situations. We use computer simulated case studies to verify the theoretical assertions and to demonstrate the robustness of the swarm under external disturbances such as death of agents, change of shape etc. Also the performance of the proposed distributed swarm control architecture was investigated in the presence of realistic implementation issues such as localization errors, communication range limitations, boundedness of forces etc.

  3. Formations of Robotic Swarm: An Artificial Force Based Approach

    Directory of Open Access Journals (Sweden)

    Samitha W. Ekanayake

    2010-09-01

    Full Text Available Cooperative control of multiple mobile robots is an attractive and challenging problem which has drawn considerable attention in the recent past. This paper introduces a scalable decentralized control algorithm to navigate a group of mobile robots (swarm into a predefined shape in 2D space. The proposed architecture uses artificial forces to control mobile agents into the shape and spread them inside the shape while avoiding inter-member collisions. The theoretical analysis of the swarm behavior describes the motion of the complete swarm and individual members in relevant situations. We use computer simulated case studies to verify the theoretical assertions and to demonstrate the robustness of the swarm under external disturbances such as death of agents, change of shape etc. Also the performance of the proposed distributed swarm control architecture was investigated in the presence of realistic implementation issues such as localization errors, communication range limitations, boundedness of forces etc.

  4. Formations of Robotic Swarm: An Artificial Force Based Approach

    Directory of Open Access Journals (Sweden)

    Samitha W. Ekanayake

    2009-03-01

    Full Text Available Cooperative control of multiple mobile robots is an attractive and challenging problem which has drawn considerable attention in the recent past. This paper introduces a scalable decentralized control algorithm to navigate a group of mobile robots (swarm into a predefined shape in 2D space. The proposed architecture uses artificial forces to control mobile agents into the shape and spread them inside the shape while avoiding inter-member collisions. The theoretical analysis of the swarm behavior describes the motion of the complete swarm and individual members in relevant situations. We use computer simulated case studies to verify the theoretical assertions and to demonstrate the robustness of the swarm under external disturbances such as death of agents, change of shape etc. Also the performance of the proposed distributed swarm control architecture was investigated in the presence of realistic implementation issues such as localization errors, communication range limitations, boundedness of forces etc.

  5. Thermospheric neutral densities derived from Swarm accelerometer and GPS data

    DEFF Research Database (Denmark)

    Doornbos, Eelco; Encarnacao, Joao; van den IJss, Jose

    Over the past years, a lot of effort has been put into characterising and correcting the various disturbance signals that were found in the accelerometer data provided by the Swarm satellites. This effort was first and foremost aimed at the Swarm C along-track axis data, which seems to be the least...... affected and most promising data for scientific use. The goal to make the Swarm C accelerometer along-track axis data ready for further processing into level 2 thermosphere density data has now been accomplished, with the help of information on the satellite motion from the GPS tracking as well...... approach, affects the possibility of determining densities from the accelerometer measurements of the Swarm A and B satellites. We also investigate the possibility of determining crosswind speeds from Swarm data.In the meantime, we have investigated the possibility of deriving thermosphere neutral density...

  6. The Manchester earthquake swarm of October 2002

    Science.gov (United States)

    Baptie, B.; Ottemoeller, L.

    2003-04-01

    An earthquake sequence started in the Greater Manchester area of the United Kingdom on October 19, 2002. This has continued to the time of writing and has consisted of more than 100 discrete earthquakes. Three temporary seismograph stations were installed to supplement existing permanent stations and to better understand the relationship between the seismicity and local geology. Due to the urban location, these were experienced by a large number of people. The largest event on October 21 had a magnitude ML 3.9. The activity appears to be an earthquake swarm, since there is no clear distinction between a main shock and aftershocks. However, most of the energy during the sequence was actually released in two earthquakes separated by a few seconds in time, on October 21 at 11:42. Other examples of swarm activity in the UK include Comrie (1788-1801, 1839-46), Glenalmond (1970-72), Doune (1997) and Blackford (1997-98, 2000-01) in central Scotland, Constantine (1981, 1986, 1992-4) in Cornwall, and Johnstonbridge (mid1980s) and Dumfries (1991,1999). The clustering of these events in time and space does suggest that there is a causal relationship between the events of the sequence. Joint hypocenter determination was used to simultaneously locate the swarm earthquakes, determine station corrections and improve the relative locations. It seems likely that all events in the sequence originate from a relatively small source volume. This is supported by the similarities in source mechanism and waveform signals between the various events. Focal depths were found to be very shallow and of the order of about 2-3 km. Source mechanisms determined for the largest of the events show strike-slip solutions along either northeast-southwest or northwest-southeast striking fault planes. The surface expression of faults in the epicentral area is generally northwest-southeast, suggesting that this is the more likely fault plane.

  7. PSO algorithm enhanced with Lozi Chaotic Map - Tuning experiment

    International Nuclear Information System (INIS)

    Pluhacek, Michal; Senkerik, Roman; Zelinka, Ivan

    2015-01-01

    In this paper it is investigated the effect of tuning of control parameters of the Lozi Chaotic Map employed as a chaotic pseudo-random number generator for the particle swarm optimization algorithm. Three different benchmark functions are selected from the IEEE CEC 2013 competition benchmark set. The Lozi map is extensively tuned and the performance of PSO is evaluated

  8. PSO algorithm enhanced with Lozi Chaotic Map - Tuning experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pluhacek, Michal; Senkerik, Roman; Zelinka, Ivan [Tomas Bata University in Zlín, Faculty of Applied Informatics Department of Informatics and Artificial Intelligence nám. T.G. Masaryka 5555, 760 01 Zlín (Czech Republic)

    2015-03-10

    In this paper it is investigated the effect of tuning of control parameters of the Lozi Chaotic Map employed as a chaotic pseudo-random number generator for the particle swarm optimization algorithm. Three different benchmark functions are selected from the IEEE CEC 2013 competition benchmark set. The Lozi map is extensively tuned and the performance of PSO is evaluated.

  9. Do small swarms have an advantage when house hunting? The effect of swarm size on nest-site selection by Apis mellifera.

    Science.gov (United States)

    Schaerf, T M; Makinson, J C; Myerscough, M R; Beekman, M

    2013-10-06

    Reproductive swarms of honeybees are faced with the problem of finding a good site to establish a new colony. We examined the potential effects of swarm size on the quality of nest-site choice through a combination of modelling and field experiments. We used an individual-based model to examine the effects of swarm size on decision accuracy under the assumption that the number of bees actively involved in the decision-making process (scouts) is an increasing function of swarm size. We found that the ability of a swarm to choose the best of two nest sites decreases as swarm size increases when there is some time-lag between discovering the sites, consistent with Janson & Beekman (Janson & Beekman 2007 Proceedings of European Conference on Complex Systems, pp. 204-211.). However, when simulated swarms were faced with a realistic problem of choosing between many nest sites discoverable at all times, larger swarms were more accurate in their decisions than smaller swarms owing to their ability to discover nest sites more rapidly. Our experimental fieldwork showed that large swarms invest a larger number of scouts into the decision-making process than smaller swarms. Preliminary analysis of waggle dances from experimental swarms also suggested that large swarms could indeed discover and advertise nest sites at a faster rate than small swarms.

  10. Swarm Intelligence for Urban Dynamics Modelling

    Science.gov (United States)

    Ghnemat, Rawan; Bertelle, Cyrille; Duchamp, Gérard H. E.

    2009-04-01

    In this paper, we propose swarm intelligence algorithms to deal with dynamical and spatial organization emergence. The goal is to model and simulate the developement of spatial centers using multi-criteria. We combine a decentralized approach based on emergent clustering mixed with spatial constraints or attractions. We propose an extension of the ant nest building algorithm with multi-center and adaptive process. Typically, this model is suitable to analyse and simulate urban dynamics like gentrification or the dynamics of the cultural equipment in urban area.

  11. Hydrodynamics in a swarm of rising bubbles

    International Nuclear Information System (INIS)

    Riboux, G.

    2007-04-01

    In many applications, bubbles are used to agitate a liquid in order to enhance mixing and transfer. This work is devoted to the study of the hydrodynamics in a stable bubble column. Experimentally, we have determined the properties of the velocity fluctuations inside and behind a homogeneous swarm of rising bubbles for different bubble sizes and gas volume fractions α: self-similarity in α 0,4 , spectrum in k -3 and integral length scale controlled by buoyancy. Numerically, we have reproduced these properties by means of large-scale simulations, the bubbles being modeled by volume-forces. This confirms that the dynamics is controlled by wake interactions. (author)

  12. Swarm Intelligence for Urban Dynamics Modelling

    International Nuclear Information System (INIS)

    Ghnemat, Rawan; Bertelle, Cyrille; Duchamp, Gerard H. E.

    2009-01-01

    In this paper, we propose swarm intelligence algorithms to deal with dynamical and spatial organization emergence. The goal is to model and simulate the developement of spatial centers using multi-criteria. We combine a decentralized approach based on emergent clustering mixed with spatial constraints or attractions. We propose an extension of the ant nest building algorithm with multi-center and adaptive process. Typically, this model is suitable to analyse and simulate urban dynamics like gentrification or the dynamics of the cultural equipment in urban area.

  13. Swarming Robot Design, Construction and Software Implementation

    Science.gov (United States)

    Stolleis, Karl A.

    2014-01-01

    In this paper is presented an overview of the hardware design, construction overview, software design and software implementation for a small, low-cost robot to be used for swarming robot development. In addition to the work done on the robot, a full simulation of the robotic system was developed using Robot Operating System (ROS) and its associated simulation. The eventual use of the robots will be exploration of evolving behaviors via genetic algorithms and builds on the work done at the University of New Mexico Biological Computation Lab.

  14. Anesthesiology Nurse Scheduling using Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Leopoldo Altamirano

    2012-02-01

    Full Text Available In this article we present an approach designed to solve a real world problem: the Anesthesiology Nurse Scheduling Problem (ANSP at a public French hospital. The anesthesiology nurses are one of the most shared resources in the hospital and we attempt to find a fair/balanced schedule for them, taking into account a set of constraints and the nursesarsquo; stated preferences, concerning the different shifts. We propose a particle swarm optimization algorithm to solve the ANSP. Finally, we compare our technique with previous results obtained using integer programming.

  15. Constellation C3I Crew-Ground-Experimenter-Developer Collaboration Services, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Command, Control, Communications and Information (C3I) environment will be significantly different for Constellation than for Shuttle and International Space...

  16. Efficient Bit-to-Symbol Likelihood Mappings

    Science.gov (United States)

    Moision, Bruce E.; Nakashima, Michael A.

    2010-01-01

    This innovation is an efficient algorithm designed to perform bit-to-symbol and symbol-to-bit likelihood mappings that represent a significant portion of the complexity of an error-correction code decoder for high-order constellations. Recent implementation of the algorithm in hardware has yielded an 8- percent reduction in overall area relative to the prior design.

  17. The BRITE Constellation Nanosatellite Mission: Testing, Commissioning, and Operations

    Science.gov (United States)

    Pablo, H.; Whittaker, G. N.; Popowicz, A.; Mochnacki, S. M.; Kuschnig, R.; Grant, C. C.; Moffat, A. F. J.; Rucinski, S. M.; Matthews, J. M.; Schwarzenberg-Czerny, A.; Handler, G.; Weiss, W. W.; Baade, D.; Wade, G. A.; Zocłońska, E.; Ramiaramanantsoa, T.; Unterberger, M.; Zwintz, K.; Pigulski, A.; Rowe, J.; Koudelka, O.; Orleański, P.; Pamyatnykh, A.; Neiner, C.; Wawrzaszek, R.; Marciniszyn, G.; Romano, P.; Woźniak, G.; Zawistowski, T.; Zee, R. E.

    2016-12-01

    BRIght Target Explorer (BRITE) Constellation, the first nanosatellite mission applied to astrophysical research, is a collaboration among Austria, Canada and Poland. The fleet of satellites (6 launched; 5 functioning) performs precise optical photometry of the brightest stars in the night sky. A pioneering mission like BRITE—with optics and instruments restricted to small volume, mass and power in several nanosatellites, whose measurements must be coordinated in orbit—poses many unique challenges. We discuss the technical issues, including problems encountered during on-orbit commissioning (especially higher-than-expected sensitivity of the CCDs to particle radiation). We describe in detail how the BRITE team has mitigated these problems, and provide a complete overview of mission operations. This paper serves as a template for how to effectively plan, build and operate future low-cost niche-driven space astronomy missions. Based on data collected by the BRITE Constellation satellite mission, designed, built, launched, operated and supported by the Austrian Research Promotion Agency (FFG), the University of Vienna, the Technical University of Graz, the Canadian Space Agency (CSA), the University of Toronto Institute for Aerospace Studies (UTIAS), the Foundation for Polish Science & Technology (FNiTP MNiSW), and National Science Centre (NCN).

  18. Dynamic replanning on demand of UAS constellations performing ISR missions

    Science.gov (United States)

    Stouch, Daniel W.; Zeidman, Ernest; Callahan, William; McGraw, Kirk

    2011-05-01

    Unmanned aerial systems (UAS) have proven themselves to be indispensable in providing intelligence, surveillance, and reconnaissance (ISR) over the battlefield. Constellations of heterogeneous, multi-purpose UAS are being tasked to provide ISR in an unpredictable environment. This necessitates the dynamic replanning of critical missions as weather conditions change, new observation targets are identified, aircraft are lost or equipment malfunctions, and new airspace restrictions are introduced. We present a method to generate coordinated mission plans for constellations of UAS with multiple flight goals and potentially competing objectives, and update them on demand as the operational situation changes. We use a fast evolutionary algorithm-based, multi-objective optimization technique. The updated flight routes maintain continuity by considering where the ISR assets have already flown and where they still need to go. Both the initial planning and replanning take into account factors such as area of analysis coverage, restricted operating zones, maximum control station range, adverse weather effects, military terrain value, and sensor performance. Our results demonstrate that by constraining the space of potential solutions using an intelligently-formed air maneuver network with a subset of potential airspace corridors and navigational waypoints, we can ensure global optimization for multiple objectives considering the situation both before and after the replanning is initiated. We employ sophisticated visualization techniques using a geographic information system to help the user 'look under the hood" of the algorithms to understand the effectiveness and viability of the generated ISR mission plans and identify potential gaps in coverage.

  19. Rare ADH variant constellations are specific for alcohol dependence.

    Science.gov (United States)

    Zuo, Lingjun; Zhang, Heping; Malison, Robert T; Li, Chiang-Shan R; Zhang, Xiang-Yang; Wang, Fei; Lu, Lingeng; Lu, Lin; Wang, Xiaoping; Krystal, John H; Zhang, Fengyu; Deng, Hong-Wen; Luo, Xingguang

    2013-01-01

    Some of the well-known functional alcohol dehydrogenase (ADH) gene variants (e.g. ADH1B*2, ADH1B*3 and ADH1C*2) that significantly affect the risk of alcohol dependence are rare variants in most populations. In the present study, we comprehensively examined the associations between rare ADH variants [minor allele frequency (MAF) constellation across the entire ADH gene cluster was significantly associated with alcohol dependence in European-Americans (Fp1: simulated global P = 0.045), European-Australians (Fp5: global P = 0.027; collapsing: P = 0.038) and African-Americans (Fp5: global P = 0.050; collapsing: P = 0.038), but not with any other neuropsychiatric disease. Association signals in this region came principally from ADH6, ADH7, ADH1B and ADH1C. In particular, a rare ADH6 variant constellation showed a replicable association with alcohol dependence across these three independent cohorts. No individual rare variants were statistically significantly associated with any disease examined after group- and region-wide correction for multiple comparisons. We conclude that rare ADH variants are specific for alcohol dependence. The ADH gene cluster may harbor a causal variant(s) for alcohol dependence.

  20. Research on constellation refueling based on formation flying

    Science.gov (United States)

    Bo, Xu; Feng, Quansheng

    2011-06-01

    A new scheme for refueling satellite constellation is proposed in this paper. Compared with the traditional research, where the satellite refueling is implemented through spacecraft rendezvous and docking, the new pattern studied here is based on formation flying, and it is more feasible, safer and more reliable. On the grounds of the proposed pattern, two refueling strategies are studied. The first is called single supplier refueling (SSR) based on formation flying. In this scenario, one fuel-sufficient satellite called a supplier, departs from its parking orbit, and after a series of orbit maneuvers, arrives at the target constellation that consists of multiple fuel-deficient satellites called workers. It then transfers equal fuel to each worker within the prescribed mission time. The second strategy is called double suppliers refueling (DSR) based on formation flying. This time two suppliers take charge of refueling half of the workers respectively in the same way as SSR. Using a genetic algorithm, the orbit of a supplier with a minimum consumption of fuel can be obtained once the mission time is fixed. Simulation results indicate that DSR is superior to SSR and that this dominance will be more distinct as the number of workers increases and the mission time decreases.

  1. Going Beyond Einstein with the Constellation-X Mission

    Science.gov (United States)

    White, Nicholas

    2007-01-01

    The Constellation-X mission will address the questions: "What happens to matter close to a black hole?" and "What is Dark Energy?" These questions are central to the NASA Beyond Einstein Program, where Constellation-X plays a central role. The mission will address these questions by using high throughput X-ray spectroscopy to observe the effects of strong gravity close to the event horizon of black holes, and to observe the formation and evolution of clusters of galaxies in order to precisely determine Cosmological parameters. To achieve these primary science goals requires a factor of 25-100 increase in sensitivity for high resolution X-ray spectroscopy.'The mission will also perform routine high-resolution X-ray spectroscopy of faint 2nd extended X-ray source populations. This will provide diagnostic information such as density, elemental abundances, velocity; and ionization state for a wide range of astrophysical problems, including new constraints on the Neutron Star equation of state.

  2. Generalized BICM-T transceivers: Constellation and multiplexer design

    KAUST Repository

    Malik, Muhammad Talha

    2013-09-01

    Recently, it has been shown that the performance of bit-interleaved coded modulation (BICM) using convolutional codes in nonfading channels can be significantly improved if the coded bits are not interleaved at all. This particular BICM design is referred to as BICM trivial (BICM-T) and is shown to be asymptotically as good as Ungerboeck\\'s one dimensional (1D) trellis coded modulation (TCM). This BICM-T design and analysis considered a simple case of rate 1/2 channel encoder with equally spaced 16-ary quadrature amplitude modulation (QAM) constellation where the code rate matches with the modulation order as required in TCM transmission. In this paper, we consider and analyze a new BICM-T design that uses a non equally spaced signal constellation in conjunction with a bit level multiplexer. With this design and analysis, one can not only exploit the full benefit of BICM-T design by jointly optimizing different transceiver\\'s modules but also enjoys the same design flexibility as the traditional BICM to independently choose the code rate and the modulation order. The presented numerical results for 64-ary QAM with rate 1/3 code shows that the considered design can offer gains up to 2.5 dB over the traditional optimal BICM design for a target bit error rate (BER) of 10-6. © 2013 IEEE.

  3. Antarctic krill swarm characteristics in the Southeast Atlantic sector of the Southern Ocean

    KAUST Repository

    Krafft, BA

    2012-09-28

    Knowledge about swarm dynamics and underlying causes is essential to understand the ecology and distribution of Antarctic krill Euphausia superba. We collected acoustic data and key environmental data continuously across extensive gradients in the little-studied Southeast Atlantic sector of the Southern Ocean. A total of 4791 krill swarms with swarm descriptors including swarm height and length, packing density, swimming depth and inter-swarm distance were extracted. Through multivariate statistics, swarms were categorized into 4 groups. Group 2 swarms were largest (median length 108 m and thickness 18 m), whereas swarms in both Groups 1 and 4 were on average small, but differed markedly in depth distribution (median: 52 m for Group 1 vs. 133 m for Group 4). There was a strong spatial autocorrelation in the occurrence of swarms, and an autologistic regression model found no prediction of swarm occurrence from environmental variables for any of the Groups 1, 2 or 4. Probability of occurrence of Group 3 swarms, however, increased with increasing depth and temperature. Group 3 was the most distinctive swarm group with an order of magnitude higher packing density (median: 226 ind. m−3) than swarms from any of the other groups and about twice the distance to nearest neighbor swarm (median: 493 m). The majority of the krill were present in Group 3 swarms, and the absence of association with hydrographic or topographic concentrating mechanisms strongly suggests that these swarms aggregate through their own locomotion, possibly associated with migration.

  4. Distributed allocation of mobile sensing swarms in gyre flows

    Directory of Open Access Journals (Sweden)

    K. Mallory

    2013-09-01

    Full Text Available We address the synthesis of distributed control policies to enable a swarm of homogeneous mobile sensors to maintain a desired spatial distribution in a geophysical flow environment, or workspace. In this article, we assume the mobile sensors (or robots have a "map" of the environment denoting the locations of the Lagrangian coherent structures or LCS boundaries. Using this information, we design agent-level hybrid control policies that leverage the surrounding fluid dynamics and inherent environmental noise to enable the team to maintain a desired distribution in the workspace. We discuss the stability properties of the ensemble dynamics of the distributed control policies. Since realistic quasi-geostrophic ocean models predict double-gyre flow solutions, we use a wind-driven multi-gyre flow model to verify the feasibility of the proposed distributed control strategy and compare the proposed control strategy with a baseline deterministic allocation strategy. Lastly, we validate the control strategy using actual flow data obtained by our coherent structure experimental testbed.

  5. Distributed allocation of mobile sensing swarms in gyre flows

    Science.gov (United States)

    Mallory, K.; Hsieh, M. A.; Forgoston, E.; Schwartz, I. B.

    2013-09-01

    We address the synthesis of distributed control policies to enable a swarm of homogeneous mobile sensors to maintain a desired spatial distribution in a geophysical flow environment, or workspace. In this article, we assume the mobile sensors (or robots) have a "map" of the environment denoting the locations of the Lagrangian coherent structures or LCS boundaries. Using this information, we design agent-level hybrid control policies that leverage the surrounding fluid dynamics and inherent environmental noise to enable the team to maintain a desired distribution in the workspace. We discuss the stability properties of the ensemble dynamics of the distributed control policies. Since realistic quasi-geostrophic ocean models predict double-gyre flow solutions, we use a wind-driven multi-gyre flow model to verify the feasibility of the proposed distributed control strategy and compare the proposed control strategy with a baseline deterministic allocation strategy. Lastly, we validate the control strategy using actual flow data obtained by our coherent structure experimental testbed.

  6. Slow-Slip Scaling Laws Inferred from Cascadia Tremor Swarms

    Science.gov (United States)

    Creager, K. C.; Wech, A.; Vidale, J. E.

    2010-12-01

    Episodic tremor and slip (ETS) events, each with geodetically determined moment magnitudes in the mid-6 range, repeat about every 15 months under the Olympic Peninsula/southern Vancouver Island region. We have applied an automatic waveform envelope cross-correlation and clustering (WECC) algorithm to seven Cascadia-wide subarrays to search for non-volcanic tremor in 5-minute, 50% overlapping, time windows, revealing 70,000 tremor epicenters. The tremor epicenters cluster in time and space into nearly 200 tremor swarms. The number of hours of tremor per swarm ranges from about 1 to 470 hours. The smaller (inter-ETS) tremor swarms generally locate along the downdip side of the larger ETS swarms and occur much more frequently. In northern Washington, which is currently best monitored, the ETS events, as well as the larger inter-ETS tremor swarms initiate downdip and propagate updip. For the large ETS events, tremor swarm duration is proportional to geodetically determined seismic moment. We consider tremor swarms to be a proxy for slow slip for the smaller events as well, even though slip would be below current geodetic detection thresholds. An interpretation of the observed transition from longer duration, less frequent tremor swarms up dip to smaller more frequent tremor swarms down-dip, in terms of fault strength is the subject of a presentation by Wech. The combined inter-ETS and ETS swarms follow a power law relationship such that the number of swarms, N, exceeding duration τ is given by τ -0.66. If we assume that seismic moment is proportional to τ, as proposed by Ide et al. [Nature, 2007], we find that the tremor swarms follow a standard Gutenberg-Richter logarithmic frequency-magnitude relation, log10 N ≈ -bMw, with b = 1.0, which lies in the range for normal earthquake catalogs. Finally, crude estimates of the spatial dimensions of tremor swarms L suggest that L ≈ τ 1/n where n is between 2 and 3. A value of 2 is consistent with slip propagation rates

  7. A unique constellation of spacecraft constellations to study Kelvin-Helmholtz Instability in 2017-2020: MMS, Cluster and Themis

    Science.gov (United States)

    Masson, A.; Nykyri, K.

    2017-12-01

    The Cluster and the Themis missions have shed a total new light on the Kelvin-Helmholtz Instability (KHI) mechanism at the magnetopause. To name a few, these missions have enabled the observation of KHI rolled-up vortices, for the first time with four spacecraft (Hasegawa et al., 2004). They revealed its presence under any Interplanetary Magnetic Field (IMF) conditions (Hwang et al., 2011, 2012). They also revealed that their occurence may have been largely underestimated (Kavosi and Raeder, 2015). Very recently, the presence of ion magnetosonic waves with sufficient energy to account for the observed level of ion heating within a KHI vortex may be the first evidence of cross-scale energy transport (Moore et al., 2016). After presenting some the main highlights of Cluster and Themis on this phenomenon, we will present upcoming new observations with MMS, Cluster and Themis in 2017-2020 timeframe. Together, they will form a unique constellation of spacecraft constellations to study this phenomenon for the first time. We will present some of the key scientific questions these new data will enable to tackle.

  8. Middleware Design for Swarm-Driving Robots Accompanying Humans.

    Science.gov (United States)

    Kim, Min Su; Kim, Sang Hyuck; Kang, Soon Ju

    2017-02-17

    Research on robots that accompany humans is being continuously studied. The Pet-Bot provides walking-assistance and object-carrying services without any specific controls through interaction between the robot and the human in real time. However, with Pet-Bot, there is a limit to the number of robots a user can use. If this limit is overcome, the Pet-Bot can provide services in more areas. Therefore, in this study, we propose a swarm-driving middleware design adopting the concept of a swarm, which provides effective parallel movement to allow multiple human-accompanying robots to accomplish a common purpose. The functions of middleware divide into three parts: a sequence manager for swarm process, a messaging manager, and a relative-location identification manager. This middleware processes the sequence of swarm-process of robots in the swarm through message exchanging using radio frequency (RF) communication of an IEEE 802.15.4 MAC protocol and manages an infrared (IR) communication module identifying relative location with IR signal strength. The swarm in this study is composed of the master interacting with the user and the slaves having no interaction with the user. This composition is intended to control the overall swarm in synchronization with the user activity, which is difficult to predict. We evaluate the accuracy of the relative-location estimation using IR communication, the response time of the slaves to a change in user activity, and the time to organize a network according to the number of slaves.

  9. Operating Small Sat Swarms as a Single Entity: Introducing SODA

    Science.gov (United States)

    Conn, Tracie; Plice, Laura E.; Dono Perez, Andres; Ho, Michael

    2017-01-01

    NASA's decadal survey determined that simultaneous measurements from a 3D volume of space are advantageous for a variety of studies in space physics and Earth science. Therefore, swarm concepts with multiple spacecraft in close proximity are a growing topic of interest in the small satellite community. Among the capabilities needed for swarm missions is a means to maintain operator-specified geometry, alignment, or separation. Swarm stationkeeping poses a planning challenge due to the limited scalability of ground resources. To address scalable control of orbital dynamics, we introduce SODA - Swarm Orbital Dynamics Advisor - a tool that accepts high-level configuration commands and provides the orbital maneuvers needed to achieve the desired type of swarm relative motion. Rather than conventional path planning, SODA's innovation is the use of artificial potential functions to define boundaries and keepout regions. The software architecture includes high fidelity propagation, accommodates manual or automated inputs, displays motion animations, and returns maneuver commands and analytical results. Currently, two swarm types are enabled: in-train distribution and an ellipsoid volume container. Additional swarm types, simulation applications, and orbital destinations are in planning stages.

  10. Chaotic Particle Swarm Optimization with Mutation for Classification

    Science.gov (United States)

    Assarzadeh, Zahra; Naghsh-Nilchi, Ahmad Reza

    2015-01-01

    In this paper, a chaotic particle swarm optimization with mutation-based classifier particle swarm optimization is proposed to classify patterns of different classes in the feature space. The introduced mutation operators and chaotic sequences allows us to overcome the problem of early convergence into a local minima associated with particle swarm optimization algorithms. That is, the mutation operator sharpens the convergence and it tunes the best possible solution. Furthermore, to remove the irrelevant data and reduce the dimensionality of medical datasets, a feature selection approach using binary version of the proposed particle swarm optimization is introduced. In order to demonstrate the effectiveness of our proposed classifier, mutation-based classifier particle swarm optimization, it is checked out with three sets of data classifications namely, Wisconsin diagnostic breast cancer, Wisconsin breast cancer and heart-statlog, with different feature vector dimensions. The proposed algorithm is compared with different classifier algorithms including k-nearest neighbor, as a conventional classifier, particle swarm-classifier, genetic algorithm, and Imperialist competitive algorithm-classifier, as more sophisticated ones. The performance of each classifier was evaluated by calculating the accuracy, sensitivity, specificity and Matthews's correlation coefficient. The experimental results show that the mutation-based classifier particle swarm optimization unequivocally performs better than all the compared algorithms. PMID:25709937

  11. Colias: An Autonomous Micro Robot for Swarm Robotic Applications

    Directory of Open Access Journals (Sweden)

    Farshad Arvin

    2014-07-01

    Full Text Available Robotic swarms that take inspiration from nature are becoming a fascinating topic for multi-robot researchers. The aim is to control a large number of simple robots in order to solve common complex tasks. Due to the hardware complexities and cost of robot platforms, current research in swarm robotics is mostly performed by simulation software. The simulation of large numbers of these robots in robotic swarm applications is extremely complex and often inaccurate due to the poor modelling of external conditions. In this paper, we present the design of a low-cost, open-platform, autonomous micro-robot (Colias for robotic swarm applications. Colias employs a circular platform with a diameter of 4 cm. It has a maximum speed of 35 cm/s which enables it to be used in swarm scenarios very quickly over large arenas. Long-range infrared modules with an adjustable output power allow the robot to communicate with its direct neighbours at a range of 0.5 cm to 2 m. Colias has been designed as a complete platform with supporting software development tools for robotics education and research. It has been tested in both individual and swarm scenarios, and the observed results demonstrate its feasibility for use as a micro-sized mobile robot and as a low-cost platform for robot swarm applications.

  12. Chaotic particle swarm optimization with mutation for classification.

    Science.gov (United States)

    Assarzadeh, Zahra; Naghsh-Nilchi, Ahmad Reza

    2015-01-01

    In this paper, a chaotic particle swarm optimization with mutation-based classifier particle swarm optimization is proposed to classify patterns of different classes in the feature space. The introduced mutation operators and chaotic sequences allows us to overcome the problem of early convergence into a local minima associated with particle swarm optimization algorithms. That is, the mutation operator sharpens the convergence and it tunes the best possible solution. Furthermore, to remove the irrelevant data and reduce the dimensionality of medical datasets, a feature selection approach using binary version of the proposed particle swarm optimization is introduced. In order to demonstrate the effectiveness of our proposed classifier, mutation-based classifier particle swarm optimization, it is checked out with three sets of data classifications namely, Wisconsin diagnostic breast cancer, Wisconsin breast cancer and heart-statlog, with different feature vector dimensions. The proposed algorithm is compared with different classifier algorithms including k-nearest neighbor, as a conventional classifier, particle swarm-classifier, genetic algorithm, and Imperialist competitive algorithm-classifier, as more sophisticated ones. The performance of each classifier was evaluated by calculating the accuracy, sensitivity, specificity and Matthews's correlation coefficient. The experimental results show that the mutation-based classifier particle swarm optimization unequivocally performs better than all the compared algorithms.

  13. A minimal model of predator-swarm interactions.

    Science.gov (United States)

    Chen, Yuxin; Kolokolnikov, Theodore

    2014-05-06

    We propose a minimal model of predator-swarm interactions which captures many of the essential dynamics observed in nature. Different outcomes are observed depending on the predator strength. For a 'weak' predator, the swarm is able to escape the predator completely. As the strength is increased, the predator is able to catch up with the swarm as a whole, but the individual prey is able to escape by 'confusing' the predator: the prey forms a ring with the predator at the centre. For higher predator strength, complex chasing dynamics are observed which can become chaotic. For even higher strength, the predator is able to successfully capture the prey. Our model is simple enough to be amenable to a full mathematical analysis, which is used to predict the shape of the swarm as well as the resulting predator-prey dynamics as a function of model parameters. We show that, as the predator strength is increased, there is a transition (owing to a Hopf bifurcation) from confusion state to chasing dynamics, and we compute the threshold analytically. Our analysis indicates that the swarming behaviour is not helpful in avoiding the predator, suggesting that there are other reasons why the species may swarm. The complex shape of the swarm in our model during the chasing dynamics is similar to the shape of a flock of sheep avoiding a shepherd.

  14. Particle Swarm Optimization With Interswarm Interactive Learning Strategy.

    Science.gov (United States)

    Qin, Quande; Cheng, Shi; Zhang, Qingyu; Li, Li; Shi, Yuhui

    2016-10-01

    The learning strategy in the canonical particle swarm optimization (PSO) algorithm is often blamed for being the primary reason for loss of diversity. Population diversity maintenance is crucial for preventing particles from being stuck into local optima. In this paper, we present an improved PSO algorithm with an interswarm interactive learning strategy (IILPSO) by overcoming the drawbacks of the canonical PSO algorithm's learning strategy. IILPSO is inspired by the phenomenon in human society that the interactive learning behavior takes place among different groups. Particles in IILPSO are divided into two swarms. The interswarm interactive learning (IIL) behavior is triggered when the best particle's fitness value of both the swarms does not improve for a certain number of iterations. According to the best particle's fitness value of each swarm, the softmax method and roulette method are used to determine the roles of the two swarms as the learning swarm and the learned swarm. In addition, the velocity mutation operator and global best vibration strategy are used to improve the algorithm's global search capability. The IIL strategy is applied to PSO with global star and local ring structures, which are termed as IILPSO-G and IILPSO-L algorithm, respectively. Numerical experiments are conducted to compare the proposed algorithms with eight popular PSO variants. From the experimental results, IILPSO demonstrates the good performance in terms of solution accuracy, convergence speed, and reliability. Finally, the variations of the population diversity in the entire search process provide an explanation why IILPSO performs effectively.

  15. GRAVITATIONAL LENS MODELING WITH GENETIC ALGORITHMS AND PARTICLE SWARM OPTIMIZERS

    International Nuclear Information System (INIS)

    Rogers, Adam; Fiege, Jason D.

    2011-01-01

    Strong gravitational lensing of an extended object is described by a mapping from source to image coordinates that is nonlinear and cannot generally be inverted analytically. Determining the structure of the source intensity distribution also requires a description of the blurring effect due to a point-spread function. This initial study uses an iterative gravitational lens modeling scheme based on the semilinear method to determine the linear parameters (source intensity profile) of a strongly lensed system. Our 'matrix-free' approach avoids construction of the lens and blurring operators while retaining the least-squares formulation of the problem. The parameters of an analytical lens model are found through nonlinear optimization by an advanced genetic algorithm (GA) and particle swarm optimizer (PSO). These global optimization routines are designed to explore the parameter space thoroughly, mapping model degeneracies in detail. We develop a novel method that determines the L-curve for each solution automatically, which represents the trade-off between the image χ 2 and regularization effects, and allows an estimate of the optimally regularized solution for each lens parameter set. In the final step of the optimization procedure, the lens model with the lowest χ 2 is used while the global optimizer solves for the source intensity distribution directly. This allows us to accurately determine the number of degrees of freedom in the problem to facilitate comparison between lens models and enforce positivity on the source profile. In practice, we find that the GA conducts a more thorough search of the parameter space than the PSO.

  16. Analog Circuit Fault Diagnosis Approach Based on Improved Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Ming-Fang WANG

    2014-07-01

    Full Text Available The basic thought of particle swarm optimization is introduced firstly, then particle swarm optimization algorithm model is established. The application of the improved particle swarm optimization algorithm to power supply system fault diagnosis is analyzed in accordance with problem of the algorithm, and migration strategy is added to particle swarm optimization algorithm. Finally the parameters of the wide area damping controller are adjusted by the improved particle swarm optimization algorithm.

  17. Fractional order Darwinian particle swarm optimization applications and evaluation of an evolutionary algorithm

    CERN Document Server

    Couceiro, Micael

    2015-01-01

    This book examines the bottom-up applicability of swarm intelligence to solving multiple problems, such as curve fitting, image segmentation, and swarm robotics. It compares the capabilities of some of the better-known bio-inspired optimization approaches, especially Particle Swarm Optimization (PSO), Darwinian Particle Swarm Optimization (DPSO) and the recently proposed Fractional Order Darwinian Particle Swarm Optimization (FODPSO), and comprehensively discusses their advantages and disadvantages. Further, it demonstrates the superiority and key advantages of using the FODPSO algorithm, suc

  18. POLICE OFFICE MODEL IMPROVEMENT FOR SECURITY OF SWARM ROBOTIC SYSTEMS

    Directory of Open Access Journals (Sweden)

    I. A. Zikratov

    2014-09-01

    Full Text Available This paper focuses on aspects of information security for group of mobile robotic systems with swarm intellect. The ways for hidden attacks realization by the opposing party on swarm algorithm are discussed. We have fulfilled numerical modeling of potentially destructive information influence on the ant shortest path algorithm. We have demonstrated the consequences of attacks on the ant algorithm with different concentration in a swarm of subversive robots. Approaches are suggested for information security mechanisms in swarm robotic systems, based on the principles of centralized security management for mobile agents. We have developed the method of forming a self-organizing information security management system for robotic agents in swarm groups implementing POM (Police Office Model – a security model based on police offices, to provide information security in multi-agent systems. The method is based on the usage of police station network in the graph nodes, which have functions of identification and authentication of agents, identifying subversive robots by both their formal characteristics and their behavior in the swarm. We have suggested a list of software and hardware components for police stations, consisting of: communication channels between the robots in police office, nodes register, a database of robotic agents, a database of encryption and decryption module. We have suggested the variants of logic for the mechanism of information security in swarm systems with different temporary diagrams of data communication between police stations. We present comparative analysis of implementation of protected swarm systems depending on the functioning logic of police offices, integrated in swarm system. It is shown that the security model saves the ability to operate in noisy environments, when the duration of the interference is comparable to the time necessary for the agent to overcome the path between police stations.

  19. Software Project Scheduling Management by Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Dinesh B. Hanchate

    2014-12-01

    Full Text Available PSO (Particle Swarm Optimization is, like GA, a heuristic global optimization method based on swarm intelligence. In this paper, we present a particle swarm optimization algorithm to solve software project scheduling problem. PSO itself inherits very efficient local search method to find the near optimal and best-known solutions for all instances given as inputs required for SPSM (Software Project Scheduling Management. At last, this paper imparts PSO and research situation with SPSM. The effect of PSO parameter on project cost and time is studied and some better results in terms of minimum SCE (Software Cost Estimation and time as compared to GA and ACO are obtained.

  20. Cold, muon-catalyzed fusion - just another swarm experiment?

    International Nuclear Information System (INIS)

    Robson, R.E.

    1992-01-01

    The paper briefly reviewed the muon-catalyzed fusion cycle and indicated how it may be likened to a swarm experiment. In particular, it has been pointed out that an external electric field can influence the properties of a muon swarm (and reactive derivatives), just as it can for ion and electron swarms. Since n 0 is typically around liquid hydrogen densities, very large fields, E≥10 9 V/m, would be required to achieve the desired outcome. This is presently achievable in small regions of intense laser focus, but it remains to be seen whether muon-catalyzed fusion experiments can actually be influenced in this way. 20 refs., 4 figs

  1. A Machine Learning and Optimization Toolkit for the Swarm

    Science.gov (United States)

    2014-11-17

    Ptolemy  II   TerraSwarm Research Center 6 11/17/14 Machine  Learning:   1...Toolkit  in   Ptolemy  II   TerraSwarm Research Center 7 11/17/14 State  Es0ma0on:   •  Par0cle  Filtering     The  Machine...Learning  Toolkit  in   Ptolemy  II   TerraSwarm Research Center 8 11/17/14 Op0miza0on:   •  CompositeOp0mizer:  An  actor-­‐

  2. Cell motility and antibiotic tolerance of bacterial swarms

    Science.gov (United States)

    Zuo, Wenlong

    Many bacteria species can move across moist surfaces in a coordinated manner known as swarming. It is reported that swarm cells show higher tolerance to a wide variety of antibiotics than planktonic cells. We used the model bacterium E. coli to study how motility affects the antibiotic tolerance of swarm cells. Our results provide new insights for the control of pathogenic invasion via regulating cell motility. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: zwlong@live.com.

  3. Particle Swarm Imaging (PSIM). A swarming algorithm for the reporting of robust, optimal measurement uncertainties

    International Nuclear Information System (INIS)

    Parvin, Dan; Clarke, Sean

    2015-01-01

    Particle Swarm Imaging (PSIM) overcomes some of the challenges associated with the accurate declaration of measurement uncertainties of radionuclide inventories within waste items when the distribution of activity is unknown. Implementation requires minimal equipment, making use of gamma‑ray measurements taken from different locations around the waste item, using only a single electrically cooled HRGS gamma‑ray detector for objects up to a UK ISO freight container in size. The PSIM technique is a computational method that iteratively ‘homes‑in’ on the true location of activity concentrations in waste items. PSIM differs from conventional assay techniques by allowing only viable solutions - that is those that could actually give rise to the measured data - to be considered. Thus PSIM avoids the drawback of conventional analyses, namely, the adoption of unrealistic assumptions about the activity distribution that inevitably leads to the declaration of pessimistic (and in some cases optimistic) activity estimates and uncertainties. PSIM applies an optimisation technique based upon ‘particle swarming’ methods to determine a set of candidate solutions within a ‘search space’ defined by the interior volume of a waste item. The positions and activities of the swarm are used in conjunction with a mathematical model to simulate the measurement response for the current swarm location. The swarm is iteratively updated (with modified positions and activities) until a match with sufficient quality is obtained between the simulated and actual measurement data. This process is repeated to build up a distribution of candidate solutions, which is subsequently analysed to calculate a measurement result and uncertainty along with a visual image of the activity distribution. The application of ‘swarming’ computational methods to non‑destructive assay (NDA) measurements is considered novel and this paper is intended to introduce the PSIM concept and provide

  4. A Study of Sasin-Animal Sky Map on Chonmunryucho

    Directory of Open Access Journals (Sweden)

    Hong-Jin Yang

    2003-03-01

    Full Text Available Chon-Mun-Ryu-Cho, written (edited by Lee Sun-Ji during the period of King Se-Jong, is a representative astronomy book of Cho-Sun (A.D. 1392 -1910 Dynasty. We find and study in the first page of the book; the description of 28 oriental constellations as a Sasin (four mythical oriental animals-animal sky map which is not widely known yet. The map consists of four groups of constellations, each of which represents the Sasin: Chang-Ryong (dragon, Baek-Ho (tigers with Ki-Rin [Oriental giraffe], Ju-Jak (Chinese phoenix, Hyun-Mu (a tortoise interwined with a snake. Each group (animals spans 2˜7 of 28 oriental constellations As we know from the illustration of the Chon-Sang-Yol-Cha-Bun-Ya-Ji-Do a representative sky map of Cho-Sun Dynasty, astronomy in Cho-Sun Dynasty is closely related to that in Go-Gu-Ryer (B.C. 37 -A.D. 668 Dynasty. Since these Sasin-animals appear in most mural paintings of Go-Gu-Ryer tombs, visualization of sky with these animal constellations could have been established as early as in Go-Gu-Ryer Dynasty. We also reconstruct this ''A Sasin-animal Korean sky map'' based on the shapes of the Sasin and Ki-Rin from Go-Gu-Ryer paintings and 28 oriental constellations in Chon-Sang-Yol-Cha-Bun-Ya-Ji-Do.

  5. A Swarm Optimization Genetic Algorithm Based on Quantum-Behaved Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Tao Sun

    2017-01-01

    Full Text Available Quantum-behaved particle swarm optimization (QPSO algorithm is a variant of the traditional particle swarm optimization (PSO. The QPSO that was originally developed for continuous search spaces outperforms the traditional PSO in search ability. This paper analyzes the main factors that impact the search ability of QPSO and converts the particle movement formula to the mutation condition by introducing the rejection region, thus proposing a new binary algorithm, named swarm optimization genetic algorithm (SOGA, because it is more like genetic algorithm (GA than PSO in form. SOGA has crossover and mutation operator as GA but does not need to set the crossover and mutation probability, so it has fewer parameters to control. The proposed algorithm was tested with several nonlinear high-dimension functions in the binary search space, and the results were compared with those from BPSO, BQPSO, and GA. The experimental results show that SOGA is distinctly superior to the other three algorithms in terms of solution accuracy and convergence.

  6. A new hybrid optimization method inspired from swarm intelligence: Fuzzy adaptive swallow swarm optimization algorithm (FASSO

    Directory of Open Access Journals (Sweden)

    Mehdi Neshat

    2015-11-01

    Full Text Available In this article, the objective was to present effective and optimal strategies aimed at improving the Swallow Swarm Optimization (SSO method. The SSO is one of the best optimization methods based on swarm intelligence which is inspired by the intelligent behaviors of swallows. It has been able to offer a relatively strong method for solving optimization problems. However, despite its many advantages, the SSO suffers from two shortcomings. Firstly, particles movement speed is not controlled satisfactorily during the search due to the lack of an inertia weight. Secondly, the variables of the acceleration coefficient are not able to strike a balance between the local and the global searches because they are not sufficiently flexible in complex environments. Therefore, the SSO algorithm does not provide adequate results when it searches in functions such as the Step or Quadric function. Hence, the fuzzy adaptive Swallow Swarm Optimization (FASSO method was introduced to deal with these problems. Meanwhile, results enjoy high accuracy which are obtained by using an adaptive inertia weight and through combining two fuzzy logic systems to accurately calculate the acceleration coefficients. High speed of convergence, avoidance from falling into local extremum, and high level of error tolerance are the advantages of proposed method. The FASSO was compared with eleven of the best PSO methods and SSO in 18 benchmark functions. Finally, significant results were obtained.

  7. Story Constellations: A Narrative Approach to Contextualizing Teachers' Knowledge of School Reform

    Science.gov (United States)

    Craig, Cheryl J.

    2007-01-01

    This article traces the roots of narrative research in the social sciences and education, then centers on "story constellations," a version of narrative inquiry that uncovers teachers' knowledge of school reform in context. A fluid form of investigation that unfolds in a three-dimensional inquiry space, story constellations consists of a flexible…

  8. Tabitha's One Teacher Rural School: Insights into the Arts through the Use of a Story Constellation

    Science.gov (United States)

    Garvis, Susanne

    2011-01-01

    This paper presents a story constellation about a beginning teacher (who is also the principal) located in a one-teacher school in an isolated community in Queensland, Australia. The constellation documents the teacher's self-efficacy for teaching the arts (music, dance, drama, visual arts and media). Tabitha, the participant, shares insights…

  9. Factorization properties of the optimal signaling distribution of multi-dimensional QAM constellations

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Forchhammer, Søren; Larsen, Knud J.

    2014-01-01

    In this work we study the properties of the optimal Proba- bility Mass Function (PMF) of a discrete input to a general Multiple Input Multiple Output (MIMO) channel. We prove that when the input constellation is constructed as a Cartesian product of 1-dimensional constellations, the optimal PMF...

  10. System Constellations as a Tool Supporting Organisational Learning and Change Processes

    Science.gov (United States)

    Birkenkrahe, Marcus

    2008-01-01

    Originally developed in the context of family therapy, system constellations are introduced using an organisational learning and system theoretical framework. Constellations are systemic group interventions using a spatial representation of the system elements. They correspond to deutero-learning processes and use higher-order systemic thinking.…

  11. Light Water Reactor Sustainability Constellation Pilot Project FY11 Summary Report

    International Nuclear Information System (INIS)

    Johansen, R.

    2011-01-01

    Summary report for Fiscal Year 2011 activities associated with the Constellation Pilot Project. The project is a joint effor between Constellation Nuclear Energy Group (CENG), EPRI, and the DOE Light Water Reactor Sustainability Program. The project utilizes two CENG reactor stations: R.E. Ginna and Nine Point Unit 1. Included in the report are activities associate with reactor internals and concrete containments.

  12. Copernican stem cells: regulatory constellations in adult hippocampal neurogenesis.

    Science.gov (United States)

    Fabel, Klaus; Toda, Hiroki; Fabel, Konstanze; Palmer, Theo

    2003-01-01

    In the adult, neurogenesis occurs where constellations of signaling molecules are correctly orchestrated and where competent cells are present to interpret these signals. As the instruments used to observe adult neurogenesis become more sophisticated, the concept of a discrete competent "stem cell" has become less concrete. Neural progenitor cells once thought committed to a single lineage can be influenced to become multipotent and somatic tissues appear to yield cells capable of tremendous peripheral and central lineage potential. The variety of cell types that appear competent to generate neurons suggests that the "Hilios" of adult neurogenesis may not necessarily be a single cellular entity but rather the sum of signals that dictate, "Make a new neuron here." These signals may not be limited to the recruitment of preexisting neural stem cells but may also, in some subtle way, reprogram local precursors to create "stem-like cells," where needed. Copyright 2002 Wiley-Liss, Inc.

  13. Hyperspectral Cubesat Constellation for Rapid Natural Hazard Response

    Science.gov (United States)

    Mandl, Daniel; Huemmrich, Karl; Crum, Gary; Ly, Vuong; Handy, Matthew; Ong, Lawrence

    2015-01-01

    Earth Observing 1 (E0-1) satellite has an imaging spectrometer (hyperspectral) instrument called Hyperion. The satellite is able to image any spot on Earth in the nadir looking direction every 16 days. With slewing of the satellite and allowing for up to a 23 degree view angle, any spot on the Earth can be imaged approximately every 2 to 3 days. EO-1 has been used to track many natural hazards such as wildfires, volcanoes and floods. An enhanced capability that is sought is the ability to image natural hazards in a daily time series for space based imaging spectrometers. The Hyperion can not provide this capability on EO-1 with the present polar orbit. However, a constellation of cubesats, each with the same imaging spectrometer, positioned strategically in the same orbit, can be used to provide daily coverage, cost-effectively.

  14. Cell assemblies at multiple time scales with arbitrary lag constellations.

    Science.gov (United States)

    Russo, Eleonora; Durstewitz, Daniel

    2017-01-11

    Hebb's idea of a cell assembly as the fundamental unit of neural information processing has dominated neuroscience like no other theoretical concept within the past 60 years. A range of different physiological phenomena, from precisely synchronized spiking to broadly simultaneous rate increases, has been subsumed under this term. Yet progress in this area is hampered by the lack of statistical tools that would enable to extract assemblies with arbitrary constellations of time lags, and at multiple temporal scales, partly due to the severe computational burden. Here we present such a unifying methodological and conceptual framework which detects assembly structure at many different time scales, levels of precision, and with arbitrary internal organization. Applying this methodology to multiple single unit recordings from various cortical areas, we find that there is no universal cortical coding scheme, but that assembly structure and precision significantly depends on the brain area recorded and ongoing task demands.

  15. Constellation Program Electrical Ground Support Equipment Research and Development

    Science.gov (United States)

    McCoy, Keegan S.

    2010-01-01

    At the Kennedy Space Center, I engaged in the research and development of electrical ground support equipment for NASA's Constellation Program. Timing characteristics playa crucial role in ground support communications. Latency and jitter are two problems that must be understood so that communications are timely and consistent within the Kennedy Ground Control System (KGCS). I conducted latency and jitter tests using Alien-Bradley programmable logic controllers (PLCs) so that these two intrinsic network properties can be reduced. Time stamping and clock synchronization also play significant roles in launch processing and operations. Using RSLogix 5000 project files and Wireshark network protocol analyzing software, I verified master/slave PLC Ethernet module clock synchronization, master/slave IEEE 1588 communications, and time stamping capabilities. All of the timing and synchronization test results are useful in assessing the current KGCS operational level and determining improvements for the future.

  16. World Digital Magnetic Anomaly Map, development towards the Second Edition. (Invited)

    Science.gov (United States)

    Korhonen, J. V.

    2009-12-01

    Magnetic anomalies are small deviations in the Earth’s main magnetic field, caused by variation of magnetization in the uppermost lithosphere. Magnetic anomalies provide spatial key information for understanding the structure and evolution of the Earths crust. In practice these anomalies are used e.g. for assessment and prospecting of geological natural resources and planning of land use. A common way to calculate a magnetic anomaly value has been to subtract International Geomagnetic Reference Field (IGRF) from a total field measurement that is cleaned from short term variation of the Earth's magnetic field. World Digital Magnetic Anomaly Map (WDMAM) is a collaborative project between member organizations of International Association of Geomagnetism and Aeronomy (IAGA) and the Commission for Geological Map of the World (CGMW). The First Edition of the map was published in 2007. It consisted of a paper map 1:50 Million and a 3 minutes global grid of total field anomalies at an altitude of 5 km above the geoid. The First Edition was aimed to compile as much as possible available land and sea magnetic data, and homogenize it by comparing anomalies with a satellite magnetic lithospheric field model. This first version was prepared in a tight schedule, to show the usefulness of the map to the community and to form a basis for later development and future editions of the map. Hence, much was left to be improved for the second edition, including sparse coverage in two continents and all southern seas. The satellite models were understood to gain more detail in near future when the CHAMP-satellite would reach lower orbits, and hence higher resolution. The SWARM-satellite constellation was seen to produce even more suitable data in a few years thereafter. Ocean magnetic data sets required careful processing and leveling. The method of homogenization of anomalies included replacing long wavelength information by satellite model spectral data, and hence rejecting

  17. Genesis and genetic constellations of swine influenza viruses in Thailand.

    Science.gov (United States)

    Poonsuk, Sukontip; Sangthong, Pradit; Petcharat, Nantawan; Lekcharoensuk, Porntippa

    2013-12-27

    Swine influenza virus (SIV) is one of the most important zoonotic agents and the origin of the most recent pandemic virus. Asia is considered to be the epicenter for genetic exchanging of influenza A viruses and Southeast Asia including Thailand serves as a reservoir to maintain the persistence of the viruses for seeding other regions. Therefore, searching for new reassortants in this area has been routinely required. Although SIVs in Thailand have been characterized, collective information regarding their genetic evolution and gene constellations is limited. In this study, whole genomes of 30 SIVs isolated during clinical target surveillance plus all available sequences of past and currently circulating Thai SIVs were genetically characterized based on their evolutionary relationships. All genetic pools of Thai SIVs are comprised of four lineages including classical swine (CS), Eurasian swine (EAs), Triple reassortants (TRIG) and Seasonal human (Shs). Out of 84 isolates, nine H1N1, six H3N2 and one H1N2 strains were identified. Gene constellations of SIVs in Thailand are highly complex resulting from multiple reassortments among concurrently circulating SIVs and temporally introduced foreign genes. Most strains contain gene segments from both EAs and CS lineages and appeared transiently. TRIG lineage has been recently introduced into Thai SIV gene pools. The existence of EAs and TRIG lineages in this region may increase rates of genetic exchange and diversity while Southeast Asia is a persistent reservoir for influenza A viruses. Continual monitoring of SIV evolution in this region is crucial in searching for the next potential pandemic viruses. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Swarm intelligence in animals and humans.

    Science.gov (United States)

    Krause, Jens; Ruxton, Graeme D; Krause, Stefan

    2010-01-01

    Electronic media have unlocked a hitherto largely untapped potential for swarm intelligence (SI; generally, the realisation that group living can facilitate solving cognitive problems that go beyond the capacity of single animals) in humans with relevance for areas such as company management, prediction of elections, product development and the entertainment industry. SI is a rapidly developing topic that has become a hotbed for both innovative research and wild speculation. Here, we tie together approaches from seemingly disparate areas by means of a general definition of SI to unite SI work on both animal and human groups. Furthermore, we identify criteria that are important for SI to operate and propose areas in which further progress with SI research can be made. Copyright 2009 Elsevier Ltd. All rights reserved.

  19. Cosmological parameter estimation using Particle Swarm Optimization

    International Nuclear Information System (INIS)

    Prasad, J; Souradeep, T

    2014-01-01

    Constraining parameters of a theoretical model from observational data is an important exercise in cosmology. There are many theoretically motivated models, which demand greater number of cosmological parameters than the standard model of cosmology uses, and make the problem of parameter estimation challenging. It is a common practice to employ Bayesian formalism for parameter estimation for which, in general, likelihood surface is probed. For the standard cosmological model with six parameters, likelihood surface is quite smooth and does not have local maxima, and sampling based methods like Markov Chain Monte Carlo (MCMC) method are quite successful. However, when there are a large number of parameters or the likelihood surface is not smooth, other methods may be more effective. In this paper, we have demonstrated application of another method inspired from artificial intelligence, called Particle Swarm Optimization (PSO) for estimating cosmological parameters from Cosmic Microwave Background (CMB) data taken from the WMAP satellite

  20. Semisupervised Particle Swarm Optimization for Classification

    Directory of Open Access Journals (Sweden)

    Xiangrong Zhang

    2014-01-01

    Full Text Available A semisupervised classification method based on particle swarm optimization (PSO is proposed. The semisupervised PSO simultaneously uses limited labeled samples and large amounts of unlabeled samples to find a collection of prototypes (or centroids that are considered to precisely represent the patterns of the whole data, and then, in principle of the “nearest neighborhood,” the unlabeled data can be classified with the obtained prototypes. In order to validate the performance of the proposed method, we compare the classification accuracy of PSO classifier, k-nearest neighbor algorithm, and support vector machine on six UCI datasets, four typical artificial datasets, and the USPS handwritten dataset. Experimental results demonstrate that the proposed method has good performance even with very limited labeled samples due to the usage of both discriminant information provided by labeled samples and the structure information provided by unlabeled samples.

  1. Cosmological parameter estimation using Particle Swarm Optimization

    Science.gov (United States)

    Prasad, J.; Souradeep, T.

    2014-03-01

    Constraining parameters of a theoretical model from observational data is an important exercise in cosmology. There are many theoretically motivated models, which demand greater number of cosmological parameters than the standard model of cosmology uses, and make the problem of parameter estimation challenging. It is a common practice to employ Bayesian formalism for parameter estimation for which, in general, likelihood surface is probed. For the standard cosmological model with six parameters, likelihood surface is quite smooth and does not have local maxima, and sampling based methods like Markov Chain Monte Carlo (MCMC) method are quite successful. However, when there are a large number of parameters or the likelihood surface is not smooth, other methods may be more effective. In this paper, we have demonstrated application of another method inspired from artificial intelligence, called Particle Swarm Optimization (PSO) for estimating cosmological parameters from Cosmic Microwave Background (CMB) data taken from the WMAP satellite.

  2. An Approach to Speed up Single-Frequency PPP Convergence with Quad-Constellation GNSS and GIM.

    Science.gov (United States)

    Cai, Changsheng; Gong, Yangzhao; Gao, Yang; Kuang, Cuilin

    2017-06-06

    The single-frequency precise point positioning (PPP) technique has attracted increasing attention due to its high accuracy and low cost. However, a very long convergence time, normally a few hours, is required in order to achieve a positioning accuracy level of a few centimeters. In this study, an approach is proposed to accelerate the single-frequency PPP convergence by combining quad-constellation global navigation satellite system (GNSS) and global ionospheric map (GIM) data. In this proposed approach, the GPS, GLONASS, BeiDou, and Galileo observations are directly used in an uncombined observation model and as a result the ionospheric and hardware delay (IHD) can be estimated together as a single unknown parameter. The IHD values acquired from the GIM product and the multi-GNSS differential code bias (DCB) product are then utilized as pseudo-observables of the IHD parameter in the observation model. A time varying weight scheme has also been proposed for the pseudo-observables to gradually decrease its contribution to the position solutions during the convergence period. To evaluate the proposed approach, datasets from twelve Multi-GNSS Experiment (MGEX) stations on seven consecutive days are processed and analyzed. The numerical results indicate that the single-frequency PPP with quad-constellation GNSS and GIM data are able to reduce the convergence time by 56%, 47%, 41% in the east, north, and up directions compared to the GPS-only single-frequency PPP.

  3. Investigating the auroral electrojets using Swarm

    Science.gov (United States)

    Smith, Ashley; Macmillan, Susan; Beggan, Ciaran; Whaler, Kathy

    2016-04-01

    The auroral electrojets are large horizontal currents that flow within the ionosphere in ovals around the polar regions. They are an important aspect of space weather and their position and intensity vary with solar wind conditions and geomagnetic activity. The electrojet positions are also governed by the Earth's main magnetic field. During more active periods, the auroral electrojets typically move equatorward and become more intense. This causes a range of effects on Earth and in space, including geomagnetically induced currents in power transmission networks, disturbance to radio communications and increased drag on satellites due to expansion of the atmosphere. They are also indicative of where the aurora are visible. Monitoring of the auroral electrojets in the pre-satellite era was limited to the network of ground-based magnetic observatories, from which the traditional AE activity indices are produced. These suffer in particular from the stations' poor distribution in position and so this motivates the use of satellite-based measurements. With polar low-Earth orbit satellites carrying magnetometers, all latitudes can be sampled with excellent resolution. This poster presents an investigation using Swarm's magnetometer data to detect the electrojets as the spacecraft move above them. We compare and contrast two approaches, one which uses vector data and the other which uses scalar data (Hamilton and Macmillan 2013, Vennerstrom and Moretto, 2013). Using ideas from both approaches we determine the oval positions and intensities from Swarm and earlier satellites. The variation in latitude and intensity with solar wind conditions, geomagnetic activity and secular variation of the main field is investigated. We aim to elucidate the relative importance of these factors. Hamilton, B. and Macmillan, S., 2013. Investigation of decadal scale changes in the auroral oval positions using Magsat and CHAMP data. Poster at IAGA 12th Scientific Assembly, 2013. http

  4. General considerations for a Sentinel-1 constellation InSAR time series processing chain for ground deformation measurements

    Science.gov (United States)

    Gonzalez, P. J.; Wright, T. J.; Hooper, A. J.; Walters, R. J.

    2014-12-01

    Sentinel-1A was launched on April 3rd, 2014. It is the first satellite of a European Space Agency (ESA) constellation that promises to revolutionize measurement of deformation of the Earth's surface. The constellation is designed to acquire data globally as frequently as every 6 days on the same orbital pass, and every 3 days in alternating ascending and descending orbits over the same regions. This data acquisition plan is possible due to a much larger swath coverage than previous SAR (Synthetic Aperture Radar) sensors. In addition, all observations from Copernicus, the European Commission Earth Observation program, have a liberal data policy, which will enable full exploitation of the archived Sentinel-1 big data, both for scientific and commercial use.Sentinel-1, and similar future constellations, shape a new landscape in the way that InSAR data have traditionally been processed. We have started to develop a completely new re-engineered and adapted InSAR time series processing approach, which efficiently processes the data from this new type of SAR constellation, with the goal to deliver ground deformation products with the highest possible precision. In summary, the proposed system approach will require the development of an automatic, almost unsupervised, system that integrates methods to obtain time-dependent surface deformation estimates and correction products for atmospheric noise and refined orbits. The ground velocity maps will ideally meet the desired precision of 1 mm/yr / 100 km to measure strain-rates (10 nanostrain/yr) at a comparable level of precision to current existing sparse regional GPS measurement networks.In this communication, we describe the different steps we have adopted to partially solve: 1) coregistration of TOPS (Terrain Observation with Progressive Scans) SAR images to enable interferometry, 2) how to manage the ambiguity between ground motion in azimuth and in line-of-sight for TOPS InSAR, 3) how to process efficiently newly

  5. LinkMind: link optimization in swarming mobile sensor networks.

    Science.gov (United States)

    Ngo, Trung Dung

    2011-01-01

    A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation.

  6. Formation control of robotic swarm using bounded artificial forces.

    Science.gov (United States)

    Qin, Long; Zha, Yabing; Yin, Quanjun; Peng, Yong

    2013-01-01

    Formation control of multirobot systems has drawn significant attention in the recent years. This paper presents a potential field control algorithm, navigating a swarm of robots into a predefined 2D shape while avoiding intermember collisions. The algorithm applies in both stationary and moving targets formation. We define the bounded artificial forces in the form of exponential functions, so that the behavior of the swarm drove by the forces can be adjusted via selecting proper control parameters. The theoretical analysis of the swarm behavior proves the stability and convergence properties of the algorithm. We further make certain modifications upon the forces to improve the robustness of the swarm behavior in the presence of realistic implementation considerations. The considerations include obstacle avoidance, local minima, and deformation of the shape. Finally, detailed simulation results validate the efficiency of the proposed algorithm, and the direction of possible futrue work is discussed in the conclusions.

  7. Algorithmic requirements for swarm intelligence in differently coupled collective systems

    Science.gov (United States)

    Stradner, Jürgen; Thenius, Ronald; Zahadat, Payam; Hamann, Heiko; Crailsheim, Karl; Schmickl, Thomas

    2013-01-01

    Swarm systems are based on intermediate connectivity between individuals and dynamic neighborhoods. In natural swarms self-organizing principles bring their agents to that favorable level of connectivity. They serve as interesting sources of inspiration for control algorithms in swarm robotics on the one hand, and in modular robotics on the other hand. In this paper we demonstrate and compare a set of bio-inspired algorithms that are used to control the collective behavior of swarms and modular systems: BEECLUST, AHHS (hormone controllers), FGRN (fractal genetic regulatory networks), and VE (virtual embryogenesis). We demonstrate how such bio-inspired control paradigms bring their host systems to a level of intermediate connectivity, what delivers sufficient robustness to these systems for collective decentralized control. In parallel, these algorithms allow sufficient volatility of shared information within these systems to help preventing local optima and deadlock situations, this way keeping those systems flexible and adaptive in dynamic non-deterministic environments. PMID:23805030

  8. Behavior-Based Formation Control of Swarm Robots

    Directory of Open Access Journals (Sweden)

    Dongdong Xu

    2014-01-01

    Full Text Available Swarm robotics is a specific research field of multirobotics where a large number of mobile robots are controlled in a coordinated way. Formation control is one of the most challenging goals for the coordination control of swarm robots. In this paper, a behavior-based control design approach is proposed for two kinds of important formation control problems: efficient initial formation and formation control while avoiding obstacles. In this approach, a classification-based searching method for generating large-scale robot formation is presented to reduce the computational complexity and speed up the initial formation process for any desired formation. The behavior-based method is applied for the formation control of swarm robot systems while navigating in an unknown environment with obstacles. Several groups of experimental results demonstrate the success of the proposed approach. These methods have potential applications for various swarm robot systems in both the simulation and the practical environments.

  9. Self-Assembling Wireless Autonomous Reconfigurable Modules (SWARM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. and the MIT Space Systems Laboratory propose Self-assembling, Wireless, Autonomous, Reconfigurable Modules (SWARM) as an innovative approach to...

  10. Stable swarming using adaptive long-range interactions

    Science.gov (United States)

    Gorbonos, Dan; Gov, Nir S.

    2017-04-01

    Sensory mechanisms in biology, from cells to humans, have the property of adaptivity, whereby the response produced by the sensor is adapted to the overall amplitude of the signal, reducing the sensitivity in the presence of strong stimulus, while increasing it when it is weak. This property is inherently energy consuming and a manifestation of the nonequilibrium nature of living organisms. We explore here how adaptivity affects the effective forces that organisms feel due to others in the context of a uniform swarm, in both two and three dimensions. The interactions between the individuals are taken to be attractive and long-range and of power-law form. We find that the effects of adaptivity inside the swarm are dramatic, where the effective forces decrease (or remain constant) with increasing swarm density. Linear stability analysis demonstrates how this property prevents collapse (Jeans instability), when the forces are adaptive. Adaptivity therefore endows swarms with a natural mechanism for self-stabilization.

  11. Algorithmic requirements for swarm intelligence in differently coupled collective systems.

    Science.gov (United States)

    Stradner, Jürgen; Thenius, Ronald; Zahadat, Payam; Hamann, Heiko; Crailsheim, Karl; Schmickl, Thomas

    2013-05-01

    Swarm systems are based on intermediate connectivity between individuals and dynamic neighborhoods. In natural swarms self-organizing principles bring their agents to that favorable level of connectivity. They serve as interesting sources of inspiration for control algorithms in swarm robotics on the one hand, and in modular robotics on the other hand. In this paper we demonstrate and compare a set of bio-inspired algorithms that are used to control the collective behavior of swarms and modular systems: BEECLUST, AHHS (hormone controllers), FGRN (fractal genetic regulatory networks), and VE (virtual embryogenesis). We demonstrate how such bio-inspired control paradigms bring their host systems to a level of intermediate connectivity, what delivers sufficient robustness to these systems for collective decentralized control. In parallel, these algorithms allow sufficient volatility of shared information within these systems to help preventing local optima and deadlock situations, this way keeping those systems flexible and adaptive in dynamic non-deterministic environments.

  12. Adaptive routing in wireless communication networks using swarm intelligence

    Science.gov (United States)

    Arabshahi, P.; Gray, A.; Kassabalidis, I.; Das, A.; Narayanan, S.; Sharkawi, M. El; Marks, R. J.

    2001-01-01

    In this paper we focus on the network routing problem, and survey swarm intelligent approaches for its efficient solution, after a brief overview of power-aware routing schemes, which are important in the network examples outlined above.

  13. Self-Assembling Wireless Autonomous Reconfigurable Modules (SWARM), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. and the MIT Space Systems Laboratory propose Self-assembling, Wireless, Autonomous, Reconfigurable Modules (SWARM) as an innovative approach to...

  14. Amphibious Quadcopter Swarm for the Exploration of Titan

    Science.gov (United States)

    Rajguru, A.; Faler, A. C.; Franz, B.

    2014-06-01

    This is a proposal for a low mass and cost effective mission architecture consisting of an amphibious quadcopter swarm flight vehicle system for the exploration of Titan's liquid methane lake, Ligeia Mare. The paper focuses on the EDL and operations.

  15. Femto-satellite Swarm State and Density Estimation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA is planning future missions involving fleets of small satellites in LEO and GEO that can exhibit autonomous collective behavior. Such a "swarm of...

  16. Formation Control of Robotic Swarm Using Bounded Artificial Forces

    Directory of Open Access Journals (Sweden)

    Long Qin

    2013-01-01

    Full Text Available Formation control of multirobot systems has drawn significant attention in the recent years. This paper presents a potential field control algorithm, navigating a swarm of robots into a predefined 2D shape while avoiding intermember collisions. The algorithm applies in both stationary and moving targets formation. We define the bounded artificial forces in the form of exponential functions, so that the behavior of the swarm drove by the forces can be adjusted via selecting proper control parameters. The theoretical analysis of the swarm behavior proves the stability and convergence properties of the algorithm. We further make certain modifications upon the forces to improve the robustness of the swarm behavior in the presence of realistic implementation considerations. The considerations include obstacle avoidance, local minima, and deformation of the shape. Finally, detailed simulation results validate the efficiency of the proposed algorithm, and the direction of possible futrue work is discussed in the conclusions.

  17. Self-Assembling Wireless Autonomous Reconfigurable Modules (SWARM), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. and the MIT Space Systems Laboratory propose Self-assembling, Wireless, Autonomous, Reconfigurable Modules (SWARM) as an innovative approach to...

  18. Swarm-based Sequencing Recommendations in E-learning

    NARCIS (Netherlands)

    Van den Berg, Bert; Tattersall, Colin; Janssen, José; Brouns, Francis; Kurvers, Hub; Koper, Rob

    2005-01-01

    Van den Berg, B., Tattersall, C., Janssen, J., Brouns, F., Kurvers, H., & Koper, R. (2006). Swarm-based Sequencing Recommendations in E-learning. International Journal of Computer Science & Applications, III(III), 1-11.

  19. A Markov Chain Approach to Probabilistic Swarm Guidance

    Science.gov (United States)

    Acikmese, Behcet; Bayard, David S.

    2012-01-01

    This paper introduces a probabilistic guidance approach for the coordination of swarms of autonomous agents. The main idea is to drive the swarm to a prescribed density distribution in a prescribed region of the configuration space. In its simplest form, the probabilistic approach is completely decentralized and does not require communication or collabo- ration between agents. Agents make statistically independent probabilistic decisions based solely on their own state, that ultimately guides the swarm to the desired density distribution in the configuration space. In addition to being completely decentralized, the probabilistic guidance approach has a novel autonomous self-repair property: Once the desired swarm density distribution is attained, the agents automatically repair any damage to the distribution without collaborating and without any knowledge about the damage.

  20. Intermittent swarming of copepods in Versova mangrove, Mumbai

    Digital Repository Service at National Institute of Oceanography (India)

    Stephen, R.; Jayalakshmy, K.V.; Nair, V.R.

    Some zooplankton taxa like copepods, ostracods, ctenophores and medusae exhibit dense aggregations in a wide range of marine environment. Copepods have been frequently reported to occur in swarms from coral and mangrove ecosystems. This has been...

  1. Investigating Ground Swarm Robotics Using Agent Based Simulation

    National Research Council Canada - National Science Library

    Ho, Sze-Tek T

    2006-01-01

    The concept of employing ground swarm robotics to accomplish tasks has been proposed for future use in humanitarian de-mining, plume monitoring, searching for survivors in a disaster site, and other hazardous activities...

  2. Parallel Global Optimization with the Particle Swarm Algorithm (Preprint)

    National Research Council Canada - National Science Library

    Schutte, J. F; Reinbolt, J. A; Fregly, B. J; Haftka, R. T; George, A. D

    2004-01-01

    .... To obtain enhanced computational throughput and global search capability, we detail the coarse-grained parallelization of an increasingly popular global search method, the Particle Swarm Optimization (PSO) algorithm...

  3. Foundations of Swarm Intelligence: From Principles to Practice

    National Research Council Canada - National Science Library

    Fleischer, Mark

    2003-01-01

    Swarm Intelligence (SI) is a relatively new paradigm being applied in a host of research settings to improve the management and control of large numbers of interacting entities such as communication, computer and sensor...

  4. Formation Control of Robotic Swarm Using Bounded Artificial Forces

    Science.gov (United States)

    Zha, Yabing; Peng, Yong

    2013-01-01

    Formation control of multirobot systems has drawn significant attention in the recent years. This paper presents a potential field control algorithm, navigating a swarm of robots into a predefined 2D shape while avoiding intermember collisions. The algorithm applies in both stationary and moving targets formation. We define the bounded artificial forces in the form of exponential functions, so that the behavior of the swarm drove by the forces can be adjusted via selecting proper control parameters. The theoretical analysis of the swarm behavior proves the stability and convergence properties of the algorithm. We further make certain modifications upon the forces to improve the robustness of the swarm behavior in the presence of realistic implementation considerations. The considerations include obstacle avoidance, local minima, and deformation of the shape. Finally, detailed simulation results validate the efficiency of the proposed algorithm, and the direction of possible futrue work is discussed in the conclusions. PMID:24453809

  5. LinkMind: Link Optimization in Swarming Mobile Sensor Networks

    Directory of Open Access Journals (Sweden)

    Trung Dung Ngo

    2011-08-01

    Full Text Available A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation.

  6. Algorithmic requirements for swarm intelligence in differently coupled collective systems

    International Nuclear Information System (INIS)

    Stradner, Jürgen; Thenius, Ronald; Zahadat, Payam; Hamann, Heiko; Crailsheim, Karl; Schmickl, Thomas

    2013-01-01

    Swarm systems are based on intermediate connectivity between individuals and dynamic neighborhoods. In natural swarms self-organizing principles bring their agents to that favorable level of connectivity. They serve as interesting sources of inspiration for control algorithms in swarm robotics on the one hand, and in modular robotics on the other hand. In this paper we demonstrate and compare a set of bio-inspired algorithms that are used to control the collective behavior of swarms and modular systems: BEECLUST, AHHS (hormone controllers), FGRN (fractal genetic regulatory networks), and VE (virtual embryogenesis). We demonstrate how such bio-inspired control paradigms bring their host systems to a level of intermediate connectivity, what delivers sufficient robustness to these systems for collective decentralized control. In parallel, these algorithms allow sufficient volatility of shared information within these systems to help preventing local optima and deadlock situations, this way keeping those systems flexible and adaptive in dynamic non-deterministic environments

  7. Investigating Ground Swarm Robotics Using Agent Based Simulation

    Science.gov (United States)

    2006-12-01

    interesting to see how alternatives like MANA (and even Pythagoras 3 ) measure up to the calling. If indeed MANA has rarely been dedicated to model swarm... Pythagoras is an agent based simulation package developed by Northrop Grumman 5 Figure 2. Simulation packages used to models robot swarms... Pythagoras , an agent based software platform developed by Northrop Grumman. 93 As mentioned before, the model is not complete without modeling the

  8. A new inertia weight control strategy for particle swarm optimization

    Science.gov (United States)

    Zhu, Xianming; Wang, Hongbo

    2018-04-01

    Particle Swarm Optimization is a member of swarm intelligence algorithms, which is inspired by the behavior of bird flocks. The inertia weight, one of the most important parameters of PSO, is crucial for PSO, for it balances the performance of exploration and exploitation of the algorithm. This paper proposes a new inertia weight control strategy and PSO with this new strategy is tested by four benchmark functions. The results shows that the new strategy provides the PSO with better performance.

  9. Origin of meteor swarms of the Arietid and Geminid types

    International Nuclear Information System (INIS)

    Lebedinets, V.N.

    1985-01-01

    The author proposes a physical mechanism for the formation of meteor swarms on orbits of small size and very small perihelion distance, similar to the orbits of Arietid and Geminid meteor swarms, which are rarely encountered among the larger bodies of the solar system, and he justifies the mechanism mathematically. He shows that comets can transfer to such orbits from orbits of large size during evaporation of their ice nuclei under the action of reactive drag

  10. Extending Particle Swarm Optimisers with Self-Organized Criticality

    DEFF Research Database (Denmark)

    Løvbjerg, Morten; Krink, Thiemo

    2002-01-01

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

  11. Investigating the polar electrojet using Swarm satellite magnetic data

    DEFF Research Database (Denmark)

    Aakjær, Cecilie Drost; Olsen, Nils; Finlay, Chris

    The aim of this study is to investigate the magnetic perturbations caused by the polar electrojets, which are described by means of a model consisting of a series of infinite line currents placed at the height of the ionosphere along QD latitudes. The method is applied to Swarm magnetic scalar...... of the polar electrojets as well as their temporal evolution. In addition, applying the method to data taken by the Swarm satellites Alpha and Beta allows investigating longitudinal differences of the electrojets....

  12. Virtual spring damper method for nonholonomic robotic swarm self-organization and leader following

    Science.gov (United States)

    Wiech, Jakub; Eremeyev, Victor A.; Giorgio, Ivan

    2018-04-01

    In this paper, we demonstrate a method for self-organization and leader following of nonholonomic robotic swarm based on spring damper mesh. By self-organization of swarm robots we mean the emergence of order in a swarm as the result of interactions among the single robots. In other words the self-organization of swarm robots mimics some natural behavior of social animals like ants among others. The dynamics of two-wheel robot is derived, and a relation between virtual forces and robot control inputs is defined in order to establish stable swarm formation. Two cases of swarm control are analyzed. In the first case the swarm cohesion is achieved by virtual spring damper mesh connecting nearest neighboring robots without designated leader. In the second case we introduce a swarm leader interacting with nearest and second neighbors allowing the swarm to follow the leader. The paper ends with numeric simulation for performance evaluation of the proposed control method.

  13. Pisgah Lava Cave Communication Test: Science Case Study for the Networked Constellations Initiative

    Science.gov (United States)

    Belov, K.; Ellison, D.; Fraeman, A.

    2017-01-01

    As part of the science case study for the Networked Constellations initiative, a team of JPL scientists explore the possibility of a mission to study the lava caves on Mars. Natural caves on Mars and the Moon present a unique opportunity to learn about the planetary geology and to provide a shelter for human explorers. Due to power and communication challenges, a network of assets has significant advantages over a single asset sent inside a cave. However, communication between the assets and the data downlink present significant difficulties due to the presence of rough walls, boulders, and other obstacles with unknown dielectric constant inside a typical cave, disturbing the propagation of the radio waves. A detailed study is needed to establish the limitations of the current communication technologies and to develop requirements for the new communication technology applicable to the cave environment. On May 4 of 2017, Konstantin Belov, Doug Ellison, and Abby Fraeman visited a lava cave in Pisgah, CA. The purpose of the visit was to build a 3D map of the cave, which could be used to create a model of radio wave propagation, and to conduct a series of communication tests using off-the-shelf equipment to verify the in-cave communication challenges. This experiment should be considered as a simple 'proof of concept' and is the subject of this report.

  14. Light-Controlled Swarming and Assembly of Colloidal Particles

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2018-02-01

    Full Text Available Swarms and assemblies are ubiquitous in nature and they can perform complex collective behaviors and cooperative functions that they cannot accomplish individually. In response to light, some colloidal particles (CPs, including light active and passive CPs, can mimic their counterparts in nature and organize into complex structures that exhibit collective functions with remote controllability and high temporospatial precision. In this review, we firstly analyze the structural characteristics of swarms and assemblies of CPs and point out that light-controlled swarming and assembly of CPs are generally achieved by constructing light-responsive interactions between CPs. Then, we summarize in detail the recent advances in light-controlled swarming and assembly of CPs based on the interactions arisen from optical forces, photochemical reactions, photothermal effects, and photoisomerizations, as well as their potential applications. In the end, we also envision some challenges and future prospects of light-controlled swarming and assembly of CPs. With the increasing innovations in mechanisms and control strategies with easy operation, low cost, and arbitrary applicability, light-controlled swarming and assembly of CPs may be employed to manufacture programmable materials and reconfigurable robots for cooperative grasping, collective cargo transportation, and micro- and nanoengineering.

  15. Assessing Human Judgment of Computationally Generated Swarming Behavior

    Directory of Open Access Journals (Sweden)

    John Harvey

    2018-02-01

    Full Text Available Computer-based swarm systems, aiming to replicate the flocking behavior of birds, were first introduced by Reynolds in 1987. In his initial work, Reynolds noted that while it was difficult to quantify the dynamics of the behavior from the model, observers of his model immediately recognized them as a representation of a natural flock. Considerable analysis has been conducted since then on quantifying the dynamics of flocking/swarming behavior. However, no systematic analysis has been conducted on human identification of swarming. In this paper, we assess subjects’ assessment of the behavior of a simplified version of Reynolds’ model. Factors that affect the identification of swarming are discussed and future applications of the resulting models are proposed. Differences in decision times for swarming-related questions asked during the study indicate that different brain mechanisms may be involved in different elements of the behavior assessment task. The relatively simple but finely tunable model used in this study provides a useful methodology for assessing individual human judgment of swarming behavior.

  16. UAV Swarming? So What are Those Swarms, What are the Implications, and How Do We Handle Them?

    National Research Council Canada - National Science Library

    Clough, Bruce

    2002-01-01

    ... not. The aerospace research community is working hard at developing UAV control technology that requires as little human supervision as possible, and concepts using swarms are receiving serious attention...

  17. A Mars Communication Constellation For Human Exploration and Network Science

    Science.gov (United States)

    Castellini, Francesco; Lavagna, Michèle; Simonetto, Andrea

    Mars is perhaps the primary target of all space exploration programs, and a massive robotic and human exploration will ask for a suitable communication link between Earth and the Red planet. The paper analyses the possibility of exploiting a small spacecrafts constellation around Mars to offer a complete and continuous coverage of possible elements on the planet, taking advantage of optical transmission techniques. Since the first human expedition will most likely not be launched in the next 15-20 years, the study foresees such a communications mission to be implemented after 2020, and in light of the future presence of explorers on the surface a high data rate requirement is imposed, in order to allow video transmissions. In addition, the set-up of a communication constellation around Mars would give the opportunity of exploiting this multi-platform infrastructure to perform network science, that would largely increase our knowledge of the planet. The paper covers all technical aspects of the feasibility study for the primary communications mission, and secondary scientific opportunities are suggested. The proposed communication architecture is quite complex and includes six 530kg spacecrafts on two different orbital planes, plus one redundant unit per plane, that ensure complete coverage of the planet's surface; communications between the satellites and Earth are achieved through optical links, that allow high data rates with lower mass and power consumption with respect to traditional radio-frequency technology (1) (2), while inter-satellite links and spacecrafts-to- Mars connections are ensured by radio transmissions. The worst-case optical link data rate varies from 10.2 Mbps in downlink to 13.7 Mbps in uplink. Inter-satellites data rate stays the 4.3-7.8 Mbps range on Ka-band, while spacecraft-Mars surface communications occur on the X band offering a 4.3 Mbps data rate. A complete trade-off analysis has been performed in terms of on board subsystems design

  18. Electron drift velocity and longitudinal diffusion coefficient of an electron swarm in hydrogen at elevated swarm energies

    International Nuclear Information System (INIS)

    Blevin, H.A.; Fletcher, J.; Hunter, S.R.

    1976-02-01

    A study of the photons produced at electron-molecule excitation collisions has been used to obtain information on the behaviour of an electron swarm moving through a neutral gas under the influence of a uniform electric field. Specifically values have been obtained for the electron drift velocity and the longitudinal diffusion coefficients under equilibrium swarm conditions, i.e. remote from any electrode. (author)

  19. The electron drift velocity and longitudinal diffusion coefficient of an electron swarm in hydrogen at elevated swarm energies

    International Nuclear Information System (INIS)

    Blevin, H.A.; Fletcher, J.; Hunter, S.R.

    1976-01-01

    A study of the photons produced at electron-molecule excitation collisions has been used to obtain information on the behaviour of an electron swarm moving through a neutral gas under the influence of a uniform electric field. Specifically, values have been obtained for the electron drift velocity and the longitudinal diffusion coefficients under equilibrium swarm conditions, i.e. remote from any electrode. (author)

  20. Cubesat-Based Dtv Receiver Constellation for Ionospheric Tomography

    Science.gov (United States)

    Bahcivan, H.; Leveque, K.; Doe, R. A.

    2013-12-01

    The Radio Aurora Explorer mission, funded by NSF's Space Weather and Atmospheric Research program, has demonstrated the utility of CubeSat-based radio receiver payloads for ionospheric research. RAX has primarily been an investigation of microphysics of meter-scale ionospheric structures; however, the data products are also suitable for research on ionospheric effects on radio propagation. To date, the spacecraft has acquired (1) ground-based UHF radar signals that are backscattered from meter-scale ionospheric irregularities, which have been used to measure the dispersion properties of meter-scale plasma waves and (2) ground-based signals, directly on the transmitter-spacecraft path, which have been used to measure radio propagation disturbances (scintillations). Herein we describe the application of a CubeSat constellation of UHF receivers to expand the latter research topic for global-scale ionospheric tomography. The enabling factor for this expansion is the worldwide availability of ground-based digital television (DTV) broadcast signals whose characteristics are optimal for scintillation analysis. A significant part of the populated world have transitioned, or soon to be transitioned, to DTV. The DTV signal has a standard format that contains a highly phase-stable pilot carrier that can be readily adapted for propagation diagnostics. A multi-frequency software-defined radar receiver, similar to the RAX payload, can measure these signals at a large number of pilot carrier frequencies to make radio ray and diffraction tomographic measurements of the ionosphere and the irregularities contained in it. A constellation of CubeSats, launched simultaneously, or in sequence over years, similar to DMSPs, can listen to the DTV stations, providing a vast and dense probing of the ionosphere. Each spacecraft can establish links to a preprogrammed list of DTV stations and cycle through them using time-division frequency multiplexing (TDFM) method. An on board program can

  1. COMET-LICSAR: Systematic Deformation Monitoring of Fault Zones and Volcanoes with the Sentinel-1 Constellation

    Science.gov (United States)

    Spaans, K.; Wright, T. J.; Hooper, A. J.; Hatton, E. L.; González, P. J.; Bhattarai, S.; Biggs, J.; Crippa, P.; Ebmeier, S. K.; Elliott, J.; Gaddes, M.; Li, Z.; Parsons, B.; Qiu, Q.; McDougall, A.; Walters, R. J.; Weiss, J. R.; Ziebart, M.

    2017-12-01

    The Sentinel-1 constellation represents a major advance in our ability to monitor our planet's hazardous tectonic and volcanic zones. Here we present the latest progress from COMET (*), where we are now providing deformation results to the community for volcanoes and the tectonic belts (**). COMET now responds routinely to most significant continental earthquakes - Sentinel-1 allows us to do this within a few days for most earthquakes. For example, after the M7.8 Kaikoura (New Zealand) earthquake we supplied a processed interferogram to the community just 5 hours and 37 minutes after the Sentinel-1 acquisition. By the end of 2017, we will be producing interferogram products systematically for all earthquakes larger than M 6.0. For deformation data to be useful for preparedness, we need accuracy on the order of 1 mm/yr or better. This requires mass processing of long time series of radar acquisitions. We are currently (July 2017) processing interferograms systematically for the entire Alpine-Himalayan belt ( 9000 x 2000 km) using our LiCSAR chain, making interferograms and coherence products available to the community. By December 2017, we plan to process a wider tectonic area and the majority of subaerial volcanoes. We currently serve displacement and coherence grids, but plan to provide average deformation rates and time series. Results are available through our dedicated portal (**), and are being linked to the ESA G-TEP and EPOS during 2017. We will show the latest results for tectonics and volcanism, and discuss how these can be used to build value-added products, including (i) maps of tectonic strain (ii) maps of seismic hazard (iii) volcano deformation alerts. The accuracy of these products will improve as the number of data products acquired by Sentinel-1 increases, and as the time series lengthen. *http://comet.nerc.ac.uk**http://comet.nerc.ac.uk/COMET-LiCS-portal/

  2. Information-Theoretic Analysis of a Family of Improper Discrete Constellations

    Directory of Open Access Journals (Sweden)

    Ignacio Santamaria

    2018-01-01

    Full Text Available Non-circular or improper Gaussian signaling has proven beneficial in several interference-limited wireless networks. However, all implementable coding schemes are based on finite discrete constellations rather than Gaussian signals. In this paper, we propose a new family of improper constellations generated by widely linear processing of a square M-QAM (quadrature amplitude modulation signal. This family of discrete constellations is parameterized by κ , the circularity coefficient and a phase ϕ . For uncoded communication systems, this phase should be optimized as ϕ * ( κ to maximize the minimum Euclidean distance between points of the improper constellation, therefore minimizing the bit error rate (BER. For the more relevant case of coded communications, where the coded symbols are constrained to be in this family of improper constellations using ϕ * ( κ , it is shown theoretically and further corroborated by simulations that, except for a shaping loss of 1.53 dB encountered at a high signal-to-noise ratio (snr, there is no rate loss with respect to the improper Gaussian capacity. In this sense, the proposed family of constellations can be viewed as the improper counterpart of the standard proper M-QAM constellations widely used in coded communication systems.

  3. Bats Swarm Where They Hibernate: Compositional Similarity between Autumn Swarming and Winter Hibernation Assemblages at Five Underground Sites.

    Science.gov (United States)

    van Schaik, Jaap; Janssen, René; Bosch, Thijs; Haarsma, Anne-Jifke; Dekker, Jasja J A; Kranstauber, Bart

    2015-01-01

    During autumn in the temperate zone of both the new and old world, bats of many species assemble at underground sites in a behaviour known as swarming. Autumn swarming behaviour is thought to primarily serve as a promiscuous mating system, but may also be related to the localization and assessment of hibernacula. Bats subsequently make use of the same underground sites during winter hibernation, however it is currently unknown if the assemblages that make use of a site are comparable across swarming and hibernation seasons. Our purpose was to characterize the bat assemblages found at five underground sites during both the swarming and the hibernation season and compare the assemblages found during the two seasons both across sites and within species. We found that the relative abundance of individual species per site, as well as the relative proportion of a species that makes use of each site, were both significantly correlated between the swarming and hibernation seasons. These results suggest that swarming may indeed play a role in the localization of suitable hibernation sites. Additionally, these findings have important conservation implications, as this correlation can be used to improve monitoring of underground sites and predict the importance of certain sites for rare and cryptic bat species.

  4. A hybrid search algorithm for swarm robots searching in an unknown environment.

    Directory of Open Access Journals (Sweden)

    Shoutao Li

    Full Text Available This paper proposes a novel method to improve the efficiency of a swarm of robots searching in an unknown environment. The approach focuses on the process of feeding and individual coordination characteristics inspired by the foraging behavior in nature. A predatory strategy was used for searching; hence, this hybrid approach integrated a random search technique with a dynamic particle swarm optimization (DPSO search algorithm. If a search robot could not find any target information, it used a random search algorithm for a global search. If the robot found any target information in a region, the DPSO search algorithm was used for a local search. This particle swarm optimization search algorithm is dynamic as all the parameters in the algorithm are refreshed synchronously through a communication mechanism until the robots find the target position, after which, the robots fall back to a random searching mode. Thus, in this searching strategy, the robots alternated between two searching algorithms until the whole area was covered. During the searching process, the robots used a local communication mechanism to share map information and DPSO parameters to reduce the communication burden and overcome hardware limitations. If the search area is very large, search efficiency may be greatly reduced if only one robot searches an entire region given the limited resources available and time constraints. In this research we divided the entire search area into several subregions, selected a target utility function to determine which subregion should be initially searched and thereby reduced the residence time of the target to improve search efficiency.

  5. Precise Point Positioning Using Triple GNSS Constellations in Various Modes

    Directory of Open Access Journals (Sweden)

    Akram Afifi

    2016-05-01

    Full Text Available This paper introduces a new dual-frequency precise point positioning (PPP model, which combines the observations from three different global navigation satellite system (GNSS constellations, namely GPS, Galileo, and BeiDou. Combining measurements from different GNSS systems introduces additional biases, including inter-system bias and hardware delays, which require rigorous modelling. Our model is based on the un-differenced and between-satellite single-difference (BSSD linear combinations. BSSD linear combination cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. Forming the BSSD linear combination requires a reference satellite, which can be selected from any of the GPS, Galileo, and BeiDou systems. In this paper three BSSD scenarios are tested; each considers a reference satellite from a different GNSS constellation. Natural Resources Canada’s GPSPace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets collected at four different IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX network are used to correct the GPS, Galileo, and BeiDou measurements in the post-processing PPP mode. A real-time PPP solution is also obtained, which is referred to as RT-PPP in the sequel, through the use of the IGS real-time service (RTS for satellite orbit and clock corrections. However, only GPS and Galileo observations are used for the RT-PPP solution, as the RTS-IGS satellite products are not presently available for BeiDou system. All post-processed and real-time PPP solutions are compared with the traditional un-differenced GPS-only counterparts. It is shown that combining the GPS, Galileo, and BeiDou observations in the post-processing mode improves the

  6. Precise Point Positioning Using Triple GNSS Constellations in Various Modes.

    Science.gov (United States)

    Afifi, Akram; El-Rabbany, Ahmed

    2016-05-28

    This paper introduces a new dual-frequency precise point positioning (PPP) model, which combines the observations from three different global navigation satellite system (GNSS) constellations, namely GPS, Galileo, and BeiDou. Combining measurements from different GNSS systems introduces additional biases, including inter-system bias and hardware delays, which require rigorous modelling. Our model is based on the un-differenced and between-satellite single-difference (BSSD) linear combinations. BSSD linear combination cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. Forming the BSSD linear combination requires a reference satellite, which can be selected from any of the GPS, Galileo, and BeiDou systems. In this paper three BSSD scenarios are tested; each considers a reference satellite from a different GNSS constellation. Natural Resources Canada's GPSPace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets collected at four different IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX) network are used to correct the GPS, Galileo, and BeiDou measurements in the post-processing PPP mode. A real-time PPP solution is also obtained, which is referred to as RT-PPP in the sequel, through the use of the IGS real-time service (RTS) for satellite orbit and clock corrections. However, only GPS and Galileo observations are used for the RT-PPP solution, as the RTS-IGS satellite products are not presently available for BeiDou system. All post-processed and real-time PPP solutions are compared with the traditional un-differenced GPS-only counterparts. It is shown that combining the GPS, Galileo, and BeiDou observations in the post-processing mode improves the PPP convergence

  7. SWARMS Early Trials Management for The SWARMs ECSEL-H2020 Project

    Science.gov (United States)

    Alcaraz, Daniel; Morales, Tania; Castro, Ayoze; Barrera, Carlos; Hernández, Joaquín; Llinás, Octavio

    2017-04-01

    The work presented on this paper is aimed to explain how the Early Trials of the Project SWARMS were managed in order to complete the first field demonstrations on real environment. SWARMs aims to reduce the operational cost in the use of maritime robots and vehicles, in order to increase the safety of tasks and reduce profesional divers risks. This will be achieved enabling the AUVs/ROVs to work in a cooperative mesh. The challenge is to design and develop an integrated platform (a set of Software/Hardware components), incorporated into the current generation of underwater vehicles in order to improve autonomy, cooperation, robustness, cost-effectiveness, and reliability of the offshore operations. The first demonstration of the project has been performed at PLOCAN (The Oceanic Platform of the Canary Islands) where these technologies were validated on its first stage. The Early Trials have represented the first in situ deployment and test of the novel technologies developed during the initial 14 months of the Project. Going into the sea supposed a huge challenge also in terms of management. The 32 partners of SWARMS had very different requirements (logistics, technical needs, software/computation needs, etc.), and a limited time frame to test and prove their individual developments. In order to fullfill the project objectives, all these tests were divided in 7 missions that were aimed to cover this early demonstration requiements. From PLOCAN, a management protocol was designed in order to cover all the partners needs and make an efficient resource asignment from the begining. These results will be extended to other two demonstrations of the project that forseen to be held in Romania (2017) and Norway (2018).

  8. Simulating the Liaison Navigation Concept in a Geo + Earth-Moon Halo Constellation

    Science.gov (United States)

    Fujimoto, K.; Leonard, J. M.; McGranaghan, R. M.; Parker, J. S.; Anderson, R. L.; Born, G. H.

    2012-01-01

    Linked Autonomous Interplanetary Satellite Orbit Navigation, or LiAISON, is a novel satellite navigation technique where relative radiometric measurements between two or more spacecraft in a constellation are processed to obtain the absolute state of all spacecraft. The method leverages the asymmetry of the gravity field that the constellation exists in. This paper takes a step forward in developing a high fidelity navigation simulation for the LiAISON concept in an Earth-Moon constellation. In particular, we aim to process two-way Doppler measurements between a satellite in GEO orbit and another in a halo orbit about the Earth-Moon L1 point.

  9. Space Technology 5 – Enabling Future Constellation Missions Using Micro-Satellites for Space Weather

    OpenAIRE

    Le, Guan; Moore, Thomas; Slavin, James

    2007-01-01

    Space Technology 5 (ST5) is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn – dusk, sun synchronous polar orbit on March 22, 2006. The spacecraft were maintained in a “pearls on a string” constellation with controlled spacing ranging from just over 5000 km down to under 50 km. Each spacecraft carried a miniature tri-axial fluxgate magnetometer (MAG). Although the short 90-day mission was designed to flight validate new technologies, the constellation mission returned...

  10. Orbital Maneuvers Using Low Thrust to Place a Satellite in a Constellation

    Directory of Open Access Journals (Sweden)

    Vivian Martins Gomes

    2007-01-01

    Full Text Available This paper considers the problem of low thrust suboptimal maneuvers to insert a satellite in a constellation. It is assumed that a satellite constellation is given with all the Keplerian elements of the satellite members having known values. Then, it is necessary to maneuver a new satellite from a parking orbit to its position in the constellation. The control available to perform this maneuver is the application of a low thrust to the satellite and the objective is to perform this maneuver with minimum fuel consumption.

  11. Using Seismic Interferometry to Investigate Seismic Swarms

    Science.gov (United States)

    Matzel, E.; Morency, C.; Templeton, D. C.

    2017-12-01

    Seismicity provides a direct means of measuring the physical characteristics of active tectonic features such as fault zones. Hundreds of small earthquakes often occur along a fault during a seismic swarm. This seismicity helps define the tectonically active region. When processed using novel geophysical techniques, we can isolate the energy sensitive to the fault, itself. Here we focus on two methods of seismic interferometry, ambient noise correlation (ANC) and the virtual seismometer method (VSM). ANC is based on the observation that the Earth's background noise includes coherent energy, which can be recovered by observing over long time periods and allowing the incoherent energy to cancel out. The cross correlation of ambient noise between a pair of stations results in a waveform that is identical to the seismogram that would result if an impulsive source located at one of the stations was recorded at the other, the Green function (GF). The calculation of the GF is often stable after a few weeks of continuous data correlation, any perturbations to the GF after that point are directly related to changes in the subsurface and can be used for 4D monitoring.VSM is a style of seismic interferometry that provides fast, precise, high frequency estimates of the Green's function (GF) between earthquakes. VSM illuminates the subsurface precisely where the pressures are changing and has the potential to image the evolution of seismicity over time, including changes in the style of faulting. With hundreds of earthquakes, we can calculate thousands of waveforms. At the same time, VSM collapses the computational domain, often by 2-3 orders of magnitude. This allows us to do high frequency 3D modeling in the fault region. Using data from a swarm of earthquakes near the Salton Sea, we demonstrate the power of these techniques, illustrating our ability to scale from the far field, where sources are well separated, to the near field where their locations fall within each other

  12. George Marinesco in the Constellation of Modern Neuroscience

    Directory of Open Access Journals (Sweden)

    Ioan Opris

    2017-12-01

    Full Text Available George Marinesco is the founder of Romanian School of Neurology and one of the most remarkable neuroscientists of the last century. He was the pupil of Jean-Martin Charcot in Salpêtrière Hospital in Paris, France, but visited many other neurological centers where he met the entire constellation of neurologists of his time, including Camillo Golgi and Santiago Ramón y Cajal. The last made the preface of Nervous Cell, written in French by Marinesco. The original title was “La Cellule Nerveuse” and is considered even now a basic reference book for specialists in the field. He was a refined clinical observer with an integrative approach, as could be seen from the multitude of his discoveries. The descriptions of the succulent hand in syringomyelia, senile plaque in old subjects, palmar jaw reflex known as Marinesco-Radovici sign, or the application of cinematography in medicine are some of his important contributions. He was the first who described changes of locus niger in a patient affected by tuberculosis, as a possible cause in Parkinson disease. Before modern genetics, Marinesco and Sjögren described a rare and complex syndrome bearing their names. He was a hardworking man, focused on his scientific research, did not accepted flattering of others and was a great fighter against the injustice of the time.

  13. George Marinesco in the Constellation of Modern Neuroscience.

    Science.gov (United States)

    Opris, Ioan; Nestianu, Valeriu S; Nestianu, Adrian; Bilteanu, Liviu; Ciurea, Jean

    2017-01-01

    George Marinesco is the founder of Romanian School of Neurology and one of the most remarkable neuroscientists of the last century. He was the pupil of Jean-Martin Charcot in Salpêtrière Hospital in Paris, France, but visited many other neurological centers where he met the entire constellation of neurologists of his time, including Camillo Golgi and Santiago Ramón y Cajal. The last made the preface of Nervous Cell, written in French by Marinesco. The original title was "La Cellule Nerveuse" and is considered even now a basic reference book for specialists in the field. He was a refined clinical observer with an integrative approach, as could be seen from the multitude of his discoveries. The descriptions of the succulent hand in syringomyelia, senile plaque in old subjects, palmar jaw reflex known as Marinesco-Radovici sign, or the application of cinematography in medicine are some of his important contributions. He was the first who described changes of locus niger in a patient affected by tuberculosis, as a possible cause in Parkinson disease. Before modern genetics, Marinesco and Sjögren described a rare and complex syndrome bearing their names. He was a hardworking man, focused on his scientific research, did not accepted flattering of others and was a great fighter against the injustice of the time.

  14. Optimal Earth's reentry disposal of the Galileo constellation

    Science.gov (United States)

    Armellin, Roberto; San-Juan, Juan F.

    2018-02-01

    Nowadays there is international consensus that space activities must be managed to minimize debris generation and risk. The paper presents a method for the end-of-life (EoL) disposal of spacecraft in Medium Earth Orbit (MEO). The problem is formulated as a multiobjective optimisation one, which is solved with an evolutionary algorithm. An impulsive manoeuvre is optimised to reenter the spacecraft in Earth's atmosphere within 100 years. Pareto optimal solutions are obtained using the manoeuvre Δv and the time-to-reentry as objective functions to be minimised. To explore at the best the search space a semi-analytical orbit propagator, which can propagate an orbit for 100 years in few seconds, is adopted. An in-depth analysis of the results is carried out to understand the conditions leading to a fast reentry with minimum propellant. For this aim a new way of representing the disposal solutions is introduced. With a single 2D plot we are able to fully describe the time evolution of all the relevant orbital parameters as well as identify the conditions that enables the eccentricity build-up. The EoL disposal of the Galileo constellation is used as test case.

  15. [Genetic analysis of family constellation for cochlear implant recipients].

    Science.gov (United States)

    Zhang, Chu-Qin; Chen, Bo-Bei; Huang, Jia-Yun; Sun, Dong-Mei; Chen, Ying-Ying; Xiang, Song-Jie; Guan, Min-Xin

    2008-11-01

    GJB2, SLC26A4 (PDS) and mitochondrial DNA (mtDNA) have been associated with sensorineural hearing loss. In the present study, the clinical, genetic and molecular analysis of 14 cochlear implant recipients and their parents was studied from April 2006 to September 2007. Of the 14 subjects, 35.7% had gene mutations; 28.6% had homozygous GJB2 235delC mutation, whose parents carried heterozygous GJB2 235delC mutation; and 7.1% had mtDNA A1555G mutation, whose mother carried mtDNA A1555G mutation too. There was no SLC26A4 (PDS) mutation. These results strongly suggested that the mutation in GJB2 gene was a major cause of deafness in cochlear implant recipients and the mutation of mtDNA A1555G was another important cause. Genetic test of hot-spots and analysis of family constellation can offer an accurate genetic counseling to deaf family and reduce the incidence of hearing loss.

  16. From value chain to value constellation: designing interactive strategy.

    Science.gov (United States)

    Normann, R; Ramírez, R

    1993-01-01

    In today's fast-changing competitive environment, strategy is no longer a matter of positioning a fixed set of activities along that old industrial model, the value chain. Successful companies increasingly do not just add value, they reinvent it. The key strategic task is to reconfigure roles and relationships among a constellation of actors--suppliers, partners, customers--in order to mobilize the creation of value by new combinations of players. What is so different about this new logic of value? It breaks down the distinction between products and services and combines them into activity-based "offerings" from which customers can create value for themselves. But as potential offerings grow more complex, so do the relationships necessary to create them. As a result, a company's strategic task becomes the ongoing reconfiguration and integration of its competencies and customers. The authors provide three illustrations of these new rules of strategy. IKEA has blossomed into the world's largest retailer of home furnishings by redefining the relationships and organizational practices of the furniture business. Danish pharmacies and their national association have used the opportunity of health care reform to reconfigure their relationships with customers, doctors, hospitals, drug manufacturers, and with Danish and international health organizations to enlarge their role, competencies, and profits. French public-service concessionaires have mastered the art of conducting a creative dialogue between their customers--local governments in France and around the world--and a perpetually expanding set of infrastructure competencies.

  17. Middleware Design for Swarm-Driving Robots Accompanying Humans

    Directory of Open Access Journals (Sweden)

    Min Su Kim

    2017-02-01

    Full Text Available Research on robots that accompany humans is being continuously studied. The Pet-Bot provides walking-assistance and object-carrying services without any specific controls through interaction between the robot and the human in real time. However, with Pet-Bot, there is a limit to the number of robots a user can use. If this limit is overcome, the Pet-Bot can provide services in more areas. Therefore, in this study, we propose a swarm-driving middleware design adopting the concept of a swarm, which provides effective parallel movement to allow multiple human-accompanying robots to accomplish a common purpose. The functions of middleware divide into three parts: a sequence manager for swarm process, a messaging manager, and a relative-location identification manager. This middleware processes the sequence of swarm-process of robots in the swarm through message exchanging using radio frequency (RF communication of an IEEE 802.15.4 MAC protocol and manages an infrared (IR communication module identifying relative location with IR signal strength. The swarm in this study is composed of the master interacting with the user and the slaves having no interaction with the user. This composition is intended to control the overall swarm in synchronization with the user activity, which is difficult to predict. We evaluate the accuracy of the relative-location estimation using IR communication, the response time of the slaves to a change in user activity, and the time to organize a network according to the number of slaves.

  18. Swarm intelligence: when uncertainty meets conflict.

    Science.gov (United States)

    Conradt, Larissa; List, Christian; Roper, Timothy J

    2013-11-01

    Good decision making is important for the survival and fitness of stakeholders, but decisions usually involve uncertainty and conflict. We know surprisingly little about profitable decision-making strategies in conflict situations. On the one hand, sharing decisions with others can pool information and decrease uncertainty (swarm intelligence). On the other hand, sharing decisions can hand influence to individuals whose goals conflict. Thus, when should an animal share decisions with others? Using a theoretical model, we show that, contrary to intuition, decision sharing by animals with conflicting goals often increases individual gains as well as decision accuracy. Thus, conflict-far from hampering effective decision making-can improve decision outcomes for all stakeholders, as long as they share large-scale goals. In contrast, decisions shared by animals without conflict were often surprisingly poor. The underlying mechanism is that animals with conflicting goals are less correlated in individual choice errors. These results provide a strong argument in the interest of all stakeholders for not excluding other (e.g., minority) factions from collective decisions. The observed benefits of including diverse factions among the decision makers could also be relevant to human collective decision making.

  19. Human behavior-based particle swarm optimization.

    Science.gov (United States)

    Liu, Hao; Xu, Gang; Ding, Gui-Yan; Sun, Yu-Bo

    2014-01-01

    Particle swarm optimization (PSO) has attracted many researchers interested in dealing with various optimization problems, owing to its easy implementation, few tuned parameters, and acceptable performance. However, the algorithm is easy to trap in the local optima because of rapid losing of the population diversity. Therefore, improving the performance of PSO and decreasing the dependence on parameters are two important research hot points. In this paper, we present a human behavior-based PSO, which is called HPSO. There are two remarkable differences between PSO and HPSO. First, the global worst particle was introduced into the velocity equation of PSO, which is endowed with random weight which obeys the standard normal distribution; this strategy is conducive to trade off exploration and exploitation ability of PSO. Second, we eliminate the two acceleration coefficients c 1 and c 2 in the standard PSO (SPSO) to reduce the parameters sensitivity of solved problems. Experimental results on 28 benchmark functions, which consist of unimodal, multimodal, rotated, and shifted high-dimensional functions, demonstrate the high performance of the proposed algorithm in terms of convergence accuracy and speed with lower computation cost.

  20. Particle Swarm Optimization for Structural Design Problems

    Directory of Open Access Journals (Sweden)

    Hamit SARUHAN

    2010-02-01

    Full Text Available The aim of this paper is to employ the Particle Swarm Optimization (PSO technique to a mechanical engineering design problem which is minimizing the volume of a cantilevered beam subject to bending strength constraints. Mechanical engineering design problems are complex activities which are computing capability are more and more required. The most of these problems are solved by conventional mathematical programming techniques that require gradient information. These techniques have several drawbacks from which the main one is becoming trapped in local optima. As an alternative to gradient-based techniques, the PSO does not require the evaluation of gradients of the objective function. The PSO algorithm employs the generation of guided random positions when they search for the global optimum point. The PSO which is a nature inspired heuristics search technique imitates the social behavior of bird flocking. The results obtained by the PSO are compared with Mathematical Programming (MP. It is demonstrated that the PSO performed and obtained better convergence reliability on the global optimum point than the MP. Using the MP, the volume of 2961000 mm3 was obtained while the beam volume of 2945345 mm3 was obtained by the PSO.

  1. The April 2007 earthquake swarm near Lake Trichonis and implications for active tectonics in western Greece

    Science.gov (United States)

    Kiratzi, A.; Sokos, E.; Ganas, A.; Tselentis, A.; Benetatos, C.; Roumelioti, Z.; Serpetsidaki, A.; Andriopoulos, G.; Galanis, O.; Petrou, P.

    2008-06-01

    We investigate the properties of the April 2007 earthquake swarm (Mw 5.2) which occurred at the vicinity of Lake Trichonis (western Greece). First we relocated the earthquakes, using P- and S-wave arrivals to the stations of the Hellenic Unified Seismic Network (HUSN), and then we applied moment tensor inversion to regional broad-band waveforms to obtain the focal mechanisms of the strongest events of the 2007 swarm. The relocated epicentres, cluster along the eastern banks of the lake, and follow a distinct NNW-ESE trend. The previous strong sequence close to Lake Trichonis occurred in June-December 1975. We applied teleseismic body waveform inversion, to obtain the focal mechanism solution of the strongest earthquake of this sequence, i.e. the 31 December 1975 (Mw 6.0) event. Our results indicate that: a) the 31 December 1975 Mw 6.0 event was produced by a NW-SE normal fault, dipping to the NE, with considerable sinistral strike-slip component; we relocated its epicentre: i) using phase data reported to ISC and its coordinates are 38.486°N, 21.661°E; ii) using the available macroseismic data, and the coordinates of the macroseismic epicentre are 38.49°N, 21.63°E, close to the strongly affected village of Kato Makrinou; b) the earthquakes of the 2007 swarm indicate a NNW-SSE strike for the activated main structure, parallel to the eastern banks of Lake Trichonis, dipping to the NE and characterized by mainly normal faulting, occasionally combined with sinistral strike-slip component. The 2007 earthquake swarm did not rupture the well documented E-W striking Trichonis normal fault that bounds the southern flank of the lake, but on the contrary it is due to rupture of a NW-SE normal fault that strikes at a ˜ 45° angle to the Trichonis fault. The left-lateral component of faulting is mapped for the first time to the north of the Gulf of Patras which was previously regarded as the boundary for strike-slip motions in western Greece. This result signifies the

  2. Reserve-Constrained Multiarea Environmental/Economic Dispatch Using Enhanced Particle Swarm Optimization

    OpenAIRE

    Wang, Lingfeng; Singh, Chanan

    2007-01-01

    Source: Swarm Intelligence: Focus on Ant and Particle Swarm Optimization, Book edited by: Felix T. S. Chan and Manoj Kumar Tiwari, ISBN 978-3-902613-09-7, pp. 532, December 2007, Itech Education and Publishing, Vienna, Austria

  3. Exploitation of Self Organization in UAV Swarms for Optimization in Combat Environments

    National Research Council Canada - National Science Library

    Nowak, Dustin J

    2008-01-01

    ...) swarms using autonomous self-organized cooperative control. This development required the design of a new abstract UAV swarm control model which flows from an abstract Markov structure, a Partially Observable Markov Decision Process...

  4. Electron Swarm Parameters and Electron Collision Cross Sections

    International Nuclear Information System (INIS)

    Nakamura, Yoshiharu

    2012-01-01

    Electron collision cross section data for atoms and molecules and electron swarm data in respective gases are important for quantitative modeling of related plasmas. This fact and wide application of plasmas in various fields boos data collection and evaluation activities worldwide. We have been measuring electron swarm parameters (drift velocity, longitudinal diffusion coefficient, ionization/attachment coefficients, and so on) over a wide E/N range (where E is the electric field and N the gas number density) in a number of gases. We also derived a set of electron collision cross sections for each gas so that the set was consistent with our experimental swarm data. Our speciality in studying molecular target is to measure swarm parameters not only in the pure molecular gas but also in dilute molecular gas-argon gas mixtures, the mix rations of the molecule are 0.5-5.0%. The swarm parameters in pure molecular gas depend primarily on the elastic momentum transfer cross section of the molecule and its vibrational excitation cross sections. Those in the mixtures, on the other hand, depend mainly on the elastic momentum transfer cross section of major argon atom and the vibrational cross sections of minor admixed molecule. Alternative use of swarm parameters in pure molecular gas and those in the mixtures enable us to derive the momentum transfer cross section and vibrational cross sections for the molecule separately. Combination of the Ramsauer-Townsend minimum of argon atom and sharp structures in vibrational cross sections of the molecule frequently gives rise prominent E/N dependences in swarm parameters, which can be used to determine the position and magnitude of resonances in the vibrational excitation cross sections. Detailed accounts of the procedure, including estimated uncertainty in our electron swarm data and also in the resultant set of electron collision cross sections, will be given in the presentation by referring to our recent results. Stress will be

  5. Constellation Program Human-System Integration Requirements. Revision E, Nov. 19, 2010

    Science.gov (United States)

    Dory, Jonathan

    2010-01-01

    The Human-Systems Integration Requirements (HSIR) in this document drive the design of space vehicles, their systems, and equipment with which humans interface in the Constellation Program (CxP). These requirements ensure that the design of Constellation (Cx) systems is centered on the needs, capabilities, and limitations of the human. The HSIR provides requirements to ensure proper integration of human-to-system interfaces. These requirements apply to all mission phases, including pre-launch, ascent, Earth orbit, trans-lunar flight, lunar orbit, lunar landing, lunar ascent, Earth return, Earth entry, Earth landing, post-landing, and recovery. The Constellation Program must meet NASA's Agency-level human rating requirements, which are intended to ensure crew survival without permanent disability. The HSIR provides a key mechanism for achieving human rating of Constellation systems.

  6. 77 FR 16828 - Constellation Energy Commodities Group, Inc.; Notice of Designation of Certain Commission...

    Science.gov (United States)

    2012-03-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Constellation Energy Commodities Group, Inc.; Notice of Designation of Certain Commission Personnel as Non-Decisional Commission staff members Sandra Waldstein and Joyce...

  7. The Family Constellation: A Clue to the Behavior of Elementary School Children

    Science.gov (United States)

    Hillman, Bill W.

    1972-01-01

    This article presents information about the family constellation concept which can provide clues to understanding the sometimes perplexing behavior of children. It has also been suggested how this information can be used by the elementary school counselors. (Author)

  8. Modelling Oil-Spill Detection with Swarm Drones

    Directory of Open Access Journals (Sweden)

    F. Aznar

    2014-01-01

    Full Text Available Nowadays, swarm robotics research is having a great increase due to the benefits derived from its use, such as robustness, parallelism, and flexibility. Unlike distributed robotic systems, swarm robotics emphasizes a large number of robots, and promotes scalability. Among the multiple applications of such systems we could find are exploring unstructured environments, resource monitoring, or distributed sensing. Two of these applications, monitoring, and perimeter/area detection of a given resource, have several ecological uses. One of them is the detection and monitoring of pollutants to delimit their perimeter and area accurately. Maritime activity has been increasing gradually in recent years. Many ships carry products such as oil that can adversely affect the environment. Such products can produce high levels of pollution in case of being spilled into sea. In this paper we will present a distributed system which monitors, covers, and surrounds a resource by using a swarm of homogeneous low cost drones. These drones only use their local sensory information and do not require any direct communication between them. Taking into account the properties of this kind of oil spills we will present a microscopic model for a swarm of drones, capable of monitoring these spills properly. Furthermore, we will analyse the proper macroscopic operation of the swarm. The analytical and experimental results presented here show the proper evolution of our system.

  9. Intelligent discrete particle swarm optimization for multiprocessor task scheduling problem

    Directory of Open Access Journals (Sweden)

    S Sarathambekai

    2017-03-01

    Full Text Available Discrete particle swarm optimization is one of the most recently developed population-based meta-heuristic optimization algorithm in swarm intelligence that can be used in any discrete optimization problems. This article presents a discrete particle swarm optimization algorithm to efficiently schedule the tasks in the heterogeneous multiprocessor systems. All the optimization algorithms share a common algorithmic step, namely population initialization. It plays a significant role because it can affect the convergence speed and also the quality of the final solution. The random initialization is the most commonly used method in majority of the evolutionary algorithms to generate solutions in the initial population. The initial good quality solutions can facilitate the algorithm to locate the optimal solution or else it may prevent the algorithm from finding the optimal solution. Intelligence should be incorporated to generate the initial population in order to avoid the premature convergence. This article presents a discrete particle swarm optimization algorithm, which incorporates opposition-based technique to generate initial population and greedy algorithm to balance the load of the processors. Make span, flow time, and reliability cost are three different measures used to evaluate the efficiency of the proposed discrete particle swarm optimization algorithm for scheduling independent tasks in distributed systems. Computational simulations are done based on a set of benchmark instances to assess the performance of the proposed algorithm.

  10. Rapid movement and instability of an invasive hybrid swarm.

    Science.gov (United States)

    Glotzbecker, Gregory J; Walters, David M; Blum, Michael J

    2016-07-01

    Unstable hybrid swarms that arise following the introduction of non-native species can overwhelm native congeners, yet the stability of invasive hybrid swarms has not been well documented over time. Here, we examine genetic variation and clinal stability across a recently formed hybrid swarm involving native blacktail shiner (Cyprinella venusta) and non-native red shiner (C. lutrensis) in the Upper Coosa River basin, which is widely considered to be a global hot spot of aquatic biodiversity. Examination of phenotypic, multilocus genotypic, and mitochondrial haplotype variability between 2005 and 2011 revealed that the proportion of hybrids has increased over time, with more than a third of all sampled individuals exhibiting admixture in the final year of sampling. Comparisons of clines over time indicated that the hybrid swarm has been rapidly progressing upstream, but at a declining and slower pace than rates estimated from historical collection records. Clinal comparisons also showed that the hybrid swarm has been expanding and contracting over time. Additionally, we documented the presence of red shiner and hybrids farther downstream than prior studies have detected, which suggests that congeners in the Coosa River basin, including all remaining populations of the threatened blue shiner (Cyprinella caerulea), are at greater risk than previously thought.

  11. Discordant introgression in a rapidly expanding hybrid swarm

    Science.gov (United States)

    Ward, Jessica L.; Blum, Mike J.; Walters, David M.; Porter, Brady A.; Burkhead, Noel; Freeman, Byron

    2012-01-01

    The erosion of species boundaries can involve rapid evolutionary change. Consequently, many aspects of the process remain poorly understood, including the formation, expansion, and evolution of hybrid swarms. Biological invasions involving hybridization present exceptional opportunities to study the erosion of species boundaries because timelines of interactions and outcomes are frequently well known. Here, we examined clinal variation across codominant and maternally inherited genetic markers as well as phenotypic traits to characterize the expansion and evolution of a hybrid swarm between native Cyprinella venusta and invasive Cyprinella lutrensis minnows. Discordant introgression of phenotype, microsatellite multilocus genotype, and mtDNA haplotype indicates that the observable expansion of the C. venusta x C. lutrensis hybrid swarm is a false invasion front. Both parental and hybrid individuals closely resembling C. lutrensis are numerically dominant in the expansion wake, indicating that the non-native parental phenotype may be selectively favored. These findings show that cryptic introgression can extend beyond the phenotypic boundaries of hybrid swarms and that hybrid swarms likely expand more rapidly than can be documented from phenotypic variation alone. Similarly, dominance of a single parental phenotype following an introduction event may lead to instances of species erosion being mistaken for species displacement without hybridization.

  12. Swarm Robotics with Circular Formation Motion Including Obstacles Avoidance

    Directory of Open Access Journals (Sweden)

    Nabil M. Hewahi

    2017-07-01

    Full Text Available The robots science has been developed over the past few years, where robots have become used to accomplish difficult, repetitive or accurate tasks, which are very hard for humans to carry out. In this paper, we propose an algorithm to control the motion of a swarm of robots and make them able to avoid obstacles. The proposed solution is based on forming the robots in circular fashion. A group set of robots consists of multiple groups of robots, each group of robots consists of robots forming a circular shape and each group set is a circular form of robots. The proposed algorithm is concerned with first locating the randomly generated robots in groups and secondly with the swarm robot motion and finally with the swarm obstacle avoidance and swarm reorganization after crossing the obstacle. The proposed algorithm has been simulated with five different obstacles with various numbers of randomly generated robots. The results show that the swarm in the circular form can deal with the obstacles very effectively by passing the obstacles smoothly. The proposed algorithm has been compared with flocking algorithm and it is shown that the circular formation algorithm does not need extensive computation after obstacle avoidance whereas the flocking algorithm needs extensive computation. In addition, the circular formation algorithm maintains every robot in its group after avoiding the obstacles whereas with flocking algorithm does not.

  13. Swarm, genetic and evolutionary programming algorithms applied to multiuser detection

    Directory of Open Access Journals (Sweden)

    Paul Jean Etienne Jeszensky

    2005-02-01

    Full Text Available In this paper, the particles swarm optimization technique, recently published in the literature, and applied to Direct Sequence/Code Division Multiple Access systems (DS/CDMA with multiuser detection (MuD is analyzed, evaluated and compared. The Swarm algorithm efficiency when applied to the DS-CDMA multiuser detection (Swarm-MuD is compared through the tradeoff performance versus computational complexity, being the complexity expressed in terms of the number of necessary operations in order to reach the performance obtained through the optimum detector or the Maximum Likelihood detector (ML. The comparison is accomplished among the genetic algorithm, evolutionary programming with cloning and Swarm algorithm under the same simulation basis. Additionally, it is proposed an heuristics-MuD complexity analysis through the number of computational operations. Finally, an analysis is carried out for the input parameters of the Swarm algorithm in the attempt to find the optimum parameters (or almost-optimum for the algorithm applied to the MuD problem.

  14. Coverage Optimization with Connectivity Preservation for UAV Swarms Applying Chaotic Dynamics

    OpenAIRE

    Rosalie, Martin; Brust, Matthias,; Danoy, Grégoire; Chaumette, Serge; Bouvry, Pascal

    2017-01-01

    International audience; Cooperative usage of multiple UAVs as a swarm can deliver high-quality surveillance performance. However, the communication capabilities within the UAV swarm must be maintained for local data propagation to swarm members in favor of achieving an efficient global behavior. In this paper, we address the problem of optimizing two adversary criteria for such a UAV swarm: (a) maximizing the area coverage, while (b) preserving network connectivity. Our approach, called CACOC...

  15. Effect of high-flux astronomical sources on the constellation-X microcalorimeter spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa-Feliciano, E. E-mail: enectali.figueroa@gsfc.nasa.gov; Bandler, S.; Boyce, K.; Chervenak, J.; Finkbeiner, F.; Kelley, R.; Lindeman, M.A.; Porter, S.F.; Saab, T.; Stahle, C.K

    2004-03-11

    We study the effects of high flux on transition-edge sensors by using a non-linear microcalorimeter model with parameters suitable for the Constellation-X mission. A photon event list was created that simulated the flux and spectrum of the Crab nebula incident on the detector when folded through the Constellation-X optics and filters. Simulations show that even at Crab levels of flux, the Con-X microcalorimeter does not 'latch' into the normal state.

  16. SPOT Tandem completed: A unique constellation of optical satellites from Europe

    OpenAIRE

    Lemmens, M.J.P.M.

    2014-01-01

    The launch of SPOT 7 on 30 June 2014 at 6:22 a.m. CET completed the constellation of four optical spacecraft operating in the same orbit. The constellation further consists of twin sister SPOT 6 and Pléiades 1A and 1B. To mark the occasion, the author discusses the features of the extended family of 7 SPOT satellites here.

  17. Constant Envelope Precoding with Adaptive Receiver Constellation in MISO Fading Channel

    OpenAIRE

    Zhang, Shuowen; Zhang, Rui; Lim, Teng Joon

    2015-01-01

    Constant envelope (CE) precoding is an appealing transmission technique which enables the realization of high power amplifier (PA) efficiency. For CE precoding in a single-user multiple-input single-output (MISO) channel, a desired constellation is feasible at the receiver if and only if it can be scaled to lie in an annulus, whose boundaries are characterized by the instantaneous channel realization. Therefore, if a fixed receiver constellation is used for CE precoding in a fading channel, w...

  18. Constellation Program Lessons Learned. Volume 2; Detailed Lessons Learned

    Science.gov (United States)

    Rhatigan, Jennifer; Neubek, Deborah J.; Thomas, L. Dale

    2011-01-01

    These lessons learned are part of a suite of hardware, software, test results, designs, knowledge base, and documentation that comprises the legacy of the Constellation Program. The context, summary information, and lessons learned are presented in a factual format, as known and described at the time. While our opinions might be discernable in the context, we have avoided all but factually sustainable statements. Statements should not be viewed as being either positive or negative; their value lies in what we did and what we learned that is worthy of passing on. The lessons include both "dos" and "don ts." In many cases, one person s "do" can be viewed as another person s "don t"; therefore, we have attempted to capture both perspectives when applicable and useful. While Volume I summarizes the views of those who managed the program, this Volume II encompasses the views at the working level, describing how the program challenges manifested in day-to-day activities. Here we see themes that were perhaps hinted at, but not completely addressed, in Volume I: unintended consequences of policies that worked well at higher levels but lacked proper implementation at the working level; long-term effects of the "generation gap" in human space flight development, the need to demonstrate early successes at the expense of thorough planning, and the consequences of problems and challenges not yet addressed because other problems and challenges were more immediate or manifest. Not all lessons learned have the benefit of being operationally vetted, since the program was cancelled shortly after Preliminary Design Review. We avoid making statements about operational consequences (with the exception of testing and test flights that did occur), but we do attempt to provide insight into how operational thinking influenced design and testing. The lessons have been formatted with a description, along with supporting information, a succinct statement of the lesson learned, and

  19. Using constellation pharmacology to define comprehensively a somatosensory neuronal subclass

    Science.gov (United States)

    Teichert, Russell W.; Memon, Tosifa; Aman, Joseph W.; Olivera, Baldomero M.

    2014-01-01

    Change is intrinsic to nervous systems; change is required for learning and conditioning and occurs with disease progression, normal development, and aging. To better understand mammalian nervous systems and effectively treat nervous-system disorders, it is essential to track changes in relevant individual neurons. A critical challenge is to identify and characterize the specific cell types involved and the molecular-level changes that occur in each. Using an experimental strategy called constellation pharmacology, we demonstrate that we can define a specific somatosensory neuronal subclass, cold thermosensors, across different species and track changes in these neurons as a function of development. Cold thermosensors are uniformly responsive to menthol and innocuous cool temperature (17 °C), indicating that they express TRPM8 channels. A subset of cold thermosensors expressed α7 nicotinic acetylcholine receptors (nAChRs) but not other nAChR subtypes. Differences in temperature threshold of cold thermosensors correlated with functional expression of voltage-gated K channels Kv1.1/1.2: Relatively higher expression of KV1.1/1.2 channels resulted in a higher threshold response to cold temperature. Other signaling components varied during development and between species. In cold thermosensors of neonatal mice and rats, ATP receptors were functionally expressed, but the expression disappeared with development. This developmental change occurred earlier in low-threshold than high-threshold cold thermosensors. Most rat cold thermosensors expressed TRPA1 channels, whereas mouse cold thermosensors did not. The broad implications of this study are that it is now feasible to track changes in receptor and ion-channel expression in individual neuronal subclasses as a function of development, learning, disease, or aging. PMID:24469798

  20. Small Spacecraft Constellation Concept for Mars Atmospheric Radio Occultations

    Science.gov (United States)

    Asmar, S. W.; Mannucci, A. J.; Ao, C. O.; Kobayashi, M. M.; Lazio, J.; Marinan, A.; Massone, G.; McCandless, S. E.; Preston, R. A.; Seubert, J.; Williamson, W.

    2017-12-01

    First demonstrated in 1965 when Mariner IV flew by Mars and determined the salient features of its atmosphere, radio occultation experiments have been carried out on numerous planetary missions with great discoveries. These experiments utilize the now classic configuration of a signal from a single planetary spacecraft to Earth receiving stations, where the science data are acquired. The Earth science community advanced the technique to utilizing a constellation of spacecraft with the radio occultation links between the spacecraft, enabled by the infrastructure of the Global Positioning System. With the advent of small and less costly spacecraft, such as planetary CubeSats and other variations, such as the anticipated innovative Mars Cube One mission, crosslinks among small spacecraft can be used to study other planets in the near future. Advantages of this type of experiment include significantly greater geographical coverage, which could reach global coverage over a few weeks with a small number of spacecraft. Repeatability of the global coverage can lead to examining temperature-pressure profiles and ionospheric electron density profiles, on daily, seasonal, annual, or other time scales of interest. The higher signal-to-noise ratio for inter-satellite links, compared to a link to Earth, decreases the design demands on the instrumentation (smaller antennas and transmitters, etc.). After an actual Mars crosslink demonstration, this concept has been in development using Mars as a possible target. Scientific objectives, delivery methods, operational scenarios and end-to-end configuration have been documented. Science objectives include determining the state and variability of the lower Martian atmosphere, which has been an identified as a high priority objective by the Mars Exploration Program Analysis Group, particularly as it relates to entry, descent, and landing and ascent for future crewed and robotic missions. This paper will present the latest research on the

  1. The lost constellations a history of obsolete, extinct, or forgotten star lore

    CERN Document Server

    Barentine, John C

    2016-01-01

    Casual stargazers are familiar with many classical figures and asterisms composed of bright stars (e.g., Orion and the Plough), but this book reveals not just the constellations of today but those of yesteryear. The history of the human identification of constellations among the stars is explored through the stories of some influential celestial cartographers whose works determined whether new inventions survived. The history of how the modern set of 88 constellations was defined by the professional astronomy community is recounted, explaining how the constellations described in the book became permanently “extinct.”  Dr. Barentine addresses why some figures were tried and discarded, and also directs observers to how those figures can still be picked out on a clear night if one knows where to look. These lost constellations are described in great detail using historical references, ennabling observers to rediscover them on their own surveys of the sky. Treatment of the obsolete constellations as ...

  2. An Investigation into Establishing a Formation of Small Satellites in a Lunar Flower Constellation

    Science.gov (United States)

    McManus, Lauren

    Lunar science missions such as LADEE and GRAIL achieved unprecedented measurements of the Lunar exosphere and gravity field. These missions were performed with one (LADEE) or two (GRAIL) traditional satellites. The global coverage achieved by these missions could have been greatly enhanced with the use of a constellation of satellites. A constellation of communication satellites at the Moon would also be necessary if a Lunar human base were to be established. Constellations with many satellites are expensive with traditional technology, but have become feasible through the technological advancements and affordability of cubesats. Cubesat constellations allow for full surface coverage in science or communication missions at a reasonable mission cost. Repeat ground track orbits offer interesting options for science or communication constellations, since they provide repeat coverage of the surface at a fixed time between sequential visits. Flower constellations are a family of constellations being studied primarily by Daniele Mortari at Texas A&M; University that make use of repeat ground tracks. Orbital parameters are selected such that the nodal period of the orbit matches the nodal period of the primary body by a factor dependent on the number of days and the number of revolutions to repeat the ground track. All orbits in a flower constellation have identical orbital elements, with the exception of the right ascension of the ascending node (RAAN) and the initial mean anomaly, which are determined based on the desired phasing scheme desired. Flower constellations have thus far primarily been studied at Earth. A flower constellation at the Moon could be quite useful for science or communication purposes. In this scenario, the flower constellation satellites would be small satellites, which introduces many unique challenges. The cubesats would have limited propulsion capability and would need to be deployed from a mothercraft. Orbital maintenance would then be

  3. Swarm prevention and spring treatment against Varroa destructor in honey bee colonies (Apis mellifera)

    NARCIS (Netherlands)

    Cornelissen, B.; Gerritsen, L.J.M.

    2006-01-01

    In 2004 and 2005 experiments were carried out to test the efficacy and efficiency of Varroa control combined with swarm prevention methods in spring. Honey bee colonies were split in an artificial swarm and a brood carrier. Hereafter the swarms were treated with oxalic acid and the brood carriers

  4. Multi-objective swarm intelligence theoretical advances and applications

    CERN Document Server

    Jagadev, Alok; Panda, Mrutyunjaya

    2015-01-01

    The aim of this book is to understand the state-of-the-art theoretical and practical advances of swarm intelligence. It comprises seven contemporary relevant chapters. In chapter 1, a review of Bacteria Foraging Optimization (BFO) techniques for both single and multiple criterions problem is presented. A survey on swarm intelligence for multiple and many objectives optimization is presented in chapter 2 along with a topical study on EEG signal analysis. Without compromising the extensive simulation study, a comparative study of variants of MOPSO is provided in chapter 3. Intractable problems like subset and job scheduling problems are discussed in chapters 4 and 7 by different hybrid swarm intelligence techniques. An attempt to study image enhancement by ant colony optimization is made in chapter 5. Finally, chapter 7 covers the aspect of uncertainty in data by hybrid PSO.       

  5. Swarm- Validation of Star Tracker and Accelerometer Data

    Science.gov (United States)

    Schack, Peter; Schlicht, Anja; Pail, Roland; Gruber, Thomas

    2016-08-01

    The ESA Swarm mission is designed to advance studies in the field of magnetosphere, thermosphere and gravity field. To be fortunate on this task precise knowledge of the orientation of the Swarm satellites is required together with knowledge about external forces acting on the satellites. The key sensors providing this information are the star trackers and the accelerometers. Based on star tracker studies conducted by the Denmark Technical University (DTU), we found interesting patterns in the interboresight angles on all three satellites, which are partly induced by temperature alterations. Additionally, structures of horizontal stripes seem to be caused by the unique distribution of observed stars on the charge-coupled device of the star trackers. Our accelerometer analyses focus on spikes and pulses in the observations. Those short term events on Swarm might originate from electrical processes introduced by sunlight illuminating the nadir foil. Comparisons to GOCE and GRACE are included.

  6. Composite Particle Swarm Optimizer With Historical Memory for Function Optimization.

    Science.gov (United States)

    Li, Jie; Zhang, JunQi; Jiang, ChangJun; Zhou, MengChu

    2015-10-01

    Particle swarm optimization (PSO) algorithm is a population-based stochastic optimization technique. It is characterized by the collaborative search in which each particle is attracted toward the global best position (gbest) in the swarm and its own best position (pbest). However, all of particles' historical promising pbests in PSO are lost except their current pbests. In order to solve this problem, this paper proposes a novel composite PSO algorithm, called historical memory-based PSO (HMPSO), which uses an estimation of distribution algorithm to estimate and preserve the distribution information of particles' historical promising pbests. Each particle has three candidate positions, which are generated from the historical memory, particles' current pbests, and the swarm's gbest. Then the best candidate position is adopted. Experiments on 28 CEC2013 benchmark functions demonstrate the superiority of HMPSO over other algorithms.

  7. Monte Carlo simulation of electron swarms in H2

    International Nuclear Information System (INIS)

    Hunter, S.R.

    1977-01-01

    A Monte Carlo simulation of the motion of an electron swarm in molecular hydrogen has been studied in the range E/N 1.4-170 Td. The simulation was performed for 400-600 electrons at several values of E/N for two different sets of inelastic collision cross sections at high E/N. Results were obtained for the longitudinal diffusion coefficient Dsub(L), lateral diffusion coefficient D, swarm drift velocity W, average swarm energy and ionization and excitation production coefficients, and these were compared with experimental data where available. It is found that the results differ significantly from the experimental values and this is attributed to the isotropic scattering model used in this work. However, the results lend support to the experimental technique used recently by Blevin et al. to determine these transport parameters, and in particular confirm their results that Dsub(L) > D at high values of E/N. (Author)

  8. A Diversity-Guided Particle Swarm Optimizer - the ARPSO

    DEFF Research Database (Denmark)

    Vesterstrøm, Jacob Svaneborg; Riget, Jacques

    2002-01-01

    The particle swarm optimization (PSO) algorithm is a new population based search strat- egy, which has exhibited good performance on well-known numerical test problems. How- ever, on strongly multi-modal test problems the PSO tends to suffer from premature convergence. This is due to a decrease...... of diversity in search space that leads to a to- tal implosion and ultimately fitness stagnation of the swarm. An accepted hypothesis is that maintenance of high diversity is crucial for preventing premature convergence in multi-modal optimization. We introduce the attractive and repulsive PSO (ARPSO......) in trying to overcome the problem of premature convergence. It uses a diversity measure to control the swarm. The result is an algorithm that alternates between phases of attraction and repulsion. The performance of the ARPSO is compared to a basic PSO (bPSO) and a genetic algorithm (GA). The results show...

  9. Implementasi Algoritma Particle Swarm untuk Menyelesaikan Sistem Persamaan Nonlinear

    Directory of Open Access Journals (Sweden)

    Ardiana Rosita

    2012-09-01

    Full Text Available Penyelesaian sistem persamaan nonlinear merupakan salah satu permasalahan yang sulit pada komputasi numerik dan berbagai aplikasi teknik. Beberapa metode telah dikembangkan untuk menyelesaikan sistem persamaan ini dan metode Newton merupakan metode yang paling sering digunakan. Namun metode ini memerlukan perkiraan solusi awal dan memilih perkiraan solusi awal yang baik untuk sebagian besar sistem persamaan nonlinear tidaklah mudah. Pada makalah ini, algoritma Particle Swarm yang diusulkan oleh Jaberipour dan kawan-kawan[1] diimplementasikan. Algoritma ini merupakan pengembangan dari algoritma Particle Swarm Optimization (PSO. Algoritma ini meyelesaikan sistem persamaan nonlinear yang sebelumnya telah diubah menjadi permasalahan optimasi. Uji coba dilakukan terhadap beberapa fungsi dan sistem persamaan nonlinear untuk menguji kinerja dan efisiensi algoritma. Berdasarkan hasil uji coba, beberapa fungsi dan sistem persamaan nonlinear telah konvergen pada iterasi ke 10 sampai 20 dan terdapat fungsi yang konvergen pada iterasi ke 200. Selain itu, solusi yang dihasilkan algoritma Particle Swarm mendekati solusi eksak.

  10. Cell-Division Behavior in a Heterogeneous Swarm Environment.

    Science.gov (United States)

    Erskine, Adam; Herrmann, J Michael

    2015-01-01

    We present a system of virtual particles that interact using simple kinetic rules. It is known that heterogeneous mixtures of particles can produce particularly interesting behaviors. Here we present a two-species three-dimensional swarm in which a behavior emerges that resembles cell division. We show that the dividing behavior exists across a narrow but finite band of parameters and for a wide range of population sizes. When executed in a two-dimensional environment the swarm's characteristics and dynamism manifest differently. In further experiments we show that repeated divisions can occur if the system is extended by a biased equilibrium process to control the split of populations. We propose that this repeated division behavior provides a simple model for cell-division mechanisms and is of interest for the formation of morphological structure and to swarm robotics.

  11. Recent advances in swarm intelligence and evolutionary computation

    CERN Document Server

    2015-01-01

    This timely review volume summarizes the state-of-the-art developments in nature-inspired algorithms and applications with the emphasis on swarm intelligence and bio-inspired computation. Topics include the analysis and overview of swarm intelligence and evolutionary computation, hybrid metaheuristic algorithms, bat algorithm, discrete cuckoo search, firefly algorithm, particle swarm optimization, and harmony search as well as convergent hybridization. Application case studies have focused on the dehydration of fruits and vegetables by the firefly algorithm and goal programming, feature selection by the binary flower pollination algorithm, job shop scheduling, single row facility layout optimization, training of feed-forward neural networks, damage and stiffness identification, synthesis of cross-ambiguity functions by the bat algorithm, web document clustering, truss analysis, water distribution networks, sustainable building designs and others. As a timely review, this book can serve as an ideal reference f...

  12. Quantitative analysis of distributed control paradigms of robot swarms

    DEFF Research Database (Denmark)

    Ngo, Trung Dung

    2010-01-01

    Given a task of designing controller for mobile robots in swarms, one might wonder which distributed control paradigms should be selected. Until now, paradigms of robot controllers have been within either behaviour based control or neural network based control, which have been recognized as two...... mainstreams of controller design for mobile robots. However, in swarm robotics, it is not clear how to determine control paradigms. In this paper we study the two control paradigms with various experiments of swarm aggregation. First, we introduce the two control paradigms for mobile robots. Second, we...... describe the physical and simulated robots, experiment scenario, and experiment setup. Third, we present our robot controllers based on behaviour based and neural network based paradigms. Fourth, we graphically show their experiment results and quantitatively analyse the results in comparison of the two...

  13. Cosmological parameter estimation using particle swarm optimization

    Science.gov (United States)

    Prasad, Jayanti; Souradeep, Tarun

    2012-06-01

    Constraining theoretical models, which are represented by a set of parameters, using observational data is an important exercise in cosmology. In Bayesian framework this is done by finding the probability distribution of parameters which best fits to the observational data using sampling based methods like Markov chain Monte Carlo (MCMC). It has been argued that MCMC may not be the best option in certain problems in which the target function (likelihood) poses local maxima or have very high dimensionality. Apart from this, there may be examples in which we are mainly interested to find the point in the parameter space at which the probability distribution has the largest value. In this situation the problem of parameter estimation becomes an optimization problem. In the present work we show that particle swarm optimization (PSO), which is an artificial intelligence inspired population based search procedure, can also be used for cosmological parameter estimation. Using PSO we were able to recover the best-fit Λ cold dark matter (LCDM) model parameters from the WMAP seven year data without using any prior guess value or any other property of the probability distribution of parameters like standard deviation, as is common in MCMC. We also report the results of an exercise in which we consider a binned primordial power spectrum (to increase the dimensionality of problem) and find that a power spectrum with features gives lower chi square than the standard power law. Since PSO does not sample the likelihood surface in a fair way, we follow a fitting procedure to find the spread of likelihood function around the best-fit point.

  14. Group A human rotavirus genomics: evidence that gene constellations are influenced by viral protein interactions.

    Science.gov (United States)

    Heiman, Erica M; McDonald, Sarah M; Barro, Mario; Taraporewala, Zenobia F; Bar-Magen, Tamara; Patton, John T

    2008-11-01

    Group A human rotaviruses (HRVs) are the major cause of severe viral gastroenteritis in infants and young children. To gain insight into the level of genetic variation among HRVs, we determined the genome sequences for 10 strains belonging to different VP7 serotypes (G types). The HRVs chosen for this study, D, DS-1, P, ST3, IAL28, Se584, 69M, WI61, A64, and L26, were isolated from infected persons and adapted to cell culture to use as serotype references. Our sequencing results revealed that most of the individual proteins from each HRV belong to one of three genotypes (1, 2, or 3) based on their similarities to proteins of genogroup strains (Wa, DS-1, or AU-1, respectively). Strains D, P, ST3, IAL28, and WI61 encode genotype 1 (Wa-like) proteins, whereas strains DS-1 and 69M encode genotype 2 (DS-1-like) proteins. Of the 10 HRVs sequenced, 3 of them (Se584, A64, and L26) encode proteins belonging to more than one genotype, indicating that they are intergenogroup reassortants. We used amino acid sequence alignments to identify residues that distinguish proteins belonging to HRV genotype 1, 2, or 3. These genotype-specific changes cluster in definitive regions within each viral protein, many of which are sites of known protein-protein interactions. For the intermediate viral capsid protein (VP6), the changes map onto the atomic structure at the VP2-VP6, VP4-VP6, and VP7-VP6 interfaces. The results of this study provide evidence that group A HRV gene constellations exist and may be influenced by interactions among viral proteins during replication.

  15. Distributed UAV-Swarm Real-Time Geomatic Data Collection Under Dynamically Changing Resolution Requirements

    Science.gov (United States)

    Almeida, Miguel; Hildmann, Hanno; Solmaz, Gürkan

    2017-08-01

    Unmanned Aerial Vehicles (UAVs) have been used for reconnaissance and surveillance missions as far back as the Vietnam War, but with the recent rapid increase in autonomy, precision and performance capabilities - and due to the massive reduction in cost and size - UAVs have become pervasive products, available and affordable for the general public. The use cases for UAVs are in the areas of disaster recovery, environmental mapping & protection and increasingly also as extended eyes and ears of civil security forces such as fire-fighters and emergency response units. In this paper we present a swarm algorithm that enables a fleet of autonomous UAVs to collectively perform sensing tasks related to environmental and rescue operations and to dynamically adapt to e.g. changing resolution requirements. We discuss the hardware used to build our own drones and the settings under which we validate the proposed approach.

  16. DISTRIBUTED UAV-SWARM-BASED REAL-TIME GEOMATIC DATA COLLECTION UNDER DYNAMICALLY CHANGING RESOLUTION REQUIREMENTS

    Directory of Open Access Journals (Sweden)

    M. Almeida

    2017-08-01

    Full Text Available Unmanned Aerial Vehicles (UAVs have been used for reconnaissance and surveillance missions as far back as the Vietnam War, but with the recent rapid increase in autonomy, precision and performance capabilities – and due to the massive reduction in cost and size – UAVs have become pervasive products, available and affordable for the general public. The use cases for UAVs are in the areas of disaster recovery, environmental mapping & protection and increasingly also as extended eyes and ears of civil security forces such as fire-fighters and emergency response units. In this paper we present a swarm algorithm that enables a fleet of autonomous UAVs to collectively perform sensing tasks related to environmental and rescue operations and to dynamically adapt to e.g. changing resolution requirements. We discuss the hardware used to build our own drones and the settings under which we validate the proposed approach.

  17. Parameter estimation for chaotic systems using improved bird swarm algorithm

    Science.gov (United States)

    Xu, Chuangbiao; Yang, Renhuan

    2017-12-01

    Parameter estimation of chaotic systems is an important problem in nonlinear science and has aroused increasing interest of many research fields, which can be basically reduced to a multidimensional optimization problem. In this paper, an improved boundary bird swarm algorithm is used to estimate the parameters of chaotic systems. This algorithm can combine the good global convergence and robustness of the bird swarm algorithm and the exploitation capability of improved boundary learning strategy. Experiments are conducted on the Lorenz system and the coupling motor system. Numerical simulation results reveal the effectiveness and with desirable performance of IBBSA for parameter estimation of chaotic systems.

  18. Swarm intelligence metaheuristics for enhanced data analysis and optimization.

    Science.gov (United States)

    Hanrahan, Grady

    2011-09-21

    The swarm intelligence (SI) computing paradigm has proven itself as a comprehensive means of solving complicated analytical chemistry problems by emulating biologically-inspired processes. As global optimum search metaheuristics, associated algorithms have been widely used in training neural networks, function optimization, prediction and classification, and in a variety of process-based analytical applications. The goal of this review is to provide readers with critical insight into the utility of swarm intelligence tools as methods for solving complex chemical problems. Consideration will be given to algorithm development, ease of implementation and model performance, detailing subsequent influences on a number of application areas in the analytical, bioanalytical and detection sciences.

  19. Gravity inversion of a fault by Particle swarm optimization (PSO).

    Science.gov (United States)

    Toushmalani, Reza

    2013-01-01

    Particle swarm optimization is a heuristic global optimization method and also an optimization algorithm, which is based on swarm intelligence. It comes from the research on the bird and fish flock movement behavior. In this paper we introduce and use this method in gravity inverse problem. We discuss the solution for the inverse problem of determining the shape of a fault whose gravity anomaly is known. Application of the proposed algorithm to this problem has proven its capability to deal with difficult optimization problems. The technique proved to work efficiently when tested to a number of models.

  20. Particle swarm optimization - Genetic algorithm (PSOGA) on linear transportation problem

    Science.gov (United States)

    Rahmalia, Dinita

    2017-08-01

    Linear Transportation Problem (LTP) is the case of constrained optimization where we want to minimize cost subject to the balance of the number of supply and the number of demand. The exact method such as northwest corner, vogel, russel, minimal cost have been applied at approaching optimal solution. In this paper, we use heurisitic like Particle Swarm Optimization (PSO) for solving linear transportation problem at any size of decision variable. In addition, we combine mutation operator of Genetic Algorithm (GA) at PSO to improve optimal solution. This method is called Particle Swarm Optimization - Genetic Algorithm (PSOGA). The simulations show that PSOGA can improve optimal solution resulted by PSO.