Modelling charge transfer reactions with the frozen density embedding formalism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavanello, Michele; Neugebauer, Johannes

2011-12-21

The frozen density embedding (FDE) subsystem formulation of density-functional theory is a useful tool for studying charge transfer reactions. In this work charge-localized, diabatic states are generated directly with FDE and used to calculate electronic couplings of hole transfer reactions in two {pi}-stacked nucleobase dimers of B-DNA: 5{sup '}-GG-3{sup '} and 5{sup '}-GT-3{sup '}. The calculations rely on two assumptions: the two-state model, and a small differential overlap between donor and acceptor subsystem densities. The resulting electronic couplings agree well with benchmark values for those exchange-correlation functionals that contain a high percentage of exact exchange. Instead, when semilocal GGA functionalsmore » are used the electronic couplings are grossly overestimated.« less

Holographic entanglement entropy of a 1 + 1 dimensional p-wave superconductor

NASA Astrophysics Data System (ADS)

Das, Sumit R.; Fujita, Mitsutoshi; Kim, Bom Soo

2017-09-01

We examine the behavior of entanglement entropy S A EE of a subsystem A in a fully backreacted holographic model of a 1 + 1 dimensional p wave superconductor across the phase transition. For a given temperature, the system goes to a superconducting phase beyond a critical value of the charge density. The entanglement entropy, considered as a function of the charge density at a given temperature, has a cusp at the critical point. In addition, we find that there are three different behaviors in the condensed phase, depending on the subsystem size. For a subsystem size l smaller than a critical size l c1, S A EE continues to increase as a function of the charge density as we cross the phase transition. When l lies between l c1 and another critical size l c2 the entanglement entropy displays a non-monotonic behavior, while for l > l c2 it decreases monotonically. At large charge densities S A EE appears to saturate. The non-monotonic behavior leads to a novel phase diagram for this system.

Subsystem functional and the missing ingredient of confinement physics in density functionals.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armiento, Rickard Roberto; Mattsson, Ann Elisabet; Hao, Feng

2010-08-01

The subsystem functional scheme is a promising approach recently proposed for constructing exchange-correlation density functionals. In this scheme, the physics in each part of real materials is described by mapping to a characteristic model system. The 'confinement physics,' an essential physical ingredient that has been left out in present functionals, is studied by employing the harmonic-oscillator (HO) gas model. By performing the potential {yields} density and the density {yields} exchange energy per particle mappings based on two model systems characterizing the physics in the interior (uniform electron-gas model) and surface regions (Airy gas model) of materials for the HO gases,more » we show that the confinement physics emerges when only the lowest subband of the HO gas is occupied by electrons. We examine the approximations of the exchange energy by several state-of-the-art functionals for the HO gas, and none of them produces adequate accuracy in the confinement dominated cases. A generic functional that incorporates the description of the confinement physics is needed.« less

Avoiding fractional electrons in subsystem DFT based ab-initio molecular dynamics yields accurate models for liquid water and solvated OH radical

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genova, Alessandro, E-mail: alessandro.genova@rutgers.edu; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu; Ceresoli, Davide, E-mail: davide.ceresoli@cnr.it

2016-06-21

In this work we achieve three milestones: (1) we present a subsystem DFT method capable of running ab-initio molecular dynamics simulations accurately and efficiently. (2) In order to rid the simulations of inter-molecular self-interaction error, we exploit the ability of semilocal frozen density embedding formulation of subsystem DFT to represent the total electron density as a sum of localized subsystem electron densities that are constrained to integrate to a preset, constant number of electrons; the success of the method relies on the fact that employed semilocal nonadditive kinetic energy functionals effectively cancel out errors in semilocal exchange–correlation potentials that aremore » linked to static correlation effects and self-interaction. (3) We demonstrate this concept by simulating liquid water and solvated OH{sup •} radical. While the bulk of our simulations have been performed on a periodic box containing 64 independent water molecules for 52 ps, we also simulated a box containing 256 water molecules for 22 ps. The results show that, provided one employs an accurate nonadditive kinetic energy functional, the dynamics of liquid water and OH{sup •} radical are in semiquantitative agreement with experimental results or higher-level electronic structure calculations. Our assessments are based upon comparisons of radial and angular distribution functions as well as the diffusion coefficient of the liquid.« less

Avoiding fractional electrons in subsystem DFT based ab-initio molecular dynamics yields accurate models for liquid water and solvated OH radical.

PubMed

Genova, Alessandro; Ceresoli, Davide; Pavanello, Michele

2016-06-21

In this work we achieve three milestones: (1) we present a subsystem DFT method capable of running ab-initio molecular dynamics simulations accurately and efficiently. (2) In order to rid the simulations of inter-molecular self-interaction error, we exploit the ability of semilocal frozen density embedding formulation of subsystem DFT to represent the total electron density as a sum of localized subsystem electron densities that are constrained to integrate to a preset, constant number of electrons; the success of the method relies on the fact that employed semilocal nonadditive kinetic energy functionals effectively cancel out errors in semilocal exchange-correlation potentials that are linked to static correlation effects and self-interaction. (3) We demonstrate this concept by simulating liquid water and solvated OH(•) radical. While the bulk of our simulations have been performed on a periodic box containing 64 independent water molecules for 52 ps, we also simulated a box containing 256 water molecules for 22 ps. The results show that, provided one employs an accurate nonadditive kinetic energy functional, the dynamics of liquid water and OH(•) radical are in semiquantitative agreement with experimental results or higher-level electronic structure calculations. Our assessments are based upon comparisons of radial and angular distribution functions as well as the diffusion coefficient of the liquid.

Accelerating wavefunction in density-functional-theory embedding by truncating the active basis set

NASA Astrophysics Data System (ADS)

Bennie, Simon J.; Stella, Martina; Miller, Thomas F.; Manby, Frederick R.

2015-07-01

Methods where an accurate wavefunction is embedded in a density-functional description of the surrounding environment have recently been simplified through the use of a projection operator to ensure orthogonality of orbital subspaces. Projector embedding already offers significant performance gains over conventional post-Hartree-Fock methods by reducing the number of correlated occupied orbitals. However, in our first applications of the method, we used the atomic-orbital basis for the full system, even for the correlated wavefunction calculation in a small, active subsystem. Here, we further develop our method for truncating the atomic-orbital basis to include only functions within or close to the active subsystem. The number of atomic orbitals in a calculation on a fixed active subsystem becomes asymptotically independent of the size of the environment, producing the required O ( N 0 ) scaling of cost of the calculation in the active subsystem, and accuracy is controlled by a single parameter. The applicability of this approach is demonstrated for the embedded many-body expansion of binding energies of water hexamers and calculation of reaction barriers of SN2 substitution of fluorine by chlorine in α-fluoroalkanes.

Describing long-range charge-separation processes with subsystem density-functional theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solovyeva, Alisa; Neugebauer, Johannes, E-mail: j.neugebauer@uni-muenster.de; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu

2014-04-28

Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants inmore » Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge — charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange–correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states.« less

Exact kinetic energy enables accurate evaluation of weak interactions by the FDE-vdW method.

PubMed

Sinha, Debalina; Pavanello, Michele

2015-08-28

The correlation energy of interaction is an elusive and sought-after interaction between molecular systems. By partitioning the response function of the system into subsystem contributions, the Frozen Density Embedding (FDE)-vdW method provides a computationally amenable nonlocal correlation functional based on the adiabatic connection fluctuation dissipation theorem applied to subsystem density functional theory. In reproducing potential energy surfaces of weakly interacting dimers, we show that FDE-vdW, either employing semilocal or exact nonadditive kinetic energy functionals, is in quantitative agreement with high-accuracy coupled cluster calculations (overall mean unsigned error of 0.5 kcal/mol). When employing the exact kinetic energy (which we term the Kohn-Sham (KS)-vdW method), the binding energies are generally closer to the benchmark, and the energy surfaces are also smoother.

Exact kinetic energy enables accurate evaluation of weak interactions by the FDE-vdW method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinha, Debalina; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu

2015-08-28

The correlation energy of interaction is an elusive and sought-after interaction between molecular systems. By partitioning the response function of the system into subsystem contributions, the Frozen Density Embedding (FDE)-vdW method provides a computationally amenable nonlocal correlation functional based on the adiabatic connection fluctuation dissipation theorem applied to subsystem density functional theory. In reproducing potential energy surfaces of weakly interacting dimers, we show that FDE-vdW, either employing semilocal or exact nonadditive kinetic energy functionals, is in quantitative agreement with high-accuracy coupled cluster calculations (overall mean unsigned error of 0.5 kcal/mol). When employing the exact kinetic energy (which we term themore » Kohn-Sham (KS)-vdW method), the binding energies are generally closer to the benchmark, and the energy surfaces are also smoother.« less

Solvatochromic shifts from coupled-cluster theory embedded in density functional theory

NASA Astrophysics Data System (ADS)

Höfener, Sebastian; Gomes, André Severo Pereira; Visscher, Lucas

2013-09-01

Building on the framework recently reported for determining general response properties for frozen-density embedding [S. Höfener, A. S. P. Gomes, and L. Visscher, J. Chem. Phys. 136, 044104 (2012)], 10.1063/1.3675845, in this work we report a first implementation of an embedded coupled-cluster in density-functional theory (CC-in-DFT) scheme for electronic excitations, where only the response of the active subsystem is taken into account. The formalism is applied to the calculation of coupled-cluster excitation energies of water and uracil in aqueous solution. We find that the CC-in-DFT results are in good agreement with reference calculations and experimental results. The accuracy of calculations is mainly sensitive to factors influencing the correlation treatment (basis set quality, truncation of the cluster operator) and to the embedding treatment of the ground-state (choice of density functionals). This allows for efficient approximations at the excited state calculation step without compromising the accuracy. This approximate scheme makes it possible to use a first principles approach to investigate environment effects with specific interactions at coupled-cluster level of theory at a cost comparable to that of calculations of the individual subsystems in vacuum.

Revealing electronic open quantum systems with subsystem TDDFT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishtal, Alisa, E-mail: alisa.krishtal@rutgers.edu; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu

2016-03-28

Open quantum systems (OQSs) are perhaps the most realistic systems one can approach through simulations. In recent years, describing OQSs with Density Functional Theory (DFT) has been a prominent avenue of research with most approaches based on a density matrix partitioning in conjunction with an ad-hoc description of system-bath interactions. We propose a different theoretical approach to OQSs based on partitioning of the electron density. Employing the machinery of subsystem DFT (and its time-dependent extension), we provide a novel way of isolating and analyzing the various terms contributing to the coupling between the system and the surrounding bath. To illustratemore » the theory, we provide numerical simulations on a toy system (a molecular dimer) and on a condensed phase system (solvated excimer). The simulations show that non-Markovian dynamics in the electronic system-bath interactions are important in chemical applications. For instance, we show that the superexchange mechanism of transport in donor-bridge-acceptor systems is a non-Markovian interaction between the donor-acceptor (OQS) with the bridge (bath) which is fully characterized by real-time subsystem time-dependent DFT.« less

Revealing electronic open quantum systems with subsystem TDDFT.

PubMed

Krishtal, Alisa; Pavanello, Michele

2016-03-28

Open quantum systems (OQSs) are perhaps the most realistic systems one can approach through simulations. In recent years, describing OQSs with Density Functional Theory (DFT) has been a prominent avenue of research with most approaches based on a density matrix partitioning in conjunction with an ad-hoc description of system-bath interactions. We propose a different theoretical approach to OQSs based on partitioning of the electron density. Employing the machinery of subsystem DFT (and its time-dependent extension), we provide a novel way of isolating and analyzing the various terms contributing to the coupling between the system and the surrounding bath. To illustrate the theory, we provide numerical simulations on a toy system (a molecular dimer) and on a condensed phase system (solvated excimer). The simulations show that non-Markovian dynamics in the electronic system-bath interactions are important in chemical applications. For instance, we show that the superexchange mechanism of transport in donor-bridge-acceptor systems is a non-Markovian interaction between the donor-acceptor (OQS) with the bridge (bath) which is fully characterized by real-time subsystem time-dependent DFT.

Revealing electronic open quantum systems with subsystem TDDFT

NASA Astrophysics Data System (ADS)

Krishtal, Alisa; Pavanello, Michele

2016-03-01

Open quantum systems (OQSs) are perhaps the most realistic systems one can approach through simulations. In recent years, describing OQSs with Density Functional Theory (DFT) has been a prominent avenue of research with most approaches based on a density matrix partitioning in conjunction with an ad-hoc description of system-bath interactions. We propose a different theoretical approach to OQSs based on partitioning of the electron density. Employing the machinery of subsystem DFT (and its time-dependent extension), we provide a novel way of isolating and analyzing the various terms contributing to the coupling between the system and the surrounding bath. To illustrate the theory, we provide numerical simulations on a toy system (a molecular dimer) and on a condensed phase system (solvated excimer). The simulations show that non-Markovian dynamics in the electronic system-bath interactions are important in chemical applications. For instance, we show that the superexchange mechanism of transport in donor-bridge-acceptor systems is a non-Markovian interaction between the donor-acceptor (OQS) with the bridge (bath) which is fully characterized by real-time subsystem time-dependent DFT.

Constituents and functional implications of the rat default mode network.

PubMed

Hsu, Li-Ming; Liang, Xia; Gu, Hong; Brynildsen, Julia K; Stark, Jennifer A; Ash, Jessica A; Lin, Ching-Po; Lu, Hanbing; Rapp, Peter R; Stein, Elliot A; Yang, Yihong

2016-08-02

The default mode network (DMN) has been suggested to support a variety of self-referential functions in humans and has been fractionated into subsystems based on distinct responses to cognitive tasks and functional connectivity architecture. Such subsystems are thought to reflect functional hierarchy and segregation within the network. Because preclinical models can inform translational studies of neuropsychiatric disorders, partitioning of the DMN in nonhuman species, which has previously not been reported, may inform both physiology and pathophysiology of the human DMN. In this study, we sought to identify constituents of the rat DMN using resting-state functional MRI (rs-fMRI) and diffusion tensor imaging. After identifying DMN using a group-level independent-component analysis on the rs-fMRI data, modularity analyses fractionated the DMN into an anterior and a posterior subsystem, which were further segregated into five modules. Diffusion tensor imaging tractography demonstrates a close relationship between fiber density and the functional connectivity between DMN regions, and provides anatomical evidence to support the detected DMN subsystems. Finally, distinct modulation was seen within and between these DMN subcomponents using a neurocognitive aging model. Taken together, these results suggest that, like the human DMN, the rat DMN can be partitioned into several subcomponents that may support distinct functions. These data encourage further investigation into the neurobiological mechanisms of DMN processing in preclinical models of both normal and disease states.

Kinetic energy as functional of the correlation hole

NASA Astrophysics Data System (ADS)

Nalewajski, Roman F.

2003-01-01

Using the marginal decomposition of the many-body probability distribution the electronic kinetic energy is expressed as the functional of the electron density and correlation hole. The analysis covers both the molecule as a whole and its constituent subsystems. The importance of the Fisher information for locality is emphasized.

Uniform magnetic fields in density-functional theory

NASA Astrophysics Data System (ADS)

Tellgren, Erik I.; Laestadius, Andre; Helgaker, Trygve; Kvaal, Simen; Teale, Andrew M.

2018-01-01

We construct a density-functional formalism adapted to uniform external magnetic fields that is intermediate between conventional density functional theory and Current-Density Functional Theory (CDFT). In the intermediate theory, which we term linear vector potential-DFT (LDFT), the basic variables are the density, the canonical momentum, and the paramagnetic contribution to the magnetic moment. Both a constrained-search formulation and a convex formulation in terms of Legendre-Fenchel transformations are constructed. Many theoretical issues in CDFT find simplified analogs in LDFT. We prove results concerning N-representability, Hohenberg-Kohn-like mappings, existence of minimizers in the constrained-search expression, and a restricted analog to gauge invariance. The issue of additivity of the energy over non-interacting subsystems, which is qualitatively different in LDFT and CDFT, is also discussed.

Uniform magnetic fields in density-functional theory.

PubMed

Tellgren, Erik I; Laestadius, Andre; Helgaker, Trygve; Kvaal, Simen; Teale, Andrew M

2018-01-14

We construct a density-functional formalism adapted to uniform external magnetic fields that is intermediate between conventional density functional theory and Current-Density Functional Theory (CDFT). In the intermediate theory, which we term linear vector potential-DFT (LDFT), the basic variables are the density, the canonical momentum, and the paramagnetic contribution to the magnetic moment. Both a constrained-search formulation and a convex formulation in terms of Legendre-Fenchel transformations are constructed. Many theoretical issues in CDFT find simplified analogs in LDFT. We prove results concerning N-representability, Hohenberg-Kohn-like mappings, existence of minimizers in the constrained-search expression, and a restricted analog to gauge invariance. The issue of additivity of the energy over non-interacting subsystems, which is qualitatively different in LDFT and CDFT, is also discussed.

Design, processing and testing of LSI arrays hybrid microelectronics task

NASA Technical Reports Server (NTRS)

Himmel, R. P.; Stuhlbarg, S. M.; Salmassy, S.

1978-01-01

Those factors affecting the cost of electronic subsystems utilizing LSI microcircuits were determined and the most efficient methods for low cost packaging of LSI devices as a function of density and reliability were developed.

Verification and Validation Testing of the Parachute Decelerator System Prior to the First Supersonic Flight Dynamics Test for the Low Density Supersonic Decelerator Program

NASA Technical Reports Server (NTRS)

Gallon, John C.; Witkowski, Allen

2015-01-01

The Parachute Decelerator System (PDS) is comprised of all components associated with the supersonic parachute and its associated deployment. During the Supersonic Flight Dynamics Test (SFDT), for the Low Density Supersonic Decelerators Program, the PDS was required to deploy the supersonic parachute in a defined fashion. The PDS hardware includes three major subsystems that must function together. The first subsystem is the Parachute Deployment Device (PDD), which acts as a modified pilot deployment system. It is comprised of a pyrotechnic mortar, a Kevlar ballute, a lanyard actuated pyrotechnic inflation aid, and rigging with its associated thermal protection material (TPS). The second subsystem is the supersonic parachute deployment hardware. This includes all of the parachute specific rigging that includes the parachute stowage can and the rigging including TPS and bridle stiffeners for bridle management during deployment. The third subsystem is the Supersonic Parachute itself, which includes the main parachute and deployment bags. This paper summarizes the verification and validation of the deployment process, from the initialization of the PDS system through parachute bag strip that was done prior to the first SFDT.

A lumped parameter mathematical model for simulation of subsonic wind tunnels

NASA Technical Reports Server (NTRS)

Krosel, S. M.; Cole, G. L.; Bruton, W. M.; Szuch, J. R.

1986-01-01

Equations for a lumped parameter mathematical model of a subsonic wind tunnel circuit are presented. The equation state variables are internal energy, density, and mass flow rate. The circuit model is structured to allow for integration and analysis of tunnel subsystem models which provide functions such as control of altitude pressure and temperature. Thus the model provides a useful tool for investigating the transient behavior of the tunnel and control requirements. The model was applied to the proposed NASA Lewis Altitude Wind Tunnel (AWT) circuit and included transfer function representations of the tunnel supply/exhaust air and refrigeration subsystems. Both steady state and frequency response data are presented for the circuit model indicating the type of results and accuracy that can be expected from the model. Transient data for closed loop control of the tunnel and its subsystems are also presented, demonstrating the model's use as a control analysis tool.

Density functional theory for d- and f-electron materials and compounds

DOE PAGES

Mattson, Ann E.; Wills, John M.

2016-02-12

Here, the fundamental requirements for a computationally tractable Density Functional Theory-based method for relativistic f- and (nonrelativistic) d-electron materials and compounds are presented. The need for basing the Kohn–Sham equations on the Dirac equation is discussed. The full Dirac scheme needs exchange-correlation functionals in terms of four-currents, but ordinary functionals, using charge density and spin-magnetization, can be used in an approximate Dirac treatment. The construction of a functional that includes the additional confinement physics needed for these materials is illustrated using the subsystem-functional scheme. If future studies show that a full Dirac, four-current based, exchange-correlation functional is needed, the subsystemmore » functional scheme is one of the few schemes that can still be used for constructing functional approximations.« less

Generalized Reduction Formula for Discrete Wigner Functions of Multiqubit Systems

NASA Astrophysics Data System (ADS)

Srinivasan, K.; Raghavan, G.

2018-03-01

Density matrices and Discrete Wigner Functions are equally valid representations of multiqubit quantum states. For density matrices, the partial trace operation is used to obtain the quantum state of subsystems, but an analogous prescription is not available for discrete Wigner Functions. Further, the discrete Wigner function corresponding to a density matrix is not unique but depends on the choice of the quantum net used for its reconstruction. In the present work, we derive a reduction formula for discrete Wigner functions of a general multiqubit state which works for arbitrary quantum nets. These results would be useful for the analysis and classification of entangled states and the study of decoherence purely in a discrete phase space setting and also in applications to quantum computing.

Exact-exchange spin-density functional theory of Wigner localization and phase transitions in quantum rings

NASA Astrophysics Data System (ADS)

Arnold, Thorsten; Siegmund, Marc; Pankratov, Oleg

2011-08-01

We apply exact-exchange spin-density functional theory in the Krieger-Li-Iafrate approximation to interacting electrons in quantum rings of different widths. The rings are threaded by a magnetic flux that induces a persistent current. A weak space and spin symmetry breaking potential is introduced to allow for localized solutions. As the electron-electron interaction strength described by the dimensionless parameter rS is increased, we observe—at a fixed spin magnetic moment—the subsequent transition of both spin sub-systems from the Fermi liquid to the Wigner crystal state. A dramatic signature of Wigner crystallization is that the persistent current drops sharply with increasing rS. We observe simultaneously the emergence of pronounced oscillations in the spin-resolved densities and in the electron localization functions indicating a spatial electron localization showing ferrimagnetic order after both spin sub-systems have undergone the Wigner crystallization. The critical rSc at the transition point is substantially smaller than in a fully spin-polarized system and decreases further with decreasing ring width. Relaxing the constraint of a fixed spin magnetic moment, we find that on increasing rS the stable phase changes from an unpolarized Fermi liquid to an antiferromagnetic Wigner crystal and finally to a fully polarized Fermi liquid.

Exact-exchange spin-density functional theory of Wigner localization and phase transitions in quantum rings.

PubMed

Arnold, Thorsten; Siegmund, Marc; Pankratov, Oleg

2011-08-24

We apply exact-exchange spin-density functional theory in the Krieger-Li-Iafrate approximation to interacting electrons in quantum rings of different widths. The rings are threaded by a magnetic flux that induces a persistent current. A weak space and spin symmetry breaking potential is introduced to allow for localized solutions. As the electron-electron interaction strength described by the dimensionless parameter r(S) is increased, we observe-at a fixed spin magnetic moment-the subsequent transition of both spin sub-systems from the Fermi liquid to the Wigner crystal state. A dramatic signature of Wigner crystallization is that the persistent current drops sharply with increasing r(S). We observe simultaneously the emergence of pronounced oscillations in the spin-resolved densities and in the electron localization functions indicating a spatial electron localization showing ferrimagnetic order after both spin sub-systems have undergone the Wigner crystallization. The critical r(S)(c) at the transition point is substantially smaller than in a fully spin-polarized system and decreases further with decreasing ring width. Relaxing the constraint of a fixed spin magnetic moment, we find that on increasing r(S) the stable phase changes from an unpolarized Fermi liquid to an antiferromagnetic Wigner crystal and finally to a fully polarized Fermi liquid. © 2011 IOP Publishing Ltd

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Chen, E-mail: chuang3@fsu.edu

A key element in the density functional embedding theory (DFET) is the embedding potential. We discuss two major issues related to the embedding potential: (1) its non-uniqueness and (2) the numerical difficulty for solving for it, especially for the spin-polarized systems. To resolve the first issue, we extend DFET to finite temperature: all quantities, such as the subsystem densities and the total system’s density, are calculated at a finite temperature. This is a physical extension since materials work at finite temperatures. We show that the embedding potential is strictly unique at T > 0. To resolve the second issue, wemore » introduce an efficient iterative embedding potential solver. We discuss how to relax the magnetic moments in subsystems and how to equilibrate the chemical potentials across subsystems. The solver is robust and efficient for several non-trivial examples, in all of which good quality spin-polarized embedding potentials were obtained. We also demonstrate the solver on an extended periodic system: iron body-centered cubic (110) surface, which is related to the modeling of the heterogeneous catalysis involving iron, such as the Fischer-Tropsch and the Haber processes. This work would make it efficient and accurate to perform embedding simulations of some challenging material problems, such as the heterogeneous catalysis and the defects of complicated spin configurations in electronic materials.« less

A Density Functional Approach to Polarizable Models: A Kim-Gordon-Response Density Interaction Potential for Molecular Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tabacchi, G; Hutter, J; Mundy, C

2005-04-07

A combined linear response--frozen electron density model has been implemented in a molecular dynamics scheme derived from an extended Lagrangian formalism. This approach is based on a partition of the electronic charge distribution into a frozen region described by Kim-Gordon theory, and a response contribution determined by the instaneous ionic configuration of the system. The method is free from empirical pair-potentials and the parameterization protocol involves only calculations on properly chosen subsystems. They apply this method to a series of alkali halides in different physical phases and are able to reproduce experimental structural and thermodynamic properties with an accuracy comparablemore » to Kohn-Sham density functional calculations.« less

Parallel integrated frame synchronizer chip

NASA Technical Reports Server (NTRS)

Solomon, Jeffrey Michael (Inventor); Ghuman, Parminder Singh (Inventor); Bennett, Toby Dennis (Inventor)

2000-01-01

A parallel integrated frame synchronizer which implements a sequential pipeline process wherein serial data in the form of telemetry data or weather satellite data enters the synchronizer by means of a front-end subsystem and passes to a parallel correlator subsystem or a weather satellite data processing subsystem. When in a CCSDS mode, data from the parallel correlator subsystem passes through a window subsystem, then to a data alignment subsystem and then to a bit transition density (BTD)/cyclical redundancy check (CRC) decoding subsystem. Data from the BTD/CRC decoding subsystem or data from the weather satellite data processing subsystem is then fed to an output subsystem where it is output from a data output port.

Residual stresses and vector hysteresis modeling

NASA Astrophysics Data System (ADS)

Ktena, Aphrodite

2016-04-01

Residual stresses in magnetic materials, whether the result of processing or intentional loading, leave their footprint on macroscopic data, such hysteresis loops and differential permeability measurements. A Preisach-type vector model is used to reproduce the phenomenology observed based on assumptions deduced from the data: internal stresses lead to smaller and misaligned grains, hence increased domain wall pinning and angular dispersion of local easy axes, favouring rotation as a magnetization reversal mechanism; misaligned grains contribute to magnetostatic fields opposing the direction of the applied field. The model is using a vector operator which accounts for both reversible and irreversible processes; the Preisach concept for interactions for the role of stress related demagnetizing fields; and a characteristic probability density function which is constructed as a weighed sum of constituent functions: the material is modeled as consisting of various subsystems, e.g. reversal mechanisms or areas subject to strong/weak long range interactions and each subsystem is represented by a constituent probability density function. Our assumptions are validated since the model reproduces the hysteresis loops and differential permeability curves observed experimentally and calculations involving rotating inputs at various residual stress levels are consistent and in agreement with experimental evidence.

Entanglement transitions induced by large deviations

NASA Astrophysics Data System (ADS)

Bhosale, Udaysinh T.

2017-12-01

The probability of large deviations of the smallest Schmidt eigenvalue for random pure states of bipartite systems, denoted as A and B , is computed analytically using a Coulomb gas method. It is shown that this probability, for large N , goes as exp[-β N2Φ (ζ ) ] , where the parameter β is the Dyson index of the ensemble, ζ is the large deviation parameter, while the rate function Φ (ζ ) is calculated exactly. Corresponding equilibrium Coulomb charge density is derived for its large deviations. Effects of the large deviations of the extreme (largest and smallest) Schmidt eigenvalues on the bipartite entanglement are studied using the von Neumann entropy. Effect of these deviations is also studied on the entanglement between subsystems 1 and 2, obtained by further partitioning the subsystem A , using the properties of the density matrix's partial transpose ρ12Γ. The density of states of ρ12Γ is found to be close to the Wigner's semicircle law with these large deviations. The entanglement properties are captured very well by a simple random matrix model for the partial transpose. The model predicts the entanglement transition across a critical large deviation parameter ζ . Log negativity is used to quantify the entanglement between subsystems 1 and 2. Analytical formulas for it are derived using the simple model. Numerical simulations are in excellent agreement with the analytical results.

Entanglement transitions induced by large deviations.

PubMed

Bhosale, Udaysinh T

2017-12-01

The probability of large deviations of the smallest Schmidt eigenvalue for random pure states of bipartite systems, denoted as A and B, is computed analytically using a Coulomb gas method. It is shown that this probability, for large N, goes as exp[-βN^{2}Φ(ζ)], where the parameter β is the Dyson index of the ensemble, ζ is the large deviation parameter, while the rate function Φ(ζ) is calculated exactly. Corresponding equilibrium Coulomb charge density is derived for its large deviations. Effects of the large deviations of the extreme (largest and smallest) Schmidt eigenvalues on the bipartite entanglement are studied using the von Neumann entropy. Effect of these deviations is also studied on the entanglement between subsystems 1 and 2, obtained by further partitioning the subsystem A, using the properties of the density matrix's partial transpose ρ_{12}^{Γ}. The density of states of ρ_{12}^{Γ} is found to be close to the Wigner's semicircle law with these large deviations. The entanglement properties are captured very well by a simple random matrix model for the partial transpose. The model predicts the entanglement transition across a critical large deviation parameter ζ. Log negativity is used to quantify the entanglement between subsystems 1 and 2. Analytical formulas for it are derived using the simple model. Numerical simulations are in excellent agreement with the analytical results.

Non-Markovianity in the optimal control of an open quantum system described by hierarchical equations of motion

NASA Astrophysics Data System (ADS)

Mangaud, E.; Puthumpally-Joseph, R.; Sugny, D.; Meier, C.; Atabek, O.; Desouter-Lecomte, M.

2018-04-01

Optimal control theory is implemented with fully converged hierarchical equations of motion (HEOM) describing the time evolution of an open system density matrix strongly coupled to the bath in a spin-boson model. The populations of the two-level sub-system are taken as control objectives; namely, their revivals or exchange when switching off the field. We, in parallel, analyze how the optimal electric field consequently modifies the information back flow from the environment through different non-Markovian witnesses. Although the control field has a dipole interaction with the central sub-system only, its indirect influence on the bath collective mode dynamics is probed through HEOM auxiliary matrices, revealing a strong correlation between control and dissipation during a non-Markovian process. A heterojunction is taken as an illustrative example for modeling in a realistic way the two-level sub-system parameters and its spectral density function leading to a non-perturbative strong coupling regime with the bath. Although, due to strong system-bath couplings, control performances remain rather modest, the most important result is a noticeable increase of the non-Markovian bath response induced by the optimally driven processes.

Does a Single Eigenstate Encode the Full Hamiltonian?

NASA Astrophysics Data System (ADS)

Garrison, James R.; Grover, Tarun

2018-04-01

The eigenstate thermalization hypothesis (ETH) posits that the reduced density matrix for a subsystem corresponding to an excited eigenstate is "thermal." Here we expound on this hypothesis by asking: For which class of operators, local or nonlocal, is ETH satisfied? We show that this question is directly related to a seemingly unrelated question: Is the Hamiltonian of a system encoded within a single eigenstate? We formulate a strong form of ETH where, in the thermodynamic limit, the reduced density matrix of a subsystem corresponding to a pure, finite energy density eigenstate asymptotically becomes equal to the thermal reduced density matrix, as long as the subsystem size is much less than the total system size, irrespective of how large the subsystem is compared to any intrinsic length scale of the system. This allows one to access the properties of the underlying Hamiltonian at arbitrary energy densities (or temperatures) using just a single eigenstate. We provide support for our conjecture by performing an exact diagonalization study of a nonintegrable 1D quantum lattice model with only energy conservation. In addition, we examine the case in which the subsystem size is a finite fraction of the total system size, and we find that, even in this case, many operators continue to match their canonical expectation values, at least approximately. In particular, the von Neumann entanglement entropy equals the thermal entropy as long as the subsystem is less than half the total system. Our results are consistent with the possibility that a single eigenstate correctly predicts the expectation values of all operators with support on less than half the total system, as long as one uses a microcanonical ensemble with vanishing energy width for comparison. We also study, both analytically and numerically, a particle-number conserving model at infinite temperature that substantiates our conjectures.

Two-level system in spin baths: Non-adiabatic dynamics and heat transport

NASA Astrophysics Data System (ADS)

Segal, Dvira

2014-04-01

We study the non-adiabatic dynamics of a two-state subsystem in a bath of independent spins using the non-interacting blip approximation, and derive an exact analytic expression for the relevant memory kernel. We show that in the thermodynamic limit, when the subsystem-bath coupling is diluted (uniformly) over many (infinite) degrees of freedom, our expression reduces to known results, corresponding to the harmonic bath with an effective, temperature-dependent, spectral density function. We then proceed and study the heat current characteristics in the out-of-equilibrium spin-spin-bath model, with a two-state subsystem bridging two thermal spin-baths of different temperatures. We compare the behavior of this model to the case of a spin connecting boson baths, and demonstrate pronounced qualitative differences between the two models. Specifically, we focus on the development of the thermal diode effect, and show that the spin-spin-bath model cannot support it at weak (subsystem-bath) coupling, while in the intermediate-strong coupling regime its rectifying performance outplays the spin-boson model.

An accurate and linear-scaling method for calculating charge-transfer excitation energies and diabatic couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavanello, Michele; Van Voorhis, Troy; Visscher, Lucas

2013-02-07

Quantum-mechanical methods that are both computationally fast and accurate are not yet available for electronic excitations having charge transfer character. In this work, we present a significant step forward towards this goal for those charge transfer excitations that take place between non-covalently bound molecules. In particular, we present a method that scales linearly with the number of non-covalently bound molecules in the system and is based on a two-pronged approach: The molecular electronic structure of broken-symmetry charge-localized states is obtained with the frozen density embedding formulation of subsystem density-functional theory; subsequently, in a post-SCF calculation, the full-electron Hamiltonian and overlapmore » matrix elements among the charge-localized states are evaluated with an algorithm which takes full advantage of the subsystem DFT density partitioning technique. The method is benchmarked against coupled-cluster calculations and achieves chemical accuracy for the systems considered for intermolecular separations ranging from hydrogen-bond distances to tens of Angstroms. Numerical examples are provided for molecular clusters comprised of up to 56 non-covalently bound molecules.« less

An accurate and linear-scaling method for calculating charge-transfer excitation energies and diabatic couplings.

PubMed

Pavanello, Michele; Van Voorhis, Troy; Visscher, Lucas; Neugebauer, Johannes

2013-02-07

Quantum-mechanical methods that are both computationally fast and accurate are not yet available for electronic excitations having charge transfer character. In this work, we present a significant step forward towards this goal for those charge transfer excitations that take place between non-covalently bound molecules. In particular, we present a method that scales linearly with the number of non-covalently bound molecules in the system and is based on a two-pronged approach: The molecular electronic structure of broken-symmetry charge-localized states is obtained with the frozen density embedding formulation of subsystem density-functional theory; subsequently, in a post-SCF calculation, the full-electron Hamiltonian and overlap matrix elements among the charge-localized states are evaluated with an algorithm which takes full advantage of the subsystem DFT density partitioning technique. The method is benchmarked against coupled-cluster calculations and achieves chemical accuracy for the systems considered for intermolecular separations ranging from hydrogen-bond distances to tens of Ångstroms. Numerical examples are provided for molecular clusters comprised of up to 56 non-covalently bound molecules.

A 37.5-kW point design comparison of the nickel-cadmium battery, bipolar nickel-hydrogen battery, and regenerative hydrogen-oxygen fuel cell energy storage subsystems for low earth orbit

NASA Technical Reports Server (NTRS)

Manzo, M. A.; Hoberecht, M. A.

1984-01-01

Nickel-cadmium batteries, bipolar nickel-hydrogen batteries, and regenerative fuel cell storage subsystems were evaluated for use as the storage subsystem in a 37.5 kW power system for Space Station. Design requirements were set in order to establish a common baseline for comparison purposes. The storage subsystems were compared on the basis of effective energy density, round trip electrical efficiency, total subsystem weight and volume, and life.

A 37.5-kW point design comparison of the nickel-cadmium battery, bipolar nickel-hydrogen battery, and regenerative hydrogen-oxygen fuel cell energy storage subsystems for low Earth orbit

NASA Technical Reports Server (NTRS)

Manzo, M. A.; Hoberecht, M. A.

1984-01-01

Nickel-cadmium batteries, bipolar nickel-hydrogen batteries, and regenerative fuel cell storage subsystems were evaluated for use as the storage subsystem in a 37.5 kW power system for space station. Design requirements were set in order to establish a common baseline for comparison purposes. The storage subsystems were compared on the basis of effective energy density, round trip electrical efficiency, total subsystem weight and volume, and life.

Default Mode Network Subsystems are Differentially Disrupted in Posttraumatic Stress Disorder

PubMed Central

Miller, Danielle R.; Hayes, Scott M.; Hayes, Jasmeet P.; Spielberg, Jeffrey M.; Lafleche, Ginette; Verfaellie, Mieke

2017-01-01

Background Posttraumatic stress disorder (PTSD) is a psychiatric disorder characterized by debilitating re-experiencing, avoidance, and hyperarousal symptoms following trauma exposure. Recent evidence suggests that individuals with PTSD show disrupted functional connectivity in the default mode network, an intrinsic network that consists of a midline core, a medial temporal lobe (MTL) subsystem, and a dorsomedial prefrontal cortex (dMPFC) subsystem. The present study examined whether functional connectivity in these subsystems is differentially disrupted in PTSD. Methods Sixty-nine returning war Veterans with PTSD and 44 trauma-exposed Veterans without PTSD underwent resting state functional MRI (rs-fMRI). To examine functional connectivity, seeds were placed in the core hubs of the default mode network, namely the posterior cingulate cortex (PCC) and anterior medial PFC (aMPFC), and in each subsystem. Results Compared to controls, individuals with PTSD had reduced functional connectivity between the PCC and the hippocampus, a region of the MTL subsystem. Groups did not differ in connectivity between the PCC and dMPFC subsystem or between the aMPFC and any region within either subsystem. In the PTSD group, connectivity between the PCC and hippocampus was negatively associated with avoidance/numbing symptoms. Examination of the MTL and dMPFC subsystems revealed reduced anticorrelation between the ventromedial PFC (vMPFC) seed of the MTL subsystem and the dorsal anterior cingulate cortex in the PTSD group. Conclusions Our results suggest that selective alterations in functional connectivity in the MTL subsystem of the default mode network in PTSD may be an important factor in PTSD pathology and symptomatology. PMID:28435932

Default Mode Network Subsystems are Differentially Disrupted in Posttraumatic Stress Disorder.

PubMed

Miller, Danielle R; Hayes, Scott M; Hayes, Jasmeet P; Spielberg, Jeffrey M; Lafleche, Ginette; Verfaellie, Mieke

2017-05-01

Posttraumatic stress disorder (PTSD) is a psychiatric disorder characterized by debilitating re-experiencing, avoidance, and hyperarousal symptoms following trauma exposure. Recent evidence suggests that individuals with PTSD show disrupted functional connectivity in the default mode network, an intrinsic network that consists of a midline core, a medial temporal lobe (MTL) subsystem, and a dorsomedial prefrontal cortex (dMPFC) subsystem. The present study examined whether functional connectivity in these subsystems is differentially disrupted in PTSD. Sixty-nine returning war Veterans with PTSD and 44 trauma-exposed Veterans without PTSD underwent resting state functional MRI (rs-fMRI). To examine functional connectivity, seeds were placed in the core hubs of the default mode network, namely the posterior cingulate cortex (PCC) and anterior medial PFC (aMPFC), and in each subsystem. Compared to controls, individuals with PTSD had reduced functional connectivity between the PCC and the hippocampus, a region of the MTL subsystem. Groups did not differ in connectivity between the PCC and dMPFC subsystem or between the aMPFC and any region within either subsystem. In the PTSD group, connectivity between the PCC and hippocampus was negatively associated with avoidance/numbing symptoms. Examination of the MTL and dMPFC subsystems revealed reduced anticorrelation between the ventromedial PFC (vMPFC) seed of the MTL subsystem and the dorsal anterior cingulate cortex in the PTSD group. Our results suggest that selective alterations in functional connectivity in the MTL subsystem of the default mode network in PTSD may be an important factor in PTSD pathology and symptomatology.

Evolution of magnetic disk subsystems

NASA Astrophysics Data System (ADS)

Kaneko, Satoru

1994-06-01

The higher recording density of magnetic disk realized today has brought larger storage capacity per unit and smaller form factors. If the required access performance per MB is constant, the performance of large subsystems has to be several times better. This article describes mainly the technology for improving the performance of the magnetic disk subsystems and the prospects of their future evolution. Also considered are 'crosscall pathing' which makes the data transfer channel more effective, 'disk cache' which improves performance coupling with solid state memory technology, and 'RAID' which improves the availability and integrity of disk subsystems by organizing multiple disk drives in a subsystem. As a result, it is concluded that since the performance of the subsystem is dominated by that of the disk cache, maximation of the performance of the disk cache subsystems is very important.

Limits of applicability of a two-temperature model under nonuniform heating of metal by an ultrashort laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polyakov, D S; Yakovlev, E B

The heating of metals (silver and aluminium) by ultrashort laser pulses is analysed proceeding from a spatially nonuniform kinetic equation for the electron distribution function. The electron subsystem thermalisation is estimated in a wide range of absorbed pulse energy density. The limits of applicability are determined for the two-temperature model. (interaction of laser radiation with matter)

Reliability estimation of a N- M-cold-standby redundancy system in a multicomponent stress-strength model with generalized half-logistic distribution

NASA Astrophysics Data System (ADS)

Liu, Yiming; Shi, Yimin; Bai, Xuchao; Zhan, Pei

2018-01-01

In this paper, we study the estimation for the reliability of a multicomponent system, named N- M-cold-standby redundancy system, based on progressive Type-II censoring sample. In the system, there are N subsystems consisting of M statistically independent distributed strength components, and only one of these subsystems works under the impact of stresses at a time and the others remain as standbys. Whenever the working subsystem fails, one from the standbys takes its place. The system fails when the entire subsystems fail. It is supposed that the underlying distributions of random strength and stress both belong to the generalized half-logistic distribution with different shape parameter. The reliability of the system is estimated by using both classical and Bayesian statistical inference. Uniformly minimum variance unbiased estimator and maximum likelihood estimator for the reliability of the system are derived. Under squared error loss function, the exact expression of the Bayes estimator for the reliability of the system is developed by using the Gauss hypergeometric function. The asymptotic confidence interval and corresponding coverage probabilities are derived based on both the Fisher and the observed information matrices. The approximate highest probability density credible interval is constructed by using Monte Carlo method. Monte Carlo simulations are performed to compare the performances of the proposed reliability estimators. A real data set is also analyzed for an illustration of the findings.

Multicomponent density functional theory embedding formulation.

PubMed

Culpitt, Tanner; Brorsen, Kurt R; Pak, Michael V; Hammes-Schiffer, Sharon

2016-07-28

Multicomponent density functional theory (DFT) methods have been developed to treat two types of particles, such as electrons and nuclei, quantum mechanically at the same level. In the nuclear-electronic orbital (NEO) approach, all electrons and select nuclei, typically key protons, are treated quantum mechanically. For multicomponent DFT methods developed within the NEO framework, electron-proton correlation functionals based on explicitly correlated wavefunctions have been designed and used in conjunction with well-established electronic exchange-correlation functionals. Herein a general theory for multicomponent embedded DFT is developed to enable the accurate treatment of larger systems. In the general theory, the total electronic density is separated into two subsystem densities, denoted as regular and special, and different electron-proton correlation functionals are used for these two electronic densities. In the specific implementation, the special electron density is defined in terms of spatially localized Kohn-Sham electronic orbitals, and electron-proton correlation is included only for the special electron density. The electron-proton correlation functional depends on only the special electron density and the proton density, whereas the electronic exchange-correlation functional depends on the total electronic density. This scheme includes the essential electron-proton correlation, which is a relatively local effect, as well as the electronic exchange-correlation for the entire system. This multicomponent DFT-in-DFT embedding theory is applied to the HCN and FHF(-) molecules in conjunction with two different electron-proton correlation functionals and three different electronic exchange-correlation functionals. The results illustrate that this approach provides qualitatively accurate nuclear densities in a computationally tractable manner. The general theory is also easily extended to other types of partitioning schemes for multicomponent systems.

Multicomponent density functional theory embedding formulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Culpitt, Tanner; Brorsen, Kurt R.; Pak, Michael V.

Multicomponent density functional theory (DFT) methods have been developed to treat two types of particles, such as electrons and nuclei, quantum mechanically at the same level. In the nuclear-electronic orbital (NEO) approach, all electrons and select nuclei, typically key protons, are treated quantum mechanically. For multicomponent DFT methods developed within the NEO framework, electron-proton correlation functionals based on explicitly correlated wavefunctions have been designed and used in conjunction with well-established electronic exchange-correlation functionals. Herein a general theory for multicomponent embedded DFT is developed to enable the accurate treatment of larger systems. In the general theory, the total electronic density ismore » separated into two subsystem densities, denoted as regular and special, and different electron-proton correlation functionals are used for these two electronic densities. In the specific implementation, the special electron density is defined in terms of spatially localized Kohn-Sham electronic orbitals, and electron-proton correlation is included only for the special electron density. The electron-proton correlation functional depends on only the special electron density and the proton density, whereas the electronic exchange-correlation functional depends on the total electronic density. This scheme includes the essential electron-proton correlation, which is a relatively local effect, as well as the electronic exchange-correlation for the entire system. This multicomponent DFT-in-DFT embedding theory is applied to the HCN and FHF{sup −} molecules in conjunction with two different electron-proton correlation functionals and three different electronic exchange-correlation functionals. The results illustrate that this approach provides qualitatively accurate nuclear densities in a computationally tractable manner. The general theory is also easily extended to other types of partitioning schemes for multicomponent systems.« less

Functional Performance of an Enabling Atmosphere Revitalization Subsystem Architecture for Deep Space Exploration Missions

NASA Technical Reports Server (NTRS)

Perry, Jay L.; Abney, Morgan B.; Frederick, Kenneth R.; Greenwood, Zachary W.; Kayatin, Matthew J.; Newton, Robert L.; Parrish, Keith J.; Roman, Monsi C.; Takada, Kevin C.; Miller, Lee A.;

Integration of functional safety systems on the Daniel K. Inouye Solar Telescope

NASA Astrophysics Data System (ADS)

Williams, Timothy R.; Hubbard, Robert P.; Shimko, Steve

2016-07-01

The Daniel K. Inouye Solar Telescope (DKIST) was envisioned from an early stage to incorporate a functional safety system to ensure the safety of personnel and equipment within the facility. Early hazard analysis showed the need for a functional safety system. The design used a distributed approach in which each major subsystem contains a PLC-based safety controller. This PLC-based system complies with the latest international standards for functional safety. The use of a programmable controller also allows for flexibility to incorporate changes in the design of subsystems without adversely impacting safety. Various subsystems were built by different contractors and project partners but had to function as a piece of the overall control system. Using distributed controllers allows project contractors and partners to build components as standalone subsystems that then need to be integrated into the overall functional safety system. Recently factory testing was concluded on the major subsystems of the facility. Final integration of these subsystems is currently underway on the site. Building on lessons learned in early factory tests, changes to the interface between subsystems were made to improve the speed and ease of integration of the entire system. Because of the distributed design each subsystem can be brought online as it is delivered and assembled rather than waiting until the entire facility is finished. This enhances safety during the risky period of integration and testing. The DKIST has implemented a functional safety system that has allowed construction of subsystems in geographically diverse locations but that function cohesively once they are integrated into the facility currently under construction.

Control aspects of the Schuchuli Village stand-alone photovoltaic power system

NASA Astrophysics Data System (ADS)

Groumpos, P. P.; Culler, J. E.; Delombard, R.

1984-11-01

A photovoltaic power system in an Arizona Indian village was installed. The control subsystem of this photovoltaic power system was analyzed. The four major functions of the control subsystem are: (1) voltage regulation; (2) load management; (3) water pump control; and (4) system protection. The control subsystem functions flowcharts for the control subsystem operation, and a computer program that models the control subsystem are presented.

Control aspects of the Schuchuli Village stand-alone photovoltaic power system

NASA Technical Reports Server (NTRS)

Groumpos, P. P.; Culler, J. E.; Delombard, R.

1984-01-01

A photovoltaic power system in an Arizona Indian village was installed. The control subsystem of this photovoltaic power system was analyzed. The four major functions of the control subsystem are: (1) voltage regulation; (2) load management; (3) water pump control; and (4) system protection. The control subsystem functions flowcharts for the control subsystem operation, and a computer program that models the control subsystem are presented.

Nonlocal kinetic energy functionals by functional integration.

PubMed

Mi, Wenhui; Genova, Alessandro; Pavanello, Michele

2018-05-14

Since the seminal studies of Thomas and Fermi, researchers in the Density-Functional Theory (DFT) community are searching for accurate electron density functionals. Arguably, the toughest functional to approximate is the noninteracting kinetic energy, T s [ρ], the subject of this work. The typical paradigm is to first approximate the energy functional and then take its functional derivative, δT s [ρ]δρ(r), yielding a potential that can be used in orbital-free DFT or subsystem DFT simulations. Here, this paradigm is challenged by constructing the potential from the second-functional derivative via functional integration. A new nonlocal functional for T s [ρ] is prescribed [which we dub Mi-Genova-Pavanello (MGP)] having a density independent kernel. MGP is constructed to satisfy three exact conditions: (1) a nonzero "Kinetic electron" arising from a nonzero exchange hole; (2) the second functional derivative must reduce to the inverse Lindhard function in the limit of homogenous densities; (3) the potential is derived from functional integration of the second functional derivative. Pilot calculations show that MGP is capable of reproducing accurate equilibrium volumes, bulk moduli, total energy, and electron densities for metallic (body-centered cubic, face-centered cubic) and semiconducting (crystal diamond) phases of silicon as well as of III-V semiconductors. The MGP functional is found to be numerically stable typically reaching self-consistency within 12 iterations of a truncated Newton minimization algorithm. MGP's computational cost and memory requirements are low and comparable to the Wang-Teter nonlocal functional or any generalized gradient approximation functional.

Nonlocal kinetic energy functionals by functional integration

NASA Astrophysics Data System (ADS)

Mi, Wenhui; Genova, Alessandro; Pavanello, Michele

2018-05-01

Since the seminal studies of Thomas and Fermi, researchers in the Density-Functional Theory (DFT) community are searching for accurate electron density functionals. Arguably, the toughest functional to approximate is the noninteracting kinetic energy, Ts[ρ], the subject of this work. The typical paradigm is to first approximate the energy functional and then take its functional derivative, δ/Ts[ρ ] δ ρ (r ) , yielding a potential that can be used in orbital-free DFT or subsystem DFT simulations. Here, this paradigm is challenged by constructing the potential from the second-functional derivative via functional integration. A new nonlocal functional for Ts[ρ] is prescribed [which we dub Mi-Genova-Pavanello (MGP)] having a density independent kernel. MGP is constructed to satisfy three exact conditions: (1) a nonzero "Kinetic electron" arising from a nonzero exchange hole; (2) the second functional derivative must reduce to the inverse Lindhard function in the limit of homogenous densities; (3) the potential is derived from functional integration of the second functional derivative. Pilot calculations show that MGP is capable of reproducing accurate equilibrium volumes, bulk moduli, total energy, and electron densities for metallic (body-centered cubic, face-centered cubic) and semiconducting (crystal diamond) phases of silicon as well as of III-V semiconductors. The MGP functional is found to be numerically stable typically reaching self-consistency within 12 iterations of a truncated Newton minimization algorithm. MGP's computational cost and memory requirements are low and comparable to the Wang-Teter nonlocal functional or any generalized gradient approximation functional.

Age differences in the intrinsic functional connectivity of default network subsystems

PubMed Central

Campbell, Karen L.; Grigg, Omer; Saverino, Cristina; Churchill, Nathan; Grady, Cheryl L.

2013-01-01

Recent work suggests that the default mode network (DMN) includes two core regions, the ventromedial prefrontal cortex and posterior cingulate cortex (PCC), and several unique subsystems that are functionally distinct. These include a medial temporal lobe (MTL) subsystem, active during remembering and future projection, and a dorsomedial prefrontal cortex (dmPFC) subsystem, active during self-reference. The PCC has been further subdivided into ventral (vPCC) and dorsal (dPCC) regions that are more strongly connected with the DMN and cognitive control networks, respectively. The goal of this study was to examine age differences in resting state functional connectivity within these subsystems. After applying a rigorous procedure to reduce the effects of head motion, we used a multivariate technique to identify both common and unique patterns of functional connectivity in the MTL vs. the dmPFC, and in vPCC vs. dPCC. All four areas had robust functional connectivity with other DMN regions, and each also showed distinct connectivity patterns in both age groups. Young and older adults had equivalent functional connectivity in the MTL subsystem. Older adults showed weaker connectivity in the vPCC and dmPFC subsystems, particularly with other DMN areas, but stronger connectivity than younger adults in the dPCC subsystem, which included areas involved in cognitive control. Our data provide evidence for distinct subsystems involving DMN nodes, which are maintained with age. Nevertheless, there are age differences in the strength of functional connectivity within these subsystems, supporting prior evidence that DMN connectivity is particularly vulnerable to age, whereas connectivity involving cognitive control regions is relatively maintained. These results suggest an age difference in the integrated activity among brain networks that can have implications for cognition in older adults. PMID:24294203

Age differences in the intrinsic functional connectivity of default network subsystems.

PubMed

Campbell, Karen L; Grigg, Omer; Saverino, Cristina; Churchill, Nathan; Grady, Cheryl L

2013-01-01

Recent work suggests that the default mode network (DMN) includes two core regions, the ventromedial prefrontal cortex and posterior cingulate cortex (PCC), and several unique subsystems that are functionally distinct. These include a medial temporal lobe (MTL) subsystem, active during remembering and future projection, and a dorsomedial prefrontal cortex (dmPFC) subsystem, active during self-reference. The PCC has been further subdivided into ventral (vPCC) and dorsal (dPCC) regions that are more strongly connected with the DMN and cognitive control networks, respectively. The goal of this study was to examine age differences in resting state functional connectivity within these subsystems. After applying a rigorous procedure to reduce the effects of head motion, we used a multivariate technique to identify both common and unique patterns of functional connectivity in the MTL vs. the dmPFC, and in vPCC vs. dPCC. All four areas had robust functional connectivity with other DMN regions, and each also showed distinct connectivity patterns in both age groups. Young and older adults had equivalent functional connectivity in the MTL subsystem. Older adults showed weaker connectivity in the vPCC and dmPFC subsystems, particularly with other DMN areas, but stronger connectivity than younger adults in the dPCC subsystem, which included areas involved in cognitive control. Our data provide evidence for distinct subsystems involving DMN nodes, which are maintained with age. Nevertheless, there are age differences in the strength of functional connectivity within these subsystems, supporting prior evidence that DMN connectivity is particularly vulnerable to age, whereas connectivity involving cognitive control regions is relatively maintained. These results suggest an age difference in the integrated activity among brain networks that can have implications for cognition in older adults.

Typical entanglement

NASA Astrophysics Data System (ADS)

Deelan Cunden, Fabio; Facchi, Paolo; Florio, Giuseppe; Pascazio, Saverio

2013-05-01

Let a pure state | ψ> be chosen randomly in an NM-dimensional Hilbert space, and consider the reduced density matrix ρ A of an N-dimensional subsystem. The bipartite entanglement properties of | ψ> are encoded in the spectrum of ρ A . By means of a saddle point method and using a "Coulomb gas" model for the eigenvalues, we obtain the typical spectrum of reduced density matrices. We consider the cases of an unbiased ensemble of pure states and of a fixed value of the purity. We finally obtain the eigenvalue distribution by using a statistical mechanics approach based on the introduction of a partition function.

Large-scale structure of randomly jammed spheres

NASA Astrophysics Data System (ADS)

Ikeda, Atsushi; Berthier, Ludovic; Parisi, Giorgio

2017-05-01

We numerically analyze the density field of three-dimensional randomly jammed packings of monodisperse soft frictionless spherical particles, paying special attention to fluctuations occurring at large length scales. We study in detail the two-point static structure factor at low wave vectors in Fourier space. We also analyze the nature of the density field in real space by studying the large-distance behavior of the two-point pair correlation function, of density fluctuations in subsystems of increasing sizes, and of the direct correlation function. We show that such real space analysis can be greatly improved by introducing a coarse-grained density field to disentangle genuine large-scale correlations from purely local effects. Our results confirm that both Fourier and real space signatures of vanishing density fluctuations at large scale are absent, indicating that randomly jammed packings are not hyperuniform. In addition, we establish that the pair correlation function displays a surprisingly complex structure at large distances, which is however not compatible with the long-range negative correlation of hyperuniform systems but fully compatible with an analytic form for the structure factor. This implies that the direct correlation function is short ranged, as we also demonstrate directly. Our results reveal that density fluctuations in jammed packings do not follow the behavior expected for random hyperuniform materials, but display instead a more complex behavior.

Subsystem eigenstate thermalization hypothesis

NASA Astrophysics Data System (ADS)

Dymarsky, Anatoly; Lashkari, Nima; Liu, Hong

2018-01-01

Motivated by the qualitative picture of canonical typicality, we propose a refined formulation of the eigenstate thermalization hypothesis (ETH) for chaotic quantum systems. This formulation, which we refer to as subsystem ETH, is in terms of the reduced density matrix of subsystems. This strong form of ETH outlines the set of observables defined within the subsystem for which it guarantees eigenstate thermalization. We discuss the limits when the size of the subsystem is small or comparable to its complement. In the latter case we outline the way to calculate the leading volume-proportional contribution to the von Neumann and Renyi entanglment entropies. Finally, we provide numerical evidence for the proposal in the case of a one-dimensional Ising spin chain.

Local electric dipole moments for periodic systems via density functional theory embedding.

PubMed

Luber, Sandra

2014-12-21

We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange-correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.

The development of the intrinsic functional connectivity of default network subsystems from age 3 to 5.

PubMed

Xiao, Yaqiong; Zhai, Hongchang; Friederici, Angela D; Jia, Fucang

2016-03-01

In recent years, research on human functional brain imaging using resting-state fMRI techniques has been increasingly prevalent. The term "default mode" was proposed to describe a baseline or default state of the brain during rest. Recent studies suggested that the default mode network (DMN) is comprised of two functionally distinct subsystems: a dorsal-medial prefrontal cortex (DMPFC) subsystem involved in self-oriented cognition (i.e., theory of mind) and a medial temporal lobe (MTL) subsystem engaged in memory and scene construction; both subsystems interact with the anterior medial prefrontal cortex (aMPFC) and posterior cingulate (PCC) as the core regions of DMN. The present study explored the development of DMN core regions and these two subsystems in both hemispheres from 3- to 5-year-old children. The analysis of the intrinsic activity showed strong developmental changes in both subsystems, and significant changes were specifically found in MTL subsystem, but not in DMPFC subsystem, implying distinct developmental trajectories for DMN subsystems. We found stronger interactions between the DMPFC and MTL subsystems in 5-year-olds, particularly in the left subsystems that support the development of environmental adaptation and relatively complex mental activities. These results also indicate that there is stronger right hemispheric lateralization at age 3, which then changes as bilateral development gradually increases through to age 5, suggesting in turn the hemispheric dominance in DMN subsystems changing with age. The present results provide primary evidence for the development of DMN subsystems in early life, which might be closely related to the development of social cognition in childhood.

Projected Hybrid Orbitals: A General QM/MM Method

PubMed Central

2015-01-01

A projected hybrid orbital (PHO) method was described to model the covalent boundary in a hybrid quantum mechanical and molecular mechanical (QM/MM) system. The PHO approach can be used in ab initio wave function theory and in density functional theory with any basis set without introducing system-dependent parameters. In this method, a secondary basis set on the boundary atom is introduced to formulate a set of hybrid atomic orbtials. The primary basis set on the boundary atom used for the QM subsystem is projected onto the secondary basis to yield a representation that provides a good approximation to the electron-withdrawing power of the primary basis set to balance electronic interactions between QM and MM subsystems. The PHO method has been tested on a range of molecules and properties. Comparison with results obtained from QM calculations on the entire system shows that the present PHO method is a robust and balanced QM/MM scheme that preserves the structural and electronic properties of the QM region. PMID:25317748

Suit study - The impact of VMS in subsystem integration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, B.; Watts, R.

1992-02-01

One of the thrusts of the Wright Laboratory/FIVE-sponsored Subsystem Integration Technology (SUIT) study is to investigate the impact of emerging vehicle management system (VMS) concepts on subsystem integration. This paper summarizes the issues relating to VMS/subsystem integration as examined during the Northrop SUIT study. Projected future weapon system requirements are identified and their impact on VMS and subsystem design interpreted. Integrated VMS/subsystem control and management functions are proposed. A candidate system VMS architecture satisfying the aforementioned weapon system requirements and providing the identified control and management functions is proposed. This architecture is used, together with the environmental control system, asmore » an illustrative subsystem example, to address the risks associated with the design, development, procurement, integration and testing of integrated VMS/subsystem concepts. The conclusion is that the development process requires an airframer to adopt the role of subsystem integrator, the consequences of which are discussed. 2 refs.« less

Ground-state-entanglement bound for quantum energy teleportation of general spin-chain models

NASA Astrophysics Data System (ADS)

Hotta, Masahiro

2013-03-01

Many-body quantum systems in the ground states have zero-point energy due to the uncertainty relation. In many cases, the system in the ground state accompanies spatially entangled energy density fluctuation via the noncommutativity of the energy density operators, though the total energy takes a fixed value, i.e., the lowest eigenvalue of the Hamiltonian. Quantum energy teleportation (QET) is a protocol for the extraction of the zero-point energy out of one subsystem using information of a remote measurement of another subsystem. From an operational viewpoint of protocol users, QET can be regarded as an effective rapid energy transportation without breaking all physical laws, including causality and local energy conservation. In the protocol, the ground-state entanglement plays a crucial role. In this paper, we show analytically for a general class of spin-chain systems that the entanglement entropy is lower bounded by a positive quadratic function of the teleported energy between the regions of a QET protocol. This supports a general conjecture that ground-state entanglement is an evident physical resource for energy transportation in the context of QET. The result may also deepen our understanding of the energy density fluctuation in condensed-matter systems from a perspective of quantum information theory.

Extending density functional embedding theory for covalently bonded systems.

PubMed

Yu, Kuang; Carter, Emily A

2017-12-19

Quantum embedding theory aims to provide an efficient solution to obtain accurate electronic energies for systems too large for full-scale, high-level quantum calculations. It adopts a hierarchical approach that divides the total system into a small embedded region and a larger environment, using different levels of theory to describe each part. Previously, we developed a density-based quantum embedding theory called density functional embedding theory (DFET), which achieved considerable success in metals and semiconductors. In this work, we extend DFET into a density-matrix-based nonlocal form, enabling DFET to study the stronger quantum couplings between covalently bonded subsystems. We name this theory density-matrix functional embedding theory (DMFET), and we demonstrate its performance in several test examples that resemble various real applications in both chemistry and biochemistry. DMFET gives excellent results in all cases tested thus far, including predicting isomerization energies, proton transfer energies, and highest occupied molecular orbital-lowest unoccupied molecular orbital gaps for local chromophores. Here, we show that DMFET systematically improves the quality of the results compared with the widely used state-of-the-art methods, such as the simple capped cluster model or the widely used ONIOM method.

Orbital maneuvering subsystem functional path analysis for performance monitoring fault detection and annunciation

NASA Technical Reports Server (NTRS)

Keesler, E. L.

1974-01-01

The functional paths of the Orbital Maneuver Subsystem (OMS) is defined. The operational flight instrumentation required for performance monitoring, fault detection, and annunciation is described. The OMS is a pressure fed rocket engine propulsion subsystem. One complete OMS shares each of the two auxiliary propulsion subsystem pods with a reaction control subsystem. Each OMS is composed of a pressurization system, a propellant tanking system, and a gimbaled rocket engine. The design, development, and operation of the system are explained. Diagrams of the system are provided.

Novel operation and control of an electric vehicle aluminum/air battery system

NASA Astrophysics Data System (ADS)

Zhang, Xin; Yang, Shao Hua; Knickle, Harold

The objective of this paper is to create a method to size battery subsystems for an electric vehicle to optimize battery performance. Optimization of performance includes minimizing corrosion by operating at a constant current density. These subsystems will allow for easy mechanical recharging. A proper choice of battery subsystem will allow for longer battery life, greater range and performance. For longer life, the current density and reaction rate should be nearly constant. The control method requires control of power by controlling electrolyte flow in battery sub modules. As power is increased more sub modules come on line and more electrolyte is needed. Solenoid valves open in a sequence to provide the required power. Corrosion is limited because there is no electrolyte in the modules not being used.

Advanced Extravehicular Protective Systems (AEPS) study

NASA Technical Reports Server (NTRS)

Williams, J. L.; Copeland, R. J.; Webbon, B. W.

1971-01-01

A description is given of life support subsystem concepts for advanced extravehicular protective systems (AEPS) intended for use on future orbital, lunar surface, and Mars surface missions in the late 1970's and 1980's. Primary interest was centered around the thermal control and carbon dioxide control subsystems because they offer the greatest potential for total weight savings. Emphasis was placed on the generation of regenerable subsystem concepts; however, partially regenerable and expendable concepts were also considered. Previously conceived and developed subsystem concepts were included in the study. Concepts were evaluated on the basis of subsystem weight and volume, and subsystem contribution to parent vehicle weight and volume, which included spares, regeneration equipment, expendables, expandables storage penalty, power penalty, and process heating or cooling penalty. Results are presented showing total weight and volume penalty as a function of total mission extravehicular activity (EVA) hours, and showing EVA weight and volume as a function of EVA duration. Subsystem concepts are recommended for each life support function, and secondary concepts which should be developed are also identified.

Entanglement and magnetism in high-spin graphene nanodisks

NASA Astrophysics Data System (ADS)

Hagymási, I.; Legeza, Ö.

2018-01-01

We investigate the ground-state properties of triangular graphene nanoflakes with zigzag edge configurations. The description of zero-dimensional nanostructures requires accurate many-body techniques since the widely used density-functional theory with local density approximation or Hartree-Fock methods cannot handle the strong quantum fluctuations. Applying the unbiased density-matrix renormalization group algorithm we calculate the magnetization and entanglement patterns with high accuracy for different interaction strengths and compare them to the mean-field results. With the help of quantum information analysis and subsystem density matrices we reveal that the edges are strongly entangled with each other. We also address the effect of electron and hole doping and demonstrate that the magnetic properties of triangular nanoflakes can be controlled by an electric field, which reveals features of flat-band ferromagnetism. This may open up new avenues in graphene based spintronics.

Metal viscoplasticity with two-temperature thermodynamics and two dislocation densities

NASA Astrophysics Data System (ADS)

Roy Chowdhury, Shubhankar; Kar, Gurudas; Roy, Debasish; Reddy, J. N.

2018-03-01

Posed within the two-temperature theory of non-equilibrium thermodynamics, we propose a model for thermoviscoplastic deformation in metals. We incorporate the dynamics of dislocation densities-mobile and forest—that play the role of internal state variables in the formulation. The description based on two temperatures appears naturally when one recognizes that the thermodynamic system undergoing viscoplastic deformation is composed of two weakly interacting subsystems, viz. a kinetic-vibrational subsystem of the vibrating atomic lattices and a configurational subsystem of the slower degrees of freedom relating to defect motion, each with its own temperature. Starting with a basic model that involves only homogeneous deformation, a three-dimensional model for inhomogeneous viscoplasticity applicable to finite deformation is charted out in an overstress driven viscoplastic deformation framework. The model shows how the coupled evolutions of mobile and forest dislocation densities, which are critically influenced by the dynamics of configurational temperature, govern the strength and ductility of the metal. Unlike most contemporary models, the current proposal also affords a prediction of certain finer details as observed in the experimental data on stress-strain behaviour of metals and this in turn enhances the understanding of the evolving and interacting dislocation densities.

MRI morphometry of mamillary bodies, caudate nuclei, and prefrontal cortices after chemotherapy for childhood leukemia: multivariate models of early and late developing memory subsystems.

PubMed

Ciesielski, K T; Lesnik, P G; Benzel, E C; Hart, B L; Sanders, J A

1999-06-01

Neurotoxic intrathecal chemotherapy for childhood acute lymphoblastic leukemia (ALL) affects developing structures and functions of memory and learning subsystems selectively. Results show significant reductions in magnetic resonance imaging morphometry of mamillary bodies, components of the corticolimbic-diencephalic subsystem subserving functionally later developing, single-trial memory, nonsignificant changes in bilateral heads of the caudate nuclei, components of the corticostriatal subsystem subserving functionally earlier developing, multitrial learning, significant reductions in prefrontal cortical volume, visual and verbal single-trial memory deficits, and visuospatial, but not verbal, multitrial learning deficits. Multiple regression models provide evidence for partial dissociation and connectivity between the subsystems, and suggest that greater involvement of caudate may compensate for inefficient corticolimbic-diencephalic components.

Solar electric propulsion thrust subsystem development

NASA Technical Reports Server (NTRS)

Masek, T. D.

1973-01-01

The Solar Electric Propulsion System developed under this program was designed to demonstrate all the thrust subsystem functions needed on an unmanned planetary vehicle. The demonstration included operation of the basic elements, power matching input and output voltage regulation, three-axis thrust vector control, subsystem automatic control including failure detection and correction capability (using a PDP-11 computer), operation of critical elements in thermal-vacuum-, zero-gravity-type propellant storage, and data outputs from all subsystem elements. The subsystem elements, functions, unique features, and test setup are described. General features and capabilities of the test-support data system are also presented. The test program culminated in a 1500-h computer-controlled, system-functional demonstration. This included simultaneous operation of two thruster/power conditioner sets. The results of this testing phase satisfied all the program goals.

Quantification of Interactions between Dynamic Cellular Network Functionalities by Cascaded Layering

PubMed Central

Prescott, Thomas P.; Lang, Moritz; Papachristodoulou, Antonis

2015-01-01

Large, naturally evolved biomolecular networks typically fulfil multiple functions. When modelling or redesigning such systems, functional subsystems are often analysed independently first, before subsequent integration into larger-scale computational models. In the design and analysis process, it is therefore important to quantitatively analyse and predict the dynamics of the interactions between integrated subsystems; in particular, how the incremental effect of integrating a subsystem into a network depends on the existing dynamics of that network. In this paper we present a framework for simulating the contribution of any given functional subsystem when integrated together with one or more other subsystems. This is achieved through a cascaded layering of a network into functional subsystems, where each layer is defined by an appropriate subset of the reactions. We exploit symmetries in our formulation to exhaustively quantify each subsystem’s incremental effects with minimal computational effort. When combining subsystems, their isolated behaviour may be amplified, attenuated, or be subject to more complicated effects. We propose the concept of mutual dynamics to quantify such nonlinear phenomena, thereby defining the incompatibility and cooperativity between all pairs of subsystems when integrated into any larger network. We exemplify our theoretical framework by analysing diverse behaviours in three dynamic models of signalling and metabolic pathways: the effect of crosstalk mechanisms on the dynamics of parallel signal transduction pathways; reciprocal side-effects between several integral feedback mechanisms and the subsystems they stabilise; and consequences of nonlinear interactions between elementary flux modes in glycolysis for metabolic engineering strategies. Our analysis shows that it is not sufficient to just specify subsystems and analyse their pairwise interactions; the environment in which the interaction takes place must also be explicitly defined. Our framework provides a natural representation of nonlinear interaction phenomena, and will therefore be an important tool for modelling large-scale evolved or synthetic biomolecular networks. PMID:25933116

Solar powered hybrid sensor module program

NASA Technical Reports Server (NTRS)

Johnson, J. M.; Holmes, H. K.

1985-01-01

Geo-orbital systems of the near future will require more sophisticated electronic and electromechanical monitoring and control systems than current satellite systems with an emphasis in the design on the electronic density and autonomy of the subsystem components. Results of a project to develop, design, and implement a proof-of-concept sensor system for space applications, with hybrids forming the active subsystem components are described. The design of the solar power hybrid sensor modules is discussed. Module construction and function are described. These modules combined low power CMOS electronics, GaAs solar cells, a crystal oscillatory standard UART data formatting, and a bidirectional optical data link into a single 1.25 x 1.25 x 0.25 inch hybrid package which has no need for electrical input or output. Several modules were built and tested. Applications of such a system for future space missions are also discussed.

Minimal-Approximation-Based Decentralized Backstepping Control of Interconnected Time-Delay Systems.

PubMed

Choi, Yun Ho; Yoo, Sung Jin

2016-12-01

A decentralized adaptive backstepping control design using minimal function approximators is proposed for nonlinear large-scale systems with unknown unmatched time-varying delayed interactions and unknown backlash-like hysteresis nonlinearities. Compared with existing decentralized backstepping methods, the contribution of this paper is to design a simple local control law for each subsystem, consisting of an actual control with one adaptive function approximator, without requiring the use of multiple function approximators and regardless of the order of each subsystem. The virtual controllers for each subsystem are used as intermediate signals for designing a local actual control at the last step. For each subsystem, a lumped unknown function including the unknown nonlinear terms and the hysteresis nonlinearities is derived at the last step and is estimated by one function approximator. Thus, the proposed approach only uses one function approximator to implement each local controller, while existing decentralized backstepping control methods require the number of function approximators equal to the order of each subsystem and a calculation of virtual controllers to implement each local actual controller. The stability of the total controlled closed-loop system is analyzed using the Lyapunov stability theorem.

PC-403: Pioneer Venus multiprobe spacecraft mission operational characteristics document, volume 2

NASA Technical Reports Server (NTRS)

Barker, F. C.

1978-01-01

The data handling subsystem, command subsystem, communications subsystem, power subsystem, and mission operations of the Pioneer Venus multiprobe are presented. The multiprobe spacecraft performance in normal operating modes that correspond to the performance of specific functions at the time of specific events in the mission is described.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zúñiga-Segundo, Arturo; Juárez-Amaro, Raúl; Aguilar-Loreto, Omar

We study the atom–field interaction when the field is in a mixture of coherent states. We show that in this case it is possible to calculate analytically the field entropy for times of the order of twice the collapse time. Such analytical results are done with the help of numerical analysis. We also give an expression in terms of Chebyshev polynomials for power of density matrices. - Highlights: • We calculate the field entropy for times of the order of twice the collapse time. • We give a relation between powers of the density matrices of the subsystems. • Entropymore » operators for both subsystems are obtained.« less

Density functional with full exact exchange, balanced nonlocality of correlations, and constraint satisfaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tao, Jianmin; Perdew, John P; Staroverov, Viktor N

2008-01-01

We construct a nonlocal density functional approximation with full exact exchange, while preserving the constraint-satisfaction approach and justified error cancellations of simpler semilocal functionals. This is achieved by interpolating between different approximations suitable for two extreme regions of the electron density. In a 'normal' region, the exact exchange-correlation hole density around an electron is semilocal because its spatial range is reduced by correlation and because it integrates over a narrow range to -1. These regions are well described by popular semilocal approximations (many of which have been constructed nonempirically), because of proper accuracy for a slowly-varying density or because ofmore » error cancellation between exchange and correlation. 'Abnormal' regions, where non locality is unveiled, include those in which exchange can dominate correlation (one-electron, nonuniform high-density, and rapidly-varying limits), and those open subsystems of fluctuating electron number over which the exact exchange-correlation hole integrates to a value greater than -1. Regions between these extremes are described by a hybrid functional mixing exact and semi local exchange energy densities locally (i.e., with a mixing fraction that is a function of position r and a functional of the density). Because our mixing fraction tends to 1 in the high-density limit, we employ full exact exchange according to the rigorous definition of the exchange component of any exchange-correlation energy functional. Use of full exact exchange permits the satisfaction of many exact constraints, but the nonlocality of exchange also requires balanced nonlocality of correlation. We find that this nonlocality can demand at least five empirical parameters (corresponding roughly to the four kinds of abnormal regions). Our local hybrid functional is perhaps the first accurate size-consistent density functional with full exact exchange. It satisfies other known exact constraints, including exactness for all one-electron densities, and provides an excellent, fit 1.0 the 223 molecular enthalpies of formation of the G3/99 set and the 42 reaction barrier heights of the BH42/03 set, improving both (but especially the latter) over most semilocal functionals and global hybrids. Exact constraints, physical insights, and paradigm examples hopefully suppress 'overfitting'.« less

The Space Station air revitalization subsystem design concept

NASA Technical Reports Server (NTRS)

Ray, C. D.; Ogle, K. Y.; Tipps, R. W.; Carrasquillo, R. L.; Wieland, P.

1987-01-01

The current status of the Space Station (SS) Environmental Control and Life Support System (ECLSS) Air Revitalization Subsystem (ARS) design is outlined. ARS performance requirements are provided, along with subsystem options for each ARS function and selected evaluations of the relative merits of each subsystem. Detailed computer models that have been developed to analyze individual subsystem performance capabilities are also discussed. A summary of ARS subsystem level testing planned and completed by NASA Marshall Space Flight Center (MSFC) is given.

Introduction to the Portable Life Support Schematic and Technology Development Components

NASA Technical Reports Server (NTRS)

Conger, Bruce

2008-01-01

Conger presented the operations and functions of the baseline Constellation Program (CxP) Portable Life Support System (PLSS) schematic and key development technologies. He explained the functional descriptions of the schematic components in the fluid systems of the PLSS for multiple operational scenarios. PLSS subsystems include the oxygen subsystem, the ventilation subsystem, and the thermal subsystem. He also presented the operational PLSS modes: Nominal EVA mode, Umbilical - no recharge mode, Umbilical - with recharge mode, BENDS mode, BUDDY mode, Secondary oxygen mode, and the PLSS-removed umbilical mode.

Evaluation of an Atmosphere Revitalization Subsystem for Deep Space Exploration Missions

NASA Technical Reports Server (NTRS)

Perry, Jay L.; Abney, Morgan B.; Conrad, Ruth E.; Frederick, Kenneth R.; Greenwood, Zachary W.; Kayatin, Matthew J.; Knox, James C.; Newton, Robert L.; Parrish, Keith J.; Takada, Kevin C.;

Space Tug avionics definition study. Volume 2: Avionics functional requirements

NASA Technical Reports Server (NTRS)

1975-01-01

Flight and ground operational phases of the tug/shuttle system are analyzed to determine the general avionics support functions that are needed during each of the mission phases and sub-phases. Each of these general support functions is then expanded into specific avionics system requirements, which are then allocated to the appropriate avionics subsystems. This process is then repeated at the next lower level of detail where these subsystem requirements are allocated to each of the major components that comprise a subsystem.

Autonomous navigation - The ARMMS concept. [Autonomous Redundancy and Maintenance Management Subsystem

NASA Technical Reports Server (NTRS)

Wood, L. J.; Jones, J. B.; Mease, K. D.; Kwok, J. H.; Goltz, G. L.; Kechichian, J. A.

1984-01-01

A conceptual design is outlined for the navigation subsystem of the Autonomous Redundancy and Maintenance Management Subsystem (ARMMS). The principal function of this navigation subsystem is to maintain the spacecraft over a specified equatorial longitude to within + or - 3 deg. In addition, the navigation subsystem must detect and correct internal faults. It comprises elements for a navigation executive and for orbit determination, trajectory, maneuver planning, and maneuver command. Each of these elements is described. The navigation subsystem is to be used in the DSCS III spacecraft.

Orbiter ECLSS support of Shuttle payloads

NASA Technical Reports Server (NTRS)

Jaax, J. R.; Morris, D. W.; Prince, R. N.

1974-01-01

The orbiter ECLSS (Environmental Control and Life Support System) provides the functions of atmosphere revitalization, crew life support, and active thermal control. This paper describes these functions as they relate to the support of Shuttle payloads, including automated spacecraft, Spacelab and Department of Defense missions. Functional and performance requirements for the orbiter ECLSS which affect payload support are presented for the atmosphere revitalization subsystem, the food, water and waste subsystem, and the active thermal control subsystem. Schematics for these subsystems are also described. Finally, based on the selected orbiter configuration, preliminary design and off-design thermodynamic data are presented to quantify the baseline orbiter capability; to quantify the payload chargeable penalties for increasing this support; and to identify the significant limits of orbiter ECLSS support available to Shuttle payloads.

Balancing reliability and cost to choose the best power subsystem

NASA Technical Reports Server (NTRS)

Suich, Ronald C.; Patterson, Richard L.

1991-01-01

A mathematical model is presented for computing total (spacecraft) subsystem cost including both the basic subsystem cost and the expected cost due to the failure of the subsystem. This model is then used to determine power subsystem cost as a function of reliability and redundancy. Minimum cost and maximum reliability and/or redundancy are not generally equivalent. Two example cases are presented. One is a small satellite, and the other is an interplanetary spacecraft.

Cooperation and Environment Characterize the Low-Lying Optical Spectrum of Liquid Water.

PubMed

P, Sudheer Kumar; Genova, Alessandro; Pavanello, Michele

2017-10-19

The optical spectrum of liquid water is analyzed by subsystem time-dependent density functional theory. We provide simple explanations for several important (and so far elusive) features. Due to the disordered environment surrounding each water molecule, the joint density of states of the liquid is much broader than that of the vapor, thus explaining the red-shifted Urbach tail of the liquid compared to the gas phase. Confinement effects provided by the first solvation shell are responsible for the blue shift of the first absorption peak compared to the vapor. In addition, we also characterize many-body excitonic effects. These dramatically affect the spectral weights at low frequencies, contributing to the refractive index by a small but significant amount.

Element-resolved thermodynamics of magnetocaloric LaFe 13 – x Si x

DOE PAGES

Gruner, Markus E.; Keune, Werner; Cuenya, B. Roldan; ...

2015-02-04

By combination of two independent approaches, nuclear resonant inelastic x-ray scattering and first-principles calculations in the framework of density functional theory, we demonstrate significant changes in the element-resolved vibrational density of states across the first-order transition from the ferromagnetic low temperature to the paramagnetic high temperature phase of LaFe 13-xSi x. These changes originate from the itinerant electron metamagnetism associated with Fe and lead to a pronounced magneto-elastic softening despite the large volume decrease at the transition. As a result, the increase in lattice entropy associated with the Fe subsystem is significant and contributes cooperatively with the magnetic and electronicmore » entropy changes to the excellent magneto- and barocaloric properties.« less

Conflicting Demands of Abstract and Specific Visual Object Processing Resolved by Fronto-Parietal Networks

PubMed Central

McMenamin, Brenton W.; Marsolek, Chad J.; Morseth, Brianna K.; Speer, MacKenzie F.; Burton, Philip C.; Burgund, E. Darcy

2016-01-01

Object categorization and exemplar identification place conflicting demands on the visual system, yet humans easily perform these fundamentally contradictory tasks. Previous studies suggest the existence of dissociable visual processing subsystems to accomplish the two abilities – an abstract category (AC) subsystem that operates effectively in the left hemisphere, and a specific exemplar (SE) subsystem that operates effectively in the right hemisphere. This multiple subsystems theory explains a range of visual abilities, but previous studies have not explored what mechanisms exist for coordinating the function of multiple subsystems and/or resolving the conflicts that would arise between them. We collected functional MRI data while participants performed two variants of a cue-probe working memory task that required AC or SE processing. During the maintenance phase of the task, the bilateral intraparietal sulcus (IPS) exhibited hemispheric asymmetries in functional connectivity consistent with exerting proactive control over the two visual subsystems: greater connectivity to the left hemisphere during the AC task, and greater connectivity to the right hemisphere during the SE task. Moreover, probe-evoked activation revealed activity in a broad fronto-parietal network (containing IPS) associated with reactive control when the two visual subsystems were in conflict, and variations in this conflict signal across trials was related to the visual similarity of the cue/probe stimulus pairs. Although many studies have confirmed the existence of multiple visual processing subsystems, this study is the first to identify the mechanisms responsible for coordinating their operations. PMID:26883940

Conflicting demands of abstract and specific visual object processing resolved by frontoparietal networks.

PubMed

McMenamin, Brenton W; Marsolek, Chad J; Morseth, Brianna K; Speer, MacKenzie F; Burton, Philip C; Burgund, E Darcy

2016-06-01

Object categorization and exemplar identification place conflicting demands on the visual system, yet humans easily perform these fundamentally contradictory tasks. Previous studies suggest the existence of dissociable visual processing subsystems to accomplish the two abilities-an abstract category (AC) subsystem that operates effectively in the left hemisphere and a specific exemplar (SE) subsystem that operates effectively in the right hemisphere. This multiple subsystems theory explains a range of visual abilities, but previous studies have not explored what mechanisms exist for coordinating the function of multiple subsystems and/or resolving the conflicts that would arise between them. We collected functional MRI data while participants performed two variants of a cue-probe working memory task that required AC or SE processing. During the maintenance phase of the task, the bilateral intraparietal sulcus (IPS) exhibited hemispheric asymmetries in functional connectivity consistent with exerting proactive control over the two visual subsystems: greater connectivity to the left hemisphere during the AC task, and greater connectivity to the right hemisphere during the SE task. Moreover, probe-evoked activation revealed activity in a broad frontoparietal network (containing IPS) associated with reactive control when the two visual subsystems were in conflict, and variations in this conflict signal across trials was related to the visual similarity of the cue-probe stimulus pairs. Although many studies have confirmed the existence of multiple visual processing subsystems, this study is the first to identify the mechanisms responsible for coordinating their operations.

Concept for a Satellite-Based Advanced Air Traffic Management System : Volume 3. Subsystem Functional Description.

DOT National Transportation Integrated Search

1974-02-01

The volume presents a detailed description of the subsystems that comprise the Satellite-Based Advanced Air Traffic Management System. Described in detail are the surveillance, navigation, communications, data processing, and airport subsystems. The ...

Spacelab - From early integration to first flight. I

NASA Astrophysics Data System (ADS)

Thirkettle, A.; di Mauro, F.; Stephens, R.

1984-05-01

Spacelab is a series of flight elements that can be assembled together in different configurations. The laboratory is designed to accommodate many payloads with totally different characteristics. Two models were built: one was tested functionally, integrated into an Engineering Model and delivered to NASA. The other was used for subsystem testing. The Spacelab system consists of several functional elements within the Module, Igloo and Pallet structures: an Electric Power Distribution Subsystem, a Command and Data Management Subsystem, Software, Caution-and-Warning Subsystem and an Environmental Control Subsystem. The Engineering Model tests were conducted in Europe from April 1978 through October 1980, delivery of the laboratory to JFK Space Center, Florida was in December 1980, and the first flight was made in November 1983 on Space Shuttle STS-9.

A new estimation of HD/2H2 at high redshift using the spectrum of the quasar J 2123-0050

NASA Astrophysics Data System (ADS)

Klimenko, V. V.; Balashev, S. A.; Ivanchik, A. V.; Varshalovich, D. A.

2015-12-01

We present a new analysis of the quasar spectrum J 2123-0050 obtained using VLT/UVES. The H2/HD absorption system at z = 2.059 was analysed. This system consists of two subsystems with zA = 2.05933 and zB = 2.05955. The HD lines have been detected only in subsystem A with the column density of log N = 13.87 ± 0.06. We have determined the column density of H2 in this subsystem, log N = 17.93 ± 0.01, which is about three times larger than estimation derived early from analyses of quasar spectrum obtained using KECK/HIRES [1]. The derived ratio HD/2H2 = (4.28 ± 0.60) × 10-5 is the largest in quasar spectra, nevertheless it coincides with the primordial deuterium abundance within 2σ error. Additionally, we have found some evidence in the partial covering effect for the H2 system.

System comprising interchangeable electronic controllers and corresponding methods

NASA Technical Reports Server (NTRS)

Steele, Glen F. (Inventor); Salazar, George A. (Inventor)

2009-01-01

A system comprising an interchangeable electronic controller is provided with programming that allows the controller to adapt a behavior that is dependent upon the particular type of function performed by a system or subsystem component. The system reconfigures the controller when the controller is moved from one group of subsystem components to another. A plurality of application programs are provided by a server from which the application program for a particular electronic controller is selected. The selection is based on criteria such as a subsystem component group identifier that identifies the particular type of function associated with the system or subsystem group of components.

Stability of large-scale systems with stable and unstable subsystems.

NASA Technical Reports Server (NTRS)

Grujic, Lj. T.; Siljak, D. D.

1972-01-01

The purpose of this paper is to develop new methods for constructing vector Liapunov functions and broaden the application of Liapunov's theory to stability analysis of large-scale dynamic systems. The application, so far limited by the assumption that the large-scale systems are composed of exponentially stable subsystems, is extended via the general concept of comparison functions to systems which can be decomposed into asymptotically stable subsystems. Asymptotic stability of the composite system is tested by a simple algebraic criterion. With minor technical adjustments, the same criterion can be used to determine connective asymptotic stability of large-scale systems subject to structural perturbations. By redefining the constraints imposed on the interconnections among the subsystems, the considered class of systems is broadened in an essential way to include composite systems with unstable subsystems. In this way, the theory is brought substantially closer to reality since stability of all subsystems is no longer a necessary assumption in establishing stability of the overall composite system.

Exact density functional and wave function embedding schemes based on orbital localization

NASA Astrophysics Data System (ADS)

Hégely, Bence; Nagy, Péter R.; Ferenczy, György G.; Kállay, Mihály

2016-08-01

Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up the system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.

Fluctuation relation based continuum model for thermoviscoplasticity in metals

NASA Astrophysics Data System (ADS)

Roy Chowdhury, Shubhankar; Roy, Debasish; Reddy, J. N.; Srinivasa, Arun

2016-11-01

A continuum plasticity model for metals is presented from considerations of non-equilibrium thermodynamics. Of specific interest is the application of a fluctuation relation that subsumes the second law of thermodynamics en route to deriving the evolution equations for the internal state variables. The modelling itself is accomplished in a two-temperature framework that appears naturally by considering the thermodynamic system to be composed of two weakly interacting subsystems, viz. a kinetic vibrational subsystem corresponding to the atomic lattice vibrations and a configurational subsystem of the slower degrees of freedom describing the motion of defects in a plastically deforming metal. An apparently physical nature of the present model derives upon considering the dislocation density, which characterizes the configurational subsystem, as a state variable. Unlike the usual constitutive modelling aided by the second law of thermodynamics that merely provides a guideline to select the admissible (though possibly non-unique) processes, the present formalism strictly determines the process or the evolution equations for the thermodynamic states while including the effect of fluctuations. The continuum model accommodates finite deformation and describes plastic deformation in a yield-free setup. The theory here is essentially limited to face-centered cubic metals modelled with a single dislocation density as the internal variable. Limited numerical simulations are presented with validation against relevant experimental data.

HAL/SM system functional design specification. [systems analysis and design analysis of central processing units

NASA Technical Reports Server (NTRS)

Ross, C.; Williams, G. P. W., Jr.

1975-01-01

The functional design of a preprocessor, and subsystems is described. A structure chart and a data flow diagram are included for each subsystem. Also a group of intermodule interface definitions (one definition per module) is included immediately following the structure chart and data flow for a particular subsystem. Each of these intermodule interface definitions consists of the identification of the module, the function the module is to perform, the identification and definition of parameter interfaces to the module, and any design notes associated with the module. Also described are compilers and computer libraries.

The relationship between default mode network connectivity and social functioning in individuals at familial high-risk for schizophrenia.

PubMed

Dodell-Feder, David; Delisi, Lynn E; Hooker, Christine I

2014-06-01

Unaffected first-degree relatives of individuals with schizophrenia (i.e., those at familial high-risk [FHR]), demonstrate social dysfunction qualitatively similar though less severe than that of their affected relatives. These social difficulties may be the consequence of genetically conferred disruption to aspects of the default mode network (DMN), such as the dMPFC subsystem, which overlaps with the network of brain regions recruited during social cognitive processes. In the present study, we investigate this possibility, testing DMN connectivity and its relationship to social functioning in FHR using resting-state fMRI. Twenty FHR individuals and 17 controls underwent fMRI during a resting-state scan. Hypothesis-driven functional connectivity analyses examined ROI-to-ROI correlations between the DMN's hubs, and regions of the dMPFC subsystem and MTL subsystem. Connectivity values were examined in relationship to a measure of social functioning and empathy/perspective-taking. Results demonstrate that FHR exhibit reduced connectivity specifically within the dMPFC subsystem of the DMN. Certain ROI-to-ROI correlations predicted aspects of social functioning and empathy/perspective-taking across all participants. Together, the data indicate that disruption to the dMPFC subsystem of the DMN may be associated with familial risk for schizophrenia, and that these intrinsic connections may carry measurable consequences for social functioning. Copyright © 2014 Elsevier B.V. All rights reserved.

The relationship between default mode network connectivity and social functioning in individuals at familial high-risk for schizophrenia

PubMed Central

Dodell-Feder, David; DeLisi, Lynn E.; Hooker, Christine I.

2014-01-01

Unaffected first-degree relatives of individuals with schizophrenia (i.e., those at familial high-risk [FHR]), demonstrate social dysfunction qualitatively similar though less severe than that of their affected relatives. These social difficulties may be the consequence of genetically conferred disruption to aspects of the default mode network (DMN), such as the dMPFC subsystem, which overlaps with the network of brain regions recruited during social cognitive processes. In the present study, we investigate this possibility, testing DMN connectivity and its relationship to social functioning in FHR using resting-state fMRI. Twenty FHR individuals and 17 controls underwent fMRI during a resting-state scan. Hypothesis-driven functional connectivity analyses examined ROI-to-ROI correlations between the DMN’s hubs, and regions of the dMPFC subsystem and MTL subsystem. Connectivity values were examined in relationship to a measure of social functioning and empathy/perspective-taking. Results demonstrate that FHR exhibit reduced connectivity specifically within the dMPFC subsystem of the DMN. Certain ROI-to-ROI correlations predicted aspects of social functioning and empathy/perspective-taking across all participants. Together, the data indicate that disruption to the dMPFC subsystem of the DMN may be associated with familial risk for schizophrenia, and that these intrinsic connections may carry measurable consequences for social functioning. PMID:24768131

Asymptotic stability and instability of large-scale systems. [using vector Liapunov functions

NASA Technical Reports Server (NTRS)

Grujic, L. T.; Siljak, D. D.

1973-01-01

The purpose of this paper is to develop new methods for constructing vector Lyapunov functions and broaden the application of Lyapunov's theory to stability analysis of large-scale dynamic systems. The application, so far limited by the assumption that the large-scale systems are composed of exponentially stable subsystems, is extended via the general concept of comparison functions to systems which can be decomposed into asymptotically stable subsystems. Asymptotic stability of the composite system is tested by a simple algebraic criterion. By redefining interconnection functions among the subsystems according to interconnection matrices, the same mathematical machinery can be used to determine connective asymptotic stability of large-scale systems under arbitrary structural perturbations.

Vapor Compression Distillation Subsystem (VCDS) Component Enhancement, Testing and Expert Fault Diagnostics Development, Volume 2

NASA Technical Reports Server (NTRS)

Mallinak, E. S.

1987-01-01

A wide variety of Space Station functions will be managed via computerized controls. Many of these functions are at the same time very complex and very critical to the operation of the Space Station. The Environmental Control and Life Support System is one group of very complex and critical subsystems which directly affects the ability of the crew to perform their mission. Failure of the Environmental Control and Life Support Subsystems are to be avoided and, in the event of failure, repair must be effected as rapidly as possible. Due to the complex and diverse nature of the subsystems, it is not possible to train the Space Station crew to be experts in the operation of all of the subsystems. By applying the concepts of computer-based expert systems, it may be possible to provide the necessary expertise for these subsystems in dedicated controllers. In this way, an expert system could avoid failures and extend the operating time of the subsystems even in the event of failure of some components, and could reduce the time to repair by being able to pinpoint the cause of a failure when one cannot be avoided.

Integration & Validation of LCU with Different Sub-systems for Diacrode based amplifier

NASA Astrophysics Data System (ADS)

Rajnish, Kumar; Verma, Sriprakash; Soni, Dipal; Patel, Hriday; Suthar, Gajendra; Dalicha, Hrushikesh; Dhola, Hitesh; Patel, Amit; Upadhayay, Dishang; Jha, Akhil; Patel, Manoj; Trivedi, Rajesh; Machchhar, Harsha; Singh, Raghuraj; Mukherjee, Aparajita

2017-04-01

ITER-India is responsible to deliver nine (8+1 spare) ICH & CD Power Sources to ITER. Each power source is capable to deliver 2.5 MW at 35 to 65 MHz frequency range with a load condition up to VSWR 2:1. For remote operation of different subsystems, Local Control Unit (LCU) is developed. LCU is developed using PXI hardware and Schneider PLC with Lab VIEW-RT developmental environment. All the protection function of the amplifier is running on PXI 7841 R module that ensures hard wired protection logic. There are three level of protection function- first by power supply itself that detects overcurrent/overvoltage and trips itself and generate trip signal for further action. There are some direct hardwired signal interfaces between power supplies to protect the amplifier. Second level of protection is generated through integrated controller of amplifier i.e. Command Control Embedded (CCE) against arc and Anode over current. Third level of Protection is through LCU where different fault signals are received and processed to generate off command for different sub-systems. Before connecting different subsystem with High power RF amplifiers (Driver & Final stage), each subsystem is individually tested through LCU. All protection functions are tested before hooking up the subsystems with main amplifier and initiating RF operation.

PREVAIL-EPL alpha tool electron optics subsystem

NASA Astrophysics Data System (ADS)

Pfeiffer, Hans C.; Dhaliwal, Rajinder S.; Golladay, Steven D.; Doran, Samuel K.; Gordon, Michael S.; Kendall, Rodney A.; Lieberman, Jon E.; Pinckney, David J.; Quickle, Robert J.; Robinson, Christopher F.; Rockrohr, James D.; Stickel, Werner; Tressler, Eileen V.

2001-08-01

The IBM/Nikon alliance is continuing pursuit of an EPL stepper alpha tool based on the PREVAIL technology. This paper provides a status report of the alliance activity with particular focus on the Electron Optical Subsystem developed at IBM. We have previously reported on design features of the PREVAIL alpha system. The new state-of-the-art e-beam lithography concepts have since been reduced to practice and turned into functional building blocks of a production level lithography tool. The electron optical alpha tool subsystem has been designed, build, assembled and tested at IBM's Semiconductor Research and Development Center (SRDC) in East Fishkill, New York. After demonstrating subsystem functionality, the electron optical column and all associated control electronics hardware and software have been shipped during January 2001 to Nikon's facility in Kumagaya, Japan, for integration into the Nikon commercial e-beam stepper alpha tool. Early pre-shipment results obtained with this electron optical subsystem are presented.

A Computer Program Functional Design of the Simulation Subsystem of an Automated Central Flow Control System

DOT National Transportation Integrated Search

1976-08-01

This report contains a functional design for the simulation of a future automation concept in support of the ATC Systems Command Center. The simulation subsystem performs airport airborne arrival delay predictions and computes flow control tables for...

Decomposition-aggregation stability analysis. [for large scale dynamic systems with application to spinning Skylab control system

NASA Technical Reports Server (NTRS)

Siljak, D. D.; Weissenberger, S.; Cuk, S. M.

1973-01-01

This report presents the development and description of the decomposition aggregation approach to stability investigations of high dimension mathematical models of dynamic systems. The high dimension vector differential equation describing a large dynamic system is decomposed into a number of lower dimension vector differential equations which represent interconnected subsystems. Then a method is described by which the stability properties of each subsystem are aggregated into a single vector Liapunov function, representing the aggregate system model, consisting of subsystem Liapunov functions as components. A linear vector differential inequality is then formed in terms of the vector Liapunov function. The matrix of the model, which reflects the stability properties of the subsystems and the nature of their interconnections, is analyzed to conclude over-all system stability characteristics. The technique is applied in detail to investigate the stability characteristics of a dynamic model of a hypothetical spinning Skylab.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ritter, William Gordon

Since there are many examples in which no decoherence-free subsystems exist (among them all cases where the error generators act irreducibly on the system Hilbert space), it is of interest to search for novel mechanisms which suppress decoherence in these more general cases. Drawing on recent work (quant-ph/0502153) we present three results which indicate decoherence suppression without the need for noiseless subsystems. There is a certain trade-off; our results do not necessarily apply to an arbitrary initial density matrix or for completely generic noise parameters. On the other hand, our computational methods are novel and the result--suppression of decoherence inmore » the error-algebra approach without noiseless subsystems--is an interesting new direction.« less

Dedicated nuclear facilities for electrolytic hydrogen production

NASA Technical Reports Server (NTRS)

Foh, S. E.; Escher, W. J. D.; Donakowski, T. D.

1979-01-01

An advanced technology, fully dedicated nuclear-electrolytic hydrogen production facility is presented. This plant will produce hydrogen and oxygen only and no electrical power will be generated for off-plant use. The conceptual design was based on hydrogen production to fill a pipeline at 1000 psi and a 3000 MW nuclear base, and the base-line facility nuclear-to-shaftpower and shaftpower-to-electricity subsystems, the water treatment subsystem, electricity-to-hydrogen subsystem, hydrogen compression, efficiency, and hydrogen production cost are discussed. The final conceptual design integrates a 3000 MWth high-temperature gas-cooled reactor operating at 980 C helium reactor-out temperature, direct dc electricity generation via acyclic generators, and high-current density, high-pressure electrolyzers based on the solid polymer electrolyte approach. All subsystems are close-coupled and optimally interfaced and pipeline hydrogen is produced at 1000 psi. Hydrogen costs were about half of the conventional nuclear electrolysis process.

Development of a six-man, self-contained carbon dioxide collection subsystem for spacecraft application

NASA Technical Reports Server (NTRS)

Schubert, F. H.; Quattrone, P. D.

1974-01-01

Life Systems, working with NASA, has developed an electrochemical, six-man, self-contained carbon dioxide concentrator subsystem (CX-6) designed to normally remove 13.2 lb/day of CO2 while maintaining the CO2 partial pressure (pCO2) of the cabin atmosphere at 3 mm Hg or less. The CX-6 was subjected to extensive parametric and endurance testing. The effects of operating conditions on CO2 removal and electrical efficiencies were determined, including effects of hydrogen (H2) flow rate, process airflow rate, pCO2, operating temperature and current density. A total of 209 days of operation was accumulated. The subsystem was designed with self-contained electronic control and monitoring instrumentation. The CX-6 was redesigned and repackaged into the CO2 collection subsystem for the air revitalization group of the space station prototype.

Bounding entanglement spreading after a local quench

NASA Astrophysics Data System (ADS)

Drumond, Raphael C.; Móller, Natália S.

2017-06-01

We consider the variation of von Neumann entropy of subsystem reduced states of general many-body lattice spin systems due to local quantum quenches. We obtain Lieb-Robinson-like bounds that are independent of the subsystem volume. The main assumptions are that the Hamiltonian satisfies a Lieb-Robinson bound and that the volume of spheres on the lattice grows at most exponentially with their radius. More specifically, the bound exponentially increases with time but exponentially decreases with the distance between the subsystem and the region where the quench takes place. The fact that the bound is independent of the subsystem volume leads to stronger constraints (than previously known) on the propagation of information throughout many-body systems. In particular, it shows that bipartite entanglement satisfies an effective "light cone," regardless of system size. Further implications to t density-matrix renormalization-group simulations of quantum spin chains and limitations to the propagation of information are discussed.

The 30-centimeter ion thrust subsystem design manual

NASA Technical Reports Server (NTRS)

1979-01-01

The principal characteristics of the 30-centimeter ion propulsion thrust subsystem technology that was developed to satisfy the propulsion needs of future planetary and early orbital missions are described. Functional requirements and descriptions, interface and performance requirements, and physical characteristics of the hardware are described at the thrust subsystem, BIMOD engine system, and component level.

The human operator transfer function: Identification of the limb mechanics subsystem

NASA Technical Reports Server (NTRS)

Jones, Lynette A.; Hunter, Ian W.

1991-01-01

The objective of our research is to decompose the performance of the human operator in terms of the subsystems that determine the operator's responses in order to establish how the dynamics of these component subsystems influence the operator's performance. In the present experiment, the dynamic stiffness of the human elbow joint was measured at rest and under different levels of biceps muscle activation; this work forms part of the analysis of the limb mechanics subsystem.

Kinetic energy partition method applied to ground state helium-like atoms.

PubMed

Chen, Yu-Hsin; Chao, Sheng D

2017-03-28

We have used the recently developed kinetic energy partition (KEP) method to solve the quantum eigenvalue problems for helium-like atoms and obtain precise ground state energies and wave-functions. The key to treating properly the electron-electron (repulsive) Coulomb potential energies for the KEP method to be applied is to introduce a "negative mass" term into the partitioned kinetic energy. A Hartree-like product wave-function from the subsystem wave-functions is used to form the initial trial function, and the variational search for the optimized adiabatic parameters leads to a precise ground state energy. This new approach sheds new light on the all-important problem of solving many-electron Schrödinger equations and hopefully opens a new way to predictive quantum chemistry. The results presented here give very promising evidence that an effective one-electron model can be used to represent a many-electron system, in the spirit of density functional theory.

Functional design specification for Stowage List And Hardware Tracking System (SLAHTS). [space shuttles

NASA Technical Reports Server (NTRS)

Keltner, D. J.

1975-01-01

This functional design specification defines the total systems approach to meeting the requirements stated in the Detailed Requirements Document for Stowage List and Hardware Tracking System for the space shuttle program. The stowage list and hardware tracking system is identified at the system and subsystem level with each subsystem defined as a function of the total system.

Galileo attitude and articulation control subsystem closed loop testing

NASA Technical Reports Server (NTRS)

Lembeck, M. F.; Pignatano, N. D.

1983-01-01

In order to ensure the reliable operation of the Attitude and Articulation Control Subsystem (AACS) which will guide the Galileo spacecraft on its two and one-half year journey to Jupiter, the AACS is being rigorously tested. The primary objectives of the test program are the verification of the AACS's form, fit, and function, especially with regard to subsystem external interfaces and the functional operation of the flight software. Attention is presently given to the Galileo Closed Loop Test System, which simulates the dynamic and 'visual' flight environment for AACS components in the laboratory.

FBI fingerprint identification automation study: AIDS 3 evaluation report. Volume 9: Functional requirements

NASA Technical Reports Server (NTRS)

1980-01-01

The current system and subsystem used by the Identification Division are described. System constraints that dictate the system environment are discussed and boundaries within which solutions must be found are described. The functional requirements were related to the performance requirements. These performance requirements were then related to their applicable subsystems. The flow of data, documents, or other pieces of information from one subsystem to another or from the external world into the identification system is described. Requirements and design standards for a computer based system are presented.

Functional Specifications for the OCLC Interlibrary Loan Subsystem.

ERIC Educational Resources Information Center

Bova, Phyllis V.

This report covers functional specifications for the OCLC Interlibrary Loan (ILL) Subsystem, designed to permit participating libraries to increase the availability of library resources to patrons by enabling these libraries to form, transmit, and fulfill loan requests more rapidly and effectively. It will provide rapid access to a large on-line…

A local network integrated into a balloon-borne apparatus

NASA Astrophysics Data System (ADS)

Imori, Masatosi; Ueda, Ikuo; Shimamura, Kotaro; Maeno, Tadashi; Murata, Takahiro; Sasaki, Makoto; Matsunaga, Hiroyuki; Matsumoto, Hiroshi; Shikaze, Yoshiaki; Anraku, Kazuaki; Matsui, Nagataka; Yamagami, Takamasa

A local network is incorporated into an apparatus for a balloon-borne experiment. A balloon-borne system implemented in the apparatus is composed of subsystems interconnected through a local network, which introduces modular architecture into the system. The network decomposes the balloon-borne system into subsystems, which are similarly structured from the point of view that the systems is kept under the control of a ground station. The subsystem is functionally self-contained and electrically independent. A computer is integrated into a subsystem, keeping the subsystem under the control. An independent group of batteries, being dedicated to a subsystem, supplies the whole electricity of the subsystem. The subsystem could be turned on and off independently of the other subsystems. So communication among the subsystems needs to be based on such a protocol that could guarantee the independence of the individual subsystems. An Omninet protocol is employed to network the subsystems. A ground station sends commands to the balloon-borne system. The command is received and executed at the system, then results of the execution are returned to the ground station. Various commands are available so that the system borne on a balloon could be controlled and monitored remotely from the ground station. A subsystem responds to a specific group of commands. A command is received by a transceiver subsystem and then transferred through the network to the subsystem to which the command is addressed. Then the subsystem executes the command and returns results to the transceiver subsystem, where the results are telemetered to the ground station. The network enhances independence of the individual subsystems, which enables programs of the individual subsystems to be coded independently. Independence facilitates development and debugging of programs, improving the quality of the system borne on a balloon.

Apollo experience report: Lunar module environmental control subsystem

NASA Technical Reports Server (NTRS)

Gillen, R. J.; Brady, J. C.; Collier, F.

1972-01-01

A functional description of the environmental control subsystem is presented. Development, tests, checkout, and flight experiences of the subsystem are discussed; and the design fabrication, and operational difficulties associated with the various components and subassemblies are recorded. Detailed information is related concerning design changes made to, and problems encountered with, the various elements of the subsystem, such as the thermal control water sublimator, the carbon dioxide sensing and control units, and the water section. The problems associated with water sterilization, water/glycol formulation, and materials compatibility are discussed. The corrective actions taken are described with the expection that this information may be of value for future subsystems. Although the main experiences described are problem oriented, the subsystem has generally performed satisfactorily in flight.

Experiment/facility requirements document for the Space Station Furnace Facility. Section 1: Integrated configuration

NASA Astrophysics Data System (ADS)

1992-05-01

The function of the Space Station Furnace Facility (SSFF) is to support materials research into the crystal growth and solidification processes of electronic and photonic materials, metals and alloys, and glasses and ceramics. To support this broad base of research requirements, the SSFF will employ a variety of furnace modules which will be operated, regulated, and supported by a core of common subsystems. Furnace modules may be reconfigured or specifically developed to provide unique solidification conditions for each set of experiments. The SSFF modular approach permits the addition of new or scaled-up furnace modules to support the evolution of the facility as new science requirements are identified. The SSFF Core is of modular design to permit augmentation for enhanced capabilities. The fully integrated configuration of the SSFF will consist of three racks with the capability of supporting up to two furnace modules per rack. The initial configuration of the SSFF will consist of two of the three racks and one furnace module. This Experiment/Facility Requirements Document (E/FRD) describes the integrated facility requirements for the Space Station Freedom (SSF) Integrated Configuration-1 (IC1) mission. The IC1 SSFF will consist of two racks: the Core Rack, with the centralized subsystem equipment; and the Experiment Rack-1, with Furnace Module-1 and the distributed subsystem equipment to support the furnace. The SSFF support functions are provided by the following Core subsystems: power conditioning and distribution subsystem (SSFF PCDS); data management subsystem (SSFF DMS); thermal control Subsystem (SSFF TCS); gas distribution subsystem (SSFF GDS); and mechanical structures subsystem (SSFF MSS).

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: EOS AMSU-A1 and AMSU-A2 Receiver Assemblies

NASA Technical Reports Server (NTRS)

Ma, Y.

1995-01-01

The AMSU-A receiver subsystem comprises two separated receiver assemblies; AMSU-A1 and AMSU-A2 (P/N 1356441-1). The AMSU-A1 receiver contains 13 channels and the AMSU-A2 receiver 2 channels. The AMSU-A1 receiver assembly is further divided into two parts; AMSU-A1-1 (P/N 1356429-1) and AMSU-A1-2 (P/N 1356409-1), which contain 9 and 4 channels, respectively. The receiver assemblies are highlighted and illustrate the functional block diagrams of the AMSU-A1 and AMSU-A2 systems. The AMSU-A receiver subsystem stands in between the antenna and signal processing subsystems of the AMSU-A instrument and comprises the RF and IF components from isolators to attenuators. It receives the RF signals from the antenna subsystem, down-converts the RF signals to IF signals, amplifies and defines the IF signals to proper power level and frequency bandwidth as specified for each channel, and inputs the IF signals to the signal processing subsystem. This test report presents the test data of the EOS AMSU-A Flight Model No. 1 (FM-1) receiver subsystem. The tests are performed per the Acceptance Test Procedure for the AMSU-A Receiver Subsystem, AE-26002/6A. The functional performance tests are conducted either at the component or subsystem level. While the component-level tests are performed over the entire operating temperature range predicted by thermal analysis, the subsystem-level tests are conducted at ambient temperature only.

Experiment/facility requirements document for the Space Station Furnace Facility. Section 1: Integrated configuration

NASA Technical Reports Server (NTRS)

1992-01-01

The function of the Space Station Furnace Facility (SSFF) is to support materials research into the crystal growth and solidification processes of electronic and photonic materials, metals and alloys, and glasses and ceramics. To support this broad base of research requirements, the SSFF will employ a variety of furnace modules which will be operated, regulated, and supported by a core of common subsystems. Furnace modules may be reconfigured or specifically developed to provide unique solidification conditions for each set of experiments. The SSFF modular approach permits the addition of new or scaled-up furnace modules to support the evolution of the facility as new science requirements are identified. The SSFF Core is of modular design to permit augmentation for enhanced capabilities. The fully integrated configuration of the SSFF will consist of three racks with the capability of supporting up to two furnace modules per rack. The initial configuration of the SSFF will consist of two of the three racks and one furnace module. This Experiment/Facility Requirements Document (E/FRD) describes the integrated facility requirements for the Space Station Freedom (SSF) Integrated Configuration-1 (IC1) mission. The IC1 SSFF will consist of two racks: the Core Rack, with the centralized subsystem equipment; and the Experiment Rack-1, with Furnace Module-1 and the distributed subsystem equipment to support the furnace. The SSFF support functions are provided by the following Core subsystems: power conditioning and distribution subsystem (SSFF PCDS); data management subsystem (SSFF DMS); thermal control Subsystem (SSFF TCS); gas distribution subsystem (SSFF GDS); and mechanical structures subsystem (SSFF MSS).

PC-402 Pioneer Venus orbiter spacecraft mission operational characteristics document

NASA Technical Reports Server (NTRS)

Barker, F. C.; Butterworth, L. W.; Daniel, R. E.; Drean, R. J.; Filetti, K. A.; Fisher, J. N.; Nowak, L. A.; Porzucki, J.; Salvatore, J. O.; Tadler, G. A.

1978-01-01

The operational characteristics of the Orbiter spacecraft and its subsystems are described. In extensive detail. Description of the nominal phases, system interfaces, and the capabilities and limitations of system level performance are included along with functional and operational descriptions at the subsystem and unit level the subtleties of nominal operation as well as detailed capabilities and limitations beyond nominal performance are discussed. A command and telemetry logic flow diagram for each subsystem is included. Each diagram encountered along each command signal path into, and each telemetry signal path out of the subsystem. Normal operating modes that correspond to the performance of specific functions at the time of specific events in the mission are also discussed. Principal backup means of performing the normal Orbiter operating modes are included.

Simple debugging techniques for embedded subsystems

NASA Astrophysics Data System (ADS)

MacPherson, Matthew S.; Martin, Kevin S.

1990-08-01

This paper describes some of the tools and methods used for developing and debugging embedded subsystems at Fermilab. Specifically, these tools have been used for the Flying Wire project and are currently being employed for the New TECAR upgrade. The Flying Wire is a subsystem that swings a wire through the beam in order to measure luminosity and beam density distribution, and TECAR (Tevatron excitation controller and regulator) controls the power-supply ramp generation for the superconducting Tevatron accelerator at Fermilab. In both instances the subsystem hardware consists of a VME crate with one or more processors, shared memory and a network connection to the accelerator control system. Two real-time-operating systems are currently being used: VRTX for the Flying Wire system, and MTOS for New TECAR. The code which runs in these subsystems is a combination of C and assembler and is developed using the Microtec cross-development tools on a VAX 8650 running VMS. This paper explains how multiple debuggers are used to give the greatest possible flexibility from assembly to high-level debugging. Also discussed is how network debugging and network downloading can make a very effective and efficient means of finding bugs in the subsystem environment. The debuggers used are PROBE1, TRACER and the MTOS debugger.

Launch Vehicle Design Process: Characterization, Technical Integration, and Lessons Learned

NASA Technical Reports Server (NTRS)

Blair, J. C.; Ryan, R. S.; Schutzenhofer, L. A.; Humphries, W. R.

2001-01-01

Engineering design is a challenging activity for any product. Since launch vehicles are highly complex and interconnected and have extreme energy densities, their design represents a challenge of the highest order. The purpose of this document is to delineate and clarify the design process associated with the launch vehicle for space flight transportation. The goal is to define and characterize a baseline for the space transportation design process. This baseline can be used as a basis for improving effectiveness and efficiency of the design process. The baseline characterization is achieved via compartmentalization and technical integration of subsystems, design functions, and discipline functions. First, a global design process overview is provided in order to show responsibility, interactions, and connectivity of overall aspects of the design process. Then design essentials are delineated in order to emphasize necessary features of the design process that are sometimes overlooked. Finally the design process characterization is presented. This is accomplished by considering project technical framework, technical integration, process description (technical integration model, subsystem tree, design/discipline planes, decision gates, and tasks), and the design sequence. Also included in the document are a snapshot relating to process improvements, illustrations of the process, a survey of recommendations from experienced practitioners in aerospace, lessons learned, references, and a bibliography.

Image acquisition unit for the Mayo/IBM PACS project

NASA Astrophysics Data System (ADS)

Reardon, Frank J.; Salutz, James R.

1991-07-01

The Mayo Clinic and IBM Rochester, Minnesota, have jointly developed a picture archiving, distribution and viewing system for use with Mayo's CT and MRI imaging modalities. Images are retrieved from the modalities and sent over the Mayo city-wide token ring network to optical storage subsystems for archiving, and to server subsystems for viewing on image review stations. Images may also be retrieved from archive and transmitted back to the modalities. The subsystems that interface to the modalities and communicate to the other components of the system are termed Image Acquisition Units (LAUs). The IAUs are IBM Personal System/2 (PS/2) computers with specially developed software. They operate independently in a network of cooperative subsystems and communicate with the modalities, archive subsystems, image review server subsystems, and a central subsystem that maintains information about the content and location of images. This paper provides a detailed description of the function and design of the Image Acquisition Units.

Preprototype SAWD subsystem

NASA Technical Reports Server (NTRS)

Nalette, T. A.

1984-01-01

A regenerable, three man preprototype solid amine, water desorbed (SAWD) CO2 removal and concentation subsystem was designed, fabricated, and successfully acceptance tested by Hamilton Standard. The preprototype SAWD incorporates a single solid amine canister to perform the CO2 removal function, an accumulator to provide the CO2 storage and delivery function, and a microprocessor which automatically controls the subsystem sequential operation and performance. The SAWD subsystem was configured to have a CO2 removal and CO2 delivery capability at the rate of 0.12 kg/hr (0.264 lb/hr) over the relative humidity range of 35 to 70%. The controller was developed to provide fully automatic control over the relative humidity range via custom software that was generated specifically for the SAWD subsystem. The preprototype SAWD subsystem demonstrated a total of 281 hours (208) cycles of operation during ten acceptance tests that were conducted over the 3 to 70% relative humidity range. This operation was comprised of 178 hours (128 cycles) in the CO2 overboard mode and 103 hours (80 cycles) in the CO2 reduction mode. The average CO2 removal/delivery rate met or exceeded the design specification rate of 0.12 kg/hr (0.254 lb/hr) for all ten of the acceptance tests.

Event-Triggered Distributed Approximate Optimal State and Output Control of Affine Nonlinear Interconnected Systems.

PubMed

Narayanan, Vignesh; Jagannathan, Sarangapani

2017-06-08

This paper presents an approximate optimal distributed control scheme for a known interconnected system composed of input affine nonlinear subsystems using event-triggered state and output feedback via a novel hybrid learning scheme. First, the cost function for the overall system is redefined as the sum of cost functions of individual subsystems. A distributed optimal control policy for the interconnected system is developed using the optimal value function of each subsystem. To generate the optimal control policy, forward-in-time, neural networks are employed to reconstruct the unknown optimal value function at each subsystem online. In order to retain the advantages of event-triggered feedback for an adaptive optimal controller, a novel hybrid learning scheme is proposed to reduce the convergence time for the learning algorithm. The development is based on the observation that, in the event-triggered feedback, the sampling instants are dynamic and results in variable interevent time. To relax the requirement of entire state measurements, an extended nonlinear observer is designed at each subsystem to recover the system internal states from the measurable feedback. Using a Lyapunov-based analysis, it is demonstrated that the system states and the observer errors remain locally uniformly ultimately bounded and the control policy converges to a neighborhood of the optimal policy. Simulation results are presented to demonstrate the performance of the developed controller.

Quantifying Environmental Effects on the Decay of Hole Transfer Couplings in Biosystems.

PubMed

Ramos, Pablo; Pavanello, Michele

2014-06-10

In the past two decades, many research groups worldwide have tried to understand and categorize simple regimes in the charge transfer of such biological systems as DNA. Theoretically speaking, the lack of exact theories for electron-nuclear dynamics on one side and poor quality of the parameters needed by model Hamiltonians and nonadiabatic dynamics alike (such as couplings and site energies) on the other are the two main difficulties for an appropriate description of the charge transfer phenomena. In this work, we present an application of a previously benchmarked and linear-scaling subsystem density functional theory (DFT) method for the calculation of couplings, site energies, and superexchange decay factors (β) of several biological donor-acceptor dyads, as well as double stranded DNA oligomers composed of up to five base pairs. The calculations are all-electron and provide a clear view of the role of the environment on superexchange couplings in DNA-they follow experimental trends and confirm previous semiempirical calculations. The subsystem DFT method is proven to be an excellent tool for long-range, bridge-mediated coupling and site energy calculations of embedded molecular systems.

Waveform stimulus subsystem: An advanced technology multifunction subsystem on a card

NASA Astrophysics Data System (ADS)

Pritchard, David J.

The F-15 TISS ATE (automatic test equipment) requires subsystem-on-a-card technology to achieve the required functionality within the space constraints. The waveform stimulus subsystem (WSS), an example of this advanced technology, is considered. The WSS circuit card consists of two 40-MHz pulse generators and an 80-MHz aribtrary waveform generator. Each generator is independently programmed and is available simultaneously to the user. The implementation of this highly integrated malfunction-detection system on a card is described, and the benefits to performance and maintainability are highlighted.

Instrumentation, control and data management for the MIST (Modular Integrated Utility System) Facility

NASA Technical Reports Server (NTRS)

Celino, V. A.

1977-01-01

An appendix providing the technical data required for computerized control and/or monitoring of selected MIST subsystems is presented. Specific computerized functions to be performed are as follows: (1) Control of the MIST heating load simulator and monitoring of the diesel engine generators' cooling system; (2) Control of the MIST heating load simulator and MIST heating subsystem including the heating load simulator; and (3) Control of the MIST air conditioning load simulator subsystem and the MIST air conditioning subsystem, including cold thermal storage and condenser water flows.

Integrated Advance Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: EOS AMSU-A1 and AMSU-A2 Receivers Assemblies

NASA Technical Reports Server (NTRS)

2000-01-01

This test report presents the test data of the EOS AMSU-A Flight Model No.1 (FM-1) receiver subsystem. The tests are performed per the Acceptance Test Procedure for the AMSU-A Reseiver Subsystem, AE-26002/6A. The functional performance tests are conducted either at the component or subsystem level. While the component-level tests are performed over the entire operating temperature range predicted by thermal analysis, the subsystem-level test are conducted at ambient temperature only.

Cost-effective data storage/archival subsystem for functional PACS

NASA Astrophysics Data System (ADS)

Chen, Y. P.; Kim, Yongmin

1993-09-01

Not the least of the requirements of a workable PACS is the ability to store and archive vast amounts of information. A medium-size hospital will generate between 1 and 2 TBytes of data annually on a fully functional PACS. A high-speed image transmission network coupled with a comparably high-speed central data storage unit can make local memory and magnetic disks in the PACS workstations less critical and, in an extreme case, unnecessary. Under these circumstances, the capacity and performance of the central data storage subsystem and database is critical in determining the response time at the workstations, thus significantly affecting clinical acceptability. The central data storage subsystem not only needs to provide sufficient capacity to store about ten days worth of images (five days worth of new studies, and on the average, about one comparison study for each new study), but also supplies images to the requesting workstation in a timely fashion. The database must provide fast retrieval responses upon users' requests for images. This paper analyzes both advantages and disadvantages of multiple parallel transfer disks versus RAID disks for short-term central data storage subsystem, as well as optical disk jukebox versus digital recorder tape subsystem for long-term archive. Furthermore, an example high-performance cost-effective storage subsystem which integrates both the RAID disks and high-speed digital tape subsystem as a cost-effective PACS data storage/archival unit are presented.

Family of spherical models with special gravitational properties

NASA Astrophysics Data System (ADS)

Kondratyev, B. P.

2015-03-01

A new method for studying the structural and gravitational properties of spherical systems based on an analysis of the ratio of the potentials for their subsystems and shells has been developed. It has been proven for the first time that the gravitational virial Z( r) of the subsystem without allowance for the influence of the outer shell is equal to twice the work done to disperce the subsystem's matter to infinity. A new class of spherical models has been constructed in which: (1) the ratio of the contribution to the potential at point r from the spherical subsystem to the contribution from the outer shell does not depend on radius and is equal to a constant γ; (2) the ratio of the gravitational energy W( r) to Z( r) for the spherical subsystem does not depend on r; and (3) the models are described by a power law of the density ρ = cr - κ and potential . Expressions for the gravitational energy W( r) and virial Z( r) have been found for the subsystem. The limiting case of ρ( r) ∝ r -5/2, where the subsystem's potential at any sampling point is exactly equal to the potential from the outer shell and Z( r) is equivalent to its gravitational energy W( r), is considered in detail. The results supplement the classical potential theory. The question about the application of the models to the superdense nuclear star cluster in the center of the Milky Way is discussed.

Development of a front end controller/heap manager for PHENIX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ericson, M.N.; Allen, M.D.; Musrock, M.S.

1996-12-31

A controller/heap manager has been designed for applicability to all detector subsystem types of PHENIX. the heap manager performs all functions associated with front end electronics control including ADC and analog memory control, data collection, command interpretation and execution, and data packet forming and communication. Interfaces to the unit consist of a timing and control bus, a serial bus, a parallel data bus, and a trigger interface. The topology developed is modular so that many functional blocks are identical for a number of subsystem types. Programmability is maximized through the use of flexible modular functions and implementation using field programmablemore » gate arrays (FPGAs). Details of unit design and functionality will be discussed with particular detail given to subsystems having analog memory-based front end electronics. In addition, mode control, serial functions, and FPGA implementation details will be presented.« less

Performance monitor system functional simulator, environmental data, orbiter 101(HFT)

NASA Technical Reports Server (NTRS)

Parker, F. W.

1974-01-01

Information concerning the environment component of the space shuttle performance monitor system simulator (PMSS) and those subsystems operational on the shuttle orbiter 101 used for horizontal flight test (HFT) is provided, along with detailed data for the shuttle performance monitor system (PMS) whose software requirements evolve from three basic PMS functions: (1) fault detection and annunciation; (2) subsystem measurement management; and (3) subsystem configuration management. Information relative to the design and operation of Orbiter systems for HFT is also presented, and the functional paths are identified to the lowest level at which the crew can control the system functions. Measurement requirements are given which are necessary to adequately monitor the health status of the system. PMS process requirements, relative to the measurements which are necessary for fault detection and annunciation of a failed functional path, consist of measurement characteristics, tolerance limits, precondition tests, and correlation measurements.

MIUS Integration and Subsystem Test (MIST) data system

NASA Technical Reports Server (NTRS)

Pringle, L. M.

1977-01-01

A data system for use in testing integrated subsystems of a modular integrated utility system (MIUS) is presented. The MIUS integration and subsystem test (MIST) data system is reviewed from its conception through its checkout and operation as the controlling portion of the MIST facility. The MIST data system provides a real time monitoring and control function that allows for complete evaluation of the performance of the mechanical and electrical subsystems, as well as controls the operation of the various components of the system. In addition to the aforementioned capabilities, the MIST data system provides computerized control of test operations such that minimum manpower is necessary to set up, operate, and shut down subsystems during test periods.

Ice pack heat sink subsystem - phase 1, volume 2

NASA Technical Reports Server (NTRS)

Roebelen, G. J., Jr.

1973-01-01

The design, development, and test of a functional laboratory model ice pack heat sink subsystem are discussed. Operating instructions to include mechanical and electrical schematics, maintenance instructions, and equipment specifications are presented.

Conditions for Fully Autonomous Anticipation

NASA Astrophysics Data System (ADS)

Collier, John

2006-06-01

Anticipation allows a system to adapt to conditions that have not yet come to be, either externally to the system or internally. Autonomous systems actively control the conditions of their own existence so as to increase their overall viability. This paper will first give minimal necessary and sufficient conditions for autonomous anticipation, followed by a taxonomy of autonomous anticipation. In more complex systems, there can be semi-autonomous subsystems that can anticipate and adapt on their own. Such subsystems can be integrated into a system's overall autonomy, typically with greater efficiency due to modularity and specialization of function. However, it is also possible that semi-autonomous subsystems can act against the viability of the overall system, and have their own functions that conflict with overall system functions.

Power subsystem automation study

NASA Technical Reports Server (NTRS)

Imamura, M. S.; Moser, R. L.; Veatch, M.

1983-01-01

Generic power-system elements and their potential faults are identified. Automation functions and their resulting benefits are defined and automation functions between power subsystem, central spacecraft computer, and ground flight-support personnel are partitioned. All automation activities were categorized as data handling, monitoring, routine control, fault handling, planning and operations, or anomaly handling. Incorporation of all these classes of tasks, except for anomaly handling, in power subsystem hardware and software was concluded to be mandatory to meet the design and operational requirements of the space station. The key drivers are long mission lifetime, modular growth, high-performance flexibility, a need to accommodate different electrical user-load equipment, onorbit assembly/maintenance/servicing, and potentially large number of power subsystem components. A significant effort in algorithm development and validation is essential in meeting the 1987 technology readiness date for the space station.

Entanglement negativity and sudden death in the toric code at finite temperature

NASA Astrophysics Data System (ADS)

Hart, O.; Castelnovo, C.

2018-04-01

We study the fate of quantum correlations at finite temperature in the two-dimensional toric code using the logarithmic entanglement negativity. We are able to obtain exact results that give us insight into how thermal excitations affect quantum entanglement. The toric code has two types of elementary excitations (defects) costing different energies. We show that an O (1 ) density of the lower energy defect is required to degrade the zero-temperature entanglement between two subsystems in contact with one another. However, one type of excitation alone is not sufficient to kill all quantum correlations, and an O (1 ) density of the higher energy defect is required to cause the so-called sudden death of the negativity. Interestingly, if the energy cost of one of the excitations is taken to infinity, quantum correlations survive up to arbitrarily high temperatures, a feature that is likely shared with other quantum spin liquids and frustrated systems in general, when projected down to their low-energy states. We demonstrate this behavior both for small subsystems, where we can prove that the negativity is a necessary and sufficient condition for separability, as well as for extended subsystems, where it is only a necessary condition. We further observe that the negativity per boundary degree of freedom at a given temperature increases (parametrically) with the size of the boundary, and that quantum correlations between subsystems with extended boundaries are more robust to thermal fluctuations.

MARVEL: A knowledge-based productivity enhancement tool for real-time multi-mission and multi-subsystem spacecraft operations

NASA Astrophysics Data System (ADS)

Schwuttke, Ursula M.; Veregge, John, R.; Angelino, Robert; Childs, Cynthia L.

1990-10-01

The Monitor/Analyzer of Real-time Voyager Engineering Link (MARVEL) is described. It is the first automation tool to be used in an online mode for telemetry monitoring and analysis in mission operations. MARVEL combines standard automation techniques with embedded knowledge base systems to simultaneously provide real time monitoring of data from subsystems, near real time analysis of anomaly conditions, and both real time and non-real time user interface functions. MARVEL is currently capable of monitoring the Computer Command Subsystem (CCS), Flight Data Subsystem (FDS), and Attitude and Articulation Control Subsystem (AACS) for both Voyager spacecraft, simultaneously, on a single workstation. The goal of MARVEL is to provide cost savings and productivity enhancement in mission operations and to reduce the need for constant availability of subsystem expertise.

A Bayesian Framework for Reliability Analysis of Spacecraft Deployments

NASA Technical Reports Server (NTRS)

Evans, John W.; Gallo, Luis; Kaminsky, Mark

2012-01-01

Deployable subsystems are essential to mission success of most spacecraft. These subsystems enable critical functions including power, communications and thermal control. The loss of any of these functions will generally result in loss of the mission. These subsystems and their components often consist of unique designs and applications for which various standardized data sources are not applicable for estimating reliability and for assessing risks. In this study, a two stage sequential Bayesian framework for reliability estimation of spacecraft deployment was developed for this purpose. This process was then applied to the James Webb Space Telescope (JWST) Sunshield subsystem, a unique design intended for thermal control of the Optical Telescope Element. Initially, detailed studies of NASA deployment history, "heritage information", were conducted, extending over 45 years of spacecraft launches. This information was then coupled to a non-informative prior and a binomial likelihood function to create a posterior distribution for deployments of various subsystems uSing Monte Carlo Markov Chain sampling. Select distributions were then coupled to a subsequent analysis, using test data and anomaly occurrences on successive ground test deployments of scale model test articles of JWST hardware, to update the NASA heritage data. This allowed for a realistic prediction for the reliability of the complex Sunshield deployment, with credibility limits, within this two stage Bayesian framework.

Contributions of episodic retrieval and mentalizing to autobiographical thought: evidence from functional neuroimaging, resting-state connectivity, and fMRI meta-analyses

PubMed Central

Andrews-Hanna, Jessica R.; Saxe, Rebecca; Yarkoni, Tal

2014-01-01

A growing number of studies suggest the brain’s “default network” becomes engaged when individuals recall their personal past or simulate their future. Recent reports of heterogeneity within the network raises the possibility that these autobiographical processes are comprised of multiple component processes, each supported by distinct functional-anatomic subsystems. We previously hypothesized that a medial temporal subsystem contributes to autobiographical memory and future thought by enabling individuals to retrieve prior information and bind this information into a mental scene. Conversely, a dorsal medial subsystem was proposed to support social-reflective aspects of autobiographical thought, allowing individuals to reflect on the mental states of one’s self and others (i.e. “mentalizing”). To test these hypotheses, we first examined activity in the default network subsystems as participants performed two commonly employed tasks of episodic retrieval and mentalizing. In a subset of participants, relationships among task-evoked regions were examined at rest, in the absence of an overt task. Finally, large-scale fMRI meta-analyses were conducted to identify brain regions that most strongly predicted the presence of episodic retrieval and mentalizing, and these results were compared to meta-analyses of autobiographical tasks. Across studies, laboratory-based episodic retrieval tasks were preferentially linked to the medial temporal subsystem, while mentalizing tasks were preferentially linked to the dorsal medial subsystem. In turn, autobiographical tasks engaged aspects of both subsystems. These results suggest the default network is a heterogeneous brain system whose subsystems support distinct component processes of autobiographical thought. PMID:24486981

Contributions of episodic retrieval and mentalizing to autobiographical thought: evidence from functional neuroimaging, resting-state connectivity, and fMRI meta-analyses.

PubMed

Andrews-Hanna, Jessica R; Saxe, Rebecca; Yarkoni, Tal

2014-05-01

A growing number of studies suggest the brain's "default network" becomes engaged when individuals recall their personal past or simulate their future. Recent reports of heterogeneity within the network raise the possibility that these autobiographical processes comprised of multiple component processes, each supported by distinct functional-anatomic subsystems. We previously hypothesized that a medial temporal subsystem contributes to autobiographical memory and future thought by enabling individuals to retrieve prior information and bind this information into a mental scene. Conversely, a dorsal medial subsystem was proposed to support social-reflective aspects of autobiographical thought, allowing individuals to reflect on the mental states of one's self and others (i.e. "mentalizing"). To test these hypotheses, we first examined activity in the default network subsystems as participants performed two commonly employed tasks of episodic retrieval and mentalizing. In a subset of participants, relationships among task-evoked regions were examined at rest, in the absence of an overt task. Finally, large-scale fMRI meta-analyses were conducted to identify brain regions that most strongly predicted the presence of episodic retrieval and mentalizing, and these results were compared to meta-analyses of autobiographical tasks. Across studies, laboratory-based episodic retrieval tasks were preferentially linked to the medial temporal subsystem, while mentalizing tasks were preferentially linked to the dorsal medial subsystem. In turn, autobiographical tasks engaged aspects of both subsystems. These results suggest the default network is a heterogeneous brain system whose subsystems support distinct component processes of autobiographical thought. Copyright © 2014 Elsevier Inc. All rights reserved.

Space shuttle pogo studies. [systems stability

NASA Technical Reports Server (NTRS)

Coppolino, R. N.; Lock, M. H.; Rubin, S.

1977-01-01

Topics covered include: (1) pogo suppression for main propulsion subsystem operation; (2) application of quarter-scale low pressure oxidizer turbopump transfer functions; (3) pogo stability during orbital maneuvering subsystem operation; and (4) errors in frequency response measurements.

Large area crop inventory experiment crop assessment subsystem software requirements document

NASA Technical Reports Server (NTRS)

1975-01-01

The functional data processing requirements are described for the Crop Assessment Subsystem of the Large Area Crop Inventory Experiment. These requirements are used as a guide for software development and implementation.

Rumination and Default Mode Network Subsystems Connectivity in First-episode, Drug-Naive Young Patients with Major Depressive Disorder

PubMed Central

Zhu, Xueling; Zhu, Qiuling; Shen, Huaizhen; Liao, Weihua; Yuan, Fulai

2017-01-01

Neuroimaging evidence implicates the association between rumination and default mode network (DMN) in major depressive disorder (MDD). However, the relationship between rumination and DMN subsystems remains incompletely understood, especially in patients with MDD. Thirty-three first-episode drug-naive patients with MDD and thirty-three healthy controls (HCs) were enrolled and underwent resting-sate fMRI scanning. Functional connectivity analysis was performed based on 11 pre-defined regions of interest (ROIs) for three DMN subsystems: the midline core, dorsal medial prefrontal cortex (dMPFC) and medial temporal lobe (MTL). Compared with HCs group, patients with MDD exhibited increased within-system connectivity in the dMPFC subsystem and inter-system connectivity between the dMPFC and MTL subsystems. Decreased inter-system connectivity was identified between the midline core and dMPFC subsystem in MDD patients. Depressive rumination was positively correlated with within-system connectivity in the dMPFC subsystem (dMPFC-TempP) and with inter-system connectivity between the dMPFC and MTL subsystems (LTC-PHC). Our results suggest MDD may be characterized by abnormal DMN subsystems connectivity, which may contribute to the pathophysiology of the maladaptive self-focus in MDD patients. PMID:28225084

The conical scanner evaluation system design

NASA Technical Reports Server (NTRS)

Cumella, K. E.; Bilanow, S.; Kulikov, I. B.

1982-01-01

The software design for the conical scanner evaluation system is presented. The purpose of this system is to support the performance analysis of the LANDSAT-D conical scanners, which are infrared horizon detection attitude sensors designed for improved accuracy. The system consists of six functionally independent subsystems and five interface data bases. The system structure and interfaces of each of the subsystems is described and the content, format, and file structure of each of the data bases is specified. For each subsystem, the functional logic, the control parameters, the baseline structure, and each of the subroutines are described. The subroutine descriptions include a procedure definition and the input and output parameters.

Decentralized adaptive control of interconnected nonlinear systems with unknown control directions.

PubMed

Huang, Jiangshuai; Wang, Qing-Guo

2018-03-01

In this paper, we propose a decentralized adaptive control scheme for a class of interconnected strict-feedback nonlinear systems without a priori knowledge of subsystems' control directions. To address this problem, a novel Nussbaum-type function is proposed and a key theorem is drawn which involves quantifying the interconnections of multiple Nussbaum-type functions of the subsystems with different control directions in a single inequality. Global stability of the closed-loop system and asymptotic stabilization of subsystems' output are proved and a simulation example is given to illustrate the effectiveness of the proposed control scheme. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Some Specifications for an Undergraduate Course in Digital Subsystems. An Interim Report of the Cosine Committee.

ERIC Educational Resources Information Center

Commission on Engineering Education, Washington, DC.

This report describes an undergraduate course in digital subsystems. The course is divided into two major parts. Part I is entitled Electronic Circuits and Functional Units. The material in this part of the course proceeds from simple understandings of circuits to the progressively more complex functional units. Early emphasis is placed on basic…

Exploring relationships of human-automation interaction consequences on pilots: uncovering subsystems.

PubMed

Durso, Francis T; Stearman, Eric J; Morrow, Daniel G; Mosier, Kathleen L; Fischer, Ute; Pop, Vlad L; Feigh, Karen M

2015-05-01

We attempted to understand the latent structure underlying the systems pilots use to operate in situations involving human-automation interaction (HAI). HAI is an important characteristic of many modern work situations. Of course, the cognitive subsystems are not immediately apparent by observing a functioning system, but correlations between variables may reveal important relations. The current report examined pilot judgments of 11 HAI dimensions (e.g., Workload, Task Management, Stress/Nervousness, Monitoring Automation, and Cross-Checking Automation) across 48 scenarios that required airline pilots to interact with automation on the flight deck. We found three major clusters of the dimensions identifying subsystems on the flight deck: a workload subsystem, a management subsystem, and an awareness subsystem. Relationships characterized by simple correlations cohered in ways that suggested underlying subsystems consistent with those that had previously been theorized. Understanding the relationship among dimensions affecting HAI is an important aspect in determining how a new piece of automation designed to affect one dimension will affect other dimensions as well. © 2014, Human Factors and Ergonomics Society.

Advanced Extravehicular Protective System (AEPS) study

NASA Technical Reports Server (NTRS)

Williams, J. L.; Webbon, B. W.; Copeland, R. J.

1972-01-01

A summary is presented of Advanced Extravehicular Protective Systems (AEPS) for the future missions beyond Skylab in earth orbit, on the lunar surface, and on the Martian surface. The study concentrated on the origination of regenerable life support concepts for use in portable extravehicular protective systems, and included evaluation and comparison with expendable systems, and selection of life support subsystems. The study was conducted in two phases. In the first phase, subsystem concepts for performing life support functions in AEPS which are regenerable or partially regenerable were originated, and in addition, expendable subsystems were considered. Parametric data for each subsystem concept were evolved including subsystem weight and volume, power requirement, thermal control requirement; base regeneration equipment weight and volume, requirement. The second phase involved an evaluation of the impact of safety considerations involving redundant and/or backup systems on the selection of the regenerable life support subsystems. In addition, the impact of the space shuttle program on regenerable life support subsystem development was investigated.

Spacecraft Design Thermal Control Subsystem

NASA Technical Reports Server (NTRS)

Miyake, Robert N.

2003-01-01

This slide presentation reviews the functions of the thermal control subsystem engineers in the design of spacecraft. The goal of the thermal control subsystem that will be used in a spacecraft is to maintain the temperature of all spacecraft components, subsystems, and all the flight systems within specified limits for all flight modes from launch to the end of the mission. For most thermal control subsystems the mass, power and control and sensing systems must be kept below 10% of the total flight system resources. This means that the thermal control engineer is involved in all other flight systems designs. The two concepts of thermal control, passive and active are reviewed and the use of thermal modeling tools are explained. The testing of the thermal control is also reviewed.

White blood cell counting system

NASA Technical Reports Server (NTRS)

1972-01-01

The design, fabrication, and tests of a prototype white blood cell counting system for use in the Skylab IMSS are presented. The counting system consists of a sample collection subsystem, sample dilution and fluid containment subsystem, and a cell counter. Preliminary test results show the sample collection and the dilution subsystems are functional and fulfill design goals. Results for the fluid containment subsystem show the handling bags cause counting errors due to: (1) adsorption of cells to the walls of the container, and (2) inadequate cleaning of the plastic bag material before fabrication. It was recommended that another bag material be selected.

Spacelab output processing system architectural study

NASA Technical Reports Server (NTRS)

1977-01-01

Two different system architectures are presented. The two architectures are derived from two different data flows within the Spacelab Output Processing System. The major differences between these system architectures are in the position of the decommutation function (the first architecture performs decommutation in the latter half of the system and the second architecture performs that function in the front end of the system). In order to be examined, the system was divided into five stand-alone subsystems; Work Assembler, Mass Storage System, Output Processor, Peripheral Pool, and Resource Monitor. The work load of each subsystem was estimated independent of the specific devices to be used. The candidate devices were surveyed from a wide sampling of off-the-shelf devices. Analytical expressions were developed to quantify the projected workload in conjunction with typical devices which would adequately handle the subsystem tasks. All of the study efforts were then directed toward preparing performance and cost curves for each architecture subsystem.

Coordinated control of micro-grid based on distributed moving horizon control.

PubMed

Ma, Miaomiao; Shao, Liyang; Liu, Xiangjie

2018-05-01

This paper proposed the distributed moving horizon coordinated control scheme for the power balance and economic dispatch problems of micro-grid based on distributed generation. We design the power coordinated controller for each subsystem via moving horizon control by minimizing a suitable objective function. The objective function of distributed moving horizon coordinated controller is chosen based on the principle that wind power subsystem has the priority to generate electricity while photovoltaic power generation coordinates with wind power subsystem and the battery is only activated to meet the load demand when necessary. The simulation results illustrate that the proposed distributed moving horizon coordinated controller can allocate the output power of two generation subsystems reasonably under varying environment conditions, which not only can satisfy the load demand but also limit excessive fluctuations of output power to protect the power generation equipment. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive output feedback NN control of a class of discrete-time MIMO nonlinear systems with unknown control directions.

PubMed

Li, Yanan; Yang, Chenguang; Ge, Shuzhi Sam; Lee, Tong Heng

2011-04-01

In this paper, adaptive neural network (NN) control is investigated for a class of block triangular multiinput-multioutput nonlinear discrete-time systems with each subsystem in pure-feedback form with unknown control directions. These systems are of couplings in every equation of each subsystem, and different subsystems may have different orders. To avoid the noncausal problem in the control design, the system is transformed into a predictor form by rigorous derivation. By exploring the properties of the block triangular form, implicit controls are developed for each subsystem such that the couplings of inputs and states among subsystems have been completely decoupled. The radial basis function NN is employed to approximate the unknown control. Each subsystem achieves a semiglobal uniformly ultimately bounded stability with the proposed control, and simulation results are presented to demonstrate its efficiency.

JOB BUILDER remote batch processing subsystem

NASA Technical Reports Server (NTRS)

Orlov, I. G.; Orlova, T. L.

1980-01-01

The functions of the JOB BUILDER remote batch processing subsystem are described. Instructions are given for using it as a component of a display system developed by personnel of the System Programming Laboratory, Institute of Space Research, USSR Academy of Sciences.

Display management subsystem, version 1: A user's eye view

NASA Technical Reports Server (NTRS)

Parker, Dolores

1986-01-01

The structure and application functions of the Display Management Subsystem (DMS) are described. The DMS, a subsystem of the Transportable Applications Executive (TAE), was designed to provide a device-independent interface for an image processing and display environment. The system is callable by C and FORTRAN applications, portable to accommodate different image analysis terminals, and easily expandable to meet local needs. Generic applications are also available for performing many image processing tasks.

Apollo experience report: Guidance and control systems. Lunar module stabilization and control system

NASA Technical Reports Server (NTRS)

Shelton, D. H.

1975-01-01

A brief functional description of the Apollo lunar module stabilization and control subsystem is presented. Subsystem requirements definition, design, development, test results, and flight experiences are discussed. Detailed discussions are presented of problems encountered and the resulting corrective actions taken during the course of assembly-level testing, integrated vehicle checkout and test, and mission operations. Although the main experiences described are problem oriented, the subsystem has performed satisfactorily in flight.

Brazilian remote sensing receiving, recording and processing ground systems in the 1980's

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator)

1984-01-01

A ground station was built in Brazil to receive, record, and process TM data from LANDSAT satellites. The receiving/recording subsystem and the processing subsystem are discussed. Functional design specifications for the facility are addressed.

System impacts of solar dynamic and growth power systems on space station

NASA Technical Reports Server (NTRS)

Farmer, J. T.; Cuddihy, W. F.; Lovelace, U. M.; Badi, D. M.

1986-01-01

Concepts for the 1990's space station envision an initial operational capability with electrical power output requirements of approximately 75 kW and growth power requirements in the range of 300 kW over a period of a few years. Photovoltaic and solar dynamic power generation techniques are contenders for supplying this power to the space station. A study was performed to identify growth power subsystem impacts on other space station subsystems. Subsystem interactions that might suggest early design changes for the space station were emphasized. Quantitative analyses of the effects of power subsystem mass and projected area on space station controllability and reboost requirements were conducted for a range of growth station configurations. Impacts on space station structural dynamics as a function of power subsystem growth were also considered.

A prototype to automate the video subsystem routing for the video distribution subsystem of Space Station Freedom

NASA Astrophysics Data System (ADS)

Betz, Jessie M. Bethly

1993-12-01

The Video Distribution Subsystem (VDS) for Space Station Freedom provides onboard video communications. The VDS includes three major functions: external video switching; internal video switching; and sync and control generation. The Video Subsystem Routing (VSR) is a part of the VDS Manager Computer Software Configuration Item (VSM/CSCI). The VSM/CSCI is the software which controls and monitors the VDS equipment. VSR activates, terminates, and modifies video services in response to Tier-1 commands to connect video sources to video destinations. VSR selects connection paths based on availability of resources and updates the video routing lookup tables. This project involves investigating the current methodology to automate the Video Subsystem Routing and developing and testing a prototype as 'proof of concept' for designers.

Functional requirements for onboard management of space shuttle consumables, volume 2.

NASA Technical Reports Server (NTRS)

Graf, P. J.; Herwig, H. A.; Neel, L. W.

1973-01-01

A study was conducted to develop the functional requirements for onboard management of space shuttle consumables. A specific consumables management concept for the space shuttle vehicle was developed and the functional requirements for the onboard portion of the concept were generated. Consumables management is the process of controlling or influencing the usage of expendable materials involved in vehicle subsystem operation. The subsystems considered in the study are: (1) propulsion, (2) power generation, and (3) environmental and life support.

PC-403: Pioneer Venus multiprobe spacecraft mission operational characteristics document, volume 1

NASA Technical Reports Server (NTRS)

Barker, F. C.

1978-01-01

The operational characteristics of the multiprobe system and its subsystem are described. System level, description of the nominal phases, system interfaces, and the capabilities and limitations of system level performance are presented. Bus spacecraft functional and operational descriptions at the subsystem and unit level are presented. The subtleties of nominal operation as well as detailed capabilities and limitations beyond nominal performance are discussed. A command and telemetry logic flow diagram for each subsystem is included. Each diagram identifies in symbolic logic all signal conditioning encountered along each command signal path into, and each telemetry signal path out of the subsystem.

Dynamic visualization of data streams

DOEpatents

Wong, Pak Chung [Richalnd, WA; Foote, Harlan P [Richland, WA; Adams, Daniel R [Kennewick, WA; Cowley, Wendy E [Richland, WA; Thomas, James J [Richland, WA

2009-07-07

One embodiment of the present invention includes a data communication subsystem to receive a data stream, and a data processing subsystem responsive to the data communication subsystem to generate a visualization output based on a group of data vectors corresponding to a first portion of the data stream. The processing subsystem is further responsive to a change in rate of receipt of the data to modify the visualization output with one or more other data vectors corresponding to a second portion of the data stream as a function of eigenspace defined with the group of data vectors. The system further includes a display device responsive to the visualization output to provide a corresponding visualization.

A study of discrete control signal fault conditions in the shuttle DPS

NASA Technical Reports Server (NTRS)

Reddi, S. S.; Retter, C. T.

1976-01-01

An analysis of the effects of discrete failures on the data processing subsystem is presented. A functional description of each discrete together with a list of software modules that use this discrete are included. A qualitative description of the consequences that may ensue due to discrete failures is given followed by a probabilistic reliability analysis of the data processing subsystem. Based on the investigation conducted, recommendations were made to improve the reliability of the subsystem.

Dynamics and control of the ERK signaling pathway: Sensitivity, bistability, and oscillations.

PubMed

Arkun, Yaman; Yasemi, Mohammadreza

2018-01-01

Cell signaling is the process by which extracellular information is transmitted into the cell to perform useful biological functions. The ERK (extracellular-signal-regulated kinase) signaling controls several cellular processes such as cell growth, proliferation, differentiation and apoptosis. The ERK signaling pathway considered in this work starts with an extracellular stimulus and ends with activated (double phosphorylated) ERK which gets translocated into the nucleus. We model and analyze this complex pathway by decomposing it into three functional subsystems. The first subsystem spans the initial part of the pathway from the extracellular growth factor to the formation of the SOS complex, ShC-Grb2-SOS. The second subsystem includes the activation of Ras which is mediated by the SOS complex. This is followed by the MAPK subsystem (or the Raf-MEK-ERK pathway) which produces the double phosphorylated ERK upon being activated by Ras. Although separate models exist in the literature at the subsystems level, a comprehensive model for the complete system including the important regulatory feedback loops is missing. Our dynamic model combines the existing subsystem models and studies their steady-state and dynamic interactions under feedback. We establish conditions under which bistability and oscillations exist for this important pathway. In particular, we show how the negative and positive feedback loops affect the dynamic characteristics that determine the cellular outcome.

Electronic Structure Approach to Tunable Electronic Properties of Hybrid Organic-Inorganic Perovskites

NASA Astrophysics Data System (ADS)

Liu, Garnett; Huhn, William; Mitzi, David B.; Kanai, Yosuke; Blum, Volker

We present a study of the electronic structure of layered hybrid organic-inorganic perovskite (HOIP) materials using all-electron density-functional theory. Varying the nature of the organic and inorganic layers should enable systematically fine-tuning the carrier properties of each component. Using the HSE06 hybrid density functional including spin-orbit coupling (SOC), we validate the principle of tuning subsystem-specific parts of the electron band structures and densities of states in CH3NH3PbX3 (X=Cl, Br, I) compared to a modified organic component in layered (C6H5C2H4NH3) 2PbX4 (X=Cl, Br, I) and C20H22S4N2PbX4 (X=Cl, Br, I). We show that tunable shifts of electronic levels indeed arise by varying Cl, Br, I as the inorganic components, and CH3NH3+ , C6H5C2H4NH3+ , C20H22S4N22 + as the organic components. SOC is found to play an important role in splitting the conduction bands of the HOIP compounds investigated here. The frontier orbitals of the halide shift, increasing the gap, when Cl is substituted for Br and I.

Flexible operation strategy for environment control system in abnormal supply power condition

NASA Astrophysics Data System (ADS)

Liping, Pang; Guoxiang, Li; Hongquan, Qu; Yufeng, Fang

2017-04-01

This paper establishes an optimization method that can be applied to the flexible operation of the environment control system in an abnormal supply power condition. A proposed conception of lifespan is used to evaluate the depletion time of the non-regenerative substance. The optimization objective function is to maximize the lifespans. The optimization variables are the allocated powers of subsystems. The improved Non-dominated Sorting Genetic Algorithm is adopted to obtain the pareto optimization frontier with the constraints of the cabin environmental parameters and the adjustable operating parameters of the subsystems. Based on the same importance of objective functions, the preferred power allocation of subsystems can be optimized. Then the corresponding running parameters of subsystems can be determined to ensure the maximum lifespans. A long-duration space station with three astronauts is used to show the implementation of the proposed optimization method. Three different CO2 partial pressure levels are taken into consideration in this study. The optimization results show that the proposed optimization method can obtain the preferred power allocation for the subsystems when the supply power is at a less-than-nominal value. The method can be applied to the autonomous control for the emergency response of the environment control system.

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) spectrometer design and performance

NASA Technical Reports Server (NTRS)

Macenka, Steven A.; Chrisp, Michael P.

1987-01-01

The development of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has been completed at JPL. This paper outlines the functional requirements of the spectrometer optics subsystem, and describes the spectrometer optical design. The optical subsystem performance is shown in terms of spectral modulation transfer functions, radial energy distributions, and system transmission at selected wavelengths for the four spectrometers. An outline of the spectrometer alignment is included.

Ab initio determination of effective electron-phonon coupling factor in copper

NASA Astrophysics Data System (ADS)

Ji, Pengfei; Zhang, Yuwen

2016-04-01

The electron temperature Te dependent electron density of states g (ε), Fermi-Dirac distribution f (ε), and electron-phonon spectral function α2 F (Ω) are computed as prerequisites before achieving effective electron-phonon coupling factor Ge-ph. The obtained Ge-ph is implemented into a molecular dynamics (MD) and two-temperature model (TTM) coupled simulation of femtosecond laser heating. By monitoring temperature evolutions of electron and lattice subsystems, the result utilizing Ge-ph from ab initio calculation shows a faster decrease of Te and increase of Tl than those using Ge-ph from phenomenological treatment. The approach of calculating Ge-ph and its implementation into MD-TTM simulation is applicable to other metals.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 6: Specification for EOS Central Data Processing Facility (CDPF)

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications and functions of the Central Data Processing (CDPF) Facility which supports the Earth Observatory Satellite (EOS) are discussed. The CDPF will receive the EOS sensor data and spacecraft data through the Spaceflight Tracking and Data Network (STDN) and the Operations Control Center (OCC). The CDPF will process the data and produce high density digital tapes, computer compatible tapes, film and paper print images, and other data products. The specific aspects of data inputs and data processing are identified. A block diagram of the CDPF to show the data flow and interfaces of the subsystems is provided.

39 CFR 255.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... technology” and any equipment or interconnected system or subsystem of equipment that is used in the creation... embedded information technology that is used as an integral part of the product, but the principal function... an impairment. (f) Information technology means any equipment, or interconnected system or subsystem...

39 CFR 255.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... technology” and any equipment or interconnected system or subsystem of equipment that is used in the creation... embedded information technology that is used as an integral part of the product, but the principal function... an impairment. (f) Information technology means any equipment, or interconnected system or subsystem...

39 CFR 255.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... technology” and any equipment or interconnected system or subsystem of equipment that is used in the creation... embedded information technology that is used as an integral part of the product, but the principal function... an impairment. (f) Information technology means any equipment, or interconnected system or subsystem...

39 CFR 255.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... technology” and any equipment or interconnected system or subsystem of equipment that is used in the creation... embedded information technology that is used as an integral part of the product, but the principal function... an impairment. (f) Information technology means any equipment, or interconnected system or subsystem...

Waste management system

NASA Technical Reports Server (NTRS)

Sauer, R. L.; Jorgensen, G. K.

1975-01-01

The function of the waste management system was to control the disposition of solid and liquid wastes and waste stowage gases. The waste management system consisting of a urine subsystem and a fecal subsystem is described in detail and its overall performance is evaluated. Recommendations for improvement are given.

Neurocomputing strategies in decomposition based structural design

NASA Technical Reports Server (NTRS)

Szewczyk, Z.; Hajela, P.

1993-01-01

The present paper explores the applicability of neurocomputing strategies in decomposition based structural optimization problems. It is shown that the modeling capability of a backpropagation neural network can be used to detect weak couplings in a system, and to effectively decompose it into smaller, more tractable, subsystems. When such partitioning of a design space is possible, parallel optimization can be performed in each subsystem, with a penalty term added to its objective function to account for constraint violations in all other subsystems. Dependencies among subsystems are represented in terms of global design variables, and a neural network is used to map the relations between these variables and all subsystem constraints. A vector quantization technique, referred to as a z-Network, can effectively be used for this purpose. The approach is illustrated with applications to minimum weight sizing of truss structures with multiple design constraints.

Vulnerabilities, Influences and Interaction Paths: Failure Data for Integrated System Risk Analysis

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Fleming, Land

2006-01-01

We describe graph-based analysis methods for identifying and analyzing cross-subsystem interaction risks from subsystem connectivity information. By discovering external and remote influences that would be otherwise unexpected, these methods can support better communication among subsystem designers at points of potential conflict and to support design of more dependable and diagnosable systems. These methods identify hazard causes that can impact vulnerable functions or entities if propagated across interaction paths from the hazard source to the vulnerable target. The analysis can also assess combined impacts of And-Or trees of disabling influences. The analysis can use ratings of hazards and vulnerabilities to calculate cumulative measures of the severity and importance. Identification of cross-subsystem hazard-vulnerability pairs and propagation paths across subsystems will increase coverage of hazard and risk analysis and can indicate risk control and protection strategies.

Robust adaptive tracking control for nonholonomic mobile manipulator with uncertainties.

PubMed

Peng, Jinzhu; Yu, Jie; Wang, Jie

2014-07-01

In this paper, mobile manipulator is divided into two subsystems, that is, nonholonomic mobile platform subsystem and holonomic manipulator subsystem. First, the kinematic controller of the mobile platform is derived to obtain a desired velocity. Second, regarding the coupling between the two subsystems as disturbances, Lyapunov functions of the two subsystems are designed respectively. Third, a robust adaptive tracking controller is proposed to deal with the unknown upper bounds of parameter uncertainties and disturbances. According to the Lyapunov stability theory, the derived robust adaptive controller guarantees global stability of the closed-loop system, and the tracking errors and adaptive coefficient errors are all bounded. Finally, simulation results show that the proposed robust adaptive tracking controller for nonholonomic mobile manipulator is effective and has good tracking capacity. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Shuttle user analysis (study 2.2). Volume 4: Standardized subsystem modules analysis

NASA Technical Reports Server (NTRS)

1974-01-01

The capability to analyze payloads constructed of standardized modules was provided for the planning of future mission models. An inventory of standardized module designs previously obtained was used as a starting point. Some of the conclusions and recommendations are: (1) the two growth factor synthesis methods provide logical configurations for satellite type selection; (2) the recommended method is the one that determines the growth factor as a function of the baseline subsystem weight, since it provides a larger growth factor for small subsystem weights and results in a greater overkill due to standardization; (3) the method that is not recommended is the one that depends upon a subsystem similarity selection, since care must be used in the subsystem similarity selection; (4) it is recommended that the application of standardized subsystem factors be limited to satellites with baseline dry weights between about 700 and 6,500 lbs; and (5) the standardized satellite design approach applies to satellites maintainable in orbit or retrieved for ground maintenance.

Velocity control propulsion subsystem of the Radio Astronomy Explorer satellite for Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Braught, W.; Moore, E. K.; Steinberg, R. L.

1973-01-01

The Velocity Control Propulsion Subsystem (VCPS) was designed the propulsion required for trajectory and lunar orbit corrections of the spacecraft. A GFE clamp assembly physically attaches the VCPS to the spacecraft and the unit is ejected after completing the required corrections. The VCPS is physically and functionally separated from the spacecraft except for the electrical and telemetry interfaces. A GFE transtage provides the superstructure on which the VCPS is assembled. The subsystem consists of two 5 foot pound rocket engine assemblies, 4 propellant tanks, 2 latching valves, 2 fill and drain valves, a system filter, pressure transducer, gas and propellant manifolds and electrical heaters and thermostats. The RAE-B VCPS program covered the design, manufacture and qualification of one subsystem. This subsystem was to be manufactured, subjected to qualification tests; and refurbished, if necessary, prior to flight. The VCPS design and test program precluded the need for refurbishing the subsystem and the unit was delivered to GSFC at the conclusion of the program.

Dependence of two-proton radioactivity on nuclear pairing models

NASA Astrophysics Data System (ADS)

Oishi, Tomohiro; Kortelainen, Markus; Pastore, Alessandro

2017-10-01

Sensitivity of two-proton emitting decay to nuclear pairing correlation is discussed within a time-dependent three-body model. We focus on the 6Be nucleus assuming α +p +p configuration, and its decay process is described as a time evolution of the three-body resonance state. For a proton-proton subsystem, a schematic density-dependent contact (SDDC) pairing model is employed. From the time-dependent calculation, we observed the exponential decay rule of a two-proton emission. It is shown that the density dependence does not play a major role in determining the decay width, which can be controlled only by the asymptotic strength of the pairing interaction. This asymptotic pairing sensitivity can be understood in terms of the dynamics of the wave function driven by the three-body Hamiltonian, by monitoring the time-dependent density distribution. With this simple SDDC pairing model, there remains an impossible trinity problem: it cannot simultaneously reproduce the empirical Q value, decay width, and the nucleon-nucleon scattering length. This problem suggests that a further sophistication of the theoretical pairing model is necessary, utilizing the two-proton radioactivity data as the reference quantities.

Selected Lessons Learned in Space Shuttle Orbiter Propulsion and Power Subsystems

NASA Technical Reports Server (NTRS)

Hernandez, Francisco J.; Martinez, Hugo; Ryan, Abigail; Westover, Shayne; Davies, Frank

2011-01-01

Over its 30 years of space flight history, plus the nearly 10 years of design, development test and evaluation, the Space Shuttle Orbiter is full of lessons learned in all of its numerous and complex subsystems. In the current paper, only selected lessons learned in the areas of the Orbiter propulsion and power subsystems will be described. The particular Orbiter subsystems include: Auxiliary Power Unit (APU), Hydraulics and Water Spray Boiler (WSB), Mechanical Flight Controls, Main Propulsion System (MPS), Fuel Cells and Power Reactant and Storage Devices (PRSD), Orbital Maneuvering System (OMS), Reaction Control System (RCS), Electrical Power Distribution (EPDC), electrical wiring and pyrotechnics. Given the complexity and extensive history of each of these subsystems, and the limited scope of this paper, it is impossible to include most of the lessons learned; instead the attempt will be to present a selected few or key lessons, in the judgment of the authors. Each subsystem is presented separate, beginning with an overview of the hardware and their function, a short description of a few historical problems and their lessons, followed by a more comprehensive table listing of the major subsystem problems and lessons. These tables serve as a quick reference for lessons learned in each subsystem. In addition, this paper will establish common lessons across subsystems as well as concentrate on those lessons which are deemed to have the highest applicability to future space flight programs.

Command and data handling for Atmosphere Explorer satellite

NASA Technical Reports Server (NTRS)

Fuldner, W. V.

1974-01-01

The command and data-handling subsystem of the Atmosphere Explorer satellite provides the necessary controls for the instrumentation and telemetry, and also controls the satellite attitude and trajectory. The subsystem executes all command information within the spacecraft, either in real time (as received over the S-band command transmission link) or remote from the command site (as required by the orbit operations schedule). Power consumption in the spacecraft is optimized by suitable application and removal of power to various instruments; additional functions include control of magnetic torquers and of the orbit-adjust propulsion subsystem. Telemetry data from instruments and the spacecraft equipment are formatted into a single serial bit stream. Attention is given to command types, command formats, decoder operation, and command processing functions.

X-wing fly-by-wire vehicle management system

NASA Technical Reports Server (NTRS)

Fischer, Jr., William C. (Inventor)

1990-01-01

A complete, computer based, vehicle management system (VMS) for X-Wing aircraft using digital fly-by-wire technology controlling many subsystems and providing functions beyond the classical aircraft flight control system. The vehicle management system receives input signals from a multiplicity of sensors and provides commands to a large number of actuators controlling many subsystems. The VMS includes--segregating flight critical and mission critical factors and providing a greater level of back-up or redundancy for the former; centralizing the computation of functions utilized by several subsystems (e.g. air data, rotor speed, etc.); integrating the control of the flight control functions, the compressor control, the rotor conversion control, vibration alleviation by higher harmonic control, engine power anticipation and self-test, all in the same flight control computer (FCC) hardware units. The VMS uses equivalent redundancy techniques to attain quadruple equivalency levels; includes alternate modes of operation and recovery means to back-up any functions which fail; and uses back-up control software for software redundancy.

SUPER-FOCUS: A tool for agile functional analysis of shotgun metagenomic data

DOE PAGES

Silva, Genivaldo Gueiros Z.; Green, Kevin T.; Dutilh, Bas E.; ...

2015-10-09

Analyzing the functional profile of a microbial community from unannotated shotgun sequencing reads is one of the important goals in metagenomics. Functional profiling has valuable applications in biological research because it identifies the abundances of the functional genes of the organisms present in the original sample, answering the question what they can do. Currently, available tools do not scale well with increasing data volumes, which is important because both the number and lengths of the reads produced by sequencing platforms keep increasing. Here, we introduce SUPER-FOCUS, SUbsystems Profile by databasE Reduction using FOCUS, an agile homology-based approach using a reducedmore » reference database to report the subsystems present in metagenomic datasets and profile their abundances. We tested SUPER-FOCUS with over 70 real metagenomes, the results showing that it accurately predicts the subsystems present in the profiled microbial communities, and is up to 1000 times faster than other tools.« less

An Agile Functional Analysis of Metagenomic Data Using SUPER-FOCUS.

PubMed

Silva, Genivaldo Gueiros Z; Lopes, Fabyano A C; Edwards, Robert A

2017-01-01

One of the main goals in metagenomics is to identify the functional profile of a microbial community from unannotated shotgun sequencing reads. Functional annotation is important in biological research because it enables researchers to identify the abundance of functional genes of the organisms present in the sample, answering the question, "What can the organisms in the sample do?" Most currently available approaches do not scale with increasing data volumes, which is important because both the number and lengths of the reads provided by sequencing platforms keep increasing. Here, we present SUPER-FOCUS, SUbsystems Profile by databasE Reduction using FOCUS, an agile homology-based approach using a reduced reference database to report the subsystems present in metagenomic datasets and profile their abundances. SUPER-FOCUS was tested with real metagenomes, and the results show that it accurately predicts the subsystems present in the profiled microbial communities, is computationally efficient, and up to 1000 times faster than other tools. SUPER-FOCUS is freely available at http://edwards.sdsu.edu/SUPERFOCUS .

Software Reliability Study

DTIC Science & Technology

1976-08-01

indicates the routine’s parent subsystem and function as well. A 1 01[ Subsystem-T Function Routine PROBS Number of actual problems encountered in the...liable to be shelved in the first scheduleof manpower pinch, The n.ixt problem is one of education . Here the situation is similar to that experienced in...assurance organization, and each is feasible in the Project 5 environment. Of particular help in the date collection process was the involement of the

Environmental Control and Life Support System

NASA Technical Reports Server (NTRS)

Ray, Charles; Adams, Alan

1990-01-01

Viewgraphs on the Environmental Control and Life Support System (ECLSS) for the space station are presented. The ECLSS is divided into six subsystems: temperature and humidity control (THC), atmosphere control and supply (ACS), atmosphere revitalization (AR), fire detection and suppression (FDS), water recovery management (WRM), and waste management (WM). Topics covered include: ECLSS subsystem functions; ECLSS distributed system; ECLSS functional distribution; CO2 removal; CO2 reduction; oxygen generation; urine processor; and potable water recovery.

A statistical approach to deriving subsystem specifications. [for spacecraft shock and vibrational environment tests

NASA Technical Reports Server (NTRS)

Keegan, W. B.

1974-01-01

In order to produce cost effective environmental test programs, the test specifications must be realistic and to be useful, they must be available early in the life of a program. This paper describes a method for achieving such specifications for subsystems by utilizing the results of a statistical analysis of data acquired at subsystem mounting locations during system level environmental tests. The paper describes the details of this statistical analysis. The resultant recommended levels are a function of the subsystems' mounting location in the spacecraft. Methods of determining this mounting 'zone' are described. Recommendations are then made as to which of the various problem areas encountered should be pursued further.

Development of integrated, zero-G pneumatic transporter/rotating paddle incinerator/catalytic afterburner subsystem for processing human wastes on board spacecraft

NASA Technical Reports Server (NTRS)

Fields, S. F.; Labak, L. J.; Honegger, R. J.

1974-01-01

A four component system was developed which consists of a particle size reduction mechanism, a pneumatic waste transport system, a rotating-paddle incinerator, and a catalytic afterburner to be integrated into a six-man, zero-g subsystem for processing human wastes on board spacecraft. The study included the development of different concepts or functions, the establishment of operational specifications, and a critical evaluation for each of the four components. A series of laboratory tests was run, and a baseline subsystem design was established. An operational specification was also written in preparation for detailed design and testing of this baseline subsystem.

Development of an Organic Rankine-Cycle power module for a small community solar thermal power experiment

NASA Technical Reports Server (NTRS)

Kiceniuk, T.

1985-01-01

An organic Rankine-cycle (ORC) power module was developed for use in a multimodule solar power plant to be built and operated in a small community. Many successful components and subsystems, including the reciever, power conversion subsystem, energy transport subsystem, and control subsystem, were tested. Tests were performed on a complete power module using a test bed concentrator in place of the proposed concentrator. All major single-module program functional objectives were met and the multimodule operation presented no apparent problems. The hermetically sealed, self-contained, ORC power conversion unit subsequently successfully completed a 300-hour endurance run with no evidence of wear or operating problems.

Ice Pack Heat Sink Subsystem - Phase I. [astronaut liquid cooling garment design and testing

NASA Technical Reports Server (NTRS)

Roebelen, G. J., Jr.

1973-01-01

This paper describes the design and test at one-g of a functional laboratory model (non-flight) Ice Pack Heat Sink Subsystem to be used eventually for astronaut cooling during manned space missions. In normal use, excess heat in the liquid cooling garment (LCG) coolant is transferred to a reusable/regenerable ice pack heat sink. For emergency operation, or for extension of extravehicular activity mission time after all the ice has melted, water from the ice pack is boiled to vacuum, thereby continuing to remove heat from the LCG coolant. This subsystem incorporates a quick connect/disconnect thermal interface between the ice pack heat sink and the subsystem heat exchanger.

Ice pack heat sink subsystem - Phase 1, Volume 1

NASA Technical Reports Server (NTRS)

Roebelen, G. J., Jr.

1973-01-01

The design, development, fabrication, and test at one-g of a functional laboratory model (non-flight) ice pack heat sink subsystem to be used eventually for astronaut cooling during manned space missions are discussed. In normal use, excess heat in the liquid cooling garment (LCG) coolant is transferred to a reusable/regenerable ice pack heat sink. For emergency operation, or for extension of extravehicular activity mission time after all the ice has melted, water from the ice pack is boiled to vacuum, thereby continuing to remove heat from the LCG coolant. This subsystem incorporates a quick connect/disconnect thermal interface between the ice pack heat sink and the subsystem heat exchanger.

Lexical Problems in Large Distributed Information Systems.

ERIC Educational Resources Information Center

Berkovich, Simon Ya; Shneiderman, Ben

1980-01-01

Suggests a unified concept of a lexical subsystem as part of an information system to deal with lexical problems in local and network environments. The linguistic and control functions of the lexical subsystems in solving problems for large computer systems are described, and references are included. (Author/BK)

Predicting Speech Intelligibility Decline in Amyotrophic Lateral Sclerosis Based on the Deterioration of Individual Speech Subsystems

PubMed Central

Yunusova, Yana; Wang, Jun; Zinman, Lorne; Pattee, Gary L.; Berry, James D.; Perry, Bridget; Green, Jordan R.

2016-01-01

Purpose To determine the mechanisms of speech intelligibility impairment due to neurologic impairments, intelligibility decline was modeled as a function of co-occurring changes in the articulatory, resonatory, phonatory, and respiratory subsystems. Method Sixty-six individuals diagnosed with amyotrophic lateral sclerosis (ALS) were studied longitudinally. The disease-related changes in articulatory, resonatory, phonatory, and respiratory subsystems were quantified using multiple instrumental measures, which were subjected to a principal component analysis and mixed effects models to derive a set of speech subsystem predictors. A stepwise approach was used to select the best set of subsystem predictors to model the overall decline in intelligibility. Results Intelligibility was modeled as a function of five predictors that corresponded to velocities of lip and jaw movements (articulatory), number of syllable repetitions in the alternating motion rate task (articulatory), nasal airflow (resonatory), maximum fundamental frequency (phonatory), and speech pauses (respiratory). The model accounted for 95.6% of the variance in intelligibility, among which the articulatory predictors showed the most substantial independent contribution (57.7%). Conclusion Articulatory impairments characterized by reduced velocities of lip and jaw movements and resonatory impairments characterized by increased nasal airflow served as the subsystem predictors of the longitudinal decline of speech intelligibility in ALS. Declines in maximum performance tasks such as the alternating motion rate preceded declines in intelligibility, thus serving as early predictors of bulbar dysfunction. Following the rapid decline in speech intelligibility, a precipitous decline in maximum performance tasks subsequently occurred. PMID:27148967

Reactor Operations Monitoring System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hart, M.M.

1989-01-01

The Reactor Operations Monitoring System (ROMS) is a VME based, parallel processor data acquisition and safety action system designed by the Equipment Engineering Section and Reactor Engineering Department of the Savannah River Site. The ROMS will be analyzing over 8 million signal samples per minute. Sixty-eight microprocessors are used in the ROMS in order to achieve a real-time data analysis. The ROMS is composed of multiple computer subsystems. Four redundant computer subsystems monitor 600 temperatures with 2400 thermocouples. Two computer subsystems share the monitoring of 600 reactor coolant flows. Additional computer subsystems are dedicated to monitoring 400 signals from assortedmore » process sensors. Data from these computer subsystems are transferred to two redundant process display computer subsystems which present process information to reactor operators and to reactor control computers. The ROMS is also designed to carry out safety functions based on its analysis of process data. The safety functions include initiating a reactor scram (shutdown), the injection of neutron poison, and the loadshed of selected equipment. A complete development Reactor Operations Monitoring System has been built. It is located in the Program Development Center at the Savannah River Site and is currently being used by the Reactor Engineering Department in software development. The Equipment Engineering Section is designing and fabricating the process interface hardware. Upon proof of hardware and design concept, orders will be placed for the final five systems located in the three reactor areas, the reactor training simulator, and the hardware maintenance center.« less

Predicting Speech Intelligibility Decline in Amyotrophic Lateral Sclerosis Based on the Deterioration of Individual Speech Subsystems.

PubMed

Rong, Panying; Yunusova, Yana; Wang, Jun; Zinman, Lorne; Pattee, Gary L; Berry, James D; Perry, Bridget; Green, Jordan R

2016-01-01

To determine the mechanisms of speech intelligibility impairment due to neurologic impairments, intelligibility decline was modeled as a function of co-occurring changes in the articulatory, resonatory, phonatory, and respiratory subsystems. Sixty-six individuals diagnosed with amyotrophic lateral sclerosis (ALS) were studied longitudinally. The disease-related changes in articulatory, resonatory, phonatory, and respiratory subsystems were quantified using multiple instrumental measures, which were subjected to a principal component analysis and mixed effects models to derive a set of speech subsystem predictors. A stepwise approach was used to select the best set of subsystem predictors to model the overall decline in intelligibility. Intelligibility was modeled as a function of five predictors that corresponded to velocities of lip and jaw movements (articulatory), number of syllable repetitions in the alternating motion rate task (articulatory), nasal airflow (resonatory), maximum fundamental frequency (phonatory), and speech pauses (respiratory). The model accounted for 95.6% of the variance in intelligibility, among which the articulatory predictors showed the most substantial independent contribution (57.7%). Articulatory impairments characterized by reduced velocities of lip and jaw movements and resonatory impairments characterized by increased nasal airflow served as the subsystem predictors of the longitudinal decline of speech intelligibility in ALS. Declines in maximum performance tasks such as the alternating motion rate preceded declines in intelligibility, thus serving as early predictors of bulbar dysfunction. Following the rapid decline in speech intelligibility, a precipitous decline in maximum performance tasks subsequently occurred.

Top-down control analysis of the cadmium effects on molluscan mitochondria and the mechanisms of cadmium-induced mitochondrial dysfunction.

PubMed

Kurochkin, Ilya O; Etzkorn, Markus; Buchwalter, David; Leamy, Larry; Sokolova, Inna M

2011-01-01

Cadmium (Cd) is a toxic metal and an important environmental pollutant that can strongly affect mitochondrial function and bioenergetics in animals. We investigated the mechanisms of Cd action on mitochondrial function of a marine mollusk (the eastern oyster Crassostrea virginica) by performing a top-down control analysis of the three major mitochondrial subsystems (substrate oxidation, proton leak, and phosphorylation). Our results showed that the substrate oxidation and proton leak subsystems are the main targets for Cd toxicity in oyster mitochondria. Exposure to 12.5 μM Cd strongly inhibited the substrate oxidation subsystem and stimulated the proton conductance across the inner mitochondrial membrane. Proton conductance was also elevated and substrate oxidation inhibited by Cd in the presence of a mitochondrially targeted antioxidant, MitoVitE, indicating that Cd effects on these subsystems were to a large extent ROS independent. Cd did not affect the kinetics of the phosphorylation system, indicating that it has negligible effects on F₁, F(O) ATP synthase and/or the adenine nucleotide transporter in oyster mitochondria. Cd exposure altered the patterns of control over mitochondrial respiration, increasing the degree of control conferred by the substrate oxidation subsystem, especially in resting (state 4) mitochondria. Taken together, these data suggest that Cd-induced decrease of mitochondrial efficiency and ATP production are predominantly driven by the high sensitivity of substrate oxidation and proton leak subsystems to this metal.

Mark 4A DSN receiver-exciter and transmitter subsystems

NASA Technical Reports Server (NTRS)

Wick, M. R.

1986-01-01

The present configuration of the Mark 4A DSN Receiver-Exciter and Transmitter Subsystems is described. Functional requirements and key characteristics are given to show the differences in the capabilities required by the Networks Consolidation task for combined High Earth Orbiter and Deep Space Network tracking support.

An Algorithm for Integrated Subsystem Embodiment and System Synthesis

NASA Technical Reports Server (NTRS)

Lewis, Kemper

1997-01-01

Consider the statement,'A system has two coupled subsystems, one of which dominates the design process. Each subsystem consists of discrete and continuous variables, and is solved using sequential analysis and solution.' To address this type of statement in the design of complex systems, three steps are required, namely, the embodiment of the statement in terms of entities on a computer, the mathematical formulation of subsystem models, and the resulting solution and system synthesis. In complex system decomposition, the subsystems are not isolated, self-supporting entities. Information such as constraints, goals, and design variables may be shared between entities. But many times in engineering problems, full communication and cooperation does not exist, information is incomplete, or one subsystem may dominate the design. Additionally, these engineering problems give rise to mathematical models involving nonlinear functions of both discrete and continuous design variables. In this dissertation an algorithm is developed to handle these types of scenarios for the domain-independent integration of subsystem embodiment, coordination, and system synthesis using constructs from Decision-Based Design, Game Theory, and Multidisciplinary Design Optimization. Implementation of the concept in this dissertation involves testing of the hypotheses using example problems and a motivating case study involving the design of a subsonic passenger aircraft.

Space Station Furnace Facility. Volume 2: Summary of technical reports

NASA Technical Reports Server (NTRS)

1992-01-01

The Space Station Furnace Facility (SSFF) is a modular facility for materials research in the microgravity environment of the Space Station Freedom (SSF). The SSFF is designed for crystal growth and solidification research in the fields of electronic and photonic materials, metals and alloys, and glasses and ceramics, and will allow for experimental determination of the role of gravitational forces in the solidification process. The facility will provide a capability for basic scientific research and will evaluate the commercial viability of low-gravity processing of selected technologically important materials. In order to accommodate the furnace modules with the resources required to operate, SSFF developed a design that meets the needs of the wide range of furnaces that are planned for the SSFF. The system design is divided into subsystems which provide the functions of interfacing to the SSF services, conditioning and control for furnace module use, providing the controlled services to the furnace modules, and interfacing to and acquiring data from the furnace modules. The subsystems, described in detail, are as follows: Power Conditioning and Distribution Subsystem; Data Management Subsystem; Software; Gas Distribution Subsystem; Thermal Control Subsystem; and Mechanical Structures Subsystem.

Joint Vision 2010: Developing the System of Systems

DTIC Science & Technology

1998-04-01

The system engineering model, as described in Defense Acquisition University Coursebook , consists of five main parts and three feedback loops.4 The... physical architecture is defined and each subsystem developed. In the case of JV2010’s “system of systems” the subsystems would be the items...verify that each requirement can be traced to a system function. The purpose of the design loop is to ensure all the functions can be traced to physical

Advanced Infant Car Seat Would Increase Highway Safety

NASA Technical Reports Server (NTRS)

Dabney, Richard; Elrod, Susan

2004-01-01

An advanced infant car seat has been proposed to increase highway safety by reducing the incidence of crying, fussy behavior, and other child-related distractions that divert an adult driver s attention from driving. In addition to a conventional infant car seat with safety restraints, the proposed advanced infant car seat would include a number of components and subsystems that would function together as a comprehensive infant-care system that would keep its occupant safe, comfortable, and entertained, and would enable the driver to monitor the baby without having to either stop the car or turn around to face the infant during driving. The system would include a vibrator with bulb switch to operate; the switch would double as a squeeze toy that would make its own specific sound. A music subsystem would include loudspeakers built into the seat plus digital and analog circuitry that would utilize plug-in memory modules to synthesize music or a variety of other sounds. The music subsystem would include a built-in sound generator that could synthesize white noise or a human heartbeat to calm the baby to sleep. A second bulb switch could be used to control the music subsystem and would double as a squeeze toy that would make a distinct sound. An anti-noise sound-suppression system would isolate the baby from potentially disturbing ambient external noises. This subsystem would include small microphones, placed near the baby s ears, to detect ambient noise. The outputs of the microphone would be amplified and fed to the loudspeakers at appropriate amplitude and in a phase opposite that of the detected ambient noise, such that the net ambient sound arriving at the baby s ears would be almost completely cancelled. A video-camera subsystem would enable the driver to monitor the baby visually while continuing to face forward. One or more portable miniature video cameras could be embedded in the side of the infant car seat (see figure) or in a flip-down handle. The outputs of the video cameras would be transmitted by radio or infrared to a portable, miniature receiver/video monitor unit that would be attached to the dashboard of the car. The video-camera subsystem can also be used within transmission/reception range when the seat was removed from the car. The system would include a biotelemetric and tracking subsystem, which would include a Global Positioning System receiver for measuring its location. This subsystem would transmit the location of the infant car seat (even if the seat were not in a car) along with such biometric data as the baby s heart rate, perspiration rate, urinary status, temperature, and rate of breathing. Upon detecting any anomalies in the biometric data, this subsystem would send a warning to a paging device installed in the car or carried by the driver, so that the driver could pull the car off the road to attend to the baby. A motion detector in this subsystem would send a warning if the infant car seat were to be moved or otherwise disturbed unexpectedly while the infant was seated in it: this warning function, in combination with the position- tracking function, could help in finding a baby who had been kidnapped with the seat. Removable rechargeable batteries would enable uninterrupted functioning of all parts of the system while transporting the baby to and from the car. The batteries could be recharged via the cigarette-lighter outlet in the car or by use of an external AC-powered charger.

The development of a whole-body algorithm

NASA Technical Reports Server (NTRS)

Kay, F. J.

1973-01-01

The whole-body algorithm is envisioned as a mathematical model that utilizes human physiology to simulate the behavior of vital body systems. The objective of this model is to determine the response of selected body parameters within these systems to various input perturbations, or stresses. Perturbations of interest are exercise, chemical unbalances, gravitational changes and other abnormal environmental conditions. This model provides for a study of man's physiological response in various space applications, underwater applications, normal and abnormal workloads and environments, and the functioning of the system with physical impairments or decay of functioning components. Many methods or approaches to the development of a whole-body algorithm are considered. Of foremost concern is the determination of the subsystems to be included, the detail of the subsystems and the interaction between the subsystems.

Input and output constraints-based stabilisation of switched nonlinear systems with unstable subsystems and its application

NASA Astrophysics Data System (ADS)

Chen, Chao; Liu, Qian; Zhao, Jun

2018-01-01

This paper studies the problem of stabilisation of switched nonlinear systems with output and input constraints. We propose a recursive approach to solve this issue. None of the subsystems are assumed to be stablisable while the switched system is stabilised by dual design of controllers for subsystems and a switching law. When only dealing with bounded input, we provide nested switching controllers using an extended backstepping procedure. If both input and output constraints are taken into consideration, a Barrier Lyapunov Function is employed during operation to construct multiple Lyapunov functions for switched nonlinear system in the backstepping procedure. As a practical example, the control design of an equilibrium manifold expansion model of aero-engine is given to demonstrate the effectiveness of the proposed design method.

The Infrared Astronomical Satellite /IRAS/ Scientific Data Analysis System /SDAS/ sky flux subsystem

NASA Technical Reports Server (NTRS)

Stagner, J. R.; Girard, M. A.

1980-01-01

The sky flux subsystem of the Infrared Astronomical Satellite Scientific Data Analysis System is described. Its major output capabilities are (1) the all-sky lune maps (8-arcminute pixel size), (2) galactic plane maps (2-arcminute pixel size) and (3) regional maps of small areas such as extended sources greater than 1-degree in extent. The major processing functions are to (1) merge the CRDD and pointing data, (2) phase the detector streams, (3) compress the detector streams in the in-scan and cross-scan directions, and (4) extract data. Functional diagrams of the various capabilities of the subsystem are given. Although this device is inherently nonimaging, various calibrated and geometrically controlled imaging products are created, suitable for quantitative and qualitative scientific interpretation.

Introduction to the scientific application system of DAMPE (On behalf of DAMPE collaboration)

NASA Astrophysics Data System (ADS)

Zang, Jingjing

2016-07-01

The Dark Matter Particle Explorer (DAMPE) is a high energy particle physics experiment satellite, launched on 17 Dec 2015. The science data processing and payload operation maintenance for DAMPE will be provided by the DAMPE Scientific Application System (SAS) at the Purple Mountain Observatory (PMO) of Chinese Academy of Sciences. SAS is consisted of three subsystems - scientific operation subsystem, science data and user management subsystem and science data processing subsystem. In cooperation with the Ground Support System (Beijing), the scientific operation subsystem is responsible for proposing observation plans, monitoring the health of satellite, generating payload control commands and participating in all activities related to payload operation. Several databases developed by the science data and user management subsystem of DAMPE methodically manage all collected and reconstructed science data, down linked housekeeping data, payload configuration and calibration data. Under the leadership of DAMPE Scientific Committee, this subsystem is also responsible for publication of high level science data and supporting all science activities of the DAMPE collaboration. The science data processing subsystem of DAMPE has already developed a series of physics analysis software to reconstruct basic information about detected cosmic ray particle. This subsystem also maintains the high performance computing system of SAS to processing all down linked science data and automatically monitors the qualities of all produced data. In this talk, we will describe all functionalities of whole DAMPE SAS system and show you main performances of data processing ability.

Proposed Schematics for an Advanced Development Lunar Portable Life Support System

NASA Technical Reports Server (NTRS)

Conger, Bruce; Chullen, Cinda; Barnes, Bruce; Leavitt, Greg

2010-01-01

The latest development of the NASA space suit is an integrated assembly made up of primarily a Pressure Garment System (PGS) and a Portable Life Support System (PLSS). The PLSS is further composed of an oxygen (O2) subsystem, a ventilation subsystem, and a thermal subsystem. This paper baselines a detailed schematic of the PLSS to provide a basis for current and future PLSS development efforts. Both context diagrams and detailed schematics describe the hardware components and overall functions for all three of the PLSS subsystems. The various modes of operations for the PLSS are also presented. A comparison of the proposed PLSS to the Apollo and Shuttle PLSS designs is presented, highlighting several anticipated improvements over the historical PLSS architectures.

Stability analysis for uncertain switched neural networks with time-varying delay.

PubMed

Shen, Wenwen; Zeng, Zhigang; Wang, Leimin

2016-11-01

In this paper, stability for a class of uncertain switched neural networks with time-varying delay is investigated. By exploring the mode-dependent properties of each subsystem, all the subsystems are categorized into stable and unstable ones. Based on Lyapunov-like function method and average dwell time technique, some delay-dependent sufficient conditions are derived to guarantee the exponential stability of considered uncertain switched neural networks. Compared with general results, our proposed approach distinguishes the stable and unstable subsystems rather than viewing all subsystems as being stable, thus getting less conservative criteria. Finally, two numerical examples are provided to show the validity and the advantages of the obtained results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development and Testing of a USM High Altitude Balloon

NASA Astrophysics Data System (ADS)

Thaheer, A. S. Mohamed; Ismail, N. A.; Yusoff, S. H. Md.; Nasirudin, M. A.

2018-04-01

This paper discusses on tests conducted on the component and subsystem level during development of the USM High Altitude Balloon (HAB). The tests conducted by selecting initial components then tested individually based on several case studies such as reliability test, camera viewing, power consumption, thermal capability, and parachute performance. Then, the component is integrated into sub-system level for integration and functionality test. The preliminary result is utilized to tune the components and sub-systems and trial launch is conducted where the sample images are recorded and atmospheric data successfully collected.

Integrated flight/propulsion control - Subsystem specifications for performance

NASA Technical Reports Server (NTRS)

Neighbors, W. K.; Rock, Stephen M.

1993-01-01

A procedure is presented for calculating multiple subsystem specifications given a number of performance requirements on the integrated system. This procedure applies to problems where the control design must be performed in a partitioned manner. It is based on a structured singular value analysis, and generates specifications as magnitude bounds on subsystem uncertainties. The performance requirements should be provided in the form of bounds on transfer functions of the integrated system. This form allows the expression of model following, command tracking, and disturbance rejection requirements. The procedure is demonstrated on a STOVL aircraft design.

Results of a Formal Methods Demonstration Project

NASA Technical Reports Server (NTRS)

Kelly, J.; Covington, R.; Hamilton, D.

1994-01-01

This paper describes the results of a cooperative study conducted by a team of researchers in formal methods at three NASA Centers to demonstrate FM techniques and to tailor them to critical NASA software systems. This pilot project applied FM to an existing critical software subsystem, the Shuttle's Jet Select subsystem (Phase I of an ongoing study). The present study shows that FM can be used successfully to uncover hidden issues in a highly critical and mature Functional Subsystem Software Requirements (FSSR) specification which are very difficult to discover by traditional means.

TACAN operational description for the space shuttle orbital flight test program

NASA Technical Reports Server (NTRS)

Hughes, C. L.; Hudock, P. J.

1979-01-01

The TACAN subsystems (three TACAN transponders, six antennas, a subsystem operating program, and redundancy management software in a tutorial form) are discussed and the interaction between these subsystems and the shuttle navigation system are identified. The use of TACAN during the first space transportation system (STS-1), is followed by a brief functional description of the TACAN hardware, then proceeds to cover the software units with a view to the STS-1, and ends with a discussion on the shuttle usage of the TACAN data and anticipated performance.

Synchronous orbit power technology needs

NASA Technical Reports Server (NTRS)

Slifer, L. W., Jr.; Billerbeck, W. J.

1979-01-01

The needs are defined for future geosynchronous orbit spacecraft power subsystem components, including power generation, energy storage, and power processing. A review of the rapid expansion of the satellite communications field provides a basis for projection into the future. Three projected models, a mission model, an orbit transfer vehicle model, and a mass model for power subsystem components are used to define power requirements and mass limitations for future spacecraft. Based upon these three models, the power subsystems for a 10 kw, 10 year life, dedicated spacecraft and for a 20 kw, 20 year life, multi-mission platform are analyzed in further detail to establish power density requirements for the generation, storage and processing components of power subsystems as related to orbit transfer vehicle capabilities. Comparison of these requirements to state of the art design values shows that major improvements, by a factor of 2 or more, are needed to accomplish the near term missions. However, with the advent of large transfer vehicles, these requirements are significantly reduced, leaving the long lifetime requirement, associated with reliability and/or refurbishment, as the primary development need. A few technology advances, currently under development, are noted with regard to their impacts on future capability.

The effect of 1 to 5 keV electrons on the reproductive integrity of microorganisms

NASA Technical Reports Server (NTRS)

Barengoltz, J. B.; Brady, J.

1977-01-01

Microorganisms were exposed to simulated space environment in order to assess the effect of electrons in the energy range 1 to 5 keV on their colony-forming ability. The test system consisted of an electron gun and power supply, a dosimetry subsystem, and a vacuum subsystem. The system was capable of current densities ranging from 0.1 nA/sq cm to 5 micro A/sq cm on a 25 sq on target and an ultimate vacuum of 0.0006 N/sq m (0.000004 torr). The results of the experimental program show a significant reduction in microbial reproductive integrity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hégely, Bence; Nagy, Péter R.; Kállay, Mihály, E-mail: kallay@mail.bme.hu

Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up themore » system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.« less

Embedded correlated wavefunction schemes: theory and applications.

PubMed

Libisch, Florian; Huang, Chen; Carter, Emily A

2014-09-16

Conspectus Ab initio modeling of matter has become a pillar of chemical research: with ever-increasing computational power, simulations can be used to accurately predict, for example, chemical reaction rates, electronic and mechanical properties of materials, and dynamical properties of liquids. Many competing quantum mechanical methods have been developed over the years that vary in computational cost, accuracy, and scalability: density functional theory (DFT), the workhorse of solid-state electronic structure calculations, features a good compromise between accuracy and speed. However, approximate exchange-correlation functionals limit DFT's ability to treat certain phenomena or states of matter, such as charge-transfer processes or strongly correlated materials. Furthermore, conventional DFT is purely a ground-state theory: electronic excitations are beyond its scope. Excitations in molecules are routinely calculated using time-dependent DFT linear response; however applications to condensed matter are still limited. By contrast, many-electron wavefunction methods aim for a very accurate treatment of electronic exchange and correlation. Unfortunately, the associated computational cost renders treatment of more than a handful of heavy atoms challenging. On the other side of the accuracy spectrum, parametrized approaches like tight-binding can treat millions of atoms. In view of the different (dis-)advantages of each method, the simulation of complex systems seems to force a compromise: one is limited to the most accurate method that can still handle the problem size. For many interesting problems, however, compromise proves insufficient. A possible solution is to break up the system into manageable subsystems that may be treated by different computational methods. The interaction between subsystems may be handled by an embedding formalism. In this Account, we review embedded correlated wavefunction (CW) approaches and some applications. We first discuss our density functional embedding theory, which is formally exact. We show how to determine the embedding potential, which replaces the interaction between subsystems, at the DFT level. CW calculations are performed using a fixed embedding potential, that is, a non-self-consistent embedding scheme. We demonstrate this embedding theory for two challenging electron transfer phenomena: (1) initial oxidation of an aluminum surface and (2) hot-electron-mediated dissociation of hydrogen molecules on a gold surface. In both cases, the interaction between gas molecules and metal surfaces were treated by sophisticated CW techniques, with the remainder of the extended metal surface being treated by DFT. Our embedding approach overcomes the limitations of conventional Kohn-Sham DFT in describing charge transfer, multiconfigurational character, and excited states. From these embedding simulations, we gained important insights into fundamental processes that are crucial aspects of fuel cell catalysis (i.e., O2 reduction at metal surfaces) and plasmon-mediated photocatalysis by metal nanoparticles. Moreover, our findings agree very well with experimental observations, while offering new views into the chemistry. We finally discuss our recently formulated potential-functional embedding theory that provides a seamless, first-principles way to include back-action onto the environment from the embedded region.

Large-Scale First-Principles Molecular Dynamics Simulations with Electrostatic Embedding: Application to Acetylcholinesterase Catalysis

DOE PAGES

Fattebert, Jean-Luc; Lau, Edmond Y.; Bennion, Brian J.; ...

2015-10-22

Enzymes are complicated solvated systems that typically require many atoms to simulate their function with any degree of accuracy. We have recently developed numerical techniques for large scale First-Principles molecular dynamics simulations and applied them to study the enzymatic reaction catalyzed by acetylcholinesterase. We carried out Density functional theory calculations for a quantum mechanical (QM) sub- system consisting of 612 atoms with an O(N) complexity finite-difference approach. The QM sub-system is embedded inside an external potential field representing the electrostatic effect due to the environment. We obtained finite temperature sampling by First-Principles molecular dynamics for the acylation reaction of acetylcholinemore » catalyzed by acetylcholinesterase. Our calculations shows two energies barriers along the reaction coordinate for the enzyme catalyzed acylation of acetylcholine. In conclusion, the second barrier (8.5 kcal/mole) is rate-limiting for the acylation reaction and in good agreement with experiment.« less

An Analytical Calibration Approach for the Polarimetric Airborne C Band Radiometer

NASA Technical Reports Server (NTRS)

Pham, Hanh; Kim, Edward J.

2004-01-01

Passive microwave remote sensing is sensitive to the quantity and distribution of water in soil and vegetation. During summer 2000, the Microwave Geophysics Group at the University of Michigan conducted the 7th Radiobrightness Energy Balance Experiment (REBEX-7) over a corn canopy in Michigan. Long time series of brightness temperatures, soil moisture and micrometeorology on the plot scale were taken. This paper addresses the calibration of the NASA GSFC polarimetric airborne C band microwave radiometer (ACMR) that participated in REBEX-7. Passive polarimeters are typically calibrated using an end-to-end approach based upon a standard artificial target or a well-known geophysical target. Analyzing the major internal functional subsystems offers a different perspective. The primary goal of this approach is to provide a transfer function that not only describes the system in its entirety but also accounts for the contributions of each subsystem toward the final modified Stokes parameters. This approach also serves as a realistic instrument simulator, a useful tool for future designs. The ACMR architecture can be partitioned into several functional subsystems. Each subsystem was extensively measured and the estimated parameters were imported into the overall system model. We will present the results of polarimetric antenna measurements, the instrument model as well as four Stokes observations from REBEX-7 using a first order inversion.

Calculation of wave-functions with frozen orbitals in mixed quantum mechanics/molecular mechanics methods. Part I. Application of the Huzinaga equation.

PubMed

Ferenczy, György G

2013-04-05

Mixed quantum mechanics/quantum mechanics (QM/QM) and quantum mechanics/molecular mechanics (QM/MM) methods make computations feasible for extended chemical systems by separating them into subsystems that are treated at different level of sophistication. In many applications, the subsystems are covalently bound and the use of frozen localized orbitals at the boundary is a possible way to separate the subsystems and to ensure a sensible description of the electronic structure near to the boundary. A complication in these methods is that orthogonality between optimized and frozen orbitals has to be warranted and this is usually achieved by an explicit orthogonalization of the basis set to the frozen orbitals. An alternative to this approach is proposed by calculating the wave-function from the Huzinaga equation that guaranties orthogonality to the frozen orbitals without basis set orthogonalization. The theoretical background and the practical aspects of the application of the Huzinaga equation in mixed methods are discussed. Forces have been derived to perform geometry optimization with wave-functions from the Huzinaga equation. Various properties have been calculated by applying the Huzinaga equation for the central QM subsystem, representing the environment by point charges and using frozen strictly localized orbitals to connect the subsystems. It is shown that a two to three bond separation of the chemical or physical event from the frozen bonds allows a very good reproduction (typically around 1 kcal/mol) of standard Hartree-Fock-Roothaan results. The proposed scheme provides an appropriate framework for mixed QM/QM and QM/MM methods. Copyright © 2012 Wiley Periodicals, Inc.

Discovering novel subsystems using comparative genomics

PubMed Central

Ferrer, Luciana; Shearer, Alexander G.; Karp, Peter D.

2011-01-01

Motivation: Key problems for computational genomics include discovering novel pathways in genome data, and discovering functional interaction partners for genes to define new members of partially elucidated pathways. Results: We propose a novel method for the discovery of subsystems from annotated genomes. For each gene pair, a score measuring the likelihood that the two genes belong to a same subsystem is computed using genome context methods. Genes are then grouped based on these scores, and the resulting groups are filtered to keep only high-confidence groups. Since the method is based on genome context analysis, it relies solely on structural annotation of the genomes. The method can be used to discover new pathways, find missing genes from a known pathway, find new protein complexes or other kinds of functional groups and assign function to genes. We tested the accuracy of our method in Escherichia coli K-12. In one configuration of the system, we find that 31.6% of the candidate groups generated by our method match a known pathway or protein complex closely, and that we rediscover 31.2% of all known pathways and protein complexes of at least 4 genes. We believe that a significant proportion of the candidates that do not match any known group in E.coli K-12 corresponds to novel subsystems that may represent promising leads for future laboratory research. We discuss in-depth examples of these findings. Availability: Predicted subsystems are available at http://brg.ai.sri.com/pwy-discovery/journal.html. Contact: lferrer@ai.sri.com Supplementary information: Supplementary data are available at Bioinformatics online. PMID:21775308

The OCLC Serials Sub-System: A First Evaluation.

ERIC Educational Resources Information Center

Edgar, Neal L.; And Others

This examination of the OCLC serials control sub-system points to positive and negative aspects of the OCLC system as they relate to serials, and evaluates the system's serials cataloging capabilities. While this report assumes a knowledge of the basic operations of OCLC, it describes the system in general, its function in cataloging, and its…

ATS-6 engineering performance report. Volume 3: Telecommunications and power

NASA Technical Reports Server (NTRS)

Wales, R. O. (Editor)

1981-01-01

Functional design requirements and in-orbit operations, performance, and anomalies are discussed for (1) the communications subsystem, (2) the electrical power system, and (3) the telemetry and command subsystem. The latter includes a review of ground support. Tracking and data relay experiments and the Apollo-Soyuz test program are reviewed.

Automated Power Systems Management (APSM)

NASA Technical Reports Server (NTRS)

Bridgeforth, A. O.

1981-01-01

A breadboard power system incorporating autonomous functions of monitoring, fault detection and recovery, command and control was developed, tested and evaluated to demonstrate technology feasibility. Autonomous functions including switching of redundant power processing elements, individual load fault removal, and battery charge/discharge control were implemented by means of a distributed microcomputer system within the power subsystem. Three local microcomputers provide the monitoring, control and command function interfaces between the central power subsystem microcomputer and the power sources, power processing and power distribution elements. The central microcomputer is the interface between the local microcomputers and the spacecraft central computer or ground test equipment.

Environmental Control Subsystem Development

NASA Technical Reports Server (NTRS)

Laidlaw, Jacob; Zelik, Jonathan

2017-01-01

Kennedy Space Center's Launch Pad 39B, part of Launch Complex 39, is currently undergoing construction to prepare it for NASA's Space Launch System missions. The Environmental Control Subsystem, which provides the vehicle with an air or nitrogen gas environment, required development of its local and remote display screens. The remote displays, developed by NASA contractors and previous interns, were developed without complete functionality; the remote displays were revised, adding functionality to over 90 displays. For the local displays, multiple test procedures were developed to assess the functionality of the screens, as well as verify requirements. One local display screen was also developed.

Free-energy analysis of the electron-density fluctuation in the quantum-mechanical/molecular-mechanical simulation combined with the theory of energy representation.

PubMed

Matubayasi, Nobuyuki; Takahashi, Hideaki

2012-01-28

The relationship is investigated for QM/MM (quantum-mechanical/molecular-mechanical) systems between the fluctuations of the electronic state of the QM subsystem and of the solvation effect due to the QM-MM interaction. The free-energy change due to the electron-density fluctuation around its average is highlighted, and is evaluated through an approximate functional formulated in terms of distribution functions of the many-body coupling (pairwise non-additive) part of the QM-MM interaction energy. A set of QM/MM simulations are conducted in MM water solvent for QM water solute in ambient and supercritical conditions and for QM glycine solute in the neutral and zwitterionic forms. The variation of the electronic distortion energy of the QM solute in the course of QM/MM simulation is then shown to be compensated by the corresponding variation of the free energy of solvation. The solvation free energy conditioned by the electronic distortion energy is further analyzed with its components. It is found that the many-body contribution is essentially equal between the free energy and the average sum of solute-solvent interaction energy. © 2012 American Institute of Physics

Changes in herbivore control in arable fields by detrital subsidies depend on predator species and vary in space.

PubMed

von Berg, Karsten; Thies, Carsten; Tscharntke, Teja; Scheu, Stefan

2010-08-01

Prey from the decomposer subsystem may help sustain predator populations in arable fields. Adding organic residues to agricultural systems may therefore enhance pest control. We investigated whether resource addition (maize mulch) strengthens aboveground trophic cascades in winter wheat fields. Evaluating the flux of the maize-borne carbon into the food web after 9 months via stable isotope analysis allowed differentiating between prey in predator diets originating from the above- and belowground subsystems. Furthermore, we recorded aphid populations in predator-reduced and control plots of no-mulch and mulch addition treatments. All analyzed soil dwelling species incorporated maize-borne carbon. In contrast, only 2 out of 13 aboveground predator species incorporated maize carbon, suggesting that these 2 predators forage on prey from the above- and belowground systems. Supporting this conclusion, densities of these two predator species were increased in the mulch addition fields. Nitrogen isotope signatures suggested that these generalist predators in part fed on Collembola thereby benefiting indirectly from detrital resources. Increased density of these two predator species was associated by increased aphid control but the identity of predators responsible for aphid control varied in space. One of the three wheat fields studied even lacked aphid control despite of mulch-mediated increased density of generalist predators. The results suggest that detrital subsidies quickly enter belowground food webs but only a few aboveground predator species include prey out of the decomposer system into their diet. Variation in the identity of predator species benefiting from detrital resources between sites suggest that, depending on locality, different predator species are subsidised by prey out of the decomposer system and that these predators contribute to aphid control. Therefore, by engineering the decomposer subsystem via detrital subsidies, biological control by generalist predators may be strengthened.

Hybrid multiphoton volumetric functional imaging of large-scale bioengineered neuronal networks

NASA Astrophysics Data System (ADS)

Dana, Hod; Marom, Anat; Paluch, Shir; Dvorkin, Roman; Brosh, Inbar; Shoham, Shy

2014-06-01

Planar neural networks and interfaces serve as versatile in vitro models of central nervous system physiology, but adaptations of related methods to three dimensions (3D) have met with limited success. Here, we demonstrate for the first time volumetric functional imaging in a bioengineered neural tissue growing in a transparent hydrogel with cortical cellular and synaptic densities, by introducing complementary new developments in nonlinear microscopy and neural tissue engineering. Our system uses a novel hybrid multiphoton microscope design combining a 3D scanning-line temporal-focusing subsystem and a conventional laser-scanning multiphoton microscope to provide functional and structural volumetric imaging capabilities: dense microscopic 3D sampling at tens of volumes per second of structures with mm-scale dimensions containing a network of over 1,000 developing cells with complex spontaneous activity patterns. These developments open new opportunities for large-scale neuronal interfacing and for applications of 3D engineered networks ranging from basic neuroscience to the screening of neuroactive substances.

Challenges of Sustaining the International Space Station Through 2020 and Beyond: Reassessing Confidence Targets for System Availability

NASA Technical Reports Server (NTRS)

Lutomski, Michael G.; Carter-Journet, Katrina; Anderson, Leif; Box, Neil; Harrington, Sean; Jackson, David; DiFilippo, Denise

2012-01-01

The International Space Station (ISS) was originally designed to operate until 2015 with a plan for deorbiting the ISS in 2016. Currently, the international partnership has agreed to extend the operations until 2020 and discussions are underway to extend the life even further to 2028. Each partner is responsible for the sustaining engineering, sparing, and maintenance of their own segments. National Aeronautics and Space Administration's (NASA's) challenge is to purchase the needed number of spares to maintain the functional availability of the ISS systems necessary for the United States On-Orbit Segment s contribution. This presentation introduces an analytical approach to assessing uncertainty in ISS hardware necessary to extend the life of the vehicle. Some key areas for consideration are: establishing what confidence targets are required to ensure science can be continuously carried out on the ISS, defining what confidence targets are reasonable to ensure vehicle survivability, considering what is required to determine if the confidence targets are too high, and whether sufficient number of spares are purchased. The results of the analysis will provide a methodological basis for reassessing vehicle subsystem confidence targets. This analysis compares the probability of existing spares exceeding the total expected unit demand of the Orbital Replacement Unit (ORU) in functional hierarchies approximating the vehicle subsystems. In cases where the functional hierarchies' availability does not meet subsystem confidence targets, the analysis will further identify which ORUs may require additional spares to extend the life of the ISS. The resulting probability is dependent upon hardware reliability estimates. However, the ISS hardware fleet carries considerable epistemic uncertainty which must be factored into the development and execution of sparing risk postures. In addition, it is also recognized that uncertainty in the assessment is due to disconnects between modeled functions and actual subsystem operations. Perhaps most importantly, it is acknowledged that conservative confidence targets per subsystem are currently accepted. This presentation will also discuss how subsystem confidence targets may be relaxed based on calculating the level of uncertainty for each corresponding ORU-function. The presentation will conclude with the various strengths and limitations for implementing the analytical approach in sustaining the ISS through end of life; 2020 and beyond.

Improvement of web-based data acquisition and management system for GOSAT validation lidar data analysis

NASA Astrophysics Data System (ADS)

Okumura, Hiroshi; Takubo, Shoichiro; Kawasaki, Takeru; Abdullah, Indra Nugraha; Uchino, Osamu; Morino, Isamu; Yokota, Tatsuya; Nagai, Tomohiro; Sakai, Tetsu; Maki, Takashi; Arai, Kohei

2013-01-01

A web-base data acquisition and management system for GOSAT (Greenhouse gases Observation SATellite) validation lidar data-analysis has been developed. The system consists of data acquisition sub-system (DAS) and data management sub-system (DMS). DAS written in Perl language acquires AMeDAS (Automated Meteorological Data Acquisition System) ground-level local meteorological data, GPS Radiosonde upper-air meteorological data, ground-level oxidant data, skyradiometer data, skyview camera images, meteorological satellite IR image data and GOSAT validation lidar data. DMS written in PHP language demonstrates satellite-pass date and all acquired data. In this article, we briefly describe some improvement for higher performance and higher data usability. GPS Radiosonde upper-air meteorological data and U.S. standard atmospheric model in DAS automatically calculate molecule number density profiles. Predicted ozone density prole images above Saga city are also calculated by using Meteorological Research Institute (MRI) chemistry-climate model version 2 for comparison to actual ozone DIAL data.

Study of decoherence in a system of superconducting flux-qubits interacting with an ensemble of electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reboiro, M., E-mail: reboiro@fisica.unlp.edu.ar; Civitarese, O., E-mail: osvaldo.civitarese@fisica.unlp.edu.ar; Ramírez, R.

2017-03-15

The degree of coherence in a hybrid system composed of superconducting flux-qubits and an electron ensemble is analysed. Both, the interactions among the electrons and among the superconducting flux-qubits are taken into account. The time evolution of the hybrid system is solved exactly, and discussed in terms of the reduced density matrix of each subsystem. It is seen that the inclusion of a line width, for the electrons and for the superconducting flux-qubits, influences the pattern of spin-squeezing and the coherence of the superconducting flux qubits. - Highlights: • The degree of coherence in a hybrid system, composed of superconductingmore » flux qubits and an electron ensemble, is analysed. • The time evolution of the hybrid system is solved exactly and discussed in terms of the reduced density matrix of each subsystem. • It is shown that the initial state of the system evolves to a stationary squeezed state.« less

Distributed model predictive control for constrained nonlinear systems with decoupled local dynamics.

PubMed

Zhao, Meng; Ding, Baocang

2015-03-01

This paper considers the distributed model predictive control (MPC) of nonlinear large-scale systems with dynamically decoupled subsystems. According to the coupled state in the overall cost function of centralized MPC, the neighbors are confirmed and fixed for each subsystem, and the overall objective function is disassembled into each local optimization. In order to guarantee the closed-loop stability of distributed MPC algorithm, the overall compatibility constraint for centralized MPC algorithm is decomposed into each local controller. The communication between each subsystem and its neighbors is relatively low, only the current states before optimization and the optimized input variables after optimization are being transferred. For each local controller, the quasi-infinite horizon MPC algorithm is adopted, and the global closed-loop system is proven to be exponentially stable. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Magellan attitude and articulation control subsystem closed loop testing

NASA Technical Reports Server (NTRS)

Olschansky, David G.

1987-01-01

In the spring of 1989, the Magellan spacecraft will embark on a two-year mission to map the surface of the planet Venus. Guiding it there will be the Attitude and Articulation Control Subsystem (AACS). To ensure reliable operations the AACS is being put through a rigorous test program at Martin Marietta Denver Aerospace. Before Magellan ever leaves the Space Shuttle bay from which it is to be launched, its components will have flown a simulated spaceflight in a ground-based lab. The primary objectives of the test program are to verify form, fit, and function of the AACS, particularly subsystem external interfaces and functional operation of the flight software. This paper discusses the Magellan Closed Loop Test Systems which makes realistic tests possible by simulating the dynamic and 'visual' flight environment for AACS components in the lab.

A maintenance model for k-out-of-n subsystems aboard a fleet of advanced commercial aircraft

NASA Technical Reports Server (NTRS)

Miller, D. R.

1978-01-01

Proposed highly reliable fault-tolerant reconfigurable digital control systems for a future generation of commercial aircraft consist of several k-out-of-n subsystems. Each of these flight-critical subsystems will consist of n identical components, k of which must be functioning properly in order for the aircraft to be dispatched. Failed components are recoverable; they are repaired in a shop. Spares are inventoried at a main base where they may be substituted for failed components on planes during layovers. Penalties are assessed when failure of a k-out-of-n subsystem causes a dispatch cancellation or delay. A maintenance model for a fleet of aircraft with such control systems is presented. The goals are to demonstrate economic feasibility and to optimize.

The brain's default network: anatomy, function, and relevance to disease.

PubMed

Buckner, Randy L; Andrews-Hanna, Jessica R; Schacter, Daniel L

2008-03-01

Thirty years of brain imaging research has converged to define the brain's default network-a novel and only recently appreciated brain system that participates in internal modes of cognition. Here we synthesize past observations to provide strong evidence that the default network is a specific, anatomically defined brain system preferentially active when individuals are not focused on the external environment. Analysis of connectional anatomy in the monkey supports the presence of an interconnected brain system. Providing insight into function, the default network is active when individuals are engaged in internally focused tasks including autobiographical memory retrieval, envisioning the future, and conceiving the perspectives of others. Probing the functional anatomy of the network in detail reveals that it is best understood as multiple interacting subsystems. The medial temporal lobe subsystem provides information from prior experiences in the form of memories and associations that are the building blocks of mental simulation. The medial prefrontal subsystem facilitates the flexible use of this information during the construction of self-relevant mental simulations. These two subsystems converge on important nodes of integration including the posterior cingulate cortex. The implications of these functional and anatomical observations are discussed in relation to possible adaptive roles of the default network for using past experiences to plan for the future, navigate social interactions, and maximize the utility of moments when we are not otherwise engaged by the external world. We conclude by discussing the relevance of the default network for understanding mental disorders including autism, schizophrenia, and Alzheimer's disease.

Emergence of Landauer transport from quantum dynamics: A model Hamiltonian approach

NASA Astrophysics Data System (ADS)

Pal, Partha Pratim; Ramakrishna, S.; Seideman, Tamar

2018-04-01

The Landauer expression for computing current-voltage characteristics in nanoscale devices is efficient but not suited to transient phenomena and a time-dependent current because it is applicable only when the charge carriers transition into a steady flux after an external perturbation. In this article, we construct a very general expression for time-dependent current in an electrode-molecule-electrode arrangement. Utilizing a model Hamiltonian (consisting of the subsystem energy levels and their electronic coupling terms), we propagate the Schrödinger wave function equation to numerically compute the time-dependent population in the individual subsystems. The current in each electrode (defined in terms of the rate of change of the corresponding population) has two components, one due to the charges originating from the same electrode and the other due to the charges initially residing at the other electrode. We derive an analytical expression for the first component and illustrate that it agrees reasonably with its numerical counterpart at early times. Exploiting the unitary evolution of a wavefunction, we construct a more general Landauer style formula and illustrate the emergence of Landauer transport from our simulations without the assumption of time-independent charge flow. Our generalized Landauer formula is valid at all times for models beyond the wide-band limit, non-uniform electrode density of states and for time and energy-dependent electronic coupling between the subsystems. Subsequently, we investigate the ingredients in our model that regulate the onset time scale of this steady state. We compare the performance of our general current expression with the Landauer current for time-dependent electronic coupling. Finally, we comment on the applicability of the Landauer formula to compute hot-electron current arising upon plasmon decoherence.

Emergence of Landauer transport from quantum dynamics: A model Hamiltonian approach.

PubMed

Pal, Partha Pratim; Ramakrishna, S; Seideman, Tamar

2018-04-14

The Landauer expression for computing current-voltage characteristics in nanoscale devices is efficient but not suited to transient phenomena and a time-dependent current because it is applicable only when the charge carriers transition into a steady flux after an external perturbation. In this article, we construct a very general expression for time-dependent current in an electrode-molecule-electrode arrangement. Utilizing a model Hamiltonian (consisting of the subsystem energy levels and their electronic coupling terms), we propagate the Schrödinger wave function equation to numerically compute the time-dependent population in the individual subsystems. The current in each electrode (defined in terms of the rate of change of the corresponding population) has two components, one due to the charges originating from the same electrode and the other due to the charges initially residing at the other electrode. We derive an analytical expression for the first component and illustrate that it agrees reasonably with its numerical counterpart at early times. Exploiting the unitary evolution of a wavefunction, we construct a more general Landauer style formula and illustrate the emergence of Landauer transport from our simulations without the assumption of time-independent charge flow. Our generalized Landauer formula is valid at all times for models beyond the wide-band limit, non-uniform electrode density of states and for time and energy-dependent electronic coupling between the subsystems. Subsequently, we investigate the ingredients in our model that regulate the onset time scale of this steady state. We compare the performance of our general current expression with the Landauer current for time-dependent electronic coupling. Finally, we comment on the applicability of the Landauer formula to compute hot-electron current arising upon plasmon decoherence.

A contour for the entanglement entropies in harmonic lattices

NASA Astrophysics Data System (ADS)

Coser, Andrea; De Nobili, Cristiano; Tonni, Erik

2017-08-01

We construct a contour function for the entanglement entropies in generic harmonic lattices. In one spatial dimension, numerical analysis are performed by considering harmonic chains with either periodic or Dirichlet boundary conditions. In the massless regime and for some configurations where the subsystem is a single interval, the numerical results for the contour function are compared to the inverse of the local weight function which multiplies the energy-momentum tensor in the corresponding entanglement hamiltonian, found through conformal field theory methods, and a good agreement is observed. A numerical analysis of the contour function for the entanglement entropy is performed also in a massless harmonic chain for a subsystem made by two disjoint intervals.

Effect of Bilateral Stimulation of the Subthalamic Nucleus on Different Speech Subsystems in Patients with Parkinson's Disease

ERIC Educational Resources Information Center

Putzer, Manfred; Barry, William J.; Moringlane, Jean Richard

2008-01-01

The effect of deep brain stimulation on the two speech-production subsystems, articulation and phonation, of nine Parkinsonian patients is examined. Production parameters (stop closure voicing; stop closure, VOT, vowel) in fast syllable-repetitions were defined and measured and quantitative, objective metrics of vocal fold function were obtained…

A hierarchically distributed architecture for fault isolation expert systems on the space station

NASA Technical Reports Server (NTRS)

Miksell, Steve; Coffer, Sue

1987-01-01

The Space Station Axiomatic Fault Isolating Expert Systems (SAFTIES) system deals with the hierarchical distribution of control and knowledge among independent expert systems doing fault isolation and scheduling of Space Station subsystems. On its lower level, fault isolation is performed on individual subsystems. These fault isolation expert systems contain knowledge about the performance requirements of their particular subsystem and corrective procedures which may be involved in repsonse to certain performance errors. They can control the functions of equipment in their system and coordinate system task schedules. On a higher level, the Executive contains knowledge of all resources, task schedules for all systems, and the relative priority of all resources and tasks. The executive can override any subsystem task schedule in order to resolve use conflicts or resolve errors that require resources from multiple subsystems. Interprocessor communication is implemented using the SAFTIES Communications Interface (SCI). The SCI is an application layer protocol which supports the SAFTIES distributed multi-level architecture.

Stability analysis of switched cellular neural networks: A mode-dependent average dwell time approach.

PubMed

Huang, Chuangxia; Cao, Jie; Cao, Jinde

2016-10-01

This paper addresses the exponential stability of switched cellular neural networks by using the mode-dependent average dwell time (MDADT) approach. This method is quite different from the traditional average dwell time (ADT) method in permitting each subsystem to have its own average dwell time. Detailed investigations have been carried out for two cases. One is that all subsystems are stable and the other is that stable subsystems coexist with unstable subsystems. By employing Lyapunov functionals, linear matrix inequalities (LMIs), Jessen-type inequality, Wirtinger-based inequality, reciprocally convex approach, we derived some novel and less conservative conditions on exponential stability of the networks. Comparing to ADT, the proposed MDADT show that the minimal dwell time of each subsystem is smaller and the switched system stabilizes faster. The obtained results extend and improve some existing ones. Moreover, the validness and effectiveness of these results are demonstrated through numerical simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

International Space Station Active Thermal Control Sub-System On-Orbit Pump Performance and Reliability Using Liquid Ammonia as a Coolant

NASA Technical Reports Server (NTRS)

Morton, Richard D.; Jurick, Matthew; Roman, Ruben; Adamson, Gary; Bui, Chinh T.; Laliberte, Yvon J.

2011-01-01

The International Space Station (ISS) contains two Active Thermal Control Sub-systems (ATCS) that function by using a liquid ammonia cooling system collecting waste heat and rejecting it using radiators. These subsystems consist of a number of heat exchangers, cold plates, radiators, the Pump and Flow Control Subassembly (PFCS), and the Pump Module (PM), all of which are Orbital Replaceable Units (ORU's). The PFCS provides the motive force to circulate the ammonia coolant in the Photovoltaic Thermal Control Subsystem (PVTCS) and has been in operation since December, 2000. The Pump Module (PM) circulates liquid ammonia coolant within the External Active Thermal Control Subsystem (EATCS) cooling the ISS internal coolant (water) loops collecting waste heat and rejecting it through the ISS radiators. These PM loops have been in operation since December, 2006. This paper will discuss the original reliability analysis approach of the PFCS and Pump Module, comparing them against the current operational performance data for the ISS External Thermal Control Loops.

Optical mass memory investigation

NASA Technical Reports Server (NTRS)

1980-01-01

The MASTER 1 optical mass storage system advanced working model (AWM) was designed to demonstrate recording and playback of imagery data and to enable quantitative data to be derived as to the statistical distribution of raw errors experienced through the system. The AWM consists of two subsystems, the recorder and storage and retrieval. The recorder subsystem utilizes key technologies such as an acoustic travelling wave lens to achieve recording of digital data on fiche at a rate of 30 Mbits/sec, whereas the storage and retrieval reproducer subsystem utilizes a less complex optical system that employs an acousto-optical beam deflector to achieve data readout at a 5 Mbits/sec rate. The system has the built in capability for detecting and collecting error statistics. The recorder and storage and retrieval subsystems operate independent of one another and are each constructed in modular form with each module performing independent functions. The operation of each module and its interface to other modules is controlled by one controller for both subsystems.

An expert systems approach to automated fault management in a regenerative life support subsystem

NASA Technical Reports Server (NTRS)

Malin, J. T.; Lance, N., Jr.

1986-01-01

This paper describes FIXER, a prototype expert system for automated fault management in a regenerative life support subsystem typical of Space Station applications. The development project provided an evaluation of the use of expert systems technology to enhance controller functions in space subsystems. The software development approach permitted evaluation of the effectiveness of direct involvement of the expert in design and development. The approach also permitted intensive observation of the knowledge and methods of the expert. This paper describes the development of the prototype expert system and presents results of the evaluation.

Guidance, navigation, and control subsystem for the EOS-AM spacecraft

NASA Technical Reports Server (NTRS)

Linder, David M.; Tolek, Joseph T.; Lombardo, John

1992-01-01

This paper presents the preliminary design of the Guidance, Navigation, and Control (GN&C) subsystem for the EOS-AM spacecraft and specifically focuses on the GN&C Normal Mode design. First, a brief description of the EOS-AM science mission, instruments, and system-level spacecraft design is provided. Next, an overview of the GN&C subsystem functional and performance requirements, hardware, and operating modes is presented. Then, the GN&C Normal Mode attitude determination, attitude control, and navigation systems are detailed. Finally, descriptions of the spacecraft's overall jitter performance and Safe Mode are provided.

Symmetry-Resolved Entanglement in Many-Body Systems.

PubMed

Goldstein, Moshe; Sela, Eran

2018-05-18

Similarly to the system Hamiltonian, a subsystem's reduced density matrix is composed of blocks characterized by symmetry quantum numbers (charge sectors). We present a geometric approach for extracting the contribution of individual charge sectors to the subsystem's entanglement measures within the replica trick method, via threading appropriate conjugate Aharonov-Bohm fluxes through a multisheet Riemann surface. Specializing to the case of 1+1D conformal field theory, we obtain general exact results for the entanglement entropies and spectrum, and apply them to a variety of systems, ranging from free and interacting fermions to spin and parafermion chains, and verify them numerically. We find that the total entanglement entropy, which scales as lnL, is composed of sqrt[lnL] contributions of individual subsystem charge sectors for interacting fermion chains, or even O(L^{0}) contributions when total spin conservation is also accounted for. We also explain how measurements of the contribution to the entanglement from separate charge sectors can be performed experimentally with existing techniques.

Symmetry-Resolved Entanglement in Many-Body Systems

NASA Astrophysics Data System (ADS)

Goldstein, Moshe; Sela, Eran

2018-05-01

Similarly to the system Hamiltonian, a subsystem's reduced density matrix is composed of blocks characterized by symmetry quantum numbers (charge sectors). We present a geometric approach for extracting the contribution of individual charge sectors to the subsystem's entanglement measures within the replica trick method, via threading appropriate conjugate Aharonov-Bohm fluxes through a multisheet Riemann surface. Specializing to the case of 1 +1 D conformal field theory, we obtain general exact results for the entanglement entropies and spectrum, and apply them to a variety of systems, ranging from free and interacting fermions to spin and parafermion chains, and verify them numerically. We find that the total entanglement entropy, which scales as ln L , is composed of √{ln L } contributions of individual subsystem charge sectors for interacting fermion chains, or even O (L0) contributions when total spin conservation is also accounted for. We also explain how measurements of the contribution to the entanglement from separate charge sectors can be performed experimentally with existing techniques.

Computational Model of Population Dynamics Based on the Cell Cycle and Local Interactions

NASA Astrophysics Data System (ADS)

Oprisan, Sorinel Adrian; Oprisan, Ana

2005-03-01

Our study bridges cellular (mesoscopic) level interactions and global population (macroscopic) dynamics of carcinoma. The morphological differences and transitions between well and smooth defined benign tumors and tentacular malignat tumors suggest a theoretical analysis of tumor invasion based on the development of mathematical models exhibiting bifurcations of spatial patterns in the density of tumor cells. Our computational model views the most representative and clinically relevant features of oncogenesis as a fight between two distinct sub-systems: the immune system of the host and the neoplastic system. We implemented the neoplastic sub-system using a three-stage cell cycle: active, dormant, and necrosis. The second considered sub-system consists of cytotoxic active (effector) cells — EC, with a very broad phenotype ranging from NK cells to CTL cells, macrophages, etc. Based on extensive numerical simulations, we correlated the fractal dimensions for carcinoma, which could be obtained from tumor imaging, with the malignat stage. Our computational model was able to also simulate the effects of surgical, chemotherapeutical, and radiotherapeutical treatments.

Space power subsystem automation technology

NASA Technical Reports Server (NTRS)

Graves, J. R. (Compiler)

1982-01-01

The technology issues involved in power subsystem automation and the reasonable objectives to be sought in such a program were discussed. The complexities, uncertainties, and alternatives of power subsystem automation, along with the advantages from both an economic and a technological perspective were considered. Whereas most spacecraft power subsystems now use certain automated functions, the idea of complete autonomy for long periods of time is almost inconceivable. Thus, it seems prudent that the technology program for power subsystem automation be based upon a growth scenario which should provide a structured framework of deliberate steps to enable the evolution of space power subsystems from the current practice of limited autonomy to a greater use of automation with each step being justified on a cost/benefit basis. Each accomplishment should move toward the objectives of decreased requirement for ground control, increased system reliability through onboard management, and ultimately lower energy cost through longer life systems that require fewer resources to operate and maintain. This approach seems well-suited to the evolution of more sophisticated algorithms and eventually perhaps even the use of some sort of artificial intelligence. Multi-hundred kilowatt systems of the future will probably require an advanced level of autonomy if they are to be affordable and manageable.

Automation study for space station subsystems and mission ground support

NASA Technical Reports Server (NTRS)

1985-01-01

An automation concept for the autonomous operation of space station subsystems, i.e., electric power, thermal control, and communications and tracking are discussed. To assure that functions essential for autonomous operations are not neglected, an operations function (systems monitoring and control) is included in the discussion. It is recommended that automated speech recognition and synthesis be considered a basic mode of man/machine interaction for space station command and control, and that the data management system (DMS) and other systems on the space station be designed to accommodate fully automated fault detection, isolation, and recovery within the system monitoring function of the DMS.

Space Generic Open Avionics Architecture (SGOAA): Overview

NASA Technical Reports Server (NTRS)

Wray, Richard B.; Stovall, John R.

1992-01-01

A space generic open avionics architecture created for NASA is described. It will serve as the basis for entities in spacecraft core avionics, capable of being tailored by NASA for future space program avionics ranging from small vehicles such as Moon ascent/descent vehicles to large ones such as Mars transfer vehicles or orbiting stations. The standard consists of: (1) a system architecture; (2) a generic processing hardware architecture; (3) a six class architecture interface model; (4) a system services functional subsystem architectural model; and (5) an operations control functional subsystem architectural model.

Exciter For X-Band Transmitter And Receiver

NASA Technical Reports Server (NTRS)

Johns, Carl E.

1989-01-01

Report describes developmental X-band exciter for X-band uplink subsystem of Deep Space Network. X-band transmitter-exciting signal expected to have fractional frequency stability of 5.2 X 10 to negative 15th power during 1,000-second integration period. Generates coherent test signals for S- and X-band Block III translator of Deep Space Network, Doppler-reference signal for associated Doppler-extractor system, first-local-oscillator signal for associated receiver, and reference signal for associated ranging subsystem. Tests of prototype exciter show controlling and monitoring and internal phase-correcting loops perform according to applicable design criteria. Measurements of stability of frequency and of single-sideband noise spectral density of transmitter-exciting signal made subsequently.

Taxonomic and functional metagenomic profiling of gastrointestinal tract microbiome of the farmed adult turbot (Scophthalmus maximus).

PubMed

Xing, Mengxin; Hou, Zhanhui; Yuan, Jianbo; Liu, Yuan; Qu, Yanmei; Liu, Bin

2013-12-01

Metagenomics combined with 16S rRNA gene sequence analyses was applied to unveil the taxonomic composition and functional diversity of the farmed adult turbot gastrointestinal (GI) microbiome. Proteobacteria and Firmicutes which existed in both GI content and mucus were dominated in the turbot GI microbiome. 16S rRNA gene sequence analyses also indicated that the turbot GI tract may harbor some bacteria which originated from associated seawater. Functional analyses indicated that the clustering-based subsystem and many metabolic subsystems were dominant in the turbot GI metagenome. Compared with other gut metagenomes, quorum sensing and biofilm formation was overabundant in the turbot GI metagenome. Genes associated with quorum sensing and biofilm formation were found in species within Vibrio, including Vibrio vulnificus, Vibrio cholerae and Vibrio parahaemolyticus. In farmed fish gut metagenomes, the stress response and protein folding subsystems were over-represented and several genes concerning antibiotic and heavy metal resistance were also detected. These data suggested that the turbot GI microbiome may be affected by human factors in aquaculture. Additionally, iron acquisition and the metabolism subsystem were more abundant in the turbot GI metagenome when compared with freshwater fish gut metagenome, suggesting that unique metabolic potential may be observed in marine animal GI microbiomes. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Structural modeling and analysis of an effluent treatment process for electroplating--a graph theoretic approach.

PubMed

Kumar, Abhishek; Clement, Shibu; Agrawal, V P

2010-07-15

An attempt is made to address a few ecological and environment issues by developing different structural models for effluent treatment system for electroplating. The effluent treatment system is defined with the help of different subsystems contributing to waste minimization. Hierarchical tree and block diagram showing all possible interactions among subsystems are proposed. These non-mathematical diagrams are converted into mathematical models for design improvement, analysis, comparison, storage retrieval and commercially off-the-shelf purchases of different subsystems. This is achieved by developing graph theoretic model, matrix models and variable permanent function model. Analysis is carried out by permanent function, hierarchical tree and block diagram methods. Storage and retrieval is done using matrix models. The methodology is illustrated with the help of an example. Benefits to the electroplaters/end user are identified. 2010 Elsevier B.V. All rights reserved.

Development of the Space Station Freedom Environmental Health System

NASA Technical Reports Server (NTRS)

Richard, Elizabeth E.; Russo, Dane

1990-01-01

The Environmental Health System (EHS), a subsystem of the Space Station Freedom (SSF) Crew Health Care System, was established to ensure that crewmembers will have a safe and healthy environment in which to live and work. EHS is comprised of six subsystems: Microbiology, Toxicology, Water Quality, Radiological Health, Vibroacoustics, and Barothermal Physiology. Each subsystem contributes to the overall functions of the EHS including environmental planning, environmental monitoring, environmental monitoring, environmental health assessments, and operations support. The EHS will provide hardware for monitoring the air, water, and internal surfaces of Freedom, including capabilities for inflight sample collection, processing, and analysis. The closed environment of SSF, and its dependence on recycled air and water, will necessitate a reliable monitoring system to alert crewmembers if contamination levels exceed the maximum allowable limits established to ensure crew health and safety. This paper describes the functions and hardware design status of the EHS.

Modular space station detailed preliminary design. Volume 1: Sections 1 through 4.4

NASA Technical Reports Server (NTRS)

1971-01-01

Detailed configuration and subsystems preliminary design data are presented for the modular space station concept. Each module comprising the initial space station is described in terms of its external and internal configuration, its functional responsibilities to the initial cluster, and its orbital build up sequence. Descriptions of the subsequent build up to the growth space station are also presented. Analytical and design techniques, tradeoff considerations, and depth of design detail are discussed for each subsystem. The subsystems include the following: structural/mechanical; crew habitability and protection; experiment support; electrical power; environmental control/life support; guidance, navigation, and control; propulsion; communications; data management; and onboard checkout subsystems. The interfaces between the station and other major elements of the program are summarized. The rational for a zero-gravity station, in lieu of one with artificial-gravity capability, is also summarized.

[Attention and aging].

PubMed

Siéroff, Eric; Piquard, Ambre

2004-12-01

Due to progress in the cognitive theories in the last twenty years, the description of attentional deficits associated with normal or pathological aging has substantially improved. In this article, attentional deficits are presented according to Posner theory, which describes three sub-systems in a global network of attention: vigilance, selective attention, command. This theory not only characterizes the functions of these subsystems, but gives precise indications about their anatomical and neurochemical substrates. Several clinical tests can be described for each of these different subsystems. The main attentional deficits are presented in the second part of this paper: if some decline of the attentional command occurs in normal aging, a real deficit in this subsystem is found in most degenerative processes (frontotemporal dementia, Alzheimer and Parkinson diseases). Alzheimer disease is also frequently associated with a deficit of selective spatial attention, early in the evolution of the disease.

Effect of bilateral stimulation of the subthalamic nucleus on different speech subsystems in patients with Parkinson's disease.

PubMed

Pützer, Manfred; Barry, William J; Moringlane, Jean Richard

2008-12-01

The effect of deep brain stimulation on the two speech-production subsystems, articulation and phonation, of nine Parkinsonian patients is examined. Production parameters (stop closure voicing; stop closure, VOT, vowel) in fast syllable-repetitions were defined and measured and quantitative, objective metrics of vocal fold function were obtained during vowel production. Speech material was recorded for patients (with and without stimulation) and for a reference group of healthy control speakers. With stimulation, precision of the glottal and supraglottal articulation as well as the phonatory function is reduced for some individuals, whereas for other individuals an improvement is observed. Importantly, the improvement or deterioration is determined not only on the basis of the direction of parameter change but also on the individuals' position relative to the healthy control data. This study also notes differences within an individual in the effects of stimulation on the two speech subsystems. These findings qualify the value of global statements about the effect of neurostimulatory operations on Parkinsonian patients. They also underline the importance of careful consideration of individual differences in the effect of deep brain stimulation on different speech subsystems.

Enceladus Plume Density Modeling and Reconstruction for Cassini Attitude Control System

NASA Technical Reports Server (NTRS)

Sarani, Siamak

2010-01-01

In 2005, Cassini detected jets composed mostly of water, spouting from a set of nearly parallel rifts in the crust of Enceladus, an icy moon of Saturn. During an Enceladus flyby, either reaction wheels or attitude control thrusters on the Cassini spacecraft are used to overcome the external torque imparted on Cassini due to Enceladus plume or jets, as well as to slew the spacecraft in order to meet the pointing needs of the on-board science instruments. If the estimated imparted torque is larger than it can be controlled by the reaction wheel control system, thrusters are used to control the spacecraft. Having an engineering model that can predict and simulate the external torque imparted on Cassini spacecraft due to the plume density during all projected low-altitude Enceladus flybys is important. Equally important is being able to reconstruct the plume density after each flyby in order to calibrate the model. This paper describes an engineering model of the Enceladus plume density, as a function of the flyby altitude, developed for the Cassini Attitude and Articulation Control Subsystem, and novel methodologies that use guidance, navigation, and control data to estimate the external torque imparted on the spacecraft due to the Enceladus plume and jets. The plume density is determined accordingly. The methodologies described have already been used to reconstruct the plume density for three low-altitude Enceladus flybys of Cassini in 2008 and will continue to be used on all remaining low-altitude Enceladus flybys in Cassini's extended missions.

TINKTEP: A fully self-consistent, mutually polarizable QM/MM approach based on the AMOEBA force field

NASA Astrophysics Data System (ADS)

Dziedzic, Jacek; Mao, Yuezhi; Shao, Yihan; Ponder, Jay; Head-Gordon, Teresa; Head-Gordon, Martin; Skylaris, Chris-Kriton

2016-09-01

We present a novel quantum mechanical/molecular mechanics (QM/MM) approach in which a quantum subsystem is coupled to a classical subsystem described by the AMOEBA polarizable force field. Our approach permits mutual polarization between the QM and MM subsystems, effected through multipolar electrostatics. Self-consistency is achieved for both the QM and MM subsystems through a total energy minimization scheme. We provide an expression for the Hamiltonian of the coupled QM/MM system, which we minimize using gradient methods. The QM subsystem is described by the onetep linear-scaling DFT approach, which makes use of strictly localized orbitals expressed in a set of periodic sinc basis functions equivalent to plane waves. The MM subsystem is described by the multipolar, polarizable force field AMOEBA, as implemented in tinker. Distributed multipole analysis is used to obtain, on the fly, a classical representation of the QM subsystem in terms of atom-centered multipoles. This auxiliary representation is used for all polarization interactions between QM and MM, allowing us to treat them on the same footing as in AMOEBA. We validate our method in tests of solute-solvent interaction energies, for neutral and charged molecules, demonstrating the simultaneous optimization of the quantum and classical degrees of freedom. Encouragingly, we find that the inclusion of explicit polarization in the MM part of QM/MM improves the agreement with fully QM calculations.

SUPER-FOCUS: a tool for agile functional analysis of shotgun metagenomic data

PubMed Central

Green, Kevin T.; Dutilh, Bas E.; Edwards, Robert A.

2016-01-01

Summary: Analyzing the functional profile of a microbial community from unannotated shotgun sequencing reads is one of the important goals in metagenomics. Functional profiling has valuable applications in biological research because it identifies the abundances of the functional genes of the organisms present in the original sample, answering the question what they can do. Currently, available tools do not scale well with increasing data volumes, which is important because both the number and lengths of the reads produced by sequencing platforms keep increasing. Here, we introduce SUPER-FOCUS, SUbsystems Profile by databasE Reduction using FOCUS, an agile homology-based approach using a reduced reference database to report the subsystems present in metagenomic datasets and profile their abundances. SUPER-FOCUS was tested with over 70 real metagenomes, the results showing that it accurately predicts the subsystems present in the profiled microbial communities, and is up to 1000 times faster than other tools. Availability and implementation: SUPER-FOCUS was implemented in Python, and its source code and the tool website are freely available at https://edwards.sdsu.edu/SUPERFOCUS. Contact: redwards@mail.sdsu.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26454280

SUPER-FOCUS: a tool for agile functional analysis of shotgun metagenomic data.

PubMed

Silva, Genivaldo Gueiros Z; Green, Kevin T; Dutilh, Bas E; Edwards, Robert A

2016-02-01

Analyzing the functional profile of a microbial community from unannotated shotgun sequencing reads is one of the important goals in metagenomics. Functional profiling has valuable applications in biological research because it identifies the abundances of the functional genes of the organisms present in the original sample, answering the question what they can do. Currently, available tools do not scale well with increasing data volumes, which is important because both the number and lengths of the reads produced by sequencing platforms keep increasing. Here, we introduce SUPER-FOCUS, SUbsystems Profile by databasE Reduction using FOCUS, an agile homology-based approach using a reduced reference database to report the subsystems present in metagenomic datasets and profile their abundances. SUPER-FOCUS was tested with over 70 real metagenomes, the results showing that it accurately predicts the subsystems present in the profiled microbial communities, and is up to 1000 times faster than other tools. SUPER-FOCUS was implemented in Python, and its source code and the tool website are freely available at https://edwards.sdsu.edu/SUPERFOCUS. redwards@mail.sdsu.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press.

Systems Modeling to Implement Integrated System Health Management Capability

NASA Technical Reports Server (NTRS)

Figueroa, Jorge F.; Walker, Mark; Morris, Jonathan; Smith, Harvey; Schmalzel, John

2007-01-01

ISHM capability includes: detection of anomalies, diagnosis of causes of anomalies, prediction of future anomalies, and user interfaces that enable integrated awareness (past, present, and future) by users. This is achieved by focused management of data, information and knowledge (DIaK) that will likely be distributed across networks. Management of DIaK implies storage, sharing (timely availability), maintaining, evolving, and processing. Processing of DIaK encapsulates strategies, methodologies, algorithms, etc. focused on achieving high ISHM Functional Capability Level (FCL). High FCL means a high degree of success in detecting anomalies, diagnosing causes, predicting future anomalies, and enabling health integrated awareness by the user. A model that enables ISHM capability, and hence, DIaK management, is denominated the ISHM Model of the System (IMS). We describe aspects of the IMS that focus on processing of DIaK. Strategies, methodologies, and algorithms require proper context. We describe an approach to define and use contexts, implementation in an object-oriented software environment (G2), and validation using actual test data from a methane thruster test program at NASA SSC. Context is linked to existence of relationships among elements of a system. For example, the context to use a strategy to detect leak is to identify closed subsystems (e.g. bounded by closed valves and by tanks) that include pressure sensors, and check if the pressure is changing. We call these subsystems Pressurizable Subsystems. If pressure changes are detected, then all members of the closed subsystem become suspect of leakage. In this case, the context is defined by identifying a subsystem that is suitable for applying a strategy. Contexts are defined in many ways. Often, a context is defined by relationships of function (e.g. liquid flow, maintaining pressure, etc.), form (e.g. part of the same component, connected to other components, etc.), or space (e.g. physically close, touching the same common element, etc.). The context might be defined dynamically (if conditions for the context appear and disappear dynamically) or statically. Although this approach is akin to case-based reasoning, we are implementing it using a software environment that embodies tools to define and manage relationships (of any nature) among objects in a very intuitive manner. Context for higher level inferences (that use detected anomalies or events), primarily for diagnosis and prognosis, are related to causal relationships. This is useful to develop root-cause analysis trees showing an event linked to its possible causes and effects. The innovation pertaining to RCA trees encompasses use of previously defined subsystems as well as individual elements in the tree. This approach allows more powerful implementations of RCA capability in object-oriented environments. For example, if a pressurizable subsystem is leaking, its root-cause representation within an RCA tree will show that the cause is that all elements of that subsystem are suspect of leak. Such a tree would apply to all instances of leak-events detected and all elements in all pressurizable subsystems in the system. Example subsystems in our environment to build IMS include: Pressurizable Subsystem, Fluid-Fill Subsystem, Flow-Thru-Valve Subsystem, and Fluid Supply Subsystem. The software environment for IMS is designed to potentially allow definition of any relationship suitable to create a context to achieve ISHM capability.

Reduction of vibration by using mechatronical subsystem

NASA Astrophysics Data System (ADS)

Białas, K.; Buchacz, A.

2015-11-01

The primary aim introduced in this paper is synthesis of mechatronical system understand as planning of this type of systems. Mechatronical system is consisted of fundamental mechanical system and subsystem reducing vibration including electric elements. Fundamental system is received applying reverse task of dynamic (synthesis) and it's including inertial and elastic elements. The subsystem includes electric elements by means moving-coil transducer. The synthesis can also be used to change the already existing systems. Due to the method, introduced in this work, may be performed as early as whilst the designing of future functions. Using this way of designing is support for designers of mechanical systems with active reducing of vibrations.

The Assessment of Preterm Infants' Behavior (APIB): Furthering the Understanding and Measurement of Neurodevelopmental Competence in Preterm and Full-Term Infants

PubMed Central

Als, Heidelise; Butler, Samantha; Kosta, Sandra; McAnulty, Gloria

2014-01-01

The Assessment of Preterm Infants' Behavior (APIB) is a newborn neurobehavioral assessment appropriate for preterm, at risk, and full-term newborns, from birth to 1 month after expected due date. The APIB is based in ethological–evolutionary thought and focuses on the assessment of mutually interacting behavioral subsystems in simultaneous interaction with the environment. The subsystems of functioning assessed include the autonomic (respiration, digestion, color), motor (tone, movement, postures), state organization (range, robustness, transition patterns), attention (robustness, transitions), and self-regulation (effort, success) systems as well as the degree of facilitation required to support reorganization and subsystem balance. The environment is represented by a sequence of distal, proximal, tactile, and vestibular challenges, derived from the BNBAS. The APIB conceptualizes infant competence as the degree of differentiation of subsystem function and degree of modulation of subsystem balance at any stage in infant development. Infants are understood as actively seeking their next differentiation, while counting on good enough environments to assure progressing developmental competence. In the case of interference such as premature birth, the mismatch of expectation and actual experience causes misalignment, which may become developmentally costly. The assessment is a finely tuned dialogue between examiner and infant, which requires training, skill and self-knowledge. The APIB has well established inter-rater-reliability, concurrent and construct validity, and is clinically relevant for behavioral intervention and individually appropriate and supportive care. PMID:15856436

Cellular and subcellular structure of anterior sensory pathways in Phestilla sibogae (Gastropoda, Nudibranchia).

PubMed

Boudko, D Y; Switzer-Dunlap, M; Hadfield, M G

1999-01-05

Two sensory-cell types, subepithelial sensory cells (SSCs) and intraepithelial sensory cells (ISCs), were identified in the anterior sensory organs (ASO: pairs of rhinophores and oral tentacles, and the anterior field formed by the oral plate and cephalic shield) of the nudibranch Phestilla sibogae after filling through anterior nerves with the neuronal tracers biocytin and Lucifer Yellow. A third type of sensory cells, with subepithelial somata and tufts of stiff-cilia (TSCs, presumably rheoreceptors), was identified after uptake of the mitochondrial dye DASPEI. Each sensory-cell type has a specific spatial distribution in the ASO. The highest density of ISCs is in the oral tentacles (approximately 1,200/mm2), SSCs in the middle parts of the rhinophores (>4,000/mm2), and TSCs in the tips of cephalic tentacles (100/mm2). These morphologic data, together with electrophysiologic evidence for greater chemical sensitivity of the rhinophores than the oral tentacles (Murphy and Hadfield [1997] Comp. Biochem. Physiol. 118A:727-735; Boudko et al. [1997] Soc. Neurosci. Abstr. 23:1787), led us to conclude that the two pairs of chemosensory tentacles serve different chemosensory functions in P. sibogae; i.e., ISCs and the oral tentacles serve contact- or short-distance chemoreception, and SSCs and the rhinophores function for long-distance chemoreception or olfaction. If this is true, then the ISC subsystem probably represents an earlier stage in the evolution and adaptations of gastropod chemosensory biology, whereas among the opisthobranchs, the SSC subsystem evolved with the rhinophores from ancestral cephalaspidean opisthobranchs.

Assessing degrees of entanglement of phonon states in atomic Bose gases through the measurement of commuting observables

NASA Astrophysics Data System (ADS)

Robertson, Scott; Michel, Florent; Parentani, Renaud

2017-08-01

We show that measuring commuting observables can be sufficient to assess that a bipartite state is entangled according to either nonseparability or the stronger criterion of "steerability." Indeed, the measurement of a single observable might reveal the strength of the interferences between the two subsystems, as if an interferometer were used. For definiteness, we focus on the two-point correlation function of density fluctuations obtained by in situ measurements in homogeneous one-dimensional cold atomic Bose gases. We then compare this situation to that found in transonic stationary flows mimicking a black hole geometry where correlated phonon pairs are emitted on either side of the sonic horizon by the analogue Hawking effect. We briefly apply our considerations to two recent experiments.

Mobility power flow analysis of an L-shaped plate structure subjected to distributed loading

NASA Technical Reports Server (NTRS)

Cuschieri, J. M.; Cimmerman, B.

1990-01-01

An analytical investigation based in the Mobility Power Flow (MPF) method is presented for the determination of the vibrational response and power flow for two coupled flat plate structures in an L-shaped configuration, subjected to distributed excitation. The principle of the MPF method consists of dividing the global structure into a series of subsystems coupled together using mobility functions. Each separate subsystem is analyzed independently to determine the structural mobility functions for the junction and excitation locations. The mobility functions, together with the characteristics of the junction between the subsystems, are then used to determine the response of the global structure and the MPF. In the considered coupled plate structure, MPF expressions are derived for distributed mechanical excitation which is independent of the structure response. However using a similar approach with some modifications excitation by an acoustic plane wave can be considered. Some modifications are required to deal with the latter case are necessary because the forces (acoustic pressure) acting on the structure are dependent on the response of the structure due to the presence of the scattered pressure.

A methodology for rapid vehicle scaling and configuration space exploration

NASA Astrophysics Data System (ADS)

Balaba, Davis

2009-12-01

The Configuration-space Exploration and Scaling Methodology (CESM) entails the representation of component or sub-system geometries as matrices of points in 3D space. These typically large matrices are reduced using minimal convex sets or convex hulls. This reduction leads to significant gains in collision detection speed at minimal approximation expense. (The Gilbert-Johnson-Keerthi algorithm [79] is used for collision detection purposes in this methodology.) Once the components are laid out, their collective convex hull (from here on out referred to as the super-hull) is used to approximate the inner mold line of the minimum enclosing envelope of the vehicle concept. A sectional slicing algorithm is used to extract the sectional dimensions of this envelope. An offset is added to these dimensions in order to come up with the sectional fuselage dimensions. Once the lift and control surfaces are added, vehicle level objective functions can be evaluated and compared to other designs. The size of the design space coupled with the fact that some key constraints such as the number of collisions are discontinuous, dictate that a domain-spanning optimization routine be used. Also, as this is a conceptual design tool, the goal is to provide the designer with a diverse baseline geometry space from which to chose. For these reasons, a domain-spanning algorithm with counter-measures against speciation and genetic drift is the recommended optimization approach. The Non-dominated Sorting Genetic Algorithm (NSGA-II) [60] is shown to work well for the proof of concept study. There are two major reasons why the need to evaluate higher fidelity, custom geometric scaling laws became a part of this body of work. First of all, historical-data based regressions become implicitly unreliable when the vehicle concept in question is designed around a disruptive technology. Second, it was shown that simpler approaches such as photographic scaling can result in highly suboptimal concepts even for very small scaling factors. Yet good scaling information is critical to the success of any conceptual design process. In the CESM methodology, it is assumed that the new technology has matured enough to permit the prediction of the scaling behavior of the various subsystems in response to requirement changes. Updated subsystem geometry data is generated by applying the new requirement settings to the affected subsystems. All collisions are then eliminated using the NSGA-II algorithm. This is done while minimizing the adverse impact on the vehicle packing density. Once all collisions are eliminated, the vehicle geometry is reconstructed and system level data such as fuselage volume can be harvested. This process is repeated for all requirement settings. Dimensional analysis and regression can be carried out using this data and all other pertinent metrics in the manner described by Mendez [124] and Segel [173]. The dominant parameters for each response show up as in the dimensionally consistent groups that form the independent variables. More importantly the impact of changes in any of these variables on system level dependent variables can be easily and rapidly evaluated. In this way, the conceptual design process can be accelerated without sacrificing analysis accuracy. Scaling laws for take-off gross weight and fuselage volume as functions of fuel cell specific power and power density for a notional General Aviation vehicle are derived for the proof of concept. CESM enables the designer to maintain design freedom by portably carrying multiple designs deeper into the design process. Also since CESM is a bottom-up approach, all proposed baseline concepts are implicitly volumetrically feasible. System level geometry parameters become fall-outs as opposed to inputs. This is a critical attribute as, without the benefit of experience, a designer would be hard pressed to set the appropriate ranges for such parameters for a vehicle built around a disruptive technology. Furthermore, scaling laws generated from custom data for each concept are subject to less design noise than say, regression based approaches. Through these laws, key physics-based characteristics of vehicle subsystems such as energy density can be mapped onto key system level metrics such as fuselage volume or take-off gross weight. These laws can then substitute some historical-data based analyses thereby improving the fidelity of the analyses and reducing design time. (Abstract shortened by UMI.)

USAF (United States Air Force) Avionics Master Plan.

DTIC Science & Technology

1982-12-01

is updated annually by MAPG activities to reflect changes in emphasis resulting from new direction, threat developments , and other armament and...many different kinds of functional electronic subsystems, a building block approach to the development of new subsystems can be taken. This approach...technologies targeted for precision all weather weapon delivery. A new program will develop the capability to detect and locate ground moving targets not

The 10 micrometer transmitter

NASA Technical Reports Server (NTRS)

1976-01-01

The design, fabrication tests, and engineering model components of a 10.6 mum wideband transceiver system are reported. The effort emphasized the transmitter subsystem, including the development of the laser, the modulator driver, and included productization of both the transmitter and local oscillator lasers. The transmitter subsystem is functionally compatible with the receiver engineering model terminal, and has undergone high data rate communication system testing against that terminal.

Regional Sustainable Development Analysis Based on Information Entropy—Sichuan Province as an Example

PubMed Central

Liang, Xuedong; Si, Dongyang; Zhang, Xinli

2017-01-01

According to the implementation of a scientific development perspective, sustainable development needs to consider regional development, economic and social development, and the harmonious development of society and nature, but regional sustainable development is often difficult to quantify. Through an analysis of the structure and functions of a regional system, this paper establishes an evaluation index system, which includes an economic subsystem, an ecological environmental subsystem and a social subsystem, to study regional sustainable development capacity. A sustainable development capacity measure model for Sichuan Province was established by applying the information entropy calculation principle and the Brusselator principle. Each subsystem and entropy change in a calendar year in Sichuan Province were analyzed to evaluate Sichuan Province’s sustainable development capacity. It was found that the established model could effectively show actual changes in sustainable development levels through the entropy change reaction system, at the same time this model could clearly demonstrate how those forty-six indicators from the three subsystems impact on the regional sustainable development, which could make up for the lack of sustainable development research. PMID:29027982

Regional Sustainable Development Analysis Based on Information Entropy-Sichuan Province as an Example.

PubMed

Liang, Xuedong; Si, Dongyang; Zhang, Xinli

2017-10-13

According to the implementation of a scientific development perspective, sustainable development needs to consider regional development, economic and social development, and the harmonious development of society and nature, but regional sustainable development is often difficult to quantify. Through an analysis of the structure and functions of a regional system, this paper establishes an evaluation index system, which includes an economic subsystem, an ecological environmental subsystem and a social subsystem, to study regional sustainable development capacity. A sustainable development capacity measure model for Sichuan Province was established by applying the information entropy calculation principle and the Brusselator principle. Each subsystem and entropy change in a calendar year in Sichuan Province were analyzed to evaluate Sichuan Province's sustainable development capacity. It was found that the established model could effectively show actual changes in sustainable development levels through the entropy change reaction system, at the same time this model could clearly demonstrate how those forty-six indicators from the three subsystems impact on the regional sustainable development, which could make up for the lack of sustainable development research.

Development of a light-weight, wind-turbine-rotor-based data acquisition system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berg, D.E.; Rumsey, M.; Robertson, P.

1997-12-01

Wind-energy researchers at Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) are developing a new, light-weight, modular system capable of acquiring long-term, continuous time-series data from current-generation small or large, dynamic wind-turbine rotors. Meetings with wind-turbine research personnel at NREL and SNL resulted in a list of the major requirements that the system must meet. Initial attempts to locate a commercial system that could meet all of these requirements were not successful, but some commercially available data acquisition and radio/modem subsystems that met many of the requirements were identified. A time synchronization subsystem and a programmable logicmore » device subsystem to integrate the functions of the data acquisition, the radio/modem, and the time synchronization subsystems and to communicate with the user have been developed at SNL. This paper presents the data system requirements, describes the four major subsystems comprising the system, summarizes the current status of the system, and presents the current plans for near-term development of hardware and software.« less

ERBE Geographic Scene and Monthly Snow Data

NASA Technical Reports Server (NTRS)

Coleman, Lisa H.; Flug, Beth T.; Gupta, Shalini; Kizer, Edward A.; Robbins, John L.

1997-01-01

The Earth Radiation Budget Experiment (ERBE) is a multisatellite system designed to measure the Earth's radiation budget. The ERBE data processing system consists of several software packages or sub-systems, each designed to perform a particular task. The primary task of the Inversion Subsystem is to reduce satellite altitude radiances to fluxes at the top of the Earth's atmosphere. To accomplish this, angular distribution models (ADM's) are required. These ADM's are a function of viewing and solar geometry and of the scene type as determined by the ERBE scene identification algorithm which is a part of the Inversion Subsystem. The Inversion Subsystem utilizes 12 scene types which are determined by the ERBE scene identification algorithm. The scene type is found by combining the most probable cloud cover, which is determined statistically by the scene identification algorithm, with the underlying geographic scene type. This Contractor Report describes how the geographic scene type is determined on a monthly basis.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report, METSAT (S/N:107) AMSU-A1 Receiver Assemblies: P/N 1356429-1, S/N:F04, P/N 1356409-1,S/N F04

NASA Technical Reports Server (NTRS)

Pines, D.

1999-01-01

This is the Performance Verification Report, METSAT (S/N: 107) AMSU-A1 Receiver Assemblies, P/N 1356429-1, SIN: F04, P/N 1356409- 1, S/N: F04, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The AMSU-A receiver subsystem comprises two separated receiver assemblies; AMSU-A1 and AMSU-A2 (P/N 1356441-1). The AMSU-A1 receiver contains 13 channels and the AMSU-A2 receiver 2 channels. The AMSU-A receiver assembly is further divided into two parts; AMSU-A I - I (P/N 13 5 6429- 1) and AMSU-A 1 -2 (P/N 1356409-1), which contain 9 and 4 channels, respectively. The AMSU-A receiver subsystem is located in between the antenna and signal processing subsystems of the AMSU-A instrument and comprises the RF and IF components from isolators to attenuators. It receives the RF signals from the antenna subsystem, down-converts the RF signals to IF signals, amplifies and defines the IF signals to proper power level and frequency bandwidth as specified for each channel, and inputs the IF signals to the signal processing subsystem. The test reports for the METSAT AMSU-A receiver subsystem are prepared separately for Al and A2 receivers so that each receiver stands alone during integration of instruments into the spacecraft. This test report presents the test data of the N4ETSAT AMSU-A1 Flight Model No. 4 (FM-4) receiver subsystem. The tests are performed per the Acceptance Test Procedure (ATP) for the AMSU-A Receiver Subsystem, AE-26002/6A. The functional performance tests are conducted either at the component or subsystem level. While the component-level tests are performed over the entire operating temperature range predicted by thermal analysis, most subsystem-level tests are conducted at ambient temperature only. Key performances (bandpass characteristics and noise figure) of the receiver subsystem are verified over the operating temperature.

Controller for the Electronically Scanned Thinned Array Radiometer (ESTAR) instrument

NASA Technical Reports Server (NTRS)

Zomberg, Brian G.; Chren, William A., Jr.

1994-01-01

A prototype controller for the ESTAR (electronically scanned thinned array radiometer) instrument has been designed and tested. It manages the operation of the digital data subsystem (DDS) and its communication with the Small Explorer data system (SEDS). Among the data processing tasks that it coordinates are FEM data acquisition, noise removal, phase alignment and correlation. Its control functions include instrument calibration and testing of two critical subsystems, the output data formatter and Walsh function generator. It is implemented in a Xilinx XC3064PC84-100 field programmable gate array (FPGA) and has a maximum clocking frequency of 10 MHz.

Experiment Pointing Subsystems (EPS) requirements for Spacelab missions

NASA Technical Reports Server (NTRS)

Nein, M. E.; Nicaise, P. D.

1975-01-01

The goal of the experiment pointing subsystems (EPS) is to accommodate a broad spectrum of instrument types by providing a number of stability and control functions that greatly exceed the capability of the shuttle. These functions include target acquisition, target tracking through wide gimbal ranges, stabilization, simultaneous pointing to one or more targets, instrument rastering, and on-orbit calibration. The experiments will vary widely in size, weight, geometry, and instrument types, and many have not been completely defined. This great diversity of requirements reflects the long term plans of the user community and establishes challenging performance requirements for the EPS.

Fluids Density Functional Theory of Salt-Doped Block Copolymers

NASA Astrophysics Data System (ADS)

Brown, Jonathan R.; Hall, Lisa M.

Block copolymers have attracted a great deal of recent interest as potential non-flammable, solid-state, electrolyte materials for batteries or other charge carrying applications. The microphase separation in block copolymers combines the properties of a conductive (though mechanically soft) polymer with a mechanically robust (though non-conductive) polymer. We use fluids density functional theory (fDFT) to study the phase behavior of salt-doped block copolymers. Because the salt prefers to preferentially solvate into the conductive phase, salt doping effectively enhances the segregation strength between the two polymer types. We consider the effects of this preferential solvation and of charge correlations by separately modeling the ion-rich phase, without bonding, using the Ornstein-Zernike equation and the hypernetted-chain closure. We use the correlations from this subsystem in the inhomogeneous fDFT calculations. Initial addition of salt increases the domain spacing and sharpens the interfacial region, but for high salt loadings the interface can broaden. Addition of salt can also drive a system with a low copolymer segregation strength to order by first passing through a two phase regime with a salt-rich ordered phase and a salt-poor disordered phase. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award Number DE-SC0014209.

Early experiences building a software quality prediction model

NASA Technical Reports Server (NTRS)

Agresti, W. W.; Evanco, W. M.; Smith, M. C.

1990-01-01

Early experiences building a software quality prediction model are discussed. The overall research objective is to establish a capability to project a software system's quality from an analysis of its design. The technical approach is to build multivariate models for estimating reliability and maintainability. Data from 21 Ada subsystems were analyzed to test hypotheses about various design structures leading to failure-prone or unmaintainable systems. Current design variables highlight the interconnectivity and visibility of compilation units. Other model variables provide for the effects of reusability and software changes. Reported results are preliminary because additional project data is being obtained and new hypotheses are being developed and tested. Current multivariate regression models are encouraging, explaining 60 to 80 percent of the variation in error density of the subsystems.

Assessing and Promoting Functional Resilience in Flight Crews During Exploration Missions

NASA Technical Reports Server (NTRS)

Shelhamer, M.

2015-01-01

The NASA Human Research Program works to mitigate risks to health and performance on extended missions. However, research should be directed not only to mitigating known risks, but also to providing crews with tools to assess and enhance resilience, as a group and individually. We can draw on ideas from complexity theory to assess resilience. The entire crew or the individual crewmember can be viewed as a complex system composed of subsystems; the interactions between subsystems are of crucial importance. Understanding the interactions can provide important information even in the absence of complete information on the component subsystems. Enabled by advances in noninvasive measurement of physiological and behavioral parameters, subsystem monitoring can be implemented within a mission and during training to establish baselines. Coupled with mathematical modeling, this can provide assessment of health and function. Since the web of physiological systems (and crewmembers) can be interpreted as a network in mathematical terms, we can draw on recent work that relates the structure of such networks to their resilience (ability to self-organize in the face of perturbation). Some of the many parameters and interactions to choose from include: sleep cycles, coordination of work and meal times, cardiorespiratory rhythms, circadian rhythms and body temperature, stress markers and cognition, sleep and performance, immune function and nutritional status. Tools for resilience are then the means to measure and analyze these parameters, incorporate them into models of normal variability and interconnectedness, and recognize when parameters or their couplings are outside of normal limits.

System integration of RF based negative ion experimental facility at IPR

NASA Astrophysics Data System (ADS)

Bansal, G.; Bandyopadhyay, M.; Singh, M. J.; Gahlaut, A.; Soni, J.; Pandya, K.; Parmar, K. G.; Sonara, J.; Chakraborty, A.

2010-02-01

The setting up of RF based negative ion experimental facility shall witness the beginning of experiments on the negative ion source fusion applications in India. A 1 MHz RF generator shall launch 100 kW RF power into a single driver on the plasma source to produce a plasma of density ~5 × 1012 cm-3. The source can deliver a negative ion beam of ~10 A with a current density of ~30 mA/cm2 and accelerated to 35 kV through an electrostatic ion accelerator. The experimental system is similar to a RF based negative ion source, BATMAN, presently operating at IPP. The subsystems for source operation are designed and procured principally from indigenous resources, keeping the IPP configuration as a base line. The operation of negative ion source is supported by many subsystems e.g. vacuum pumping system with gate valves, cooling water system, gas feed system, cesium delivery system, RF generator, high voltage power supplies, data acquisition and control system, and different diagnostics. The first experiments of negative ion source are expected to start at IPR from the middle of 2009.

Development of an advanced static feed water electrolysis module. [for spacecraft

NASA Technical Reports Server (NTRS)

Schubert, F. H.; Wynveen, R. A.; Jensen, F. C.; Quattrone, P. D.

1975-01-01

A Static Feed Water Electrolysis Module (SFWEM) was developed to produce 0.92 kg/day (2.0 lb/day) of oxygen (O2). Specific objectives of the program's scope were to (1) eliminate the need for feed water cavity degassing, (2) eliminate the need for subsystem condenser/separators, (3) increase current density capability while decreasing electrolysis cell power (i.e., cell voltage) requirements, and (4) eliminate subsystem rotating parts and incorporate control and monitor instrumentation. A six-cell, one-man capacity module having an active area of 0.00929 sq m (0.10 sq ft) per cell was designed, fabricated, assembled, and subjected to 111 days (2664 hr) of parametric and endurance testing. The SFWEM was successfully operated over a current density range of 0 to 1076 mA/sq cm (0 to 1000 ASF), pressures of ambient to 2067 kN/sq m (300 psia), and temperatures of ambient to 366 K (200 F). During a 94-day endurance test, the SFWEM successfully demonstrated operation without the need for feed water compartment degassing.

Neuropathophysiology of functional gastrointestinal disorders

PubMed Central

Wood, Jackie D

2007-01-01

The investigative evidence and emerging concepts in neurogastroenterology implicate dysfunctions at the levels of the enteric and central nervous systems as underlying causes of the prominent symptoms of many of the functional gastrointestinal disorders. Neurogastroenterological research aims for improved understanding of the physiology and pathophysiology of the digestive subsystems from which the arrays of functional symptoms emerge. The key subsystems for defecation-related symptoms and visceral hyper-sensitivity are the intestinal secretory glands, the musculature and the nervous system that controls and integrates their activity. Abdominal pain and discomfort arising from these systems adds the dimension of sensory neurophysiology. This review details current concepts for the underlying pathophysiology in terms of the physiology of intestinal secretion, motility, nervous control, sensing function, immuno-neural communication and the brain-gut axis. PMID:17457962

Effect of one-step recrystallization on the grain boundary evolution of CoCrFeMnNi high entropy alloy and its subsystems.

PubMed

Chen, Bo-Ru; Yeh, An-Chou; Yeh, Jien-Wei

2016-02-29

In this study, the grain boundary evolution of equiatomic CoCrFeMnNi, CoCrFeNi, and FeCoNi alloys after one-step recrystallization were investigated. The special boundary fraction and twin density of these alloys were evaluated by electron backscatter diffraction analysis. Among the three alloys tested, FeCoNi exhibited the highest special boundary fraction and twin density after one-step recrystallization. The special boundary increment after one-step recrystallization was mainly affected by grain boundary velocity, while twin density was mainly affected by average grain boundary energy and twin boundary energy.

Phase transitions in local equation-of-state approximation and anomalies of spatial charge profiles in non-uniform plasma

NASA Astrophysics Data System (ADS)

Chigvintsev, A. Yu; Zorina, I. G.; Noginova, L. Yu; Iosilevskiy, I. L.

2018-01-01

Impressive appearance of discontinuities in equilibrium spatial charge profiles in non-uniform Coulomb systems is under discussions in wide number of thermoelectrostatics problems. Such discontinuities are considered as peculiar micro-level manifestation of phase transitions and intrinsic macro-level non-ideality effects in local equation of state (EOS), which should be used for description of non-ideal ionic subsystem in frames of local-density (or “pseudofluid”, or “jellium” etc) approximation. Such discontinuities were discussed already by the authors for electronic subsystems. Special emphasis is made in present paper on the mentioned above non-ideality effects in non-uniform ionic subsystems, such as micro-ions profile within screening “cloud” around macro-ion in complex (dusty, colloid etc) plasmas, equilibrium charge profile in ionic traps or (and) in the neighborhood vicinity of “charged wall” etc). Multiphase EOS for simplified ionic model of classical charged hard spheres on uniformly compressible electrostatic compensating background was constructed and several illustrative examples of discussed discontinuous ionic profiles were calculated.

Discrete event simulation and the resultant data storage system response in the operational mission environment of Jupiter-Saturn /Voyager/ spacecraft

NASA Technical Reports Server (NTRS)

Mukhopadhyay, A. K.

1978-01-01

The Data Storage Subsystem Simulator (DSSSIM) simulating (by ground software) occurrence of discrete events in the Voyager mission is described. Functional requirements for Data Storage Subsystems (DSS) simulation are discussed, and discrete event simulation/DSSSIM processing is covered. Four types of outputs associated with a typical DSSSIM run are presented, and DSSSIM limitations and constraints are outlined.

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Yang; Xiao, Jianyuan; Zhang, Ruili

Hamiltonian time integrators for the Vlasov-Maxwell equations are developed by a Hamiltonian splitting technique. The Hamiltonian functional is split into five parts, which produces five exactly solvable subsystems. Each subsystem is a Hamiltonian system equipped with the Morrison-Marsden-Weinstein Poisson bracket. Compositions of the exact solutions provide Poisson structure preserving/Hamiltonian methods of arbitrary high order for the Vlasov-Maxwell equations. They are then accurate and conservative over a long time because of the Poisson-preserving nature.

The National Microbial Pathogen Database Resource (NMPDR): a genomics platform based on subsystem annotation.

PubMed

McNeil, Leslie Klis; Reich, Claudia; Aziz, Ramy K; Bartels, Daniela; Cohoon, Matthew; Disz, Terry; Edwards, Robert A; Gerdes, Svetlana; Hwang, Kaitlyn; Kubal, Michael; Margaryan, Gohar Rem; Meyer, Folker; Mihalo, William; Olsen, Gary J; Olson, Robert; Osterman, Andrei; Paarmann, Daniel; Paczian, Tobias; Parrello, Bruce; Pusch, Gordon D; Rodionov, Dmitry A; Shi, Xinghua; Vassieva, Olga; Vonstein, Veronika; Zagnitko, Olga; Xia, Fangfang; Zinner, Jenifer; Overbeek, Ross; Stevens, Rick

2007-01-01

The National Microbial Pathogen Data Resource (NMPDR) (http://www.nmpdr.org) is a National Institute of Allergy and Infections Disease (NIAID)-funded Bioinformatics Resource Center that supports research in selected Category B pathogens. NMPDR contains the complete genomes of approximately 50 strains of pathogenic bacteria that are the focus of our curators, as well as >400 other genomes that provide a broad context for comparative analysis across the three phylogenetic Domains. NMPDR integrates complete, public genomes with expertly curated biological subsystems to provide the most consistent genome annotations. Subsystems are sets of functional roles related by a biologically meaningful organizing principle, which are built over large collections of genomes; they provide researchers with consistent functional assignments in a biologically structured context. Investigators can browse subsystems and reactions to develop accurate reconstructions of the metabolic networks of any sequenced organism. NMPDR provides a comprehensive bioinformatics platform, with tools and viewers for genome analysis. Results of precomputed gene clustering analyses can be retrieved in tabular or graphic format with one-click tools. NMPDR tools include Signature Genes, which finds the set of genes in common or that differentiates two groups of organisms. Essentiality data collated from genome-wide studies have been curated. Drug target identification and high-throughput, in silico, compound screening are in development.

Bayesian Approach for Reliability Assessment of Sunshield Deployment on JWST

NASA Technical Reports Server (NTRS)

Kaminskiy, Mark P.; Evans, John W.; Gallo, Luis D.

2013-01-01

Deployable subsystems are essential to mission success of most spacecraft. These subsystems enable critical functions including power, communications and thermal control. The loss of any of these functions will generally result in loss of the mission. These subsystems and their components often consist of unique designs and applications, for which various standardized data sources are not applicable for estimating reliability and for assessing risks. In this study, a Bayesian approach for reliability estimation of spacecraft deployment was developed for this purpose. This approach was then applied to the James Webb Space Telescope (JWST) Sunshield subsystem, a unique design intended for thermal control of the observatory's telescope and science instruments. In order to collect the prior information on deployable systems, detailed studies of "heritage information", were conducted extending over 45 years of spacecraft launches. The NASA Goddard Space Flight Center (GSFC) Spacecraft Operational Anomaly and Reporting System (SOARS) data were then used to estimate the parameters of the conjugative beta prior distribution for anomaly and failure occurrence, as the most consistent set of available data and that could be matched to launch histories. This allows for an emperical Bayesian prediction for the risk of an anomaly occurrence of the complex Sunshield deployment, with credibility limits, using prior deployment data and test information.

Design, fabrication, assembly, and test of a liquid hydrogen acquisition subsystem

NASA Technical Reports Server (NTRS)

Blackman, J. B.

1974-01-01

The development of a cryogenic fluid system to supply liquid hydrogen to a turbopump at flowrates up to 7.5 pounds per second for a period of approximately 5 seconds before refill, is discussed. Refill is accomplished in less than 10 seconds, during which a constant flowrate can be maintained to the pumps. Diagrams are provided to show the configuration of the system. Subsystem acceptance and functional tests, including acquisition subsystem expulsion, pressurization, and refill were performed. The tests included: (1) thermodynamic vent system operation, (2) warm-gas pressurization effects, (3) hydraulic pressure surge effects, (4) screen device operational limitations, (5) feedline vapor control, and (6) two-phase refill.

Effect of various features on the life cycle cost of the timing/synchronization subsystem of the DCS digital communications network

NASA Technical Reports Server (NTRS)

Kimsey, D. B.

1978-01-01

The effect on the life cycle cost of the timing subsystem was examined, when these optional features were included in various combinations. The features included mutual control, directed control, double-ended reference links, independence of clock error measurement and correction, phase reference combining, self-organization, smoothing for link and nodal dropouts, unequal reference weightings, and a master in a mutual control network. An overall design of a microprocessor-based timing subsystem was formulated. The microprocessor (8080) implements the digital filter portion of a digital phase locked loop, as well as other control functions such as organization of the network through communication with processors at neighboring nodes.

Analysis of the human operator subsystems

NASA Technical Reports Server (NTRS)

Jones, Lynette A.; Hunter, Ian W.

1991-01-01

Except in low-bandwidth systems, knowledge of the human operator transfer function is essential for high-performance telerobotic systems. This information has usually been derived from detailed analyses of tracking performance, in which the human operator is considered as a complete system rather than as a summation of a number of subsystems, each of which influences the operator's output. Studies of one of these subsystems, the limb mechanics system, demonstrate that large parameter variations can occur that can have a profound effect on the stability of force-reflecting telerobot systems. An objective of this research was to decompose the performance of the human operator system in order to establish how the dynamics of each of the elements influence the operator's responses.

Regenerative Life Support Evaluation

NASA Technical Reports Server (NTRS)

Kleiner, G. N.; Thompson, C. D.

1977-01-01

This paper describes the development plan and design concept of the Regenerative Life Support Evaluation (RLSE) planned for flight testing in the European Space Agency Spacelab. The development plan encompasses the ongoing advanced life support subsystem and a systems integration effort to evolve concurrently subsystem concepts that perform their function and can be integrated with other subsystems in a flight demonstration of a regenerative life support system. The design concept for RLSE comprises water-electrolysis O2 generation, electrochemically depolarized CO2 removal, and Sabatier CO2 reduction for atmosphere regeneration, urine vapor-compression distillation, and wash-water hyperfiltration for waste-water recovery. The flight demonstration by RLSE is an important step in qualifying the regenerative concepts for life support in space stations.

DREISS: Using State-Space Models to Infer the Dynamics of Gene Expression Driven by External and Internal Regulatory Networks.

PubMed

Wang, Daifeng; He, Fei; Maslov, Sergei; Gerstein, Mark

2016-10-01

Gene expression is controlled by the combinatorial effects of regulatory factors from different biological subsystems such as general transcription factors (TFs), cellular growth factors and microRNAs. A subsystem's gene expression may be controlled by its internal regulatory factors, exclusively, or by external subsystems, or by both. It is thus useful to distinguish the degree to which a subsystem is regulated internally or externally-e.g., how non-conserved, species-specific TFs affect the expression of conserved, cross-species genes during evolution. We developed a computational method (DREISS, dreiss.gerteinlab.org) for analyzing the Dynamics of gene expression driven by Regulatory networks, both External and Internal based on State Space models. Given a subsystem, the "state" and "control" in the model refer to its own (internal) and another subsystem's (external) gene expression levels. The state at a given time is determined by the state and control at a previous time. Because typical time-series data do not have enough samples to fully estimate the model's parameters, DREISS uses dimensionality reduction, and identifies canonical temporal expression trajectories (e.g., degradation, growth and oscillation) representing the regulatory effects emanating from various subsystems. To demonstrate capabilities of DREISS, we study the regulatory effects of evolutionarily conserved vs. divergent TFs across distant species. In particular, we applied DREISS to the time-series gene expression datasets of C. elegans and D. melanogaster during their embryonic development. We analyzed the expression dynamics of the conserved, orthologous genes (orthologs), seeing the degree to which these can be accounted for by orthologous (internal) versus species-specific (external) TFs. We found that between two species, the orthologs have matched, internally driven expression patterns but very different externally driven ones. This is particularly true for genes with evolutionarily ancient functions (e.g. the ribosomal proteins), in contrast to those with more recently evolved functions (e.g., cell-cell communication). This suggests that despite striking morphological differences, some fundamental embryonic-developmental processes are still controlled by ancient regulatory systems.

OXC management and control system architecture with scalability, maintenance, and distributed managing environment

NASA Astrophysics Data System (ADS)

Park, Soomyung; Joo, Seong-Soon; Yae, Byung-Ho; Lee, Jong-Hyun

2002-07-01

In this paper, we present the Optical Cross-Connect (OXC) Management Control System Architecture, which has the scalability and robust maintenance and provides the distributed managing environment in the optical transport network. The OXC system we are developing, which is divided into the hardware and the internal and external software for the OXC system, is made up the OXC subsystem with the Optical Transport Network (OTN) sub layers-hardware and the optical switch control system, the signaling control protocol subsystem performing the User-to-Network Interface (UNI) and Network-to-Network Interface (NNI) signaling control, the Operation Administration Maintenance & Provisioning (OAM&P) subsystem, and the network management subsystem. And the OXC management control system has the features that can support the flexible expansion of the optical transport network, provide the connectivity to heterogeneous external network elements, be added or deleted without interrupting OAM&P services, be remotely operated, provide the global view and detail information for network planner and operator, and have Common Object Request Broker Architecture (CORBA) based the open system architecture adding and deleting the intelligent service networking functions easily in future. To meet these considerations, we adopt the object oriented development method in the whole developing steps of the system analysis, design, and implementation to build the OXC management control system with the scalability, the maintenance, and the distributed managing environment. As a consequently, the componentification for the OXC operation management functions of each subsystem makes the robust maintenance, and increases code reusability. Also, the component based OXC management control system architecture will have the flexibility and scalability in nature.

Warm Dense Matter Demonstrating Non-Drude Conductivity from Observations of Nonlinear Plasmon Damping

NASA Astrophysics Data System (ADS)

Witte, Bastian B. L.

2017-10-01

The thermal and electrical conductivity, equation of state and the spectral opacity in warm dense matter (WDM) are essential properties for modeling, e.g., fusion experiments or the magnetic field generation in planets. In the last decade it has been shown that x-ray Thomson scattering (XRTS) is an effective tool to determine plasma parameters like temperature and density in the WDM regime. Recently, the electrical conductivity was extracted from XRTS experiments for the first time. The spectrally resolved scattering data of aluminum, isochorically heated by the Linac Coherent Light Source (LCLS), show strong dependence on electron correlations. Therefore, the damping of plasmons, the collective electron oscillations, has to be treated beyond perturbation theory. We present results for the dynamic transport properties in warm dense aluminum using density-functional-theory molecular dynamics (DFT-MD) simulations. The choice of the exchange-correlation (XC) functional, describing the interactions in the electronic subsystem, has significant impact on the ionization energy of bound electrons and the dynamic dielectric function. Our newly developed method for the calculation of XRTS signals including plasmon and bound-free transitions is based on transition matrix elements together with ionic contributions using uniquely DFT-MD simulations. The results show excellent agreement with the LCLS data if hybrid functionals are applied. The experimental finding of nonlinear plasmon damping is caused by the non-Drude conductivity in warm dense aluminum. Here, we show further validation by comparing with x-ray absorption data. These findings enable new insights into the impact of XC functionals on calculated properties of WDM and allow detailed predictions for future experiments at the unprecedented densities on the NIF. This work was performed in collaboration with P. Sperling, S.H. Glenzer, R. Redmer and was supported by the DFG via the Collaborative Research Center SFB 652 and the DOE Office of Science, Fusion Energy Science under Grant No. FWP 100182.

Mars Science Laboratory Sample Acquisition, Sample Processing and Handling: Subsystem Design and Test Challenges

NASA Technical Reports Server (NTRS)

Jandura, Louise

2010-01-01

The Sample Acquisition/Sample Processing and Handling subsystem for the Mars Science Laboratory is a highly-mechanized, Rover-based sampling system that acquires powdered rock and regolith samples from the Martian surface, sorts the samples into fine particles through sieving, and delivers small portions of the powder into two science instruments inside the Rover. SA/SPaH utilizes 17 actuated degrees-of-freedom to perform the functions needed to produce 5 sample pathways in support of the scientific investigation on Mars. Both hardware redundancy and functional redundancy are employed in configuring this sampling system so some functionality is retained even with the loss of a degree-of-freedom. Intentional dynamic environments are created to move sample while vibration isolators attenuate this environment at the sensitive instruments located near the dynamic sources. In addition to the typical flight hardware qualification test program, two additional types of testing are essential for this kind of sampling system: characterization of the intentionally-created dynamic environment and testing of the sample acquisition and processing hardware functions using Mars analog materials in a low pressure environment. The overall subsystem design and configuration are discussed along with some of the challenges, tradeoffs, and lessons learned in the areas of fault tolerance, intentional dynamic environments, and special testing

Reconfiguration of Cortical Networks in MDD Uncovered by Multiscale Community Detection with fMRI.

PubMed

He, Ye; Lim, Sol; Fortunato, Santo; Sporns, Olaf; Zhang, Lei; Qiu, Jiang; Xie, Peng; Zuo, Xi-Nian

2018-04-01

Major depressive disorder (MDD) is known to be associated with altered interactions between distributed brain regions. How these regional changes relate to the reorganization of cortical functional systems, and their modulation by antidepressant medication, is relatively unexplored. To identify changes in the community structure of cortical functional networks in MDD, we performed a multiscale community detection algorithm on resting-state functional connectivity networks of unmedicated MDD (uMDD) patients (n = 46), medicated MDD (mMDD) patients (n = 38), and healthy controls (n = 50), which yielded a spectrum of multiscale community partitions. we selected an optimal resolution level by identifying the most stable community partition for each group. uMDD and mMDD groups exhibited a similar reconfiguration of the community structure of the visual association and the default mode systems but showed different reconfiguration profiles in the frontoparietal control (FPC) subsystems. Furthermore, the central system (somatomotor/salience) and 3 frontoparietal subsystems showed strengthened connectivity with other communities in uMDD but, with the exception of 1 frontoparietal subsystem, returned to control levels in mMDD. These findings provide evidence for reconfiguration of specific cortical functional systems associated with MDD, as well as potential effects of medication in restoring disease-related network alterations, especially those of the FPC system.

A 50 kilowatt distributed grid-connected photovoltaic generation system for the University of Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, B.H.; Muknahallipatna, S.; Cupal, J.J.

The University of Wyoming (UW) campus is serving as the site for a 50 kilowatt solar photovoltaic (PV) system. Three sub-systems were sited and built on the UW campus in 1996. The first sub-system, a 10 kW roof-integrated system of PV roof tiles is located on the roof of the Engineering building. The second sub-system--a 5 kW rack-mounted, ballasted PV system is on a walkway roof of the Engineering building. The third sub-system is a 35 kW shade structure system and located adjacent to the parking lot of the university`s football stadium. The three sub-systems differ in their design strategymore » since each is being used for research and education at the university. Each sub-system, being located at some distance away from one another, supplies a different part of the campus grid. Efforts continue at setting up a central monitoring system which will receive data remotely from all locations. A part of this monitoring system is complete. While the initial monitoring data shows satisfactory performance, a number of reliability problems with PV modules and inverters have delayed full functionality of the system.« less

Charactering lidar optical subsystem using four quadrants method

NASA Astrophysics Data System (ADS)

Tian, Xiaomin; Liu, Dong; Xu, Jiwei; Wang, Zhenzhu; Wang, Bangxin; Wu, Decheng; Zhong, Zhiqing; Xie, Chenbo; Wang, Yingjian

2018-02-01

Lidar is a kind of active optical remote sensing instruments , can be applied to sound atmosphere with a high spatial and temporal resolution. Many parameter of atmosphere can be get by using different inverse algorithm with lidar backscatter signal. The basic setup of a lidar consist of a transmitter and a receiver. To make sure the quality of lidar signal data, the lidar must be calibrated before being used to measure the atmospheric variables. It is really significant to character and analyze lidar optical subsystem because a well equiped lidar optical subsystem contributes to high quality lidar signal data. we pay close attention to telecover test to character and analyze lidar optical subsystem.The telecover test is called four quadrants method consisting in dividing the telescope aperture in four quarants. when a lidar is well configured with lidar optical subsystem, the normalized signal from four qudrants will agree with each other on some level. Testing our WARL-II lidar by four quadrants method ,we find the signals of the four basically consistent with each other both in near range and in far range. But in detail, the signals in near range have some slight distinctions resulting from overlap function, some signals distinctions are induced by atmospheric instability.

Quaternary pulse position modulation electronics for free-space laser communications

NASA Technical Reports Server (NTRS)

Budinger, J. M.; Kerslake, S. D.; Nagy, L. A.; Shalkhauser, M. J.; Soni, N. J.; Cauley, M. A.; Mohamed, J. H.; Stover, J. B.; Romanofsky, R. R.; Lizanich, P. J.

1991-01-01

The development of a high data-rate communications electronic subsystem for future application in free-space, direct-detection laser communications is described. The dual channel subsystem uses quaternary pulse position modulation (GPPM) and operates at a throughput of 650 megabits per second. Transmitting functions described include source data multiplexing, channel data multiplexing, and QPPM symbol encoding. Implementation of a prototype version in discrete gallium arsenide logic, radiofrequency components, and microstrip circuitry is presented.

Quaternary pulse position modulation electronics for free-space laser communications

NASA Technical Reports Server (NTRS)

Budinger, J. M.; Kerslake, S. D.; Nagy, L. A.; Shalkhauser, M. J.; Soni, N. J.; Cauley, M. A.; Mohamed, J. H.; Stover, J. B.; Romanofsky, R. R.; Lizanich, P. J.

1991-01-01

The development of a high data-rate communications electronic subsystem for future application in free-space, direct-detection laser communications is described. The dual channel subsystem uses quaternary pulse position modulation (QPPM) and operates at a throughput of 650 megabits per second. Transmitting functions described include source data multiplexing, channel data multiplexing, and QPPM symbol encoding. Implementation of a prototype version in discrete gallium arsenide logic, radiofrequency components, and microstrip circuitry is presented.

Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices.

PubMed

Pejović, Milić M; Denić, Dragan B; Pejović, Momčilo M; Nešić, Nikola T; Vasović, Nikola

2010-10-01

This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pejovic, Milic M.; Denic, Dragan B.; Pejovic, Momcilo M.

2010-10-15

This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven bymore » TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.« less

Mass Media Functions, Knowledge and Social Control

ERIC Educational Resources Information Center

Donohue, G. A.; And Others

1973-01-01

Develops a macro-view of mass media as interdependent parts of a total social system including a series of interrelated subsystems with primary function involving the generation, dissemination, and assimilation of information. (RB)

Aerosol and nucleation research in support of NASA cloud physics experiments in space. [ice nuclei generator for the atmospheric cloud physics laboratory on Spacelab

NASA Technical Reports Server (NTRS)

Vali, G.; Rogers, D.; Gordon, G.; Saunders, C. P. R.; Reischel, M.; Black, R.

1978-01-01

Tasks performed in the development of an ice nucleus generator which, within the facility concept of the ACPL, would provide a test aerosol suitable for a large number and variety of potential experiments are described. The impact of Atmospheric Cloud Physics Laboratory scientific functional requirements on ice nuclei generation and characterization subsystems was established. Potential aerosol generating systems were evaluated with special emphasis on reliability, repeatability and general suitability for application in Spacelab. Possible contamination problems associated with aerosol generation techniques were examined. The ice nucleating abilities of candidate test aerosols were examined and the possible impact of impurities on the nucleating abilities of those aerosols were assessed as well as the relative merits of various methods of aerosol size and number density measurements.

An Analytical Calibration Approach for the Polarimetric Airborne C Band Radiometer

NASA Technical Reports Server (NTRS)

Pham, Hanh; Kim, Edward J.

2004-01-01

Passive microwave remote sensing is sensitive to the quantity and distribution of water in soil and vegetation. During summer 2000, the Microwave Geophysics Group a t the University of Michigan conducted the seventh Radiobrighness Energy Balance Experiment (REBEX-7) over a corn canopy in Michigan. Long time series of brightness temperatures, soil moisture and micrometeorology on the plot were taken. This paper addresses the calibration of the NASA GSFC polarimetric airborne C band microwave radiometer (ACMR) that participated in REBEX-7. These passive polarimeters are typically calibrated using an end-to-end approach based upon a standard artificial target or a well-known geophysical target. Analyzing the major internal functional subsystems offers a different perspective. The primary goal of this approach is to provide a transfer function that not only describes the system in its entire5 but also accounts for the contributions of each subsystem toward the final modified Stokes parameters. This approach does not assume that the radiometric system is linear as it does not take polarization isolation for granted, and it also serves as a realistic instrument simulator, a useful tool for future designs. The ACMR architecture can be partitioned into functional subsystems. The characteristics of each subsystem was extensively measured and the estimated parameters were imported into the overall dosed form system model. Inversion of the model yields a calibration for the modeled Stokes parameters with uncertainties of 0.2 K for the V and H polarizations and 2.4 K for the 3rd and 4th parameters. Application to the full Stokes parameters over a senescent cornfield is presented.

Geoinformatic subsystem for real estate market analysis). (Polish Title: Podsystem geoinformatyczny do analizy rynku nieruchomosci)

NASA Astrophysics Data System (ADS)

Basista, A.

2013-12-01

There are many tools to manage spatial data. They called Geographic Information System (GIS), which apart from data visualization in space, let users make various spatial analysis. Thanks to them, it is possible to obtain more, essential information for real estate market analysis. Many scientific research present GIS exploitation to future mass valuation, because it is necessary to use advanced tools to manage such a huge real estates' data sets gathered for mass valuation needs. In practice, appraisers use rarely these tools for single valuation, because there are not many available GIS tools to support real estate valuation. The paper presents the functionality of geoinformatic subsystem, that is used to support real estate market analysis and real estate valuation. There are showed a detailed description of the process relied to attributes' inputting into the database and the attributes' values calculation based on the proposed definition of attributes' scales. This work presents also the algorithm of similar properties selection that was implemented within the described subsystem. The main stage of this algorithm is the calculation of the price creative indicator for each real estate, using their attributes' values. The set of properties, chosen in this way, are visualized on the map. The geoinformatic subsystem is used for the un-built real estates and living premises. Geographic Information System software was used to worked out this project. The basic functionality of gvSIG software (open source software) was extended and some extra functions were added to support real estate market analysis.

Performance characterization of a Bosch CO sub 2 reduction subsystem

NASA Technical Reports Server (NTRS)

Heppner, D. B.; Hallick, T. M.; Schubert, F. H.

1980-01-01

The performance of Bosch hardware at the subsystem level (up to five-person capacity) in terms of five operating parameters was investigated. The five parameters were: (1) reactor temperature, (2) recycle loop mass flow rate, (3) recycle loop gas composition (percent hydrogen), (4) recycle loop dew point and (5) catalyst density. Experiments were designed and conducted in which the five operating parameters were varied and Bosch performance recorded. A total of 12 carbon collection cartridges provided over approximately 250 hours of operating time. Generally, one cartridge was used for each parameter that was varied. The Bosch hardware was found to perform reliably and reproducibly. No startup, reaction initiation or carbon containment problems were observed. Optimum performance points/ranges were identified for the five parameters investigated. The performance curves agreed with theoretical projections.

Dissimilarities of reduced density matrices and eigenstate thermalization hypothesis

NASA Astrophysics Data System (ADS)

He, Song; Lin, Feng-Li; Zhang, Jia-ju

2017-12-01

We calculate various quantities that characterize the dissimilarity of reduced density matrices for a short interval of length ℓ in a two-dimensional (2D) large central charge conformal field theory (CFT). These quantities include the Rényi entropy, entanglement entropy, relative entropy, Jensen-Shannon divergence, as well as the Schatten 2-norm and 4-norm. We adopt the method of operator product expansion of twist operators, and calculate the short interval expansion of these quantities up to order of ℓ9 for the contributions from the vacuum conformal family. The formal forms of these dissimilarity measures and the derived Fisher information metric from contributions of general operators are also given. As an application of the results, we use these dissimilarity measures to compare the excited and thermal states, and examine the eigenstate thermalization hypothesis (ETH) by showing how they behave in high temperature limit. This would help to understand how ETH in 2D CFT can be defined more precisely. We discuss the possibility that all the dissimilarity measures considered here vanish when comparing the reduced density matrices of an excited state and a generalized Gibbs ensemble thermal state. We also discuss ETH for a microcanonical ensemble thermal state in a 2D large central charge CFT, and find that it is approximately satisfied for a small subsystem and violated for a large subsystem.

Risk of Impaired Control of Spacecraft/Associated Systems and Decreased Mobility Due to Vestibular/Sensorimotor Alterations Associated with Space flight

NASA Technical Reports Server (NTRS)

Bloomberg, Jacob J.; Reschke, Millard F.; Clement, Gilles R.; Mulavara, Ajitkumar P.; Taylor, Laura C..

2015-01-01

Control of vehicles and other complex systems is a high-level integrative function of the central nervous system (CNS). It requires well-functioning subsystem performance, including good visual acuity, eye-hand coordination, spatial and geographic orientation perception, and cognitive function. Evidence from space flight research demonstrates that the function of each of these subsystems is altered by removing gravity, a fundamental orientation reference, which is sensed by vestibular, proprioceptive, and haptic receptors and used by the CNS for spatial orientation, posture, navigation, and coordination of movements. The available evidence also shows that the degree of alteration of each subsystem depends on a number of crew- and mission-related factors. There is only limited operational evidence that these alterations cause functional impacts on mission-critical vehicle (or complex system) control capabilities. Furthermore, while much of the operational performance data collected during space flight has not been available for independent analysis, those that have been reviewed are somewhat equivocal owing to uncontrolled (and/or unmeasured) environmental and/or engineering factors. Whether this can be improved by further analysis of previously inaccessible operational data or by development of new operational research protocols remains to be seen. The true operational risks will be estimable only after we have filled the knowledge gaps and when we can accurately assess integrated performance in off-nominal operational settings (Paloski et al. 2008). Thus, our current understanding of the Risk of Impaired Control of Spacecraft/Associated Systems and Decreased Mobility Due to Vestibular/Sensorimotor Alterations Associated with Space flight is limited primarily to extrapolation of scientific research findings, and, since there are limited ground-based analogs of the sensorimotor and vestibular changes associated with space flight, observation of their functional impacts is limited to studies performed in the space flight environment. Fortunately, many sensorimotor and vestibular experiments have been performed during and/or after space flight missions since 1959 (Reschke et al. 2007). While not all of these experiments were directly relevant to the question of vehicle/complex system control, most provide insight into changes in aspects of sensorimotor control that might bear on the physiological subsystems underlying this high-level integrated function.

Mass storage technology in networks

NASA Astrophysics Data System (ADS)

Ishii, Katsunori; Takeda, Toru; Itao, Kiyoshi; Kaneko, Reizo

1990-08-01

Trends and features of mass storage subsystems in network are surveyed and their key technologies spotlighted. Storage subsystems are becoming increasingly important in new network systems in which communications and data processing are systematically combined. These systems require a new class of high-performance mass-information storage in order to effectively utilize their processing power. The requirements of high transfer rates, high transactional rates and large storage capacities, coupled with high functionality, fault tolerance and flexibility in configuration, are major challenges in storage subsystems. Recent progress in optical disk technology has resulted in improved performance of on-line external memories to optical disk drives, which are competing with mid-range magnetic disks. Optical disks are more effective than magnetic disks in using low-traffic random-access file storing multimedia data that requires large capacity, such as in archive use and in information distribution use by ROM disks. Finally, it demonstrates image coded document file servers for local area network use that employ 130mm rewritable magneto-optical disk subsystems.

[A role of motivation for treatment in the structure of compliance in psychopharmacologically treated patients].

PubMed

Sorokin, M Yu; Lutova, N B; Wied, V D

2016-01-01

To reveal an impact of specific motivation structures on the compliance in psychiatric inpatients. The Treatment Motivation Questionnaire and the Medication Compliance Scale have been administered to 104 patients, including 67 patients with schizophrenia and schizophrenia-spectrum disorders, 15 with affective disorders, 13 with personality and neurotic disorders and 9 with organic disorders, of the department of integrative pharmaco- and psychotherapy. A motivational mechanism based on the subjective suffering from disease plays a key role in the formation of overall score of compliance. Amotivation syndrome has a negative impact on the compliance. "Passive agreement" attitude to treatment corresponds to a deficiency in both patient and physician compliance subsystems along with a reduction in insight and cognitive functions in the patient's subsystem. Extreme external motivation for treatment correlates with insufficiently constructive support on the part of significant others in patient's environment subsystem resulting in the delay of internal motivation development. Extremely low scores based on understanding of disease character leads to the deficiency of medication compliance subsystem.

Space shuttle atmospheric revitalization subsystem/active thermal control subsystem computer program (users manual)

NASA Technical Reports Server (NTRS)

1973-01-01

A shuttle (ARS) atmosphere revitalization subsystem active thermal control subsystem (ATCS) performance routine was developed. This computer program is adapted from the Shuttle EC/LSS Design Computer Program. The program was upgraded in three noteworthy areas: (1) The functional ARS/ATCS schematic has been revised to accurately synthesize the shuttle baseline system definition. (2) The program logic has been improved to provide a more accurate prediction of the integrated ARS/ATCS system performance. Additionally, the logic has been expanded to model all components and thermal loads in the ARS/ATCS system. (3) The program is designed to be used on the NASA JSC crew system division's programmable calculator system. As written the new computer routine has an average running time of five minutes. The use of desk top type calculation equipment, and the rapid response of the program provides the NASA with an analytical tool for trade studies to refine the system definition, and for test support of the RSECS or integrated Shuttle ARS/ATCS test programs.

Recovering Intrinsic Fragmental Vibrations Using the Generalized Subsystem Vibrational Analysis.

PubMed

Tao, Yunwen; Tian, Chuan; Verma, Niraj; Zou, Wenli; Wang, Chao; Cremer, Dieter; Kraka, Elfi

2018-05-08

Normal vibrational modes are generally delocalized over the molecular system, which makes it difficult to assign certain vibrations to specific fragments or functional groups. We introduce a new approach, the Generalized Subsystem Vibrational Analysis (GSVA), to extract the intrinsic fragmental vibrations of any fragment/subsystem from the whole system via the evaluation of the corresponding effective Hessian matrix. The retention of the curvature information with regard to the potential energy surface for the effective Hessian matrix endows our approach with a concrete physical basis and enables the normal vibrational modes of different molecular systems to be legitimately comparable. Furthermore, the intrinsic fragmental vibrations act as a new link between the Konkoli-Cremer local vibrational modes and the normal vibrational modes.

Attitude and articulation control system testing for Project Galileo

NASA Technical Reports Server (NTRS)

Rasmussen, R. D.

1981-01-01

A type of facility required to integrate and test a complex autonomous spacecraft subsystem is presented, using the attitude and articulation control subsystem (AACS) of Project Galileo as an example. The equipment created for testing the AACS at both the subsystem and spacecraft system levels is described, including a description of the support equipment (SE) architecture in its two main configurations, closed loop simulation techniques, the user interface to the SE, and plans for the use of the facility beyond the test period. This system is capable of providing a flight-like functional environment through the use of accurate real-time models and carefully chosen points of interaction, and flexible control capability and high visibility to the test operator.

Space station systems analysis study. Part 2, volume 3: Appendixes, Book 2: Supporting data (7 through 18)

NASA Technical Reports Server (NTRS)

1977-01-01

Topics discussed include: (1) design considerations for a MARS sample return laboratory module for space station investigations; (2) crew productivity as a function of work shift arrangement; (3) preliminary analysis of the local logistics problem on the space construction base; (4) mission hardware construction operational flows and timelines; (5) orbit transfer vehicle concept definition; (6) summary of results and findings of space processing working review; (7) crew and habitability subsystem (option L); (8) habitability subsystem considerations for shuttle tended option L; (9) orbiter utilization in manned sortie missions; (10) considerations in definition of space construction base standard module configuration (option L); (11) guidance, control, and navigation subsystems; and (12) system and design tradeoffs.

Effect of one-step recrystallization on the grain boundary evolution of CoCrFeMnNi high entropy alloy and its subsystems

PubMed Central

Chen, Bo-Ru; Yeh, An-Chou; Yeh, Jien-Wei

2016-01-01

In this study, the grain boundary evolution of equiatomic CoCrFeMnNi, CoCrFeNi, and FeCoNi alloys after one-step recrystallization were investigated. The special boundary fraction and twin density of these alloys were evaluated by electron backscatter diffraction analysis. Among the three alloys tested, FeCoNi exhibited the highest special boundary fraction and twin density after one-step recrystallization. The special boundary increment after one-step recrystallization was mainly affected by grain boundary velocity, while twin density was mainly affected by average grain boundary energy and twin boundary energy. PMID:26923713

Analysis of space vehicle structures using the transfer-function concept

NASA Technical Reports Server (NTRS)

Heer, E.; Trubert, M. R.

1969-01-01

Analysis of large complex systems is accomplished by dividing it into suitable subsystems and determining the individual dynamical and vibrational responses. Frequency transfer functions then determine the vibrational response of the whole system.

Low Ionization Absorbing Gas Kinematics Around Z ~ 1 Galaxies

NASA Astrophysics Data System (ADS)

Churchill, C. W.; Steidel, C. C.; Vogt, S. S.

1996-12-01

Absorption profiles of the Mg II lambda lambda 2796,2803 doublet arising from gas associated with 48 ``normal'' intermediate redshift (0.4 < z < 1.7) galaxies have been resolved in QSO spectra at 6 km s(-1) resolution using HIRES on Keck I. We have found evidence for pronounced redshift evolution in the subcomponent velocity two--point correlation function, suggestive that the gas surrounding galaxies has settled over a 5--10 Gyr look--back time. Based upon a sub--sample of 15 galaxies at z<1, we found no evidence for correlations between the absorbing gas kinematics and the projected galactocentric distance of the gas, galaxy luminosities, or galaxy rest--frame colors (though trends between galaxy properties and absorption properties are apparent from a larger low resolution absorption line sample). The implication is that low ionization gas surrounding early epoch galaxies was not smoothly distributed either spatially or kinematically out to a galactocentric distance ~ 40 kpc. Directly from the profiles, we have measured the number of separate absorbing ``kinematic subsystems'' associated with each galaxy, and each subsystem's profile velocity width, asymmetry (skew), and integrated column density. The distribution in these subsystem properties with velocity is highly peaked at zero, and does not exhibit a bimodality. The lack of a bimodality is suggestive that the gas kinematics is not dominated by quasi--symmetric infall into galactic potential wells. In view of absorption line studies of local galaxies, it appears that extended regions of low ionization gas surrounding galaxies represent a dynamical and active epoch of ``normal'' galaxy evolution. The reservoirs of gas for these extended ``halos'' were probably residual infalling fragments (from earlier formation processes and on--going dynamical events) whose evolution first included a settling in velocity dispersion and then more recently a decline in number. The build up of thick and/or extended gaseous disks (in the case of spirals) may be one manifestation of this process.

Mental health treatment teams and leadership: a systems model.

PubMed

Yank, G R; Barber, J W; Spradlin, W W

1994-10-01

Mental health treatment teams are living systems at the group level and comprise key productive subsystems of organizations providing mental health care. Effective treatment teams, like effective organizations, are anticipatory systems that contain subsystems that model and predict future system and environmental conditions and enable responses that increase system viability. A systems analysis of treatment teams highlights their potential instability due to their tendencies to regress toward dysfunctional partial systems and their active maintenance in nonequilibrium steady states with their organizational and external environments. Team subsystems are analyzed from the viewpoints of system processes and also with regard to individuals and their roles. Boundary processes are central to effective team functioning, assure constancy of team membership, and regulate the team's interfaces with its parent agency and with the external environment. Various causes and forms of disturbed information processing within hierarchical organizations are examined, and their effects at the treatment team level are discussed. The conclusion of the discussion focuses on team leadership and how leadership expands upon the concept of the decider subsystem to include role and personal factors to the team's leaders, and functions that are anticipatory and integrative in nature. Effective leaders must set appropriate thresholds for feedback regulation processes, and balance several pairs of seemingly opposing forces, including homeostasis and development, role differentiation and role overlap, and personal accountability and empowerment of others.

Utilizing a Suited Manikin Test Apparatus and Space Suit Ventilation Loop to Evaluate Carbon Dioxide Washout

NASA Technical Reports Server (NTRS)

Chullen, Cinda; Conger, Bruce; Korona, Adam; Kanne, Bryan; McMillin, Summer; Paul, Thomas; Norcross, Jason; Alonso, Jesus Delgado; Swickrath, Mike

2015-01-01

NASA is pursuing technology development of an Advanced Extravehicular Mobility Unit (AEMU) which is an integrated assembly made up of primarily a pressure garment system and a portable life support subsystem (PLSS). The PLSS is further composed of an oxygen subsystem, a ventilation subsystem, and a thermal subsystem. One of the key functions of the ventilation system is to remove and control the carbon dioxide (CO2) delivered to the crewmember. Carbon dioxide washout is the mechanism by which CO2 levels are controlled within the space suit helmet to limit the concentration of CO2 inhaled by the crew member. CO2 washout performance is a critical parameter needed to ensure proper and robust designs that are insensitive to human variabilities in a space suit. A suited manikin test apparatus (SMTA) was developed to augment testing of the PLSS ventilation loop in order to provide a lower cost and more controlled alternative to human testing. The CO2 removal function is performed by the regenerative Rapid Cycle Amine (RCA) within the PLSS ventilation loop and its performance is evaluated within the integrated SMTA and Ventilation Loop test system. This paper will provide a detailed description of the schematics, test configurations, and hardware components of this integrated system. Results and analysis of testing performed with this integrated system will be presented within this paper.

System control of an autonomous planetary mobile spacecraft

NASA Technical Reports Server (NTRS)

Dias, William C.; Zimmerman, Barbara A.

1990-01-01

The goal is to suggest the scheduling and control functions necessary for accomplishing mission objectives of a fairly autonomous interplanetary mobile spacecraft, while maximizing reliability. Goals are to provide an extensible, reliable system conservative in its use of on-board resources, while getting full value from subsystem autonomy, and avoiding the lure of ground micromanagement. A functional layout consisting of four basic elements is proposed: GROUND and SYSTEM EXECUTIVE system functions and RESOURCE CONTROL and ACTIVITY MANAGER subsystem functions. The system executive includes six subfunctions: SYSTEM MANAGER, SYSTEM FAULT PROTECTION, PLANNER, SCHEDULE ADAPTER, EVENT MONITOR and RESOURCE MONITOR. The full configuration is needed for autonomous operation on Moon or Mars, whereas a reduced version without the planning, schedule adaption and event monitoring functions could be appropriate for lower-autonomy use on the Moon. An implementation concept is suggested which is conservative in use of system resources and consists of modules combined with a network communications fabric. A language concept termed a scheduling calculus for rapidly performing essential on-board schedule adaption functions is introduced.

Thematic mapper flight model preshipment review data package. Volume 4: Appendix. Part G: Miscellaneous system data

NASA Technical Reports Server (NTRS)

1982-01-01

Functional and design data from various thematic mapper subsystems are presented. Coarse focus, modulation transfer function, and shim requirements are addressed along with spectral matching and spatial coverage tests.

Digitally controlled sonars

NASA Technical Reports Server (NTRS)

Hansen, G. R.

1983-01-01

Sonars are usually designed and constructed as stand alone instruments. That is, all elements or subsystems of the sonar are provided: power conditioning, displays, intercommunications, control, receiver, transmitter, and transducer. The sonars which are a part of the Advanced Ocean Test Development Platform (AOTDP) represent a departure from this manner of implementation and are configured more like an instrumentation system. Only the transducer, transmitter, and receiver which are unique to a particular sonar function; Up, Down, Side Scan, exist as separable subsystems. The remaining functions are reserved to the AOTDP and serve all sonars and other instrumentation in a shared manner. The organization and functions of the common AOTDP elements were described and then the interface with the sonars discussed. The techniques for software control of the sonar parameters were explained followed by the details of the realization of the sonar functions and some discussion of the performance of the side scan sonars.

Mobility power flow analysis of an L-shaped plate structure subjected to acoustic excitation

NASA Technical Reports Server (NTRS)

Cuschieri, J. M.

1989-01-01

An analytical investigation based on the Mobility Power Flow method is presented for the determination of the vibrational response and power flow for two coupled flat plate structures in an L-shaped configuration, subjected to acoustical excitation. The principle of the mobility power flow method consists of dividing the global structure into a series of subsystems coupled together using mobility functions. Each separate subsystem is analyzed independently to determine the structural mobility functions for the junction and excitation locations. The mobility functions, together with the characteristics of the junction between the subsystems, are then used to determine the response of the global structure and the power flow. In the coupled plate structure considered here, mobility power flow expressions are derived for excitation by an incident acoustic plane wave. In this case, the forces (acoustic pressures) acting on the structure are dependent on the response of the structure because of the scattered pressure component. The interaction between the structure and the fluid leads to the derivation of a corrected mode shape for the plates' normal surface velocity and also for the structure mobility functions. The determination of the scattered pressure components in the expressions for the power flow represents an additional component in the power flow balance for the source plate and the receiver plate. This component represents the radiated acoustical power from the plate structure.

Decentralized adaptive robust control based on sliding mode and nonlinear compensator for the control of ankle movement using functional electrical stimulation of agonist-antagonist muscles

NASA Astrophysics Data System (ADS)

Kobravi, Hamid-Reza; Erfanian, Abbas

2009-08-01

A decentralized control methodology is designed for the control of ankle dorsiflexion and plantarflexion in paraplegic subjects with electrical stimulation of tibialis anterior and calf muscles. Each muscle joint is considered as a subsystem and individual controllers are designed for each subsystem. Each controller operates solely on its associated subsystem, with no exchange of information between the subsystems. The interactions between the subsystems are taken as external disturbances for each isolated subsystem. In order to achieve robustness with respect to external disturbances, unmodeled dynamics, model uncertainty and time-varying properties of muscle-joint dynamics, a robust control framework is proposed which is based on the synergistic combination of an adaptive nonlinear compensator with a sliding mode control and is referred to as an adaptive robust control. Extensive simulations and experiments on healthy and paraplegic subjects were performed to demonstrate the robustness against the time-varying properties of muscle-joint dynamics, day-to-day variations, subject-to-subject variations, fast convergence, stability and tracking accuracy of the proposed method. The results indicate that the decentralized robust control provides excellent tracking control for different reference trajectories and can generate control signals to compensate the muscle fatigue and reject the external disturbance. Moreover, the controller is able to automatically regulate the interaction between agonist and antagonist muscles under different conditions of operating without any preprogrammed antagonist activities.

Decentralized adaptive robust control based on sliding mode and nonlinear compensator for the control of ankle movement using functional electrical stimulation of agonist-antagonist muscles.

PubMed

Kobravi, Hamid-Reza; Erfanian, Abbas

2009-08-01

A decentralized control methodology is designed for the control of ankle dorsiflexion and plantarflexion in paraplegic subjects with electrical stimulation of tibialis anterior and calf muscles. Each muscle joint is considered as a subsystem and individual controllers are designed for each subsystem. Each controller operates solely on its associated subsystem, with no exchange of information between the subsystems. The interactions between the subsystems are taken as external disturbances for each isolated subsystem. In order to achieve robustness with respect to external disturbances, unmodeled dynamics, model uncertainty and time-varying properties of muscle-joint dynamics, a robust control framework is proposed which is based on the synergistic combination of an adaptive nonlinear compensator with a sliding mode control and is referred to as an adaptive robust control. Extensive simulations and experiments on healthy and paraplegic subjects were performed to demonstrate the robustness against the time-varying properties of muscle-joint dynamics, day-to-day variations, subject-to-subject variations, fast convergence, stability and tracking accuracy of the proposed method. The results indicate that the decentralized robust control provides excellent tracking control for different reference trajectories and can generate control signals to compensate the muscle fatigue and reject the external disturbance. Moreover, the controller is able to automatically regulate the interaction between agonist and antagonist muscles under different conditions of operating without any preprogrammed antagonist activities.

Passive Thermal Control for the Low Density Supersonic Decelerator (LDSD) Test Vehicle Spin Motors Sub-System

NASA Technical Reports Server (NTRS)

Redmond, Matthew; Mastropietro, A. J.; Pauken, Michael; Mobley, Brandon

2014-01-01

Future missions to Mars will require improved entry, descent, and landing (EDL) technology over the Viking-heritage systems which recently landed the largest payload to date, the 900 kg Mars Science Laboratory. As a result, NASA's Low Density Supersonic Decelerator (LDSD) project is working to advance the state of the art in Mars EDL systems by developing and testing three key technologies which will enable heavier payloads and higher altitude landing sites on the red planet. These technologies consist of a large 33.5 m diameter Supersonic Disk Sail (SSDS) parachute and two different Supersonic Inflatable Aerodynamic Decelerator (SIAD) devices - a robotic class that inflates to a 6 m diameter torus (SIAD-R), and an exploration class that inflates to an 8 m diameter isotensoid (SIADE). All three technologies will be demonstrated on test vehicles at high earth altitudes in order to simulate the Mars EDL environment. Each vehicle will be carried to altitude by a large helium balloon, released, spun up using spin motors to stabilize the vehicle's trajectory, and accelerated to supersonic speeds using a large solid rocket motor. The vehicle will then be spun down using another set of spin motors, and will deploy either the SIAD-R or SIAD-E, followed by the SSDS parachute until the vehicle lands in the ocean. Component level testing and bounding analysis are used to ensure the survival of system components in extreme thermal environments and predict temperatures throughout the flight. This paper presents a general description of the thermal testing, model correlation, and analysis of the spin motor passive thermal control sub-system to maintain spin motor performance, prescribed vehicle trajectory, and structural integrity of the test vehicle. The spin motor subsystem is predicted to meet its requirements with margin.

Adaptations in a hierarchical food web of southeastern Lake Michigan

USGS Publications Warehouse

Krause, Ann E.; Frank, Ken A.; Jones, Michael L.; Nalepa, Thomas F.; Barbiero, Richard P.; Madenjian, Charles P.; Agy, Megan; Evans, Marlene S.; Taylor, William W.; Mason, Doran M.; Léonard, Nancy J.

2009-01-01

Two issues in ecological network theory are: (1) how to construct an ecological network model and (2) how do entire networks (as opposed to individual species) adapt to changing conditions? We present a novel method for constructing an ecological network model for the food web of southeastern Lake Michigan (USA) and we identify changes in key system properties that are large relative to their uncertainty as this ecological network adapts from one time point to a second time point in response to multiple perturbations. To construct our food web for southeastern Lake Michigan, we followed the list of seven recommendations outlined in Cohen et al. [Cohen, J.E., et al., 1993. Improving food webs. Ecology 74, 252–258] for improving food webs. We explored two inter-related extensions of hierarchical system theory with our food web; the first one was that subsystems react to perturbations independently in the short-term and the second one was that a system's properties change at a slower rate than its subsystems’ properties. We used Shannon's equations to provide quantitative versions of the basic food web properties: number of prey, number of predators, number of feeding links, and connectance (or density). We then compared these properties between the two time-periods by developing distributions of each property for each time period that took uncertainty about the property into account. We compared these distributions, and concluded that non-overlapping distributions indicated changes in these properties that were large relative to their uncertainty. Two subsystems were identified within our food web system structure (p < 0.001). One subsystem had more non-overlapping distributions in food web properties between Time 1 and Time 2 than the other subsystem. The overall system had all overlapping distributions in food web properties between Time 1 and Time 2. These results supported both extensions of hierarchical systems theory. Interestingly, the subsystem with more non-overlapping distributions in food web properties was the subsystem that contained primarily benthic taxa, contrary to expectations that the identified major perturbations (lower phosphorous inputs and invasive species) would more greatly affect the subsystem containing primarily pelagic taxa. Future food-web research should employ rigorous statistical analysis and incorporate uncertainty in food web properties for a better understanding of how ecological networks adapt.

Design distributed simulation platform for vehicle management system

NASA Astrophysics Data System (ADS)

Wen, Zhaodong; Wang, Zhanlin; Qiu, Lihua

2006-11-01

Next generation military aircraft requires the airborne management system high performance. General modules, data integration, high speed data bus and so on are needed to share and manage information of the subsystems efficiently. The subsystems include flight control system, propulsion system, hydraulic power system, environmental control system, fuel management system, electrical power system and so on. The unattached or mixed architecture is changed to integrated architecture. That means the whole airborne system is regarded into one system to manage. So the physical devices are distributed but the system information is integrated and shared. The process function of each subsystem are integrated (including general process modules, dynamic reconfiguration), furthermore, the sensors and the signal processing functions are shared. On the other hand, it is a foundation for power shared. Establish a distributed vehicle management system using 1553B bus and distributed processors which can provide a validation platform for the research of airborne system integrated management. This paper establishes the Vehicle Management System (VMS) simulation platform. Discuss the software and hardware configuration and analyze the communication and fault-tolerant method.

Development of rotorcraft interior noise control concepts. Phase 2: Full scale testing, revision 1

NASA Technical Reports Server (NTRS)

Yoerkie, C. A.; Gintoli, P. J.; Moore, J. A.

1986-01-01

The phase 2 effort consisted of a series of ground and flight test measurements to obtain data for validation of the Statistical Energy Analysis (SEA) model. Included in the gound tests were various transfer function measurements between vibratory and acoustic subsystems, vibration and acoustic decay rate measurements, and coherent source measurements. The bulk of these, the vibration transfer functions, were used for SEA model validation, while the others provided information for characterization of damping and reverberation time of the subsystems. The flight test program included measurements of cabin and cockpit sound pressure level, frame and panel vibration level, and vibration levels at the main transmission attachment locations. Comparisons between measured and predicted subsystem excitation levels from both ground and flight testing were evaluated. The ground test data show good correlation with predictions of vibration levels throughout the cabin overhead for all excitations. The flight test results also indicate excellent correlation of inflight sound pressure measurements to sound pressure levels predicted by the SEA model, where the average aircraft speech interference level is predicted within 0.2 dB.

Resilient help to switch and overlap hierarchical subsystems in a small human group

PubMed Central

Fujii, K.; Yokoyama, K.; Koyama, T.; Rikukawa, A.; Yamada, H.; Yamamoto, Y.

2016-01-01

Groups of social organisms in nature are resilient systems that can overcome unpredicted threats by helping its members. These social organisms are assumed to behave both autonomously and cooperatively as individuals, the helper, the helped and other part of a group depending on the context such as emergencies. However, the structure and function of these resilient actions, such as how helpers help colleagues and how the helper’s action is effective at multiple subsystem scales remain unclear. Here we investigated the behaviour of organised and efficient small human groups in a ballgame defence, and identified three principles of hierarchical resilient help when under attack. First, at a present high emergency level, the helper simply switched the local roles in the attacked subsystem with the helped. Second, at an intermediate emergency level, the helpers effectively acted in overlapping subsystems. Third, for the most critical emergency, the helpers globally switched the action on the overall system. These resilient actions to the benefit of the system were assumed to be observed in only humans, which help colleagues at flexibly switched and overlapped hierarchical subsystem. We suggest that these multi-layered helping behaviours can help to understand resilient cooperation in social organisms and human groups. PMID:27045443

Microbiology operations and facilities aboard restructured Space Station Freedom

NASA Technical Reports Server (NTRS)

Cioletti, Louis A.; Mishra, S. K.; Pierson, Duane L.

1992-01-01

With the restructure and funding changes for Space Station Freedom, the Environmental Health System (EHS)/Microbiology Subsystem revised its scheduling and operational requirements for component hardware. The function of the Microbiology Subsystem is to monitor the environmental quality of air, water, and internal surfaces and, in part, crew health on board Space Station. Its critical role shall be the identification of microbial contaminants in the environment that may cause system degradation, produce unsanitary or pathogenic conditions, or reduce crew and mission effectiveness. EHS/Microbiology operations and equipment shall be introduced in concert with a phased assembly sequence, from Man Tended Capability (MTC) through Permanently Manned Capability (PMC). Effective Microbiology operations and subsystem components will assure a safe, habitable, and useful spacecraft environment for life sciences research and long-term manned exploration.

Study report on interfacing major physiological subsystem models: An approach for developing a whole-body algorithm

NASA Technical Reports Server (NTRS)

Fitzjerrell, D. G.; Grounds, D. J.; Leonard, J. I.

1975-01-01

Using a whole body algorithm simulation model, a wide variety and large number of stresses as well as different stress levels were simulated including environmental disturbances, metabolic changes, and special experimental situations. Simulation of short term stresses resulted in simultaneous and integrated responses from the cardiovascular, respiratory, and thermoregulatory subsystems and the accuracy of a large number of responding variables was verified. The capability of simulating significantly longer responses was demonstrated by validating a four week bed rest study. In this case, the long term subsystem model was found to reproduce many experimentally observed changes in circulatory dynamics, body fluid-electrolyte regulation, and renal function. The value of systems analysis and the selected design approach for developing a whole body algorithm was demonstrated.

Solar Electric Propulsion System Integration Technology (SEPSIT). Volume 1: Technical summary

NASA Technical Reports Server (NTRS)

Gardner, J. A.

1972-01-01

The use of solar electric propulsion as a means of exploring space beyond the reach of ballistic missions was investigated. The method used was to study the application of this new propulsion technology to a future flight project. A 1980 Encke rendezvous mission was chosen because a design successful for Encke could be used for less difficult, but scientifically rewarding, missions. Design points for the mission and for the thrust subsystem were specified. The baseline-vehicle design was defined. A preliminary functional description document for the thrust subsystem was originated. Analyses were performed in support of the design point selection for the SEP-module thrust subsystem to specify parameters, to clarify and optimize the interface requirements, and to assure feasibility of some of the more critical technological aspects of SEP application.

Regenerable CO2 collection for spacecraft application

NASA Technical Reports Server (NTRS)

Lance, N., Jr.; Schubert, F. H.

1981-01-01

The design of the CS-3, a three-person capacity preprototype CO2 collection subsystem, is described. It is noted that the function of the CS-3 is to remove metabolically produced CO2 from the Spacelab cabin to maintain atmospheric pCO2 at 400 Pa or less. Results are presented of an extensive parametric/endurance test program characterizing the subsystem's performance. The results demonstrate the suitability of the electrochemical depolarized CO2 concentration concept for possible use in the Space Operations Center. The CS-3 is found to meet or exceed all Regenerative Life Support Evaluation requirements. Specifically, the 0.13 cu m, 46 kg subsystem is able to remove CO2 at an equivalent rate of 3.4 persons from an air stream having a pCO2 of 400 Pa.

Spacecraft attitude control for a solar electric geosynchronous transfer mission

NASA Technical Reports Server (NTRS)

Leroy, B. E.; Regetz, J. D., Jr.

1975-01-01

A study of the Attitude Control System (ACS) is made for a solar electric propulsion geosynchronous transfer mission. The basic mission considered is spacecraft injection into a low altitude, inclined orbit followed by low thrust orbit changing to achieve geosynchronous orbit. Because of the extended thrusting time, the mission performance is a strong function of the attitude control system. Two attitude control system design options for an example mission evolve from consideration of the spacecraft configuration, the environmental disturbances, and the probable ACS modes of operation. The impact of these design options on other spacecraft subsystems is discussed. The factors which must be considered in determining the ACS actuation and sensing subsystems are discussed. The effects of the actuation and sensing subsystems on the mission performance are also considered.

Solid freeform fabrication apparatus and methods

NASA Technical Reports Server (NTRS)

Taminger, Karen M. (Inventor); Watson, J. Kevin (Inventor); Hafley, Robert A. (Inventor); Petersen, Daniel D. (Inventor)

2007-01-01

An apparatus for formation of a three dimensional object comprising a sealed container; an electron beam subsystem capable of directing energy within said container; a positioning subsystem contained within said container; a wire feed subsystem contained within said container; an instrumentation subsystem electronically connected to said electron beam subsystem, positioning subsystem, and wire feed subsystem; and a power distribution subsystem electrically connected to said electron beam subsystem, positioning subsystem, wire feed subsystem, and said instrumentation subsystem.

Project Orion, Environmental Control and Life Support System Integrated Studies

NASA Technical Reports Server (NTRS)

Russell, James F.; Lewis, John F.

2008-01-01

Orion is the next vehicle for human space travel. Humans will be sustained in space by the Orion subystem, environmental control and life support (ECLS). The ECLS concept at the subsystem level is outlined by function and technology. In the past two years, the interface definition with other subsystems has increased through different integrated studies. The paper presents the key requirements and discusses three recent studies (e.g., unpressurized cargo) along with the respective impacts on the ECLS design moving forward.

Rapid Damage Assessment. Volume II. Development and Testing of Rapid Damage Assessment System.

DTIC Science & Technology

1981-02-01

pixels/s Camera Line Rate 732.4 lines/s Pixels per Line 1728 video 314 blank 4 line number (binary) 2 run number (BCD) 2048 total Pixel Resolution 8 bits...sists of an LSI-ll microprocessor, a VDI -200 video display processor, an FD-2 dual floppy diskette subsystem, an FT-I function key-trackball module...COMPONENT LIST FOR IMAGE PROCESSOR SYSTEM IMAGE PROCESSOR SYSTEM VIEWS I VDI -200 Display Processor Racks, Table FD-2 Dual Floppy Diskette Subsystem FT-l

Triton's surface properties - A preliminary analysis from ground-based, Voyager photopolarimeter subsystem, and laboratory measurements

NASA Technical Reports Server (NTRS)

Buratti, B. J.; Lane, A. L.; Gibson, J.; Burrows, H.; Nelson, R. M.; Bliss, D.; Smythe, W.; Garkanian, V.; Wallis, B.

1991-01-01

The surface properties of Triton were investigated using data from the ground-based and Voyager photopolarimeter subsystem (PPS) observations of Triton's phase curve. The results indicate that Triton has a high single-scattering albedo (0.96 +/-0.01 at 0.75 micron) and an unusually compacted surface, possibly similar to that of Europa. Results also suggest that Triton's single-particle phase function and the macroscopically rough character of its surface are similar to those of most other icy satellites.

Preliminary design of the Space Station environmental control and life support system

NASA Technical Reports Server (NTRS)

Reuter, J. L.; Turner, L. D.; Humphries, W. R.

1988-01-01

This paper outlines the current status of the Space Station Enrivonmental Control and Life Support System (ECLSS). The seven subsystem groups which comprise the ECLSS are identified and their functional descriptions are provided. The impact that the nominal and safe haven operating requirements have on the physical distribution, sizing, and number of ECLSS subsystems is described. The role that the major ECLSS interfaces with other Space Station systems and elements play in the ECLSS design is described.

System integration of pattern recognition, adaptive aided, upper limb prostheses

NASA Technical Reports Server (NTRS)

Lyman, J.; Freedy, A.; Solomonow, M.

1975-01-01

The requirements for successful integration of a computer aided control system for multi degree of freedom artificial arms are discussed. Specifications are established for a system which shares control between a human amputee and an automatic control subsystem. The approach integrates the following subsystems: (1) myoelectric pattern recognition, (2) adaptive computer aiding; (3) local reflex control; (4) prosthetic sensory feedback; and (5) externally energized arm with the functions of prehension, wrist rotation, elbow extension and flexion and humeral rotation.

AMSEC Users Guide.

DTIC Science & Technology

1976-11-01

Hardware • System functional configuration characteristics • Component aging mechanisms (engineering) • Subsystem/component FMEAs • Subsystem...modified to fit the specific mission(s) under investigation. 60 — .- m. • •. mi . ui ••_!!•»•••’ i • .. ••Mil ’’•^•^••BWW^WlWi^Wi...8217 / t / / / s y / ’ / / * y hO | -;-; • / / 1, r T ", 60 / / / • f tl’Jt, s s 1 / ’ • Mode 7 B=4.0 ^ / 7 / 0 Mode 8

Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

PubMed Central

Principi, E.; Giangrisostomi, E.; Cucini, R.; Bencivenga, F.; Battistoni, A.; Gessini, A.; Mincigrucci, R.; Saito, M.; Di Fonzo, S.; D'Amico, F.; Di Cicco, A.; Gunnella, R.; Filipponi, A.; Giglia, A.; Nannarone, S.; Masciovecchio, C.

2015-01-01

High-energy density extreme ultraviolet radiation delivered by the FERMI seeded free-electron laser has been used to create an exotic nonequilibrium state of matter in a titanium sample characterized by a highly excited electron subsystem at temperatures in excess of 10 eV and a cold solid-density ion lattice. The obtained transient state has been investigated through ultrafast absorption spectroscopy across the Ti M2,3-edge revealing a drastic rearrangement of the sample electronic structure around the Fermi level occurring on a time scale of about 100 fs. PMID:26798835

Patterns of HIV-1 Protein Interaction Identify Perturbed Host-Cellular Subsystems

PubMed Central

MacPherson, Jamie I.; Dickerson, Jonathan E.; Pinney, John W.; Robertson, David L.

2010-01-01

Human immunodeficiency virus type 1 (HIV-1) exploits a diverse array of host cell functions in order to replicate. This is mediated through a network of virus-host interactions. A variety of recent studies have catalogued this information. In particular the HIV-1, Human Protein Interaction Database (HHPID) has provided a unique depth of protein interaction detail. However, as a map of HIV-1 infection, the HHPID is problematic, as it contains curation error and redundancy; in addition, it is based on a heterogeneous set of experimental methods. Based on identifying shared patterns of HIV-host interaction, we have developed a novel methodology to delimit the core set of host-cellular functions and their associated perturbation from the HHPID. Initially, using biclustering, we identify 279 significant sets of host proteins that undergo the same types of interaction. The functional cohesiveness of these protein sets was validated using a human protein-protein interaction network, gene ontology annotation and sequence similarity. Next, using a distance measure, we group host protein sets and identify 37 distinct higher-level subsystems. We further demonstrate the biological significance of these subsystems by cross-referencing with global siRNA screens that have been used to detect host factors necessary for HIV-1 replication, and investigate the seemingly small intersect between these data sets. Our results highlight significant host-cell subsystems that are perturbed during the course of HIV-1 infection. Moreover, we characterise the patterns of interaction that contribute to these perturbations. Thus, our work disentangles the complex set of HIV-1-host protein interactions in the HHPID, reconciles these with siRNA screens and provides an accessible and interpretable map of infection. PMID:20686668

Interactions between the default network and dorsal attention network vary across default subsystems, time, and cognitive states.

PubMed

Dixon, Matthew L; Andrews-Hanna, Jessica R; Spreng, R Nathan; Irving, Zachary C; Mills, Caitlin; Girn, Manesh; Christoff, Kalina

2017-02-15

Anticorrelation between the default network (DN) and dorsal attention network (DAN) is thought to be an intrinsic aspect of functional brain organization reflecting competing functions. However, the effect size of functional connectivity (FC) between the DN and DAN has yet to be established. Furthermore, the stability of anticorrelations across distinct DN subsystems, different contexts, and time, remains unexplored. In study 1 we summarize effect sizes of DN-DAN FC from 20 studies, and in study 2 we probe the variability of DN-DAN interactions across six different cognitive states in a new data set. We show that: (i) the DN and DAN have an independent rather than anticorrelated relationship when global signal regression is not used (median effect size across studies: r=-.06; 95% CI: -.15 to .08); (ii) the DAN exhibits weak negative FC with the DN Core subsystem but is uncorrelated with the dorsomedial prefrontal and medial temporal lobe subsystems; (iii) DN-DAN interactions vary significantly across different cognitive states; (iv) DN-DAN FC fluctuates across time between periods of anticorrelation and periods of positive correlation; and (v) changes across time in the strength of DN-DAN coupling are coordinated with interactions involving the frontoparietal control network (FPCN). Overall, the observed weak effect sizes related to DN-DAN anticorrelation suggest the need to re-conceptualize the nature of interactions between these networks. Furthermore, our findings demonstrate that DN-DAN interactions are not stable, but rather, exhibit substantial variability across time and context, and are coordinated with broader network dynamics involving the FPCN. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Universality of quantum information in chaotic CFTs

NASA Astrophysics Data System (ADS)

Lashkari, Nima; Dymarsky, Anatoly; Liu, Hong

2018-03-01

We study the Eigenstate Thermalization Hypothesis (ETH) in chaotic conformal field theories (CFTs) of arbitrary dimensions. Assuming local ETH, we compute the reduced density matrix of a ball-shaped subsystem of finite size in the infinite volume limit when the full system is an energy eigenstate. This reduced density matrix is close in trace distance to a density matrix, to which we refer as the ETH density matrix, that is independent of all the details of an eigenstate except its energy and charges under global symmetries. In two dimensions, the ETH density matrix is universal for all theories with the same value of central charge. We argue that the ETH density matrix is close in trace distance to the reduced density matrix of the (micro)canonical ensemble. We support the argument in higher dimensions by comparing the Von Neumann entropy of the ETH density matrix with the entropy of a black hole in holographic systems in the low temperature limit. Finally, we generalize our analysis to the coherent states with energy density that varies slowly in space, and show that locally such states are well described by the ETH density matrix.

Adaptive Neural Networks Decentralized FTC Design for Nonstrict-Feedback Nonlinear Interconnected Large-Scale Systems Against Actuator Faults.

PubMed

Li, Yongming; Tong, Shaocheng

The problem of active fault-tolerant control (FTC) is investigated for the large-scale nonlinear systems in nonstrict-feedback form. The nonstrict-feedback nonlinear systems considered in this paper consist of unstructured uncertainties, unmeasured states, unknown interconnected terms, and actuator faults (e.g., bias fault and gain fault). A state observer is designed to solve the unmeasurable state problem. Neural networks (NNs) are used to identify the unknown lumped nonlinear functions so that the problems of unstructured uncertainties and unknown interconnected terms can be solved. By combining the adaptive backstepping design principle with the combination Nussbaum gain function property, a novel NN adaptive output-feedback FTC approach is developed. The proposed FTC controller can guarantee that all signals in all subsystems are bounded, and the tracking errors for each subsystem converge to a small neighborhood of zero. Finally, numerical results of practical examples are presented to further demonstrate the effectiveness of the proposed control strategy.The problem of active fault-tolerant control (FTC) is investigated for the large-scale nonlinear systems in nonstrict-feedback form. The nonstrict-feedback nonlinear systems considered in this paper consist of unstructured uncertainties, unmeasured states, unknown interconnected terms, and actuator faults (e.g., bias fault and gain fault). A state observer is designed to solve the unmeasurable state problem. Neural networks (NNs) are used to identify the unknown lumped nonlinear functions so that the problems of unstructured uncertainties and unknown interconnected terms can be solved. By combining the adaptive backstepping design principle with the combination Nussbaum gain function property, a novel NN adaptive output-feedback FTC approach is developed. The proposed FTC controller can guarantee that all signals in all subsystems are bounded, and the tracking errors for each subsystem converge to a small neighborhood of zero. Finally, numerical results of practical examples are presented to further demonstrate the effectiveness of the proposed control strategy.

Optical effects module. [housing instruments used to measure degradation of optical samples from contamination during orbital operations

NASA Technical Reports Server (NTRS)

1978-01-01

The possible degradation of optical samples exposed to the effluent gases and particulate matter emanating from the payload of the space transportation system during orbital operations may be determined by measuring two optical parameters for five samples exposed to this environment, namely transmittance and diffuse reflectance. Any changes detected in these parameters as a function of time during the mission are then attributable to surface contamination or to increased material absorption. These basic functions are attained in the optical effects module by virtue of the following subsystems which are described: module enclosure; light source with collimator and modulator; sample wheel with holders and rotary drive; photomultipliers for radiation detection; processing and sequencing electronic circuitry; and power conditioning interfaces. The functions of these subsystems are reviewed and specified.

Entanglement entropy of 2D conformal quantum critical points: hearing the shape of a quantum drum.

PubMed

Fradkin, Eduardo; Moore, Joel E

2006-08-04

The entanglement entropy of a pure quantum state of a bipartite system A union or logical sumB is defined as the von Neumann entropy of the reduced density matrix obtained by tracing over one of the two parts. In one dimension, the entanglement of critical ground states diverges logarithmically in the subsystem size, with a universal coefficient that for conformally invariant critical points is related to the central charge of the conformal field theory. We find that the entanglement entropy of a standard class of z=2 conformal quantum critical points in two spatial dimensions, in addition to a nonuniversal "area law" contribution linear in the size of the AB boundary, generically has a universal logarithmically divergent correction, which is completely determined by the geometry of the partition and by the central charge of the field theory that describes the critical wave function.

Spacelab Lyman Alpha-White Light Coronagraph Program

NASA Technical Reports Server (NTRS)

Kohl, J. L.

1986-01-01

The Spacelab Lyman Alpha Coronagraph (SLAC) of the Smithsonian Astrophysical Observatory (SAO) and the White Light Coronagraph (WLC) to be provided by the High Altitude Observatory (HAO) are two separate coronagraphs which would be operated in a joint fashion during Spacelab missions to be flown by the Space Shuttle. The two instruments would be used to perform joint observations of solar coronal structures from 1.2 to 8.0 solar radii from sun-center in vacuum ultraviolet and visible radiations. Temperatures, densities, and flow velocities throughout the solar wing acceleration region of the inner solar corona were measured. The Phase I Definition activity resulted in the successful definition and preliminary design of the experiment/instrumentation subsystem and associated software, ground support equipment and interfaces to the extended required to accurately estimate the scope of the investigation and prepare an Investigational Development Plan; the performance of the necessary functional, operations, and safety analyses necessary to complete the Experiment Requirements document.

A SYSTEMS ANALYSIS OF SCHOOL BOARD ACTION.

ERIC Educational Resources Information Center

SCRIBNER, JAY D.

THE BASIC ASSUMPTION OF THE FUNCTIONAL-SYSTEMS THEORY IS THAT STRUCTURES FULFILL FUNCTIONS IN SYSTEMS AND THAT SUBSYSTEMS OPERATE SEPARATELY WITHIN ANY TYPE OF STRUCTURE. RELYING MAINLY ON GABRIEL ALMOND'S PARADIGM, THE AUTHOR ATTEMPTS TO DETERMINE THE USEFULNESS OF THE FUNCTIONAL-SYSTEMS THEORY IN CONDUCTING EMPIRICAL RESEARCH OF SCHOOL BOARDS.…

Thermal Equilibrium of a Macroscopic Quantum System in a Pure State.

PubMed

Goldstein, Sheldon; Huse, David A; Lebowitz, Joel L; Tumulka, Roderich

2015-09-04

We consider the notion of thermal equilibrium for an individual closed macroscopic quantum system in a pure state, i.e., described by a wave function. The macroscopic properties in thermal equilibrium of such a system, determined by its wave function, must be the same as those obtained from thermodynamics, e.g., spatial uniformity of temperature and chemical potential. When this is true we say that the system is in macroscopic thermal equilibrium (MATE). Such a system may, however, not be in microscopic thermal equilibrium (MITE). The latter requires that the reduced density matrices of small subsystems be close to those obtained from the microcanonical, equivalently the canonical, ensemble for the whole system. The distinction between MITE and MATE is particularly relevant for systems with many-body localization for which the energy eigenfuctions fail to be in MITE while necessarily most of them, but not all, are in MATE. We note, however, that for generic macroscopic systems, including those with MBL, most wave functions in an energy shell are in both MATE and MITE. For a classical macroscopic system, MATE holds for most phase points on the energy surface, but MITE fails to hold for any phase point.

Design definition of a mechanical capacitor

NASA Technical Reports Server (NTRS)

Michaelis, T. D.; Schlieban, E. W.; Scott, R. D.

1977-01-01

A design study and analyses of a 10 kW-hr, 15 kW mechanical capacitor system was studied. It was determined that magnetically supported wheels constructed of advanced composites have the potential for high energy density and high power density. Structural concepts are analyzed that yield the highest energy density of any structural design yet reported. Particular attention was paid to the problem of 'friction' caused by magnetic and I to the second power R losses in the suspension and motor-generator subsystems, and low design friction levels have been achieved. The potentially long shelf life of this system, and the absence of wearing parts, provide superior performance over conventional flywheels supported with mechanical bearings. Costs and economies of energy storage wheels were reviewed briefly.

The Schrödinger–Langevin equation with and without thermal fluctuations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katz, R., E-mail: roland.katz@subatech.in2p3.fr; Gossiaux, P.B., E-mail: Pol-Bernard.Gossiaux@subatech.in2p3.fr

2016-05-15

The Schrödinger–Langevin equation (SLE) is considered as an effective open quantum system formalism suitable for phenomenological applications involving a quantum subsystem interacting with a thermal bath. We focus on two open issues relative to its solutions: the stationarity of the excited states of the non-interacting subsystem when one considers the dissipation only and the thermal relaxation toward asymptotic distributions with the additional stochastic term. We first show that a proper application of the Madelung/polar transformation of the wave function leads to a non zero damping of the excited states of the quantum subsystem. We then study analytically and numerically themore » SLE ability to bring a quantum subsystem to the thermal equilibrium of statistical mechanics. To do so, concepts about statistical mixed states and quantum noises are discussed and a detailed analysis is carried with two kinds of noise and potential. We show that within our assumptions the use of the SLE as an effective open quantum system formalism is possible and discuss some of its limitations.« less

Newman Unit 1 advanced solar repowering advanced conceptual design. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1982-04-01

The Newman Unit 1 solar repowering design is a water/steam central receiver concept supplying superheated steam. The work reported is to develop a refined baseline conceptual design that has potential for construction and operation by 1986, makes use of existing solar thermal technology, and provides the best economics for this application. Trade studies performed in the design effort are described, both for the conceptual design of the overall system and for the subsystem conceptual design. System-level functional requirements, design, operation, performance, cost, safety, environmental, institutional, and regulatory considerations are described. Subsystems described include the collector, receiver, fossil energy, electrical powermore » generating, and master control subsystems, site and site facilities. The conceptual design, cost, and performance of each subsystem is discussed at length. A detailed economic analysis of the repowered unit is made to realistically assess the economics of the first repowered unit using present cost data for a limited production level for solar hardware. Finally, a development plan is given, including the design, procurement, construction, checkout, startup, performance validation, and commercial operation. (LEW)« less

Independent Orbiter Assessment (IOA): Analysis of the electrical power generation/fuel cell powerplant subsystem

NASA Technical Reports Server (NTRS)

Brown, K. L.; Bertsch, P. J.

1986-01-01

Results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Generation (EPG)/Fuel Cell Powerplant (FCP) hardware. The EPG/FCP hardware is required for performing functions of electrical power generation and product water distribution in the Orbiter. Specifically, the EPG/FCP hardware consists of the following divisions: (1) Power Section Assembly (PSA); (2) Reactant Control Subsystem (RCS); (3) Thermal Control Subsystem (TCS); and (4) Water Removal Subsystem (WRS). The IOA analysis process utilized available EPG/FCP hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode.

Performance evaluation of Platform Data ManagementSystem under various degrees of protocol implementation

NASA Technical Reports Server (NTRS)

Arozullah, Mohammed

1991-01-01

The Platform Data Management System (DMS) collects Housekeeping (H/K), Payload (P/L) Engineering, and Payload Science data from various subsystems and payloads on the platform for transmission to the ground through the downlink via TDRSS. The DMS also distributes command data received from the ground to various subsystems and payloads. In addition, DMS distributes timing and safemode data. The function of collection and distribution of various types of data is performed by the Command and Data Handling (C&DH) subsystem of DMS. The C&DH subsystem uses for this purpose a number of data buses namely, Housekeeping, Payload Engineering, Payload Science, and Time and Safemode buses. Out of these buses, the H/K, P/L Engineering, and P/L Science buses are planned to be implemented by using MIL-STD 1553 bus. Most of the period covered was spent in developing a queue theoretic model of the 1553 Bus as used in the DMS. The aim is to use this model to test the performance and suitability of the 1553 Bus to the DMS under a number of alternative design scenarios.

Lp-stability (1 less than or equal to p less than or equal to infinity) of multivariable nonlinear time-varying feedback systems that are open-loop unstable. [noting unstable convolution subsystem forward control and time varying nonlinear feedback

NASA Technical Reports Server (NTRS)

Callier, F. M.; Desoer, C. A.

1973-01-01

A class of multivariable, nonlinear time-varying feedback systems with an unstable convolution subsystem as feedforward and a time-varying nonlinear gain as feedback was considered. The impulse response of the convolution subsystem is the sum of a finite number of increasing exponentials multiplied by nonnegative powers of the time t, a term that is absolutely integrable and an infinite series of delayed impulses. The main result is a theorem. It essentially states that if the unstable convolution subsystem can be stabilized by a constant feedback gain F and if incremental gain of the difference between the nonlinear gain function and F is sufficiently small, then the nonlinear system is L(p)-stable for any p between one and infinity. Furthermore, the solutions of the nonlinear system depend continuously on the inputs in any L(p)-norm. The fixed point theorem is crucial in deriving the above theorem.

Initial development and performance evaluation of a process for formation of dense carbon by pyrolysis of methane

NASA Technical Reports Server (NTRS)

Noyes, G. P.; Cusick, R. J.

1985-01-01

The three steps in pyrolytic carbon formation are: (1) gaseous hydrocarbon polymerization and aromatic formation; (2) gas-phase condensation and surface adsorption/impingement of polyaromatic hydrocarbon; and (3) final dehydration to carbon. The structure of the carbon in the various stages of formation is examined. The apparatuses and experimental procedures for the pyrolysis of methane in a 60 cm long quartz reactor tube at temperatures ranging from 1400-1600 K are described. The percentage of carbon converted and its density are calculated and tabularly presented. The results reveal that dense carbon formation is maximized and soot eliminated by this procedure. It is observed that conversion efficiency depends on the composition of the inlet gas and conversion increases with increasing temperature. Based on the experimental data a three-man carbon reactor subsystem (CRS) is developed; the functions of the Sabatier Methanation Reactor, two carbon formation reactors and fluid handling components of the CRS are analyzed. The CRS forms 16 kg of carbon at a rate of 0.8 kg/day for 20 days in a two percent volume density quartz wool packing at temperature of 1500-1600 K.

First principles study of hydrogen adsorption on carbon nanowires.

NASA Astrophysics Data System (ADS)

Tapia, Alejandro; Aguilera, Luis; Murrieta, Gabriel; de Coss, Romeo

2007-03-01

Recently has been reported a new type of one-dimensional carbon structures. Carbon nanowires formed by a linear carbon-atom chain inside an armchair (5,5) carbon nanotube has been observed using high-resolution transmission electron microscopy. In the present work we have studied the changes in the electronic structure of a carbon nanowires and (5,5) single-walled carbon nanotubes (SWCN) when a hydrogen atom is adsorbed. We used the Density Functional Theory and the calculations where performed by the pseudopotentials LCAO method (SIESTA code) and the Generalized Gradient Approximation (GGA) for the exchange-correlation potential. We have analyzed the changes in the atomic structure, density of states (LDOS), and the local orbital population. We found charge transfer from the nanotube to the linear chain and the hydrogen atom, the electronic character of the chain and nanotube sub-systems in chain@SWCN is the same that in the corresponding isolated systems, chain or SWCN. But the hydrogen adsorption produced changes in the atomic estructure and the electronic properties. This research was supported by PRIORI-UADY under Grant No. FING-05-004 and Consejo Nacional de Ciencia y Tecnolog'ia (Conacyt) under Grants No. 43830-F and 49985-J.

Lewis Base Passivation of Hybrid Halide Perovskites Slows Electron-Hole Recombination: Time-Domain Ab Initio Analysis.

PubMed

Liu, Lihong; Fang, Wei-Hai; Long, Run; Prezhdo, Oleg V

2018-03-01

Nonradiative electron-hole recombination plays a key role in determining photon conversion efficiencies in solar cells. Experiments demonstrate significant reduction in the recombination rate upon passivation of methylammonium lead iodide perovskite with Lewis base molecules. Using nonadiabatic molecular dynamics combined with time-domain density functional theory, we find that the nonradiative charge recombination is decelerated by an order of magnitude upon adsorption of the molecules. Thiophene acts by the traditional passivation mechanism, forcing electron density away from the surface. In contrast, pyridine localizes the electron at the surface while leaving it energetically near the conduction band edge. This is because pyridine creates a stronger coordinative bond with a lead atom of the perovskite and has a lower energy unoccupied orbital compared with thiophene due to the more electronegative nitrogen atom relative to thiophene's sulfur. Both molecules reduce two-fold the nonadiabatic coupling and electronic coherence time. A broad range of vibrational modes couple to the electronic subsystem, arising from inorganic and organic components. The simulations reveal the atomistic mechanisms underlying the enhancement of the excited-state lifetime achieved by the perovskite passivation, rationalize the experimental results, and advance our understanding of charge-phonon dynamics in perovskite solar cells.

Peculiarities of electron density distribution in bismuth chalcogenides, iron pnictides, cuprates and related unconventional superconductors

NASA Astrophysics Data System (ADS)

Orlov, V. G.; Sergeev, G. S.

2018-05-01

With the aim to reveal the origin of instabilities in the electron subsystem of unconventional superconductors, such as stripes or nematic symmetry breaking, electron band structure calculations were performed for a number of bismuth chalcogenides, bismuth oxide, iron pnictides, as well as for Bi2Sr2CaCu2O8, YBa2Cu3O7 and La2CuO4. It was found that bond critical points in the electron density distribution ρ(r) of all the studied compounds were characterized by positive sign of electron density Laplacian evidencing on depletion of electron charge from the area of bond critical points. A correlation was found between the Tc and the value of electron density Laplacian in the strongest bond critical points of superconductors and related substances.

Interglomerular Connectivity within the Canonical and GC-D/Necklace Olfactory Subsystems

PubMed Central

Puche, Adam C.; Munger, Steven D.

2016-01-01

The mammalian main olfactory system contains several subsystems that differ not only in the receptors they express and the glomerular targets they innervate within the main olfactory bulb (MOB), but also in the strategies they use to process odor information. The canonical main olfactory system employs a combinatorial coding strategy that represents odorant identity as a pattern of glomerular activity. By contrast, the "GC-D/necklace" olfactory subsystem—formed by olfactory sensory neurons expressing the receptor guanylyl cyclase GC-D and their target necklace glomeruli (NGs) encircling the caudal MOB—is critical for the detection of a small number of semiochemicals that promote the acquisition of food preferences. The formation of these socially-transmitted food preferences requires the animal to integrate information about two types of olfactory stimuli: these specialized social chemosignals and the food odors themselves. However, the neural mechanisms with which the GC-D/necklace subsystem processes this information are unclear. We used stimulus-induced increases in intrinsic fluorescence signals to map functional circuitry associated with NGs and canonical glomeruli (CGs) in the MOB. As expected, CG-associated activity spread laterally through both the glomerular and external plexiform layers associated with activated glomeruli. Activation of CGs or NGs resulted in activity spread between the two types of glomeruli; there was no evidence of preferential connectivity between individual necklace glomeruli. These results support previous anatomical findings that suggest the canonical and GC-D/necklace subsystems are functionally connected and may integrate general odor and semiochemical information in the MOB. PMID:27902696

An integrative approach to energy, carbon, and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803

DOE Office of Scientific and Technical Information (OSTI.GOV)

Overbeek, Ross; Fonstein, Veronika; Osterman, Andrei

2005-02-15

The team of the Fellowship for Interpretation of Genomes (FIG) under the leadership of Ross Overbeek, began working on this Project in November 2003. During the previous year, the Project was performed at Integrated Genomics Inc. A transition from the industrial environment to the public domain prompted us to adjust some aspects of the Project. Notwithstanding the challenges, we believe that these adjustments had a strong positive impact on our deliverables. Most importantly, the work of the research team led by R. Overbeek resulted in the deployment of a new open source genomic platform, the SEED (Specific Aim 1). Thismore » platform provided a foundation for the development of CyanoSEED a specialized portal to comparative analysis and metabolic reconstruction of all available cyanobacterial genomes (Specific Aim 3). The SEED represents a new generation of software for genome analysis. Briefly, it is a portable and extendable system, containing one of the largest and permanently growing collections of complete and partial genomes. The complete system with annotations and tools is freely available via browsing or via installation on a user's Mac or Linux computer. One of the important unique features of the SEED is the support of metabolic reconstruction and comparative genome analysis via encoding and projection of functional subsystems. During the project period, the FIG research team has validated the new software by developing a significant number of core subsystems, covering many aspects of central metabolism (Specific Aim 2), as well as metabolic areas specific for cyanobacteria and other photoautotrophic organisms (Specific Aim 3). In addition to providing a proof of technology and a starting point for further community-based efforts, these subsystems represent a valuable asset. An extensive coverage of central metabolism provides the bulk of information required for metabolic modeling in Synechocystis sp.PCC 6803. Detailed analysis of several subsystems covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and other cyanobacteria has been performed (Specific Aim 4). The main objectives for this year (adjusted to reflect a new, public domain, setting of the Project research team) were: Aim 1. To develop, test, and deploy a new open source system, the SEED, for integrating community-based annotation, and comparative analysis of all publicly available microbial genomes. Develop a comprehensive genomic database by integrating within SEED all publicly available complete and nearly complete genome sequences with special emphasis on genomes of cyanobacteria, phototrophic eukaryotes, and anoxygenic phototrophic bacteria--invaluable for comparative genomic studies of energy and carbon metabolism in Synechocystis sp. PCC 6803. Aim 2. To develop the SEED's biological content in the form of a collection of encoded Subsystems largely covering the conserved cellular machinery in prokaryotes (and central metabolic machinery in eukaryotes). Aim 3. To develop, utilizing core SEED technology, the CyanoSEED--a specialized WEB portal for community-based annotation, and comparative analysis of all publicly available cyanobacterial genomes. Encode the set of additional subsystems representing key metabolic transformations in cyanobacteria and other photoautotrophs. We envisioned this resource as complementary to other public access databases for comparative genomic analysis currently available to the cyanobacterial research community. Aim 4. Perform in-depth analysis of several subsystems covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and all other cyanobacteria with available genome sequences. Reveal inconsistencies and gaps in the current knowledge of these subsystems. Use functional and genome context analysis tools in CyanoSEED to predict, whenever possible, candidate genes for inferred functional roles. To disseminate freely these conjectures and predictions by publishing them on CyanoSEED (http://cyanoseed.thefig.info/) and the Subsystems Forum (http://brucella.uchicago.edu/SubsystemForum/) in order to facilitate experimental analysis by our collaborator on this Project and by other experimentalists working in various field of cyanobacterial physiology and biotechnology.« less

Bipartite non-classical correlations for a lossy two connected qubit-cavity systems: trace distance discord and Bell's non-locality

NASA Astrophysics Data System (ADS)

Mohamed, Abdel-Baset A.

2018-04-01

In this paper, some non-classical correlations are investigated for bipartite partitions of two qubits trapped in two spatially separated cavities connected by an optical fiber. The results show that the trace distance discord and Bell's non-locality introduce other quantum correlations beyond the entanglement. Moreover, the correlation functions of the trace distance discord and the Bell's non-locality are very sensitive to the initial correlations, the coupling strengths, and the dissipation rates of the cavities. The fluctuations of the correlation functions between their initial values and gained (loss) values appear due to the unitary evolution of the system. These fluctuations depend on the chosen initial correlations between the two subsystems. The maximal violations of Bell's inequality occur when the logarithmic negativity and the trace distance discord reach certain values. It is shown that the robustness of the non-classical correlations, against the dissipation rates of the cavities, depends on the bipartite partitions reduced density matrices of the system, and is also greatly enhanced by choosing appropriate coupling strengths.

Interaction among subsystems within default mode network diminished in schizophrenia patients: a dynamic connectivity approach

PubMed Central

Du, Yuhui; Pearlson, Godfrey D; Yu, Qingbao; He, Hao; Lin, Dongdong; Sui, Jing; Wu, Lei; Calhoun, Vince D.

2015-01-01

Default mode network (DMN) has been reported altered in schizophrenia (SZ) using static connectivity analysis. However, the studies on dynamic characteristics of DMN in SZ are still limited. In this work, we compare dynamic connectivity within DMN between 82 healthy controls (HC) and 82 SZ patients using resting-state fMRI. Firstly, dynamic DMN was computed using a sliding time window method for each subject. Then, the overall connectivity strengths were compared between two groups. Furthermore, we estimated functional connectivity states using K-means clustering, and then investigated group differences with respect to the connectivity strengths in states, the dwell time in each state, and the transition times between states. Finally, graph metrics of time-varying connectivity patterns and connectivity states were assessed. Results suggest that measured by the overall connectivity, HC showed stronger inter-subsystem interaction than patients. Compared to HC, patients spent less time in the states with nodes tightly connected. For each state, SZ patients presented relatively weaker connectivity strengths mainly in inter-subsystem. Patients also exhibited lower values in averaged node strength, clustering coefficient, global efficiency, and local efficiency than HC. In summary, our findings indicate that SZ showed impaired interaction among DMN subsystems, with a reduced central role for posterior cingulate cortex (PCC) and anterior medial prefrontal cortex (aMPFC) hubs as well as weaker interaction between dorsal medial prefrontal cortex (dMPFC) subsystem and medial temporal lobe (MTL) subsystem. For SZ, decreased integration of DMN may be associated with impaired ability in making self-other distinctions and coordinating present mental states with episodic decisions about future. PMID:26654933

Landsat-1 and Landsat-2 flight evaluation

NASA Technical Reports Server (NTRS)

1975-01-01

The flight performance of Landsat 1 and Landsat 2 is analyzed. Flight operations of the satellites are briefly summarized. Other topics discussed include: orbital parameters; power subsystem; attitude control subsystem; command/clock subsystem; telemetry subsystem; orbit adjust subsystem; magnetic moment compensating assembly; unified s-band/premodulation processor; electrical interface subsystem; thermal subsystem; narrowband tape recorders; wideband telemetry subsystem; attitude measurement sensor; wideband video tape recorders; return beam vidicon; multispectral scanner subsystem; and data collection subsystem.

Assessment of sediment sources throughout the proglacial area of a small Arctic catchment based on high-resolution digital elevation models

NASA Astrophysics Data System (ADS)

Kociuba, Waldemar

2017-06-01

The article presents calculations of quantitative modifications of the morphology of selected subsystems of a glacial valley through: (i) identification of the spatial distribution of important sources of sediment, (ii) assessment of the spatiotemporal variety of sediment volume and landform morphology, and (iii) assessment of the role of particular subsystems in sediment distribution. The study involved a comparison of the results of field measurements from 2010 to 2013 performed in the Scott Glacier catchment (10.1 km2) in NW Wedel Jarlsberg Land (Spitsbergen). The assessment of the landform surface changes was performed by means of a precise Terrestrial Laser Scanning (TLS) survey. The applied field and post-processing techniques for oblique laser scanning permitted the acquisition of digital elevation data at a resolution 0.01 m and density > 500 pt m- 2. This allowed the development of a detailed terrain model, and balancing spatial quantitative changes in six research test areas (10,000 m2) located within two subsystems of the catchment in a cascade arrangement. In the alluvial valley-floor subsystem, the survey covered: 1) the glacier terminus, 2) the intramarginal outwash plain, 3) the extramarginal braid-plain and 4) the alluvial fan, and in the slope subsystem: 5) the erosional-depositional slope in the gorge through terminal moraines, and 6) the solifluction slope. Three zones differing in terms of the spatiotemporal dynamics of geomorphic processes were distinguished within the two analysed valley subsystems. In the valley floor subsystem, these are: (i) the zone of basic supply (distribution throughout the melting season) and (ii) the redeposition zone (distribution particularly during floods), and in the slope subsystem: (iii) zone of periodical supply (distributed mainly in periods of increased precipitation and rapid increases in temperature in summer and during snow avalanches in winter). The glacier and the landforms of the channel and valley floor, as well as slope sediments transported as a result of mass wasting processes and activity of the active permafrost layer, constitute important sources of sediment supply over a short/3-year timescale. Evidence of major changes of the surface morphology (slopes, floodplain and channel platform) resulted in varied sediment budgets. The subtraction of consecutive DEMs of the test areas located in the alluvial valley subsystem revealed downstream spatial and volumetric differentiation, from the predominance of erosion (79% of volume; 43% of area) to the dominance of deposition (90/91%, respectively) in upper part of the valley floor to erosion predominance in the central (88/95%) and lower (87/82%) part of valley floor. The test areas located on the slope subsystem showed the opposite relationship: deposition dominance (88% of volume; 80% of area) in the upper gorge and erosion dominance (99/99%, respectively) in the lower part (solifluction slopes). The analysis of short-time repeated surveys (3-week survey) where volumes were calculated following DEM subtraction showed increased deposition (82% of volume; 79% of area) for the alluvial fan, and for solifluction slopes (70/57%, respectively).

LANDSAT-1 flight evaluation report

NASA Technical Reports Server (NTRS)

1975-01-01

Flight performance analysis for the tenth quarter of operation orbit 11467 to 12745 of LANDSAT 1 are presented. Payload subsystems discussed include: power subsystem; attitude control subsystem; telemetry subsystem; electrical interface subsystem; narrowband tape recorders; wideband telemetry subsystem; return beam vidicon subsystem; multispectral scanner subsystem; and data collection system.

Advanced Land Imager Assessment System

NASA Technical Reports Server (NTRS)

Chander, Gyanesh; Choate, Mike; Christopherson, Jon; Hollaren, Doug; Morfitt, Ron; Nelson, Jim; Nelson, Shar; Storey, James; Helder, Dennis; Ruggles, Tim;

Prediction of the vibroacoustic behavior of a submerged shell with non-axisymmetric internal substructures by a condensed transfer function method

NASA Astrophysics Data System (ADS)

Meyer, V.; Maxit, L.; Guyader, J.-L.; Leissing, T.

2016-01-01

The vibroacoustic behavior of axisymmetric stiffened shells immersed in water has been intensively studied in the past. On the contrary, little attention has been paid to the modeling of these shells coupled to non-axisymmetric internal frames. Indeed, breaking the axisymmetry couples the circumferential orders of the Fourier series and considerably increases the computational costs. In order to tackle this issue, we propose a sub-structuring approach called the Condensed Transfer Function (CTF) method that will allow assembling a model of axisymmetric stiffened shell with models of non-axisymmetric internal frames. The CTF method is developed in the general case of mechanical subsystems coupled along curves. A set of orthonormal functions called condensation functions, which depend on the curvilinear abscissa along the coupling line, is considered. This set is then used as a basis for approximating and decomposing the displacements and the applied forces at the line junctions. Thanks to the definition and calculation of condensed transfer functions for each uncoupled subsystem and by using the superposition principle for passive linear systems, the behavior of the coupled subsystems can be deduced. A plane plate is considered as a test case to study the convergence of the method with respect to the type and the number of condensation functions taken into account. The CTF method is then applied to couple a submerged non-periodically stiffened shell described using the Circumferential Admittance Approach (CAA) with internal substructures described by Finite Element Method (FEM). The influence of non-axisymmetric internal substructures can finally be studied and it is shown that it tends to increase the radiation efficiency of the shell and can modify the vibrational and acoustic energy distribution.

Waste water processing technology for Space Station Freedom - Comparative test data analysis

NASA Technical Reports Server (NTRS)

Miernik, Janie H.; Shah, Burt H.; Mcgriff, Cindy F.

1991-01-01

Comparative tests were conducted to choose the optimum technology for waste water processing on SSF. A thermoelectric integrated membrane evaporation (TIMES) subsystem and a vapor compression distillation subsystem (VCD) were built and tested to compare urine processing capability. Water quality, performance, and specific energy were compared for conceptual designs intended to function as part of the water recovery and management system of SSF. The VCD is considered the most mature and efficient technology and was selected to replace the TIMES as the baseline urine processor for SSF.

CO2 laser ranging systems study

NASA Technical Reports Server (NTRS)

Filippi, C. A.

1975-01-01

The conceptual design and error performance of a CO2 laser ranging system are analyzed. Ranging signal and subsystem processing alternatives are identified, and their comprehensive evaluation yields preferred candidate solutions which are analyzed to derive range and range rate error contributions. The performance results are presented in the form of extensive tables and figures which identify the ranging accuracy compromises as a function of the key system design parameters and subsystem performance indexes. The ranging errors obtained are noted to be within the high accuracy requirements of existing NASA/GSFC missions with a proper system design.

Common modular avionics - Partitioning and design philosophy

NASA Astrophysics Data System (ADS)

Scott, D. M.; Mulvaney, S. P.

The design objectives and definition criteria for common modular hardware that will perform digital processing functions in multiple avionic subsystems are examined. In particular, attention is given to weapon system-level objectives, such as increased supportability, reduced life cycle costs, and increased upgradability. These objectives dictate the following overall modular design goals: reduce test equipment requirements; have a large number of subsystem applications; design for architectural growth; and standardize for technology transparent implementations. Finally, specific partitioning criteria are derived on the basis of the weapon system-level objectives and overall design goals.

ERTS 1 launch and flight activation evaluation report, 23 - 26 July 1972. Launch through Orbit 35 and orbit adjust operation

NASA Technical Reports Server (NTRS)

1972-01-01

The results of the analysis conducted on the telemetry data from the prelaunch, launch, and flight activation phases of the ERTS-1 spacecraft are presented. It is presented by sub system sections and provides for inter-relationships as they exist between the several subsystems. A brief statement of subsystem characteristics precedes flight evaluation statements. The appendix contains a total list of components flow on ERTS-1 and a complete listing of commands and telemetry functions for reference.

Molecular Interaction Map of the Mammalian Cell Cycle Control and DNA Repair Systems

PubMed Central

Kohn, Kurt W.

1999-01-01

Eventually to understand the integrated function of the cell cycle regulatory network, we must organize the known interactions in the form of a diagram, map, and/or database. A diagram convention was designed capable of unambiguous representation of networks containing multiprotein complexes, protein modifications, and enzymes that are substrates of other enzymes. To facilitate linkage to a database, each molecular species is symbolically represented only once in each diagram. Molecular species can be located on the map by means of indexed grid coordinates. Each interaction is referenced to an annotation list where pertinent information and references can be found. Parts of the network are grouped into functional subsystems. The map shows how multiprotein complexes could assemble and function at gene promoter sites and at sites of DNA damage. It also portrays the richness of connections between the p53-Mdm2 subsystem and other parts of the network. PMID:10436023

Local Response of Topological Order to an External Perturbation

NASA Astrophysics Data System (ADS)

Hamma, Alioscia; Cincio, Lukasz; Santra, Siddhartha; Zanardi, Paolo; Amico, Luigi

2013-05-01

We study the behavior of the Rényi entropies for the toric code subject to a variety of different perturbations, by means of 2D density matrix renormalization group and analytical methods. We find that Rényi entropies of different index α display derivatives with opposite sign, as opposed to typical symmetry breaking states, and can be detected on a very small subsystem regardless of the correlation length. This phenomenon is due to the presence in the phase of a point with flat entanglement spectrum, zero correlation length, and area law for the entanglement entropy. We argue that this kind of splitting is common to all the phases with a certain group theoretic structure, including quantum double models, cluster states, and other quantum spin liquids. The fact that the size of the subsystem does not need to scale with the correlation length makes it possible for this effect to be accessed experimentally.

Microscopic theory of energy dissipation and decoherence in open systems: A quantum Fermi's golden rule

NASA Astrophysics Data System (ADS)

Taj, D.; Iotti, R. C.; Rossi, F.

2009-11-01

We shall revisit the conventional adiabatic or Markov approximation, which — contrary to the semiclassical case- does not preserve the positive-definite character of the corresponding density matrix, thus leading to highly non-physical results. To overcome this serious limitation, originally addressed by Davies and co-workers almost three decades ago, we shall propose an alternative more general adiabatic procedure, able to provide a reliable/robust treatment of energy-dissipation and dephasing processes in electronic quantum devices. Unlike standard master-equation formulations, our procedure guarantees a positive evolution for a variety of physical subsystem (including the common partial trace), and quantum scattering rates are well defined even for subsystems with internal structure/ continuous energy spectrum. We shall compare the proposed Markov dissipation model with the conventional one also through basic simulations of energy-relaxation versus decoherence channels in prototypical semiconductor nanodevices.

Landsat-1 and Landsat-2 evaluation report, 23 January 1975 to 23 April 1975

NASA Technical Reports Server (NTRS)

1975-01-01

A description of the work accomplished with the Landsat-1 and Landsat-2 satellites during the period 23 Jan. - 23 Apr. 1975 was presented. The following information was given for each satellite: operational summary, orbital parameters, power subsystem, attitude control subsystem, command/clock subsystem, telemetry subsystem, orbit adjust subsystem, magnetic moment compensating assembly, unified S-band/premodulation processor, electrical interface subsystem, thermal subsystem, narrowband tape recorders, wideband telemetry subsystem, attitude measurement sensor, wideband video tape recorders, return beam vidicon, multispectral scanner subsystem, and data collection subsystem.

Applications Technology Satellite ATS-6 in orbit checkout report

NASA Technical Reports Server (NTRS)

Moore, W.; Prensky, W. (Editor)

1974-01-01

The activities of the ATS-6 spacecraft for the checkout period of approximately four weeks beginning May 30, 1974 are described, along with the results of a performance evaluation of its subsystems and components. The following specific items are discussed: (1) subsystem requirements/specifications and in-orbit performance summary; (2) flight chronology; (3) spacecraft description; (4) structural/deployment subsystems; (5) electrical power subsystem; (6) thermal control subsystem; (7) telemetry and command subsystems; (8) attitude control subsystem; (9) spacecraft propulsion subsystem; (10) communication subsystem; and (12) experiment subsystem.

WMAP C&DH Software

NASA Technical Reports Server (NTRS)

Cudmore, Alan; Leath, Tim; Ferrer, Art; Miller, Todd; Walters, Mark; Savadkin, Bruce; Wu, Ji-Wei; Slegel, Steve; Stagmer, Emory

2007-01-01

The command-and-data-handling (C&DH) software of the Wilkinson Microwave Anisotropy Probe (WMAP) spacecraft functions as the sole interface between (1) the spacecraft and its instrument subsystem and (2) ground operations equipment. This software includes a command-decoding and -distribution system, a telemetry/data-handling system, and a data-storage-and-playback system. This software performs onboard processing of attitude sensor data and generates commands for attitude-control actuators in a closed-loop fashion. It also processes stored commands and monitors health and safety functions for the spacecraft and its instrument subsystems. The basic functionality of this software is the same of that of the older C&DH software of the Rossi X-Ray Timing Explorer (RXTE) spacecraft, the main difference being the addition of the attitude-control functionality. Previously, the C&DH and attitude-control computations were performed by different processors because a single RXTE processor did not have enough processing power. The WMAP spacecraft includes a more-powerful processor capable of performing both computations.

Automated micromanipulation desktop station based on mobile piezoelectric microrobots

NASA Astrophysics Data System (ADS)

Fatikow, Sergej

1996-12-01

One of the main problems of present-day research on microsystem technology (MST) is to assemble a whole micro- system from different microcomponents. This paper presents a new concept of an automated micromanipulation desktop- station including piezoelectrically driven microrobots placed on a high-precise x-y-stage of a light microscope, a CCD-camera as a local sensor subsystem, a laser sensor unit as a global sensor subsystem, a parallel computer system with C167 microcontrollers, and a Pentium PC equipped additionally with an optical grabber. The microrobots can perform high-precise manipulations (with an accuracy of up to 10 nm) and a nondestructive transport (at a speed of about 3 cm/sec) of very small objects under the microscope. To control the desktop-station automatically, an advanced control system that includes a task planning level and a real-time execution level is being developed. The main function of the task planning sub-system is to interpret the implicit action plan and to generate a sequence of explicit operations which are sent to the execution level of the control system. The main functions of the execution control level are the object recognition, image processing and feedback position control of the microrobot and the microscope stage.

Event-Triggered Distributed Control of Nonlinear Interconnected Systems Using Online Reinforcement Learning With Exploration.

PubMed

Narayanan, Vignesh; Jagannathan, Sarangapani

2017-09-07

In this paper, a distributed control scheme for an interconnected system composed of uncertain input affine nonlinear subsystems with event triggered state feedback is presented by using a novel hybrid learning scheme-based approximate dynamic programming with online exploration. First, an approximate solution to the Hamilton-Jacobi-Bellman equation is generated with event sampled neural network (NN) approximation and subsequently, a near optimal control policy for each subsystem is derived. Artificial NNs are utilized as function approximators to develop a suite of identifiers and learn the dynamics of each subsystem. The NN weight tuning rules for the identifier and event-triggering condition are derived using Lyapunov stability theory. Taking into account, the effects of NN approximation of system dynamics and boot-strapping, a novel NN weight update is presented to approximate the optimal value function. Finally, a novel strategy to incorporate exploration in online control framework, using identifiers, is introduced to reduce the overall cost at the expense of additional computations during the initial online learning phase. System states and the NN weight estimation errors are regulated and local uniformly ultimately bounded results are achieved. The analytical results are substantiated using simulation studies.

The ecology of intertidal oyster reefs of the South Atlantic Coast: A community profile

USGS Publications Warehouse

Bahr, Leonard M.; Lanier, William P.

1981-01-01

The functional role of the intertidal oyster reef community in the southeastern Atlantic coastal zone is described. This description is based on a compilation of published data, as well as some unpublished information presented as hypotheses. The profile is organized in a hierarchical manner, such that relevant details of reef oyster biology (autecology) are presented, followed by a description of the reef community level of organization. Then the reef community is described as a subsystem of the coastal marsh-ecosystem (synecoloqy). This information is also synthesized in a series of nested conceptual models of oyster reefs at the regional level, the drainage basin level, and the individual reef level. The final chapter includes a summary overview and a section on management implications and guidelines. Intertidal oyster reefs are relatively persistent features of the salt marsh estuarine ecosystem in the southeastern Atlantic coastal zone. The average areal extent of the oyster reef subsystem in this larger ecosystem is relatively small (about 0.05%). This proportion does not reflect, however, the functional importance of the reef subsystem in stablizing the marsh, providing food for estuarine consumers, mineralizing organic matter, and providing firm substrates in this otherwise soft environment.

United States Control Module Guidance, Navigation, and Control Subsystem Design Concept

NASA Technical Reports Server (NTRS)

Polites, M. E.; Bartlow, B. E.

1997-01-01

Should the Russian Space Agency (RSA) not participate in the International Space Station (ISS) program, then the United States (U.S.) National Aeronautics and Space Administration (NASA) may choose to execute the ISS mission. However, in order to do this, NASA must build two new space vehicles, which must perform the functions that the Russian vehicles and hardware were to perform. These functions include periodic ISS orbit reboost, initial ISS attitude control, and U.S. On-Orbit Segment (USOS) control Moment gyroscope (CMG) momentum desaturation. The two new NASA vehicles that must perform these functions are called the U.S. control module (USCM) and the U.S. resupply module. This paper presents a design concept for the USCM GN&C subsystem, which must play a major role in ISS orbit reboost and initial attitude control, plus USOS CMG momentum desaturation. The proposed concept is structured similar to the USOS GN&C subsystem, by design. It is very robust, in that it allows the USCM to assume a variety of vehicle attitudes and stay power-positive. It has a storage/safe mode that places the USCM in a gravity-gradient orientation and keeps it there for extended periods of time without consuming a great deal of propellant. Simulation results are presented and discussed that show the soundness of the design approach. An equipment list is included that gives detailed information on the baselined GN&C components.

Galileo IOV Electrical Power Subsystem Relies On Li-Ion Batter Charge Management Controlled By Hardware

NASA Astrophysics Data System (ADS)

Douay, N.

2011-10-01

In the frame of GALILEO In-Orbit Validation program which is composed of 4 satellites, Thales Alenia Space France has designed, developed and tested the Electrical Power Subsystem. Besides some classical design choices like: -50V regulated main power bus provided by the PCDU manufactured by Terma (DK), -Solar array, manufactured by Dutch-Space (NL), using Ga-As triple junction technology from Azur Space Power Solar GmbH, -SAFT (FR) Lithium-ion Battery for which cell package balancing function is required, -Solar Array Drive Mechanism, provided by RUAG Space Switzerland, to transfer the power. This subsystem features a fully autonomous, failure tolerant, battery charge management able to operate even after a complete unavailability of the on-board software. The battery charge management is implemented such that priority is always given to satisfy the satellite main bus needs in order to maintain the main bus regulation under MEA control. This battery charge management principle provides very high reliability and operational robustness. So, the paper describes : -the battery charge management concept using a combination of PCDU hardware and relevant battery lines monitoring, -the functional aspect of the single point failure free S4R (Sequential Switching Shunt Switch Regulator) and associated performances, -the failure modes isolated and passivated by this architecture. The paper will address as well the autonomous balancing function characteristics and performances.

fEITER - a new EIT instrument for functional brain imaging

NASA Astrophysics Data System (ADS)

Davidson, J. L.; Wright, P.; Ahsan, S. T.; Robinson, R. L.; Pomfrett, C. J. D.; McCann, H.

2010-04-01

We report on human tests of the new EIT-based system fEITER (functional Electrical Impedance Tomography of Evoked Responses), targeted principally at functional brain imaging. It is designed and built to medical standard BS EN 60601-1:2006 and clinical trials have been approved by the MHRA in the UK. fEITER integrates an EIT sub-system with an evoked response sub-system capable of providing visual, auditory or other stimuli, and the timing of each stimulus is recorded within the EIT data to a resolution of 500 microseconds. The EIT sub-system operates at 100 frames per second using 20 polar/near-polar current patterns distributed among 32 scalp electrodes that are arranged in a 3-dimensional array on the subject. Presently, current injection is fixed in firmware at 1 mA pk-pk and 10 kHz. Performance testing on inanimate subjects has shown voltage measurement SNR better than 75 dB, at 100 frames per second. We describe the fEITER system and give example topographic results for a human subject under no-stimulus (i.e. reference) conditions and on application of auditory stimuli. The system's excellent noise properties and temporal resolution show clearly the influence of basic physiological phenomena on the EIT voltages. In response to stimulus presentation, the voltage data contain fast components (~100 ms) and components that persist for many seconds.

Multiple stage multiple filter hydrate store

DOEpatents

Bjorkman, H.K. Jr.

1983-05-31

An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means for separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means. 7 figs.

Multiple stage multiple filter hydrate store

DOEpatents

Bjorkman, Jr., Harry K.

1983-05-31

An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means or separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means.

The Galileo PPS expert monitoring and diagnostic prototype

NASA Technical Reports Server (NTRS)

Bahrami, Khosrow

1989-01-01

The Galileo PPS Expert Monitoring Module (EMM) is a prototype system implemented on the SUN workstation that will demonstrate a knowledge-based approach to monitoring and diagnosis for the Galileo spacecraft Power/Pyro subsystems. The prototype will simulate an analysis module functioning within the SFOC Engineering Analysis Subsystem Environment (EASE). This document describes the implementation of a prototype EMM for the Galileo spacecraft Power Pyro Subsystem. Section 2 of this document provides an overview of the issues in monitoring and diagnosis and comparison between traditional and knowledge-based solutions to this problem. Section 3 describes various tradeoffs which must be considered when designing a knowledge-based approach to monitoring and diagnosis, and section 4 discusses how these issues were resolved in constructing the prototype. Section 5 presents conclusions and recommendations for constructing a full-scale demonstration of the EMM. A Glossary provides definitions of terms used in this text.

Simulation of magnetoelastic response of iron nanowire loop

NASA Astrophysics Data System (ADS)

Huang, Junping; Peng, Xianghe; Wang, Zhongchang; Hu, Xianzhi

2018-03-01

We analyzed the magnetoelastic responses of one-dimensional iron nanowire loop systems with quantum statistical mechanics, treating the particles in the systems as identical bosons with an arbitrary integer spin. Under the assumptions adopted, we demonstrated that the Hamiltonian of the system can be separated into two parts, corresponding to two Ising subsystems, describing the particle spin and the particle displacement, respectively. Because the energy of the particle motion at atomic scale is quantized, there should be more the strict constraint on the particle displacement Ising subsystem. Making use of the existing results for Ising system, the partition function of the system was derived into two parts, corresponding respectively to the two Ising subsystems. Then the Gibbs distribution was obtained by statistical mechanics, and the description for the magnetoelastic response was derived. The magnetoelastic responses were predicted with the developed approach, and the comparison with the results calculated with VASP demonstrates the validity of the developed approach.

Independent Orbiter Assessment (IOA): Analysis of the Electrical Power Distribution and Control Subsystem, Volume 2

NASA Technical Reports Server (NTRS)

Schmeckpeper, K. R.

1987-01-01

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C) hardware. The EPD and C hardware performs the functions of distributing, sensing, and controlling 28 volt DC power and of inverting, distributing, sensing, and controlling 117 volt 400 Hz AC power to all Orbiter subsystems from the three fuel cells in the Electrical Power Generation (EPG) subsystem. Volume 2 continues the presentation of IOA analysis worksheets and contains the potential critical items list.

Translation of Genotype to Phenotype by a Hierarchy of Cell Subsystems.

PubMed

Yu, Michael Ku; Kramer, Michael; Dutkowski, Janusz; Srivas, Rohith; Licon, Katherine; Kreisberg, Jason; Ng, Cherie T; Krogan, Nevan; Sharan, Roded; Ideker, Trey

2016-02-24

Accurately translating genotype to phenotype requires accounting for the functional impact of genetic variation at many biological scales. Here we present a strategy for genotype-phenotype reasoning based on existing knowledge of cellular subsystems. These subsystems and their hierarchical organization are defined by the Gene Ontology or a complementary ontology inferred directly from previously published datasets. Guided by the ontology's hierarchical structure, we organize genotype data into an "ontotype," that is, a hierarchy of perturbations representing the effects of genetic variation at multiple cellular scales. The ontotype is then interpreted using logical rules generated by machine learning to predict phenotype. This approach substantially outperforms previous, non-hierarchical methods for translating yeast genotype to cell growth phenotype, and it accurately predicts the growth outcomes of two new screens of 2,503 double gene knockouts impacting DNA repair or nuclear lumen. Ontotypes also generalize to larger knockout combinations, setting the stage for interpreting the complex genetics of disease.

Structural and mechanical design challenges of space shuttle solid rocket boosters separation and recovery subsystems

NASA Technical Reports Server (NTRS)

Woodis, W. R.; Runkle, R. E.

1985-01-01

The design of the space shuttle solid rocket booster (SRB) subsystems for reuse posed some unique and challenging design considerations. The separation of the SRBs from the cluster (orbiter and external tank) at 150,000 ft when the orbiter engines are running at full thrust meant the two SRBs had to have positive separation forces pushing them away. At the same instant, the large attachments that had reacted launch loads of 7.5 million pounds thrust had to be servered. These design considerations dictated the design requirements for the pyrotechnics and separation rocket motors. The recovery and reuse of the two SRBs meant they had to be safely lowered to the ocean, remain afloat, and be owed back to shore. In general, both the pyrotechnic and recovery subsystems have met or exceeded design requirements. In twelve vehicles, there has only been one instance where the pyrotechnic system has failed to function properly.

A reliability and mass perspective of SP-100 Stirling cycle lunar-base powerplant designs

NASA Technical Reports Server (NTRS)

Bloomfield, Harvey S.

1991-01-01

The purpose was to obtain reliability and mass perspectives on selection of space power system conceptual designs based on SP-100 reactor and Stirling cycle power-generation subsystems. The approach taken was to: (1) develop a criterion for an acceptable overall reliability risk as a function of the expected range of emerging technology subsystem unit reliabilities; (2) conduct reliability and mass analyses for a diverse matrix of 800-kWe lunar-base design configurations employing single and multiple powerplants with both full and partial subsystem redundancy combinations; and (3) derive reliability and mass perspectives on selection of conceptual design configurations that meet an acceptable reliability criterion with the minimum system mass increase relative to reference powerplant design. The developed perspectives provided valuable insight into the considerations required to identify and characterize high-reliability and low-mass lunar-base powerplant conceptual design.

A parametric sensitivity study for single-stage-to-orbit hypersonic vehicles using trajectory optimization

NASA Astrophysics Data System (ADS)

Lovell, T. Alan; Schmidt, D. K.

1994-03-01

The class of hypersonic vehicle configurations with single stage-to-orbit (SSTO) capability reflect highly integrated airframe and propulsion systems. These designs are also known to exhibit a large degree of interaction between the airframe and engine dynamics. Consequently, even simplified hypersonic models are characterized by tightly coupled nonlinear equations of motion. In addition, hypersonic SSTO vehicles present a major system design challenge; the vehicle's overall mission performance is a function of its subsystem efficiencies including structural, aerodynamic, propulsive, and operational. Further, all subsystem efficiencies are interrelated, hence, independent optimization of the subsystems is not likely to lead to an optimum design. Thus, it is desired to know the effect of various subsystem efficiencies on overall mission performance. For the purposes of this analysis, mission performance will be measured in terms of the payload weight inserted into orbit. In this report, a trajectory optimization problem is formulated for a generic hypersonic lifting body for a specified orbit-injection mission. A solution method is outlined, and results are detailed for the generic vehicle, referred to as the baseline model. After evaluating the performance of the baseline model, a sensitivity study is presented to determine the effect of various subsystem efficiencies on mission performance. This consists of performing a parametric analysis of the basic design parameters, generating a matrix of configurations, and determining the mission performance of each configuration. Also, the performance loss due to constraining the total head load experienced by the vehicle is evaluated. The key results from this analysis include the formulation of the sizing problem for this vehicle class using trajectory optimization, characteristics of the optimal trajectories, and the subsystem design sensitivities.

A parametric sensitivity study for single-stage-to-orbit hypersonic vehicles using trajectory optimization

NASA Technical Reports Server (NTRS)

Lovell, T. Alan; Schmidt, D. K.

1994-01-01

The class of hypersonic vehicle configurations with single stage-to-orbit (SSTO) capability reflect highly integrated airframe and propulsion systems. These designs are also known to exhibit a large degree of interaction between the airframe and engine dynamics. Consequently, even simplified hypersonic models are characterized by tightly coupled nonlinear equations of motion. In addition, hypersonic SSTO vehicles present a major system design challenge; the vehicle's overall mission performance is a function of its subsystem efficiencies including structural, aerodynamic, propulsive, and operational. Further, all subsystem efficiencies are interrelated, hence, independent optimization of the subsystems is not likely to lead to an optimum design. Thus, it is desired to know the effect of various subsystem efficiencies on overall mission performance. For the purposes of this analysis, mission performance will be measured in terms of the payload weight inserted into orbit. In this report, a trajectory optimization problem is formulated for a generic hypersonic lifting body for a specified orbit-injection mission. A solution method is outlined, and results are detailed for the generic vehicle, referred to as the baseline model. After evaluating the performance of the baseline model, a sensitivity study is presented to determine the effect of various subsystem efficiencies on mission performance. This consists of performing a parametric analysis of the basic design parameters, generating a matrix of configurations, and determining the mission performance of each configuration. Also, the performance loss due to constraining the total head load experienced by the vehicle is evaluated. The key results from this analysis include the formulation of the sizing problem for this vehicle class using trajectory optimization, characteristics of the optimal trajectories, and the subsystem design sensitivities.

A two-agent model applied to the biological control of the sugarcane borer (Diatraea saccharalis) by the egg parasitoid Trichogramma galloi and the larvae parasitoid Cotesia flavipes.

PubMed

Molnár, Sándor; López, Inmaculada; Gámez, Manuel; Garay, József

2016-03-01

The paper is aimed at a methodological development in biological pest control. The considered one pest two-agent system is modelled as a verticum-type system. Originally, linear verticum-type systems were introduced by one of the authors for modelling certain industrial systems. These systems are hierarchically composed of linear subsystems such that a part of the state variables of each subsystem affect the dynamics of the next subsystem. Recently, verticum-type system models have been applied to population ecology as well, which required the extension of the concept a verticum-type system to the nonlinear case. In the present paper the general concepts and technics of nonlinear verticum-type control systems are used to obtain biological control strategies in a two-agent system. For the illustration of this verticum-type control, these tools of mathematical systems theory are applied to a dynamic model of interactions between the egg and larvae populations of the sugarcane borer (Diatraea saccharalis) and its parasitoids: the egg parasitoid Trichogramma galloi and the larvae parasitoid Cotesia flavipes. In this application a key role is played by the concept of controllability, which means that it is possible to steer the system to an equilibrium in given time. In addition to a usual linearization, the basic idea is a decomposition of the control of the whole system into the control of the subsystems, making use of the verticum structure of the population system. The main aim of this study is to show several advantages of the verticum (or decomposition) approach over the classical control theoretical model (without decomposition). For example, in the case of verticum control the pest larval density decreases below the critical threshold value much quicker than without decomposition. Furthermore, it is also shown that the verticum approach may be better even in terms of cost effectiveness. The presented optimal control methodology also turned out to be an efficient tool for the "in silico" analysis of the cost-effectiveness of different biocontrol strategies, e.g. by answering the question how far it is cost-effective to speed up the reduction of the pest larvae density, or along which trajectory this reduction should be carried out. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Bodily systems and the spatial-functional structure of the human body.

PubMed

Smith, Barry; Munn, Katherine; Papakin, Igor

2004-01-01

The human body is a system made of systems. The body is divided into bodily systems proper, such as the endocrine and circulatory systems, which are subdivided into many sub-systems at a variety of levels, whereby all systems and subsystems engage in massive causal interaction with each other and with their surrounding environments. Here we offer an explicit definition of bodily system and provide a framework for understanding their causal interactions. Medical sciences provide at best informal accounts of basic notions such as system, process, and function, and while such informality is acceptable in documentation created for human beings, it falls short of what is needed for computer representations. In our analysis we will accordingly provide the framework for a formal definition of bodily system and of associated notions.

On the Dynamics of an Incursion Describing the Interactions between Functionally Differentiated Subsystems of a Discrete-time Anticipatory System

NASA Astrophysics Data System (ADS)

Burke, Mark E.

2010-11-01

Dubois coined the term incursion, for an inclusive or implicit recursion, to describe a discrete-time anticipatory system which computes its future states by reference to its future states as well as its current and past states. In this paper, we look at a model which has been proposed in the context of a social system which has functionally differentiated subsystems. The model is derived from a discrete-time compartmental SIS epidemic model. We analyse a low order instance of the model both in its form as a recursion with no anticipatory capacity, and also as an incursion with associated anticipatory capacity. The properties of the incursion are compared and contrasted with those of the underlying recursion.

The precision segmented reflectors: Moderate mission figure control subsystem

NASA Technical Reports Server (NTRS)

Sevaston, G.; Redding, D.; Lau, K.; Breckenridge, W.; Levine, B.; Nerheim, N.; Sirlin, S.; Kadogawa, H.

1991-01-01

A system concept for a space based segmented reflector telescope figure control subsystem is described. The concept employs a two phase architecture in which figure initialization and figure maintenance are independent functions. Figure initialization is accomplished by image sharpening using natural reference targets. Figure maintenance is performed by monitoring the relative positions and alignments of the telescope components using an optical truss. Actuation is achieved using precision positioners. Computer simulation results of figure initialization by pairwise segment coalignment/cophasing and simulated annealing are presented along with figure maintenance results using a wavefront error regulation algorithm. Both functions are shown to perform at acceptable levels for the class of submillimeter telescopes that are serving as the focus of this technology development effort. Component breadboard work as well as plans for a system testbed are discussed.

Space station automation study. Volume 2: Technical report. Autonomous systems and assembly

NASA Technical Reports Server (NTRS)

1984-01-01

The application of automation to space station functions is discussed. A summary is given of the evolutionary functions associated with long range missions and objectives. Mission tasks and requirements are defined. Space station sub-systems, mission models, assembly, and construction are discussed.

Preliminary Candidate Advanced Avionics System (PCAAS). [reduction in single pilot workload during instrument flight rules flight

NASA Technical Reports Server (NTRS)

Teper, G. L.; Hon, R. H.; Smyth, R. K.

1977-01-01

Specifications which define the system functional requirements, the subsystem and interface needs, and other requirements such as maintainability, modularity, and reliability are summarized. A design definition of all required avionics functions and a system risk analysis are presented.

AEOSS runtime manual for system analysis on Advanced Earth-Orbital Spacecraft Systems

NASA Technical Reports Server (NTRS)

Lee, Hwa-Ping

1990-01-01

Advanced earth orbital spacecraft system (AEOSS) enables users to project the required power, weight, and cost for a generic earth-orbital spacecraft system. These variables are calculated on the component and subsystem levels, and then the system level. The included six subsystems are electric power, thermal control, structure, auxiliary propulsion, attitude control, and communication, command, and data handling. The costs are computed using statistically determined models that were derived from the flown spacecraft in the past and were categorized into classes according to their functions and structural complexity. Selected design and performance analyses for essential components and subsystems are also provided. AEOSS has the feature permitting a user to enter known values of these parameters, totally and partially, at all levels. All information is of vital importance to project managers of subsystems or a spacecraft system. AEOSS is a specially tailored software coded from the relational database program of the Acius' 4th Dimension with a Macintosh version. Because of the licensing agreements, two versions of the AEOSS documents were prepared. This version, AEOSS Runtime Manual, is permitted to be distributed with a finite number of the restrictive 4D Runtime version. It can perform all contained applications without any programming alterations.

Independent Orbiter Assessment (IOA): Analysis of the electrical power distribution and control/electrical power generation subsystem

NASA Technical Reports Server (NTRS)

Patton, Jeff A.

1986-01-01

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C)/Electrical Power Generation (EPG) hardware. The EPD and C/EPG hardware is required for performing critical functions of cryogenic reactant storage, electrical power generation and product water distribution in the Orbiter. Specifically, the EPD and C/EPG hardware consists of the following components: Power Section Assembly (PSA); Reactant Control Subsystem (RCS); Thermal Control Subsystem (TCS); Water Removal Subsystem (WRS); and Power Reactant Storage and Distribution System (PRSDS). The IOA analysis process utilized available EPD and C/EPG hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode.

Integrated system for investigating sub-surface features of a rock formation

DOEpatents

Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

2015-08-18

A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

A backing device based on an embedded stiffener and retractable insertion tool for thin-film cochlear arrays

NASA Astrophysics Data System (ADS)

Tewari, Radheshyam

Intracochlear trauma from surgical insertion of bulky electrode arrays and inadequate pitch perception are areas of concern with current hand-assembled commercial cochlear implants. Parylene thin-film arrays with higher electrode densities and lower profiles are a potential solution, but lack rigidity and hence depend on manually fabricated permanently attached polyethylene terephthalate (PET) tubing based bulky backing devices. As a solution, we investigated a new backing device with two sub-systems. The first sub-system is a thin poly(lactic acid) (PLA) stiffener that will be embedded in the parylene array. The second sub-system is an attaching and detaching mechanism, utilizing a poly(N-vinylpyrrolidone)-block-poly(d,l-lactide) (PVP-b-PDLLA) copolymer-based biodegradable and water soluble adhesive, that will help to retract the PET insertion tool after implantation. As a proof-of-concept of sub-system one, a microfabrication process for patterning PLA stiffeners embedded in parylene has been developed. Conventional hot-embossing, mechanical micromachining, and standard cleanroom processes were integrated for patterning fully released and discrete stiffeners coated with parylene. The released embedded stiffeners were thermoformed to demonstrate that imparting perimodiolar shapes to stiffener-embedded arrays will be possible. The developed process when integrated with the array fabrication process will allow fabrication of stiffener-embedded arrays in a single process. As a proof-of-concept of sub-system two, the feasibility of the attaching and detaching mechanism was demonstrated by adhering 1x and 1.5x scale PET tube-based insertion tools and PLA stiffeners embedded in parylene using the copolymer adhesive. The attached devices survived qualitative adhesion tests, thermoforming, and flexing. The viability of the detaching mechanism was tested by aging the assemblies in-vitro in phosphate buffer solution. The average detachment times, 2.6 minutes and 10 minutes for 1x and 1.5x scale devices respectively, were found to be clinically relevant with respect to the reported array insertion times during surgical implantation. Eventually, the stiffener-embedded arrays would not need to be permanently attached to current insertion tools which are left behind after implantation and congest the cochlear scala tympani chamber. Finally, a simulation-based approach for accelerated failure analysis of PLA stiffeners and characterization of PVP-b-PDLLA copolymer adhesive has been explored. The residual functional life of embedded PLA stiffeners exposed to body-fluid and thereby subjected to degradation and erosion has been estimated by simulating PLA stiffeners with different parylene coating failure types and different PLA types for a given parylene coating failure type. For characterizing the PVP-b-PDLLA copolymer adhesive, several formulations of the copolymer adhesive were simulated and compared based on the insertion tool detachment times that were predicted from the dissolution, degradation, and erosion behavior of the simulated adhesive formulations. Results indicate that the simulation-based approaches could be used to reduce the total number of time consuming and expensive in-vitro tests that must be conducted.

New Generation Strategic Submarine Study

DTIC Science & Technology

1977-01-01

Ship Propulsion System . 111-22 III- A -6 Simplified Functional Diagram - Steam-Feed Flow System . 111-23 III- A -7...16 Aa Tabte XIZ- A -3 System (Element) Functional Analysis ResuZts--Engineering p Plant Subsystem SYSTEM (ELEMENT) FUNCTION Ll A . Ship Propulsion 1...FUNCTION A . Ship Propulsion (cont’d) 9. SSTG Throttle Valves * Provide frequency control of the ship’s service turbine generators, startup and

Inertial subsystem functional and design requirements for the orbiter (Phase B extension baseline)

NASA Technical Reports Server (NTRS)

Flanders, J. H.; Green, J. P., Jr.

1972-01-01

The design requirements use the Phase B extension baseline system definition. This means that a GNC computer is specified for all command control functions instead of a central computer communicating with the ISS through a databus. Forced air cooling is used instead of cold plate cooling.

Human Exploration Spacecraft Testbed for Integration and Advancement (HESTIA)

NASA Technical Reports Server (NTRS)

Banker, Brian F.; Robinson, Travis

2016-01-01

The proposed paper will cover ongoing effort named HESTIA (Human Exploration Spacecraft Testbed for Integration and Advancement), led at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) to promote a cross-subsystem approach to developing Mars-enabling technologies with the ultimate goal of integrated system optimization. HESTIA also aims to develop the infrastructure required to rapidly test these highly integrated systems at a low cost. The initial focus is on the common fluids architecture required to enable human exploration of mars, specifically between life support and in-situ resource utilization (ISRU) subsystems. An overview of the advancements in both integrated technologies, in infrastructure, in simulation, and in modeling capabilities will be presented, as well as the results and findings of integrated testing,. Due to the enormous mass gear-ratio required for human exploration beyond low-earth orbit, (for every 1 kg of payload landed on Mars, 226 kg will be required on Earth), minimization of surface hardware and commodities is paramount. Hardware requirements can be minimized by reduction of equipment performing similar functions though for different subsystems. If hardware could be developed which meets the requirements of both life support and ISRU it could result in the reduction of primary hardware and/or reduction in spares. Minimization of commodities to the surface of mars can be achieved through the creation of higher efficiency systems producing little to no undesired waste, such as a closed-loop life support subsystem. Where complete efficiency is impossible or impractical, makeup commodities could be manufactured via ISRU. Although, utilization of ISRU products (oxygen and water) for crew consumption holds great promise of reducing demands on life support hardware, there exist concerns as to the purity and transportation of commodities. To date, ISRU has been focused on production rates and purities for propulsion needs. The meshing of requirements between all potential users, producers, and cleaners of oxygen and water is crucial to guiding the development of technologies which will be used to perform these functions. Various new capabilities are being developed as part of HESTIA, which will enable the integrated testing of these technologies. This includes the upgrading of a 20' diameter habitat chamber to eventually support long duration (90+ day) human-in-the-loop testing of advanced life support systems. Additionally, a 20' diameter vacuum chamber is being modified to create Mars atmospheric pressures and compositions. This chamber, designated the Mars Environment Chamber (MEC), will eventually be upgraded to include a dusty environment and thermal shroud to simulate conditions on the surface of Mars. In view that individual technologies will be in geographically diverse locations across NASA facilities and elsewhere in the world, schedule and funding constraints will likely limit the frequency of physical integration. When this is the case, absent subsystems can be either digitally or physically simulated. Using the Integrated Power Avionics and Software (iPAS) environment, HESTIA is able to bring together data from various subsystems in simulated surroundings, insert faults, errors, time delays, etc., and feed data into computer models or physical systems capable of reproducing the output of the absent subsystems for the consumption of a local subsystems. Although imperfect, this capability provides opportunities to test subsystem integration and interactions at a fraction of the cost. When a subsystem technology is too immature for integrated testing, models can be produced using the General-Use Nodal Network Solver (GUNNS) capability to simulate the overall system performance. In doing so, even technologies not yet on the drawing board can be integrated and overall system performance estimated. Through the integrated development of technologies, as well as of the infrastructure to rapidly and at a low cost, model, simulate, and test subsystem technologies early in their development, HESTIA is pioneering a new way of developing the future of human space exploration.

A system decomposition approach to the design of functional observers

NASA Astrophysics Data System (ADS)

Fernando, Tyrone; Trinh, Hieu

2014-09-01

This paper reports a system decomposition that allows the construction of a minimum-order functional observer using a state observer design approach. The system decomposition translates the functional observer design problem to that of a state observer for a smaller decomposed subsystem. Functional observability indices are introduced, and a closed-form expression for the minimum order required for a functional observer is derived in terms of those functional observability indices.

14 CFR 417.301 - General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... undergo analysis and testing that is comparable to that required by this part to demonstrate that the...) Functions, subsystems, and components. When initiated in the event of a launch vehicle failure, a flight...

14 CFR 417.301 - General.

Code of Federal Regulations, 2013 CFR

2013-01-01

... undergo analysis and testing that is comparable to that required by this part to demonstrate that the...) Functions, subsystems, and components. When initiated in the event of a launch vehicle failure, a flight...

14 CFR 417.301 - General.

Code of Federal Regulations, 2012 CFR

2012-01-01

... undergo analysis and testing that is comparable to that required by this part to demonstrate that the...) Functions, subsystems, and components. When initiated in the event of a launch vehicle failure, a flight...

14 CFR 417.301 - General.

Code of Federal Regulations, 2014 CFR

2014-01-01

... undergo analysis and testing that is comparable to that required by this part to demonstrate that the...) Functions, subsystems, and components. When initiated in the event of a launch vehicle failure, a flight...

Transitioning from conceptual design to construction performance specification

NASA Astrophysics Data System (ADS)

Jeffers, Paul; Warner, Mark; Craig, Simon; Hubbard, Robert; Marshall, Heather

2012-09-01

On successful completion of a conceptual design review by a funding agency or customer, there is a transition phase before construction contracts can be placed. The nature of this transition phase depends on the Project's approach to construction and the particular subsystem being considered. There are generically two approaches; project retention of design authority and issuance of build to print contracts, or issuance of subsystem performance specifications with controlled interfaces. This paper relates to the latter where a proof of concept (conceptual or reference design) is translated into performance based sub-system specifications for competitive tender. This translation is not a straightforward process and there are a number of different issues to consider in the process. This paper deals with primarily the Telescope mount and Enclosure subsystems. The main subjects considered in this paper are: • Typical status of design at Conceptual Design Review compared with the desired status of Specifications and Interface Control Documents at Request for Quotation. • Options for capture and tracking of system requirements flow down from science / operating requirements and sub-system requirements, and functional requirements derived from reference design. • Requirements that may come specifically from the contracting approach. • Methods for effective use of reference design work without compromising a performance based specification. • Management of project team's expectation relating to design. • Effects on cost estimates from reference design to actual. This paper is based on experience and lessons learned through this process on both the VISTA and the ATST projects.

Deployment of community health workers across rural sub-Saharan Africa: financial considerations and operational assumptions.

PubMed

McCord, Gordon C; Liu, Anne; Singh, Prabhjot

2013-04-01

To provide cost guidance for developing a locally adaptable and nationally scalable community health worker (CHW) system within primary-health-care systems in sub-Saharan Africa. The yearly costs of training, equipping and deploying CHWs throughout rural sub-Saharan Africa were calculated using data from the literature and from the Millennium Villages Project. Model assumptions were such as to allow national governments to adapt the CHW subsystem to national needs and to deploy an average of 1 CHW per 650 rural inhabitants by 2015. The CHW subsystem described was costed by employing geographic information system (GIS) data on population, urban extents, national and subnational disease prevalence, and unit costs (from the field for wages and commodities). The model is easily replicable and configurable. Countries can adapt it to local prices, wages, population density and disease burdens in different geographic areas. The average annual cost of deploying CHWs to service the entire sub-Saharan African rural population by 2015 would be approximately 2.6 billion (i.e. 2600 million) United States dollars (US$). This sum, to be covered both by national governments and by donor partners, translates into US$ 6.86 per year per inhabitant covered by the CHW subsystem and into US$ 2.72 per year per inhabitant. Alternatively, it would take an annual average of US$ 3750 to train, equip and support each CHW. Comprehensive CHW subsystems can be deployed across sub-Saharan Africa at cost that is modest compared with the projected costs of the primary-health-care system. Given their documented successes, they offer a strong complement to facility-based care in rural African settings.

Deployment of community health workers across rural sub-Saharan Africa: financial considerations and operational assumptions

PubMed Central

McCord, Gordon C; Liu, Anne

2013-01-01

Abstract Objective To provide cost guidance for developing a locally adaptable and nationally scalable community health worker (CHW) system within primary-health-care systems in sub-Saharan Africa. Methods The yearly costs of training, equipping and deploying CHWs throughout rural sub-Saharan Africa were calculated using data from the literature and from the Millennium Villages Project. Model assumptions were such as to allow national governments to adapt the CHW subsystem to national needs and to deploy an average of 1 CHW per 650 rural inhabitants by 2015. The CHW subsystem described was costed by employing geographic information system (GIS) data on population, urban extents, national and subnational disease prevalence, and unit costs (from the field for wages and commodities). The model is easily replicable and configurable. Countries can adapt it to local prices, wages, population density and disease burdens in different geographic areas. Findings The average annual cost of deploying CHWs to service the entire sub-Saharan African rural population by 2015 would be approximately 2.6 billion (i.e. 2600 million) United States dollars (US$). This sum, to be covered both by national governments and by donor partners, translates into US$ 6.86 per year per inhabitant covered by the CHW subsystem and into US$ 2.72 per year per inhabitant. Alternatively, it would take an annual average of US$ 3750 to train, equip and support each CHW. Conclusion Comprehensive CHW subsystems can be deployed across sub-Saharan Africa at cost that is modest compared with the projected costs of the primary-health-care system. Given their documented successes, they offer a strong complement to facility-based care in rural African settings. PMID:23599547

Primary lithium cell life studies

NASA Technical Reports Server (NTRS)

Capulli, John; Donley, Sam; Deligiannis, Frank; Shen, David

1990-01-01

One solution for providing a truly independent power source is to package, within the critical subsystem element, a primary battery that can remain dormant for time periods as long as the mission life, which can be 10-15 years, maximum. When primary power from the spacecraft solar array/battery system is interrupted, the backup battery system, which is connected through a diode to the power input line, would automatically support the load to avoid a power interruption to the critical load for a time period long enough to ensure that ground control could access the satellite and correct the anomaly by sending appropriate commands to the spacecraft. Critical subsystems identified for the application are telemetry and command circuits, volatile computer memory, attitude control circuits, and some critical payloads. Due to volume packaging and weight restrictions that exist on most spacecraft, coupled with the long storage periods required, lithium cell technology was selected for the backup power source. Because of the high energy density (200-400 Wh/kg), long shelf life, and load capability, soluble cathode primary lithium technology was chosen. The most important lithium cell properties that require detail characterization for this application are capacity loss, shelf life, and the voltage delay mechanism. These are functions of storage time and temperature. During storage, a passive film builds up on the lithium electrode. The film protects the lithium electrode from progressive capacity decay but requires time to break down when a load is applied. This phenomenon results in a depressed voltage during the period of film breakdown which can last from fractions of a second to minutes.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 3: General purpose spacecraft segment and module specifications

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications for the Earth Observatory Satellite (EOS) general purpose aircraft segment are presented. The satellite is designed to provide attitude stabilization, electrical power, and a communications data handling subsystem which can support various mission peculiar subsystems. The various specifications considered include the following: (1) structures subsystem, (2) thermal control subsystem, (3) communications and data handling subsystem module, (4) attitude control subsystem module, (5) power subsystem module, and (6) electrical integration subsystem.

Modeling from Local to Subsystem Level Effects in Analog and Digital Circuits Due to Space Induced Single Event Transients

NASA Technical Reports Server (NTRS)

Perez, Reinaldo J.

2011-01-01

Single Event Transients in analog and digital electronics from space generated high energetic nuclear particles can disrupt either temporarily and sometimes permanently the functionality and performance of electronics in space vehicles. This work first provides some insights into the modeling of SET in electronic circuits that can be used in SPICE-like simulators. The work is then directed to present methodologies, one of which was developed by this author, for the assessment of SET at different levels of integration in electronics, from the circuit level to the subsystem level.

Electric and hybrid vehicles environmental control subsystem study

NASA Technical Reports Server (NTRS)

1981-01-01

An environmental control subsystem (ECS) in the passenger compartment of electric and hybrid vehicles is studied. Various methods of obtaining the desired temperature control for the battery pack is also studied. The functional requirements of ECS equipment is defined. Following categorization by methodology, technology availability and risk, all viable ECS concepts are evaluated. Each is assessed independently for benefits versus risk, as well as for its feasibility to short, intermediate and long term product development. Selection of the preferred concept is made against these requirements, as well as the study's major goal of providing safe, highly efficient and thermally confortable ECS equipment.

Food system galley for Space Shuttle

NASA Technical Reports Server (NTRS)

Murray, R. W.; Hunt, S. R.; Sauer, R. L.; Turner, T. R.

1979-01-01

The Galley, a 42 man-day meal preparation facility (with flexibility to accomodate 210 man-days) is described. The facility is designed for minimum meal preparation and clean-up time in zero g and ease of servicing, maintenance, and removal in one gravity. The Galley provides a centralized location for performing all of the food-related functions (except dining) within the orbiter. Consideration is given to the oven-water heater, personal hygiene station, water dispensers, and water supply subsystem. The Galley is positioned in the orbiting mid deck, interfacing with rehydratable food packages and the waste collector subsystem.

Hardy's test as a device-independent dimension witness

NASA Astrophysics Data System (ADS)

Mukherjee, Amit; Roy, Arup; Bhattacharya, Some Sankar; Das, Subhadipa; Gazi, Md. Rajjak; Banik, Manik

2015-08-01

Knowing the dimension of an unknown physical system has practical relevance, as dimensionality plays an important role in various information theoretic tasks. In this work we show that a modified version of Hardy's argument, which reveals the contradiction of quantum theory with local realism, turns out to be useful for inspecting the minimal subsystem dimension of an unknown correlated quantum system. The use of Hardy's test in this task has a novel advantage: the subsystem dimension can be determined without knowing the detailed functioning of the experimental devices; i.e., Hardy's test suffices to be a device-independent dimension witness.

NASA Langley's Approach to the Sandia's Structural Dynamics Challenge Problem

NASA Technical Reports Server (NTRS)

Horta, Lucas G.; Kenny, Sean P.; Crespo, Luis G.; Elliott, Kenny B.

2007-01-01

The objective of this challenge is to develop a data-based probabilistic model of uncertainty to predict the behavior of subsystems (payloads) by themselves and while coupled to a primary (target) system. Although this type of analysis is routinely performed and representative of issues faced in real-world system design and integration, there are still several key technical challenges that must be addressed when analyzing uncertain interconnected systems. For example, one key technical challenge is related to the fact that there is limited data on target configurations. Moreover, it is typical to have multiple data sets from experiments conducted at the subsystem level, but often samples sizes are not sufficient to compute high confidence statistics. In this challenge problem additional constraints are placed as ground rules for the participants. One such rule is that mathematical models of the subsystem are limited to linear approximations of the nonlinear physics of the problem at hand. Also, participants are constrained to use these models and the multiple data sets to make predictions about the target system response under completely different input conditions. Our approach involved initially the screening of several different methods. Three of the ones considered are presented herein. The first one is based on the transformation of the modal data to an orthogonal space where the mean and covariance of the data are matched by the model. The other two approaches worked solutions in physical space where the uncertain parameter set is made of masses, stiffnesses and damping coefficients; one matches confidence intervals of low order moments of the statistics via optimization while the second one uses a Kernel density estimation approach. The paper will touch on all the approaches, lessons learned, validation 1 metrics and their comparison, data quantity restriction, and assumptions/limitations of each approach. Keywords: Probabilistic modeling, model validation, uncertainty quantification, kernel density

Prefrontal gray matter morphology mediates the association between serum anticholinergicity and cognitive functioning in early course schizophrenia.

PubMed

Wojtalik, Jessica A; Eack, Shaun M; Pollock, Bruce G; Keshavan, Matcheri S

2012-11-30

Antipsychotic and other medications used in the treatment of schizophrenia place a burden on the cholinergic subsystems of the brain, which have been associated with increased cognitive impairment in the disorder. This study sought to examine the neurobiologic correlates of the association between serum anticholinergic activity (SAA) and cognitive impairments in early schizophrenia. Neurocognitive performance on measures of memory and executive function, structural magnetic resonance imaging (MRI) scans, and SAA assays were collected from 47 early course, stabilized outpatients with schizophrenia or schizoaffective disorder. Voxel-based morphometry analyses employing general linear models, adjusting for demographic and illness-related confounds, were used to investigate the associations between SAA, gray matter morphology, and neurocognitive impairment. SAA was related to working memory and executive function impairments. Higher SAA was significantly associated with lower gray matter density in broad regions of the frontal and medial-temporal lobes, including the dorsolateral prefrontal cortex (DLPFC), hippocampus, and striatum. Lower gray matter volume in the left DLPFC was found to significantly mediate the association between SAA and working memory impairment. Disease- and/or medication-related cholinergic dysfunction may be associated with brain volume abnormalities in early course schizophrenia, which may account for the association between SAA and cognitive dysfunction in the disorder. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

First-principles calculation of entropy for liquid metals.

PubMed

Desjarlais, Michael P

2013-12-01

We demonstrate the accurate calculation of entropies and free energies for a variety of liquid metals using an extension of the two-phase thermodynamic (2PT) model based on a decomposition of the velocity autocorrelation function into gas-like (hard sphere) and solid-like (harmonic) subsystems. The hard sphere model for the gas-like component is shown to give systematically high entropies for liquid metals as a direct result of the unphysical Lorentzian high-frequency tail. Using a memory function framework we derive a generally applicable velocity autocorrelation and frequency spectrum for the diffusive component which recovers the low-frequency (long-time) behavior of the hard sphere model while providing for realistic short-time coherence and high-frequency tails to the spectrum. This approach provides a significant increase in the accuracy of the calculated entropies for liquid metals and is compared to ambient pressure data for liquid sodium, aluminum, gallium, tin, and iron. The use of this method for the determination of melt boundaries is demonstrated with a calculation of the high-pressure bcc melt boundary for sodium. With the significantly improved accuracy available with the memory function treatment for softer interatomic potentials, the 2PT model for entropy calculations should find broader application in high energy density science, warm dense matter, planetary science, geophysics, and material science.

First-principles calculation of entropy for liquid metals

NASA Astrophysics Data System (ADS)

Desjarlais, Michael P.

2013-12-01

We demonstrate the accurate calculation of entropies and free energies for a variety of liquid metals using an extension of the two-phase thermodynamic (2PT) model based on a decomposition of the velocity autocorrelation function into gas-like (hard sphere) and solid-like (harmonic) subsystems. The hard sphere model for the gas-like component is shown to give systematically high entropies for liquid metals as a direct result of the unphysical Lorentzian high-frequency tail. Using a memory function framework we derive a generally applicable velocity autocorrelation and frequency spectrum for the diffusive component which recovers the low-frequency (long-time) behavior of the hard sphere model while providing for realistic short-time coherence and high-frequency tails to the spectrum. This approach provides a significant increase in the accuracy of the calculated entropies for liquid metals and is compared to ambient pressure data for liquid sodium, aluminum, gallium, tin, and iron. The use of this method for the determination of melt boundaries is demonstrated with a calculation of the high-pressure bcc melt boundary for sodium. With the significantly improved accuracy available with the memory function treatment for softer interatomic potentials, the 2PT model for entropy calculations should find broader application in high energy density science, warm dense matter, planetary science, geophysics, and material science.

Structural Probability Concepts Adapted to Electrical Engineering

NASA Technical Reports Server (NTRS)

Steinberg, Eric P.; Chamis, Christos C.

1994-01-01

Through the use of equivalent variable analogies, the authors demonstrate how an electrical subsystem can be modeled by an equivalent structural subsystem. This allows the electrical subsystem to be probabilistically analyzed by using available structural reliability computer codes such as NESSUS. With the ability to analyze the electrical subsystem probabilistically, we can evaluate the reliability of systems that include both structural and electrical subsystems. Common examples of such systems are a structural subsystem integrated with a health-monitoring subsystem, and smart structures. Since these systems have electrical subsystems that directly affect the operation of the overall system, probabilistically analyzing them could lead to improved reliability and reduced costs. The direct effect of the electrical subsystem on the structural subsystem is of secondary order and is not considered in the scope of this work.

Brake System Design Optimization : Volume 2. Supplemental Data.

DOT National Transportation Integrated Search

1981-04-01

Existing freight car braking systems, components, and subsystems are characterized both physically and functionally, and life-cycle costs are examined. Potential improvements to existing systems previously proposed or available are identified and des...

Brake System Design Optimization. Volume II : Supplemental Data.

DOT National Transportation Integrated Search

1981-06-01

Existing freight car braking systems, components, and subsystems are characterized both physically and functionally, and life-cycle costs are examined. Potential improvements to existing systems previously proposed or available are identified and des...

Analysis of technical university information system

NASA Astrophysics Data System (ADS)

Savelyev, N. A.; Boyarkin, M. A.

2018-05-01

The paper covers a set and interaction of the existing higher education institution automated control systems in φ state budgetary educational institution of higher professional education "Industrial University of Tyumen ". A structural interaction of the existing systems and their functions has been analyzed which has become a basis for identification of a number of system-related and local (related to separate modules) drawbacks of the university activities automation. The authors suggested a new structure of the automated control system, consisting of three major subsystems: management support; training and methodology support; distance and supplementary education support. Functionality for each subsystem has been defined in accordance with the educational institution automation requirements. The suggested structure of the ACS will solve the challenges facing the university during reorganization and optimization of the processes of management of the institution activities as a whole.

Apu/hydraulic/actuator Subsystem Computer Simulation. Space Shuttle Engineering and Operation Support, Engineering Systems Analysis. [for the space shuttle

NASA Technical Reports Server (NTRS)

1975-01-01

Major developments are examined which have taken place to date in the analysis of the power and energy demands on the APU/Hydraulic/Actuator Subsystem for space shuttle during the entry-to-touchdown (not including rollout) flight regime. These developments are given in the form of two subroutines which were written for use with the Space Shuttle Functional Simulator. The first subroutine calculates the power and energy demand on each of the three hydraulic systems due to control surface (inboard/outboard elevons, rudder, speedbrake, and body flap) activity. The second subroutine incorporates the R. I. priority rate limiting logic which limits control surface deflection rates as a function of the number of failed hydraulic. Typical results of this analysis are included, and listings of the subroutines are presented in appendicies.

Learning to juggle: on the assembly of functional subsystems into a task-specific dynamical organization.

PubMed

Huys, R; Daffertshofer, A; Beek, P J

2003-04-01

We examined the development of task-specific couplings among functional subsystems (i.e., ball circulation, respiration, and body sway) when learning to juggle a three-ball cascade, with a focus on learning-induced changes in the coupling between ball movements and respiration and the coupling between ball movements and body sway. Six novices practiced to juggle three balls in cascade fashion for one hour per day for twenty days. On specific days (7 in total), ball movements, center-of-pressure (CoP) trajectories and respiration traces were measured simultaneously. Discrete, time-continuous and spectral analyses revealed that the spatio-temporal variability of the juggling patterns decreased with practice and that the degree to which the task constraints were satisfied increased gradually. No conclusive evidence was found for ball movement-respiration coupling. In contrast, clear-cut evidence was found for the presence of 1:3 and 2:3 frequency locking between the vertical component of the ball trajectories and both the anterior-posterior and the medio-lateral components of the CoP. Incidence and expression of these mode locks varied across individuals and altered in the course of learning. Gradual changes in locking strength, appearances and disappearances of mode locks, as well as abrupt transitions between coupled states were observed. These results indicate that dissimilar learning dynamics may arise in the functional embedding of subsystems into a task-specific organization and that motor equivalence is an inherent property of such emerging task-specific organizations.

Non-Markovian modification of the golden rule rate expression

NASA Astrophysics Data System (ADS)

Basilevsky, M. V.; Davidovich, G. V.; Titov, S. V.; Voronin, A. I.

2006-11-01

The reformulation of the standard golden rule approach considered in this paper for treating reactive tunneling reduces the computation of the reaction rate to a derivation of band shapes for energy levels of reactant and product states. This treatment is based on the assumption that the medium environment is actively involved as a partner in the energy exchange with the reactive subsystem but its reorganization effect is negligible. Starting from the quantum relaxation equation for the density matrix, the required band shapes are represented in terms of the spectral density function, exhibiting the continuum spectrum inherent to the interaction between the reactants and the medium in the total reactive system. The simplest Lorentzian spectral bands, obtained under Redfield approximation, proved to be unsatisfactory because they produced a divergent rate expression at low temperature. The problem is resolved by invoking a refined spectral band shape, which behaves as Lorentzian one at the band center but decays exponentially at its tails. The corresponding closed non-Markovian rate expression is derived and investigated taking as an example the photochemical H-transfer reaction between fluorene and acridine proceeding in the fluorene molecular crystal. The kinetics in this reactive system was thoroughly studied experimentally in a wide temperature range [B. Prass et al., Ber. Bunsenges. Phys. Chem. 102, 498 (1998)].

A new decentralised controller design method for a class of strongly interconnected systems

NASA Astrophysics Data System (ADS)

Duan, Zhisheng; Jiang, Zhong-Ping; Huang, Lin

2017-02-01

In this paper, two interconnected structures are first discussed, under which some closed-loop subsystems must be unstable to make the whole interconnected system stable, which can be viewed as a kind of strongly interconnected systems. Then, comparisons with small gain theorem are discussed and large gain interconnected characteristics are shown. A new approach for the design of decentralised controllers is presented by determining the Lyapunov function structure previously, which allows the existence of unstable subsystems. By fully utilising the orthogonal space information of input matrix, some new understandings are presented for the construction of Lyapunov matrix. This new method can deal with decentralised state feedback, static output feedback and dynamic output feedback controllers in a unified framework. Furthermore, in order to reduce the design conservativeness and deal with robustness, a new robust decentralised controller design method is given by combining with the parameter-dependent Lyapunov function method. Some basic rules are provided for the choice of initial variables in Lyapunov matrix or new introduced slack matrices. As byproducts, some linear matrix inequality based sufficient conditions are established for centralised static output feedback stabilisation. Effects of unstable subsystems in nonlinear Lur'e systems are further discussed. The corresponding decentralised controller design method is presented for absolute stability. The examples illustrate that the new method is significantly effective.

Wireless Avionics Packet to Support Fault Tolerance for Flight Applications

NASA Technical Reports Server (NTRS)

Block, Gary L.; Whitaker, William D.; Dillon, James W.; Lux, James P.; Ahmad, Mohammad

2009-01-01

In this protocol and packet format, data traffic is monitored by all network interfaces to determine the health of transmitter and subsystems. When failures are detected, the network inter face applies its recover y policies to provide continued service despite the presence of faults. The protocol, packet format, and inter face are independent of the data link technology used. The current demonstration system supports both commercial off-the-shelf wireless connections and wired Ethernet connections. Other technologies such as 1553 or serial data links can be used for the network backbone. The Wireless Avionics packet is divided into three parts: a header, a data payload, and a checksum. The header has the following components: magic number, version, quality of service, time to live, sending transceiver, function code, payload length, source Application Data Interface (ADI) address, destination ADI address, sending node address, target node address, and a sequence number. The magic number is used to identify WAV packets, and allows the packet format to be updated in the future. The quality of service field allows routing decisions to be made based on this value and can be used to route critical management data over a dedicated channel. The time to live value is used to discard misrouted packets while the source transceiver is updated at each hop. This information is used to monitor the health of each transceiver in the network. To identify the packet type, the function code is used. Besides having a regular data packet, the system supports diagnostic packets for fault detection and isolation. The payload length specifies the number of data bytes in the payload, and this supports variable-length packets in the network. The source ADI is the address of the originating interface. This can be used by the destination application to identify the originating source of the packet where the address consists of a subnet, subsystem class within the subnet, a subsystem unit, and the local ADI number. The destination ADI is used to route the packet to its ultimate destination. At each hop, the sending interface uses the destination address to determine the next node for the data. The sending node is the node address of the interface that is broadcasting the packet. This field is used to determine the health of the subsystem that is sending the packet. In the case of a packet that traverses several intermediate nodes, it may be the node address of the intermediate node. The target node is the node address of the next hop for the packet. It may be an intermediate node, or the final destination for the packet. The sequence number is used to identify duplicate packets. Because each interface has multiple transceivers, the same packet will appear at both receivers. The sequence number allows the interface to correlate the reception and forward a single, unique packet for additional processing. The subnet field allows data traffic to be partitioned into segregated local networks to support large networks while keeping each subnet at a manageable size. This also keeps the routing table small enough so routing can be done by a simple table lookup in an FPGA device. The subsystem class identifies members of a set of redundant subsystems, and, in a hot standby configuration, all members of the subsystem class will receive the data packets. Only the active subsystem will generate data traffic. Specific units in a class of redundant units can be identified and, if the hot standby configuration is not used, packets will be directed to a specific subsystem unit.

Independent Orbiter Assessment (IOA): CIL issues resolution report, volume 2

NASA Technical Reports Server (NTRS)

1988-01-01

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes And Effects Analysis (FMEA) and Critical Items List (CIL) are presented. This report contains IOA assessment worksheets showing resolution of outstanding IOA CIL issues that were summarized in the IOA FMEA/CIL Assessment Interim Report, dated 9 March 1988. Each assessment worksheet has been updated with CIL issue resolution and rationale. Volume 2 contains the worksheets for the following subsystems: Nose Wheel Steering Subsystem; Remote Manipulator Subsystem; Atmospheric Revitalization Subsystem; Extravehicular Mobility Unit Subsystem; Power Reactant Supply and Distribution Subsystem; Main Propulsion Subsystem; and Orbital Maneuvering Subsystem.

A Glossary of Terms, Definitions, Acronyms, and Abbreviations Related to the National Airspace System (NAS)

DTIC Science & Technology

1990-06-01

System ACAS Airborne Collision Avoidance System ACB Adjacent Center Backup ACC ACCumulator ACC Area Control Center ACCAS Alto Cumulus CAtellanuS ACCC...subsystem) FFC For Further Clearance FFF Form, Fit, and Function FFF Form, Fix, and Function FFLT Familiarize FLighT FFM Far Field Monitor (associated with

Solar Electric Propulsion System Integration Technology (SEPSIT). Volume 2: Encke rendezvous mission and space vehicle functional description

NASA Technical Reports Server (NTRS)

Gardner, J. A.

1972-01-01

A solar electric propulsion system integration technology study is discussed. Detailed analyses in support of the solar electric propulsion module were performed. The thrust subsystem functional description is presented. The space vehicle and the space mission to which the propulsion system is applied are analyzed.

Qualification of Electrical Ground Support Equipment for New Space Programs

NASA Technical Reports Server (NTRS)

SotoToro, Felix A.; Vu, Bruce T.; Hamilton, Mark S.

2011-01-01

With the Space Shuttle program coming to an end, the National Aeronautics and Space Administration (NASA) is moving to a new space flight program that will allow expeditions beyond low earth orbit. The space vehicles required to comply with these missions will be carrying heavy payloads. This implies that the Earth departure stage capabilities must be of higher magnitudes, given the current propulsion technology. The engineering design of the new flight hardware comes with some structural, thermal, propulsion and other subsystems' challenges. Meanwhile, the necessary ground support equipment (GSE) used to test, validate, verify and process the flight hardware must withstand the new program specifications. This paper intends to provide the qualification considerations during implementation of new electrical GSE for space programs. A team of engineers was formed to embark on this task, and facilitate the logistics process and ensure that the electrical, mechanical and fluids subsystems conduct the proper level of testing. Ultimately, each subsystem must certify that each piece of ground support equipment used in the field is capable of withstanding the strenuous vibration, acoustics, environmental, thermal and Electromagnetic Interference (EMf) levels experienced during pre-launch, launch and post-launch activities. The benefits of capturing and sharing these findings will provide technical, cost savings and schedule impacts infon11ation to both the technical and management community. Keywords: Qualification; Testing; Ground Support Equipment; Electromagnetic Interference Testing; Vibration Testing; Acoustic Testing; Power Spectral Density.

Modelling and characteristic analysis of tri-axle trucks with hydraulically interconnected suspensions

NASA Astrophysics Data System (ADS)

Ding, Fei; Han, Xu; Luo, Zhen; Zhang, Nong

2012-12-01

In this paper, a new hydraulically interconnected suspension (HIS) system is proposed for the implementation of a resistance control for the pitch and bounce modes of tri-axle heavy trucks. A lumped-mass half-truck model is established using the free-body diagram method. The equations of motion of a mechanical and hydraulic coupled system are developed by incorporating the hydraulic strut forces into the mechanical subsystem as externally applied forces. The transfer matrix method (TMM) is used to evaluate the impedance matrix of the hydraulic subsystem consisting of models of fluid pipes, damper valves, accumulators, and three-way junctions. The TMM is further applied to find the quantitative relationships between the hydraulic strut forces and boundary flow of the mechanical-fluid interactive subsystem. The modal analysis method is employed to perform the vibration analysis between the trucks with the conventional suspension and the proposed HIS. Comparison analysis focuses on free vibration with identified eigenvalues and eigenvectors, isolation vibration capacity, and force vibration in terms of the power spectrum density responses. The obtained results show the effectiveness of the proposed HIS system in reducing the pitch motion of sprung mass and simultaneously maintaining the ride comfort. The pitch stiffness is increased while the bounce stiffness is slightly softened. The peak values of sprung mass and wheel hop motions are greatly reduced, and the vibration decay rate of sprung mass is also significantly increased.

Secure video communications system

DOEpatents

Smith, Robert L.

1991-01-01

A secure video communications system having at least one command network formed by a combination of subsystems. The combination of subsystems to include a video subsystem, an audio subsystem, a communications subsystem, and a control subsystem. The video communications system to be window driven and mouse operated, and having the ability to allow for secure point-to-point real-time teleconferencing.

First principles calculation of current-induced forces in atomic gold contacts

NASA Astrophysics Data System (ADS)

Brandbyge, Mads; Stokbro, Kurt; Taylor, Jeremy; Mozos, Jose-Luis; Ordejon, Pablo

2002-03-01

We have recently developed an first principles method [1] for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density functional theory (DFT) as implemented in the well tested SIESTA program [2]. We fully deal with the atomistic structure of the whole system, treating both the contact and the electrodes on the same footing. The effect of the finite bias (including selfconsistency and the solution of the electrostatic problem) is taken into account using nonequilibrium Green's functions. In this talk we show results for the forces acting on the contact atoms due to the nonequilibrium situation in the electronic subsystem, i.e. in the presence of an electronic current. We concentrate on one atom wide gold contacts/wires connected to bulk gold electrodes. References [1] Our implementation is called TranSIESTA and is described in M. Brandbyge, J. Taylor, K. Stokbro, J-L. Mozos, and P. Ordejon, cond-mat/0110650 [2] D. Sanchez-Portal, P. Ordejon, E. Artacho and J. Soler, Int. J. Quantum Chem. 65, 453 (1997).

Toward molecular mechanism of xenon anesthesia: a link to studies of xenon complexes with small aromatic molecules.

PubMed

Andrijchenko, Natalya N; Ermilov, Alexander Yu; Khriachtchev, Leonid; Räsänen, Markku; Nemukhin, Alexander V

2015-03-19

The present study illustrates the steps toward understanding molecular mechanism of xenon anesthesia by focusing on a link to the structures and spectra of intermolecular complexes of xenon with small aromatic molecules. A primary cause of xenon anesthesia is attributed to inhibition of N-methyl-D-aspartate (NMDA) receptors by an unknown mechanism. Following the results of quantum mechanics/molecular mechanics (QM/MM) and molecular dynamics (MD) calculations we report plausible xenon action sites in the ligand binding domain of the NMDA receptor, which are due to interaction of xenon atoms with aromatic amino-acid residues. We rely in these calculations on computational protocols adjusted in combined experimental and theoretical studies of intermolecular complexes of xenon with phenol. Successful reproduction of vibrational shifts in molecular species upon complexation with xenon measured in low-temperature matrices allowed us to select a proper functional form in density functional theory (DFT) approach for use in QM subsystems, as well as to calibrate force field parameters for MD simulations. The results of molecular modeling show that xenon atoms can compete with agonists for a place in the corresponding protein cavity, thus indicating their active role in anesthetic action.

The general setting for the zero-flux condition: The lagrangian and zero-flux conditions that give the heisenberg equation of motion.

PubMed

Anderson, James S M; Ayers, Paul W

2018-06-30

Generalizing our recent work on relativistic generalizations of the quantum theory of atoms in molecules, we present the general setting under which the principle of stationary action for a region leads to open quantum subsystems. The approach presented here is general and works for any Hamiltonian, and when a reasonable Lagrangian is selected, it often leads to the integral of the Laplacian of the electron density on the region vanishing as a necessary condition for the zero-flux surface. Alternatively, with this method, one can design a Lagrangian that leads to a surface of interest (though this Lagrangian may not be, and indeed probably will not be, "reasonable"). For any reasonable Lagrangian for the electronic wave function and any two-component method (related by integration by parts to the Hamiltonian) considered, the Bader definition of an atom is recaptured. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

A superconducting battery material: Lithium gold boride (LiAu3B)

NASA Astrophysics Data System (ADS)

Aydin, Sezgin; Şimşek, Mehmet

2018-04-01

The superconducting and potential cathode material properties of ternary boride of LiAu3B have been investigated by density functional first principles. The Li-concentration effects on the actual electronic and structural properties, namely the properties of LixAu9B3 (x = 0, 1, 2) sub-systems are studied. It is remarkably shown that the existence of Li-atoms has no considerable effect on the structural properties of Au-B skeleton in LiAu3B. Then, it can be offered as a potential cathode material for Li-ion batteries with the very small volume deviation of 0.42%, and the suitable average open circuit voltage of ∼1.30 V. Furthermore, the vibrational and superconducting properties such as electron-phonon coupling constant (λ) and critical temperature (Tc) of LiAu3B are studied. The calculated results suggest that LiAu3B should be a superconductor with Tc ∼5.8 K, also.

Theoretical study of the effect of the size of a high-energy proton beam of the Large Hadron Collider on the formation and propagation of shock waves in copper irradiated by 450-GeV proton beams

NASA Astrophysics Data System (ADS)

Ryazanov, A. I.; Stepakov, A. V.; Vasilyev, Ya. S.; Ferrari, A.

2014-02-01

The interaction of 450-GeV protons with copper, which is the material of the collimators of the Large Hadron Collider, has been theoretically studied. A theoretical model for the formation and propagation of shock waves has been proposed on the basis of the analysis of the energy released by a proton beam in the electronic subsystem of the material owing to the deceleration of secondary particles appearing in nuclear reactions induced by this beam on the electronic subsystem of the material. The subsequent transfer of the energy from the excited electronic subsystem to the crystal lattice through the electron-phonon interaction has been described within the thermal spike model [I.M. Lifshitz, M.I. Kaganov, and L.V. Tanatarov, Sov. Phys. JETP 4, 173 (1957); I.M. Lifshitz, M.I. Kaganov, and L.V. Tanatarov, At. Energ. 6, 391 (1959); K. Yasui, Nucl. Instrum. Methods Phys. Res., Sect. B 90, 409 (1994)]. The model of the formation of shock waves involves energy exchange processes between excited electronic and ionic subsystems of the irradiated material and is based on the hydrodynamic approximation proposed by Zel'dovich [Ya.B. Zel'dovich and Yu.P. Raizer, Physics of Shock Waves and High-Temperature Hydrodynamic Phenomena (Nauka, Moscow, 1966; Dover, New York, 2002)]. This model makes it possible to obtain the space-time distributions of the main physical characteristics (temperatures of the ionic and electronic subsystems, density, pressure, etc.) in materials irradiated by high-energy proton beams and to analyze the formation and propagation of shock waves in them. The nonlinear differential equations describing the conservation laws of mass, energy, and momentum of electrons and ions in the Euler variables in the case of the propagation of shock waves has been solved with the Godunov scheme [S. K. Godunov, A.V. Zabrodin, M.Ya. Ivanov, A.N. Kraiko, and G.P. Prokopov, Numerical Solution of Multidimensional Problems in Gas Dynamics (Nauka, Moscow, 1976) [in Russian

BioMEMS to bionanotechnology: state of the art in integrated biochips and future prospects

NASA Astrophysics Data System (ADS)

Gupta, Amit; Li, H.; Gomez, Rafael; Chang, W.-J.; Koo, Y. M.; Chang, H.; Andreadakis, G.; Akin, Demir; Bashir, Rashid

2004-12-01

Biomedical or Biological Micro-Electro-Mechanical- Systems (BioMEMS) have in recent years become increasingly prevalent and have found widespread use in a wide variety of applications such as diagnostics, therapeutics and tissue engineering. This paper reviews the interdisciplinary work performed in our group in recent years to develop micro-integrated devices to characterize biological entities. We present the use of electrical and mechanically based phenomena to perform characterization and various functions needed for integrated biochips. One sub-system takes advantage of the dielectrophoretic effect to sort and concentrate bacterial cells and viruses within a micro-fluidic biochip. Another sub-system measures impedance changes produced by the metabolic activity of bacterial cells to determine their viability. A third sub-system is used to detect the mass of viruses as they bind to micro-mechanical sensors. The last sub-system described has been used to detect the charge on DNA molecules as it translocates through nanopore channels. These devices with an electronic or mechanical signal output can be very useful in producing practical systems for rapid detection and characterization of cells for a wide variety of applications in the food safety and health diagnostics industries. The paper will also briefly discuss future prospects of BioMEMS and its possible impact and on bionanotechnology.

Preliminary test results from the CELSS Test Facility Engineering Development Unit

NASA Technical Reports Server (NTRS)

Kliss, Mark H.; Macelroy, R. D.; Blackwell, C. C.; Borchers, B. A.; Drews, M. E.; Longabaugh, J. R.; Yendler, B. S.; Zografos, A. I.

1994-01-01

As part of the NASA Controlled Ecological Life Support System (CELSS) Program, a CELSS Test Facility (CTF) is being planned for installation on the Space Station. The CTF will be used to provide data on the productivity and efficiency of a variety of CELSS higher plant crops grown in the microgravity environment of the Space Station. Tight environmental control will be maintained while data on gas exchange rates and biomass accumulation rates are collected. In order to obtain an early realistic determination of the subsystem and system requirements necessary to provide the environmental conditions specified for CTF crop productivity experiments, an Engineering Development Unit (EDU) has been designed, constructed and is in the process of subsystem and system testing at NASA Ames Research Center. The EDU is a ground test-bed which will be used to characterize the integrated performance of major subsystem technologies, to evaluate hardware candidates and control strategies required for the CTF, and to further define the ability to meet CTF requirements within present Space Station constraints. This paper reviews the functional requirements for the EDU, and focuses on the performance evaluation and test results of the various subsystems. Preliminary integrated performance results and control system operation are addressed, and plans for future science and technology testing are discussed.

Integrated Atmosphere Resource Recovery and Environmental Monitoring Technology Demonstration for Deep Space Exploration

NASA Technical Reports Server (NTRS)

Perry, Jay L.; Abney, Morgan B.; Knox, James C.; Parrish, Keith J.; Roman, Monserrate C.; Jan, Darrell L.

2012-01-01

Exploring the frontiers of deep space continues to be defined by the technological challenges presented by safely transporting a crew to and from destinations of scientific interest. Living and working on that frontier requires highly reliable and efficient life support systems that employ robust, proven process technologies. The International Space Station (ISS), including its environmental control and life support (ECLS) system, is the platform from which humanity's deep space exploration missions begin. The ISS ECLS system Atmosphere Revitalization (AR) subsystem and environmental monitoring (EM) technical architecture aboard the ISS is evaluated as the starting basis for a developmental effort being conducted by the National Aeronautics and Space Administration (NASA) via the Advanced Exploration Systems (AES) Atmosphere Resource Recovery and Environmental Monitoring (ARREM) Project.. An evolutionary approach is employed by the ARREM project to address the strengths and weaknesses of the ISS AR subsystem and EM equipment, core technologies, and operational approaches to reduce developmental risk, improve functional reliability, and lower lifecycle costs of an ISS-derived subsystem architecture suitable for use for crewed deep space exploration missions. The most promising technical approaches to an ISS-derived subsystem design architecture that incorporates promising core process technology upgrades will be matured through a series of integrated tests and architectural trade studies encompassing expected exploration mission requirements and constraints.

Modular space station phase B extension, preliminary system design. Volume 4: Subsystems analyses

NASA Technical Reports Server (NTRS)

Antell, R. W.

1972-01-01

The subsystems tradeoffs, analyses, and preliminary design results are summarized. Analyses were made of the structural and mechanical, environmental control and life support, electrical power, guidance and control, reaction control, information, and crew habitability subsystems. For each subsystem a summary description is presented including subsystem requirements, subsystem description, and subsystem characteristics definition (physical, performance, and interface). The major preliminary design data and tradeoffs or analyses are described in detail at each of the assembly levels.

Some recent developments in spacecraft environmental control/life support subsystems

NASA Technical Reports Server (NTRS)

Gillen, R. J.; Olcott, T. M.

1974-01-01

The subsystems considered include a flash evaporator for heat rejection, a regenerable carbon dioxide and humidity control subsystem, an iodinating subsystem for potable water, a cabin contaminant control subsystem, and a wet oxidation subsystem for processing spacecraft wastes. The flash evaporator discussed is a simple unit which efficiently controls life support system temperatures over a wide range of heat loads. For certain advanced spacecraft applications the control of cabin carbon dioxide and humidity can be successfully achieved by a regenerable solid amine subsystem.

Brake System Design Optimization : Volume 1. A Survey and Assessment.

DOT National Transportation Integrated Search

1978-06-01

Existing freight car braking systems, components, and subsystems are characterized both physically and functionally, and life-cycle costs are examined. Potential improvements to existing systems previously proposed or available are identified and des...

77 FR 22384 - Petition To Modify an Exemption of a Previously Approved Antitheft Device; Porsche

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-13

... passive, microprocessor-based device which includes a starter interrupt function, transponder key and a.... Porsche stated that the antitheft system consists of two major subsystems: a microprocessor-based...

Research Libraries--Automation and Cooperation.

ERIC Educational Resources Information Center

McDonald, David R.; Hurowitz, Robert

1982-01-01

Description of Research Libraries Information Network, an automated technical processing and information retrieval system, notes subsystems (acquisitions, cataloging, message, print, tables), functions, design, and benefits to participating libraries. (Request complimentary subscription on institution letterhead from Editor, "Perspectives in…

Air and water quality monitor assessment of life support subsystems

NASA Technical Reports Server (NTRS)

Whitley, Ken; Carrasquillo, Robyn L.; Holder, D.; Humphries, R.

1988-01-01

Preprotype air revitalization and water reclamation subsystems (Mole Sieve, Sabatier, Static Feed Electrolyzer, Trace Contaminant Control, and Thermoelectric Integrated Membrane Evaporative Subsystem) were operated and tested independently and in an integrated arrangement. During each test, water and/or gas samples were taken from each subsystem so that overall subsystem performance could be determined. The overall test design and objectives for both subsystem and integrated subsystem tests were limited, and no effort was made to meet water or gas specifications. The results of chemical analyses for each of the participating subsystems are presented along with other selected samples which were analyzed for physical properties and microbiologicals.

An object oriented extension to CLIPS

NASA Technical Reports Server (NTRS)

Sobkowicz, Clifford

1990-01-01

A presentation of software sub-system developed to augment C Language Production Systems (CLIPS) with facilities for object oriented Knowledge representation. Functions are provided to define classes, instantiate objects, access attributes, and assert object related facts. This extension is implemented via the CLIPS user function interface and does not require modification of any CLIPS code. It does rely on internal CLIPS functions for memory management and symbol representation.

DREISS: Using State-Space Models to Infer the Dynamics of Gene Expression Driven by External and Internal Regulatory Networks

PubMed Central

Gerstein, Mark

2016-01-01

Gene expression is controlled by the combinatorial effects of regulatory factors from different biological subsystems such as general transcription factors (TFs), cellular growth factors and microRNAs. A subsystem’s gene expression may be controlled by its internal regulatory factors, exclusively, or by external subsystems, or by both. It is thus useful to distinguish the degree to which a subsystem is regulated internally or externally–e.g., how non-conserved, species-specific TFs affect the expression of conserved, cross-species genes during evolution. We developed a computational method (DREISS, dreiss.gerteinlab.org) for analyzing the Dynamics of gene expression driven by Regulatory networks, both External and Internal based on State Space models. Given a subsystem, the “state” and “control” in the model refer to its own (internal) and another subsystem’s (external) gene expression levels. The state at a given time is determined by the state and control at a previous time. Because typical time-series data do not have enough samples to fully estimate the model’s parameters, DREISS uses dimensionality reduction, and identifies canonical temporal expression trajectories (e.g., degradation, growth and oscillation) representing the regulatory effects emanating from various subsystems. To demonstrate capabilities of DREISS, we study the regulatory effects of evolutionarily conserved vs. divergent TFs across distant species. In particular, we applied DREISS to the time-series gene expression datasets of C. elegans and D. melanogaster during their embryonic development. We analyzed the expression dynamics of the conserved, orthologous genes (orthologs), seeing the degree to which these can be accounted for by orthologous (internal) versus species-specific (external) TFs. We found that between two species, the orthologs have matched, internally driven expression patterns but very different externally driven ones. This is particularly true for genes with evolutionarily ancient functions (e.g. the ribosomal proteins), in contrast to those with more recently evolved functions (e.g., cell-cell communication). This suggests that despite striking morphological differences, some fundamental embryonic-developmental processes are still controlled by ancient regulatory systems. PMID:27760135

Surface-hopping dynamics and decoherence with quantum equilibrium structure.

PubMed

Grunwald, Robbie; Kim, Hyojoon; Kapral, Raymond

2008-04-28

In open quantum systems, decoherence occurs through interaction of a quantum subsystem with its environment. The computation of expectation values requires a knowledge of the quantum dynamics of operators and sampling from initial states of the density matrix describing the subsystem and bath. We consider situations where the quantum evolution can be approximated by quantum-classical Liouville dynamics and examine the circumstances under which the evolution can be reduced to surface-hopping dynamics, where the evolution consists of trajectory segments exclusively evolving on single adiabatic surfaces, with probabilistic hops between these surfaces. The justification for the reduction depends on the validity of a Markovian approximation on a bath averaged memory kernel that accounts for quantum coherence in the system. We show that such a reduction is often possible when initial sampling is from either the quantum or classical bath initial distributions. If the average is taken only over the quantum dispersion that broadens the classical distribution, then such a reduction is not always possible.

Calculating hyperfine couplings in large ionic crystals containing hundreds of QM atoms: subsystem DFT is the key.

PubMed

Kevorkyants, Ruslan; Wang, Xiqiao; Close, David M; Pavanello, Michele

2013-11-14

We present an application of the linear scaling frozen density embedding (FDE) formulation of subsystem DFT to the calculation of isotropic hyperfine coupling constants (hfcc's) of atoms belonging to a guanine radical cation embedded in a guanine hydrochloride monohydrate crystal. The model systems range from an isolated guanine to a 15,000 atom QM/MM cluster where the QM region is comprised of 36 protonated guanine cations, 36 chlorine anions, and 42 water molecules. Our calculations show that the embedding effects of the surrounding crystal cannot be reproduced by small model systems nor by a pure QM/MM procedure. Instead, a large QM region is needed to fully capture the complicated nature of the embedding effects in this system. The unprecedented system size for a relativistic all-electron isotropic hfcc calculation can be approached in this work because the local nature of the electronic structure of the organic crystals considered is fully captured by the FDE approach.

Dissipation and decoherence in nanodevices: a generalized Fermi's golden rule

NASA Astrophysics Data System (ADS)

Taj, D.; Iotti, R. C.; Rossi, F.

2009-06-01

We shall revisit the conventional adiabatic or Markov approximation, which—in contrast to the semiclassical case—does not preserve the positive-definite character of the corresponding density matrix, thus leading to highly non-physical results. To overcome this serious limitation, originally pointed out and partially solved by Davies and co-workers almost three decades ago, we shall propose an alternative more general adiabatic procedure, which (i) is physically justified under the same validity restrictions of the conventional Markov approach, (ii) in the semiclassical limit reduces to the standard Fermi's golden rule and (iii) describes a genuine Lindblad evolution, thus providing a reliable/robust treatment of energy-dissipation and dephasing processes in electronic quantum devices. Unlike standard master-equation formulations, the dependence of our approximation on the specific choice of the subsystem (that includes the common partial trace reduction) does not threaten positivity, and quantum scattering rates are well defined even in the case the subsystem is infinitely extended/has a continuous spectrum.

Propellant Feed Subsystem for a 26 kW flight arcjet propulsion system

NASA Astrophysics Data System (ADS)

Vaughan, C. E.; Morris, J. P.

1993-06-01

The USAF arcjet ATTD program demanded the development of a low-cost ammonia Propellant Feed Subsystem (PFS). A flow rate of 240 +/- 5 mg/sec during a total of ten 15-min ammonia outflows was required for the flight mission. The precision of the flow tolerance required a departure from the design of previous ammonia propellant feed systems. Since a propellant management device was not used, thermocapillary forces were explored as a means to limit outflow of liquid phase ammonia. A high energy density feedline heater with an internal wick was developed to guarantee that only gas phase propellant would reach the arcjet. A digital control algorithm was developed to implement bang-bang control of mass flow rate metered by a sonic venturi. Development tests of this system have been completed. The system is capable of continuous gas phase outflows regardless of orientation. Integrated tests with the arcjet and power conditioning unit have also been successfully completed.

The Human Subsystem - Definition and Integration

NASA Technical Reports Server (NTRS)

vonBengston, Kristian; Twyford, Evan

2007-01-01

This paper will discuss the use of the human subsystem in development phases of human space flight. Any space mission has clearly defined subsystems, managed by experts attached to these. Clearly defined subsystems and correct use provide easier and more efficient development for each independent subsystem and for the relation between these subsystems. Furthermore, this paper will argue that a defined subsystem related to humans in space has not always been clearly present, and that correct implementation is perhaps missing, based on experience and survey data. Finally, the authors will discuss why the human subsystem has not been fully integrated, why it must be a mandatory part of the programming, a re-definition of the human subsystem, and suggestions of methods to improve the integration of human factors in the development.

A component-based problem list subsystem for the HOLON testbed. Health Object Library Online.

PubMed Central

Law, V.; Goldberg, H. S.; Jones, P.; Safran, C.

1998-01-01

One of the deliverables of the HOLON (Health Object Library Online) project is the specification of a reference architecture for clinical information systems that facilitates the development of a variety of discrete, reusable software components. One of the challenges facing the HOLON consortium is determining what kinds of components can be made available in a library for developers of clinical information systems. To further explore the use of component architectures in the development of reusable clinical subsystems, we have incorporated ongoing work in the development of enterprise terminology services into a Problem List subsystem for the HOLON testbed. We have successfully implemented a set of components using CORBA (Common Object Request Broker Architecture) and Java distributed object technologies that provide a functional problem list application and UMLS-based "Problem Picker." Through this development, we have overcome a variety of obstacles characteristic of rapidly emerging technologies, and have identified architectural issues necessary to scale these components for use and reuse within an enterprise clinical information system. PMID:9929252

Development of an expert system for analysis of Shuttle atmospheric revitalization and pressure control subsystem anomalies

NASA Technical Reports Server (NTRS)

Lafuse, Sharon A.

1991-01-01

The paper describes the Shuttle Leak Management Expert System (SLMES), a preprototype expert system developed to enable the ECLSS subsystem manager to analyze subsystem anomalies and to formulate flight procedures based on flight data. The SLMES combines the rule-based expert system technology with the traditional FORTRAN-based software into an integrated system. SLMES analyzes the data using rules, and, when it detects a problem that requires simulation, it sets up the input for the FORTRAN-based simulation program ARPCS2AT2, which predicts the cabin total pressure and composition as a function of time. The program simulates the pressure control system, the crew oxygen masks, the airlock repress/depress valves, and the leakage. When the simulation has completed, other SLMES rules are triggered to examine the results of simulation contrary to flight data and to suggest methods for correcting the problem. Results are then presented in form of graphs and tables.

Optimisation study of a vehicle bumper subsystem with fuzzy parameters

NASA Astrophysics Data System (ADS)

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

2012-10-01

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

Neural network system for purposeful behavior based on foveal visual preprocessor

NASA Astrophysics Data System (ADS)

Golovan, Alexander V.; Shevtsova, Natalia A.; Klepatch, Arkadi A.

1996-10-01

Biologically plausible model of the system with an adaptive behavior in a priori environment and resistant to impairment has been developed. The system consists of input, learning, and output subsystems. The first subsystems classifies input patterns presented as n-dimensional vectors in accordance with some associative rule. The second one being a neural network determines adaptive responses of the system to input patterns. Arranged neural groups coding possible input patterns and appropriate output responses are formed during learning by means of negative reinforcement. Output subsystem maps a neural network activity into the system behavior in the environment. The system developed has been studied by computer simulation imitating a collision-free motion of a mobile robot. After some learning period the system 'moves' along a road without collisions. It is shown that in spite of impairment of some neural network elements the system functions reliably after relearning. Foveal visual preprocessor model developed earlier has been tested to form a kind of visual input to the system.

Advanced Hybrid Propulsion and Energy Management System for High Efficiency, Off Highway, 240 Ton Class, Diesel Electric Haul Trucks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richter, Tim; Slezak, Lee; Johnson, Chris

2008-12-31

The objective of this project is to reduce the fuel consumption of off-highway vehicles, specifically large tonnage mine haul trucks. A hybrid energy storage and management system will be added to a conventional diesel-electric truck that will allow capture of braking energy normally dissipated in grid resistors as heat. The captured energy will be used during acceleration and motoring, reducing the diesel engine load, thus conserving fuel. The project will work towards a system validation of the hybrid system by first selecting an energy storage subsystem and energy management subsystem. Laboratory testing at a subscale level will evaluate these selectionsmore » and then a full-scale laboratory test will be performed. After the subsystems have been proven at the full-scale lab, equipment will be mounted on a mine haul truck and integrated with the vehicle systems. The integrated hybrid components will be exercised to show functionality, capability, and fuel economy impacts in a mine setting.« less

Adaptive critic designs for optimal control of uncertain nonlinear systems with unmatched interconnections.

PubMed

Yang, Xiong; He, Haibo

2018-05-26

In this paper, we develop a novel optimal control strategy for a class of uncertain nonlinear systems with unmatched interconnections. To begin with, we present a stabilizing feedback controller for the interconnected nonlinear systems by modifying an array of optimal control laws of auxiliary subsystems. We also prove that this feedback controller ensures a specified cost function to achieve optimality. Then, under the framework of adaptive critic designs, we use critic networks to solve the Hamilton-Jacobi-Bellman equations associated with auxiliary subsystem optimal control laws. The critic network weights are tuned through the gradient descent method combined with an additional stabilizing term. By using the newly established weight tuning rules, we no longer need the initial admissible control condition. In addition, we demonstrate that all signals in the closed-loop auxiliary subsystems are stable in the sense of uniform ultimate boundedness by using classic Lyapunov techniques. Finally, we provide an interconnected nonlinear plant to validate the present control scheme. Copyright © 2018 Elsevier Ltd. All rights reserved.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: AMSU-A1 Antenna Drive Subsystem, PN 1331720-2, S/N 106

NASA Technical Reports Server (NTRS)

Luu, D.

1999-01-01

This is the Performance Verification Report, AMSU-A1 Antenna Drive Subsystem, P/N 1331720-2, S/N 106, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The antenna drive subsystem of the METSAT AMSU-A1, S/N 106, P/N 1331720-2, completed acceptance testing per A-ES Test Procedure AE-26002/lD. The test included: Scan Motion and Jitter, Pulse Load Bus Peak Current and Rise Time, Resolver Reading and Position Error, Gain/ Phase Margin, and Operational Gain Margin. The drive motors and electronic circuitry were also tested at the component level. The drive motor test includes: Starting Torque Test, Motor Commutation Test, Resolver Operation/ No-Load Speed Test, and Random Vibration. The electronic circuitry was tested at the Circuit Card Assembly (CCA) level of production; each test exercised all circuit functions. The transistor assembly was tested during the W3 cable assembly (1356941-1) test.

Graph-Based Semantic Web Service Composition for Healthcare Data Integration.

PubMed

Arch-Int, Ngamnij; Arch-Int, Somjit; Sonsilphong, Suphachoke; Wanchai, Paweena

2017-01-01

Within the numerous and heterogeneous web services offered through different sources, automatic web services composition is the most convenient method for building complex business processes that permit invocation of multiple existing atomic services. The current solutions in functional web services composition lack autonomous queries of semantic matches within the parameters of web services, which are necessary in the composition of large-scale related services. In this paper, we propose a graph-based Semantic Web Services composition system consisting of two subsystems: management time and run time. The management-time subsystem is responsible for dependency graph preparation in which a dependency graph of related services is generated automatically according to the proposed semantic matchmaking rules. The run-time subsystem is responsible for discovering the potential web services and nonredundant web services composition of a user's query using a graph-based searching algorithm. The proposed approach was applied to healthcare data integration in different health organizations and was evaluated according to two aspects: execution time measurement and correctness measurement.

Graph-Based Semantic Web Service Composition for Healthcare Data Integration

PubMed Central

2017-01-01

Within the numerous and heterogeneous web services offered through different sources, automatic web services composition is the most convenient method for building complex business processes that permit invocation of multiple existing atomic services. The current solutions in functional web services composition lack autonomous queries of semantic matches within the parameters of web services, which are necessary in the composition of large-scale related services. In this paper, we propose a graph-based Semantic Web Services composition system consisting of two subsystems: management time and run time. The management-time subsystem is responsible for dependency graph preparation in which a dependency graph of related services is generated automatically according to the proposed semantic matchmaking rules. The run-time subsystem is responsible for discovering the potential web services and nonredundant web services composition of a user's query using a graph-based searching algorithm. The proposed approach was applied to healthcare data integration in different health organizations and was evaluated according to two aspects: execution time measurement and correctness measurement. PMID:29065602

A component-based problem list subsystem for the HOLON testbed. Health Object Library Online.

PubMed

Law, V; Goldberg, H S; Jones, P; Safran, C

1998-01-01

One of the deliverables of the HOLON (Health Object Library Online) project is the specification of a reference architecture for clinical information systems that facilitates the development of a variety of discrete, reusable software components. One of the challenges facing the HOLON consortium is determining what kinds of components can be made available in a library for developers of clinical information systems. To further explore the use of component architectures in the development of reusable clinical subsystems, we have incorporated ongoing work in the development of enterprise terminology services into a Problem List subsystem for the HOLON testbed. We have successfully implemented a set of components using CORBA (Common Object Request Broker Architecture) and Java distributed object technologies that provide a functional problem list application and UMLS-based "Problem Picker." Through this development, we have overcome a variety of obstacles characteristic of rapidly emerging technologies, and have identified architectural issues necessary to scale these components for use and reuse within an enterprise clinical information system.

Operation and maintenance requirements of the Army Remotely Piloted Vehicle (RPV)

NASA Technical Reports Server (NTRS)

1983-01-01

The Remotely Piloted Vehicle (RPV) system is being developed to provide the Army with a target acquistion, target location, and laser designation capability that will significantly enhance the effectiveness of the artillery. Iterative analyses of the manpower, personnel, and training (MPT) requirements for an RPV system configured to accommodate both a daylight television and a forward looking infrared (FLIR) mission payload subsystem (FMPS) and related support subsystems are examined. Additionally, this analysis incorporates a 24 hour-a-day operational scenario. Therefore, the information presented was developed with a view towards delineating the differences (or deltas) imposed by the new requirements resulting from FMPS/24 hour operating day functions.

Architecture of the software for LAMOST fiber positioning subsystem

NASA Astrophysics Data System (ADS)

Peng, Xiaobo; Xing, Xiaozheng; Hu, Hongzhuan; Zhai, Chao; Li, Weimin

2004-09-01

The architecture of the software which controls the LAMOST fiber positioning sub-system is described. The software is composed of two parts as follows: a main control program in a computer and a unit controller program in a MCS51 single chip microcomputer ROM. And the function of the software includes: Client/Server model establishment, observation planning, collision handling, data transmission, pulse generation, CCD control, image capture and processing, and data analysis etc. Particular attention is paid to the ways in which different parts of the software can communicate. Also software techniques for multi threads, SOCKET programming, Microsoft Windows message response, and serial communications are discussed.

A computer simulator for development of engineering system design methodologies

NASA Technical Reports Server (NTRS)

Padula, S. L.; Sobieszczanski-Sobieski, J.

1987-01-01

A computer program designed to simulate and improve engineering system design methodology is described. The simulator mimics the qualitative behavior and data couplings occurring among the subsystems of a complex engineering system. It eliminates the engineering analyses in the subsystems by replacing them with judiciously chosen analytical functions. With the cost of analysis eliminated, the simulator is used for experimentation with a large variety of candidate algorithms for multilevel design optimization to choose the best ones for the actual application. Thus, the simulator serves as a development tool for multilevel design optimization strategy. The simulator concept, implementation, and status are described and illustrated with examples.