Randomized dynamical decoupling strategies and improved one-way key rates for quantum cryptography
Energy Technology Data Exchange (ETDEWEB)
Kern, Oliver
2009-05-25
The present thesis deals with various methods of quantum error correction. It is divided into two parts. In the first part, dynamical decoupling methods are considered which have the task of suppressing the influence of residual imperfections in a quantum memory. Such imperfections might be given by couplings between the finite dimensional quantum systems (qudits) constituting the quantum memory, for instance. The suppression is achieved by altering the dynamics of an imperfect quantum memory with the help of a sequence of local unitary operations applied to the qudits. Whereas up to now the operations of such decoupling sequences have been constructed in a deterministic fashion, strategies are developed in this thesis which construct the operations by random selection from a suitable set. Formulas are derived which estimate the average performance of such strategies. As it turns out, randomized decoupling strategies offer advantages and disadvantages over deterministic ones. It is possible to benefit from the advantages of both kind of strategies by designing combined strategies. Furthermore, it is investigated if and how the discussed decoupling strategies can be employed to protect a quantum computation running on the quantum memory. It is shown that a purely randomized decoupling strategy may be used by applying the decoupling operations and adjusted gates of the quantum algorithm in an alternating fashion. Again this method can be enhanced by the means of deterministic methods in order to obtain a combined decoupling method for quantum computations analogously to the combining strategies for quantum memories. The second part of the thesis deals with quantum error-correcting codes and protocols for quantum key distribution. The focus is on the BB84 and the 6-state protocol making use of only one-way communication during the error correction and privacy amplification steps. It is shown that by adding additional errors to the preliminary key (a process called
Randomized dynamical decoupling strategies and improved one-way key rates for quantum cryptography
International Nuclear Information System (INIS)
Kern, Oliver
2009-01-01
The present thesis deals with various methods of quantum error correction. It is divided into two parts. In the first part, dynamical decoupling methods are considered which have the task of suppressing the influence of residual imperfections in a quantum memory. Such imperfections might be given by couplings between the finite dimensional quantum systems (qudits) constituting the quantum memory, for instance. The suppression is achieved by altering the dynamics of an imperfect quantum memory with the help of a sequence of local unitary operations applied to the qudits. Whereas up to now the operations of such decoupling sequences have been constructed in a deterministic fashion, strategies are developed in this thesis which construct the operations by random selection from a suitable set. Formulas are derived which estimate the average performance of such strategies. As it turns out, randomized decoupling strategies offer advantages and disadvantages over deterministic ones. It is possible to benefit from the advantages of both kind of strategies by designing combined strategies. Furthermore, it is investigated if and how the discussed decoupling strategies can be employed to protect a quantum computation running on the quantum memory. It is shown that a purely randomized decoupling strategy may be used by applying the decoupling operations and adjusted gates of the quantum algorithm in an alternating fashion. Again this method can be enhanced by the means of deterministic methods in order to obtain a combined decoupling method for quantum computations analogously to the combining strategies for quantum memories. The second part of the thesis deals with quantum error-correcting codes and protocols for quantum key distribution. The focus is on the BB84 and the 6-state protocol making use of only one-way communication during the error correction and privacy amplification steps. It is shown that by adding additional errors to the preliminary key (a process called
Dynamical decoupling of unbounded Hamiltonians
Arenz, Christian; Burgarth, Daniel; Facchi, Paolo; Hillier, Robin
2018-03-01
We investigate the possibility to suppress interactions between a finite dimensional system and an infinite dimensional environment through a fast sequence of unitary kicks on the finite dimensional system. This method, called dynamical decoupling, is known to work for bounded interactions, but physical environments such as bosonic heat baths are usually modeled with unbounded interactions; hence, here, we initiate a systematic study of dynamical decoupling for unbounded operators. We develop a sufficient decoupling criterion for arbitrary Hamiltonians and a necessary decoupling criterion for semibounded Hamiltonians. We give examples for unbounded Hamiltonians where decoupling works and the limiting evolution as well as the convergence speed can be explicitly computed. We show that decoupling does not always work for unbounded interactions and we provide both physically and mathematically motivated examples.
Dynamic decoupling of secondary systems
International Nuclear Information System (INIS)
Gupta, A.K.; Tembulkar, J.M.
1984-01-01
The dynamic analysis of primary systems must often be performed decoupled from the secondary system. In doing so, one should assure that the decoupling does not significantly affect the frequencies and the response of the primary systems. The practice consists of heuristic algorithms intended to limit changes in the frequencies. The change in response is not considered. In this paper, changes in both the frequencies and the response are considered. Rational, but simple algorithms are derived to make accurate predictions. Material up to MDOF primary-SDOF secondary system is presented in this paper. MDOF-MDOF systems are treated in a companion paper. (orig.)
Optimally combining dynamical decoupling and quantum error correction.
Paz-Silva, Gerardo A; Lidar, D A
2013-01-01
Quantum control and fault-tolerant quantum computing (FTQC) are two of the cornerstones on which the hope of realizing a large-scale quantum computer is pinned, yet only preliminary steps have been taken towards formalizing the interplay between them. Here we explore this interplay using the powerful strategy of dynamical decoupling (DD), and show how it can be seamlessly and optimally integrated with FTQC. To this end we show how to find the optimal decoupling generator set (DGS) for various subspaces relevant to FTQC, and how to simultaneously decouple them. We focus on stabilizer codes, which represent the largest contribution to the size of the DGS, showing that the intuitive choice comprising the stabilizers and logical operators of the code is in fact optimal, i.e., minimizes a natural cost function associated with the length of DD sequences. Our work brings hybrid DD-FTQC schemes, and their potentially considerable advantages, closer to realization.
Fletcher, Robert; Rammelt, Crelis
2017-01-01
Central to the United Nations’ post-2015 development agenda grounded in the Sustainable Development Goals is the notion of ‘decoupling’: the need to divorce economic growth from its ecological impact. For proponents, decoupling entails increasing the efficiency with which value is derived from
Protected quantum computing: interleaving gate operations with dynamical decoupling sequences.
Zhang, Jingfu; Souza, Alexandre M; Brandao, Frederico Dias; Suter, Dieter
2014-02-07
Implementing precise operations on quantum systems is one of the biggest challenges for building quantum devices in a noisy environment. Dynamical decoupling attenuates the destructive effect of the environmental noise, but so far, it has been used primarily in the context of quantum memories. Here, we experimentally demonstrate a general scheme for combining dynamical decoupling with quantum logical gate operations using the example of an electron-spin qubit of a single nitrogen-vacancy center in diamond. We achieve process fidelities >98% for gate times that are 2 orders of magnitude longer than the unprotected dephasing time T2.
Dynamically Decoupled 13C Spins in Hyperpolarized Nanodiamond
Rej, Ewa; Gaebel, Torsten; Boele, Thomas; Waddington, David; Reilly, David
The spin-spin relaxation time, T2, which determines how long a quantum state remains coherent, is an important factor for many applications ranging from MRI to quantum computing. A common technique used in quantum information technology to extend the T2, involves averaging out certain noise spectra via dynamical decoupling sequences. Depending on the nature of the noise in the system, specific sequences, such as CPMG, UDD or KDD, can be tailored to optimize T2. Here we combine hyperpolarization techniques and dynamical decoupling sequences to extend the T2 of 13C nuclear spins in nanodiamond by three orders of magnitude.
Effects of stochastic noise on dynamical decoupling procedures
Energy Technology Data Exchange (ETDEWEB)
Bernad, Jozsef Zsolt; Frydrych, Holger; Alber, Gernot [Institut fuer Angewandte Physik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
2013-07-01
Dynamical decoupling is a well-established technique to protect quantum systems from unwanted influences of their environment by exercising active control. It has been used experimentally to drastically increase the lifetime of qubit states in various implementations. The efficiency of different dynamical decoupling schemes defines the lifetime. However, errors in control operations always limit this efficiency. We propose a stochastic model as a possible description of imperfect control pulses and discuss the impact of this kind of error on different decoupling schemes. In the limit of continuous control, i.e. if the number of pulses N → ∞, we derive a stochastic differential equation for the evolution of the density operator of the controlled system and its environment. In the context of this modified time evolution we discuss possibilities of protecting qubit states against environmental noise.
Robust dynamical decoupling for quantum computing and quantum memory.
Souza, Alexandre M; Alvarez, Gonzalo A; Suter, Dieter
2011-06-17
Dynamical decoupling (DD) is a popular technique for protecting qubits from the environment. However, unless special care is taken, experimental errors in the control pulses used in this technique can destroy the quantum information instead of preserving it. Here, we investigate techniques for making DD sequences robust against different types of experimental errors while retaining good decoupling efficiency in a fluctuating environment. We present experimental data from solid-state nuclear spin qubits and introduce a new DD sequence that is suitable for quantum computing and quantum memory.
General solution to inhomogeneous dephasing and smooth pulse dynamical decoupling
Zeng, Junkai; Deng, Xiu-Hao; Russo, Antonio; Barnes, Edwin
2018-03-01
In order to achieve the high-fidelity quantum control needed for a broad range of quantum information technologies, reducing the effects of noise and system inhomogeneities is an essential task. It is well known that a system can be decoupled from noise or made insensitive to inhomogeneous dephasing dynamically by using carefully designed pulse sequences based on square or delta-function waveforms such as Hahn spin echo or CPMG. However, such ideal pulses are often challenging to implement experimentally with high fidelity. Here, we uncover a new geometrical framework for visualizing all possible driving fields, which enables one to generate an unlimited number of smooth, experimentally feasible pulses that perform dynamical decoupling or dynamically corrected gates to arbitrarily high order. We demonstrate that this scheme can significantly enhance the fidelity of single-qubit operations in the presence of noise and when realistic limitations on pulse rise times and amplitudes are taken into account.
Automated smoother for the numerical decoupling of dynamics models.
Vilela, Marco; Borges, Carlos C H; Vinga, Susana; Vasconcelos, Ana Tereza R; Santos, Helena; Voit, Eberhard O; Almeida, Jonas S
2007-08-21
Structure identification of dynamic models for complex biological systems is the cornerstone of their reverse engineering. Biochemical Systems Theory (BST) offers a particularly convenient solution because its parameters are kinetic-order coefficients which directly identify the topology of the underlying network of processes. We have previously proposed a numerical decoupling procedure that allows the identification of multivariate dynamic models of complex biological processes. While described here within the context of BST, this procedure has a general applicability to signal extraction. Our original implementation relied on artificial neural networks (ANN), which caused slight, undesirable bias during the smoothing of the time courses. As an alternative, we propose here an adaptation of the Whittaker's smoother and demonstrate its role within a robust, fully automated structure identification procedure. In this report we propose a robust, fully automated solution for signal extraction from time series, which is the prerequisite for the efficient reverse engineering of biological systems models. The Whittaker's smoother is reformulated within the context of information theory and extended by the development of adaptive signal segmentation to account for heterogeneous noise structures. The resulting procedure can be used on arbitrary time series with a nonstationary noise process; it is illustrated here with metabolic profiles obtained from in-vivo NMR experiments. The smoothed solution that is free of parametric bias permits differentiation, which is crucial for the numerical decoupling of systems of differential equations. The method is applicable in signal extraction from time series with nonstationary noise structure and can be applied in the numerical decoupling of system of differential equations into algebraic equations, and thus constitutes a rather general tool for the reverse engineering of mechanistic model descriptions from multivariate experimental
Accuracy of dynamical-decoupling-based spectroscopy of Gaussian noise
Szańkowski, Piotr; Cywiński, Łukasz
2018-03-01
The fundamental assumption of dynamical-decoupling-based noise spectroscopy is that the coherence decay rate of qubit (or qubits) driven with a sequence of many pulses, is well approximated by the environmental noise spectrum spanned on frequency comb defined by the sequence. Here we investigate the precise conditions under which this commonly used spectroscopic approach is quantitatively correct. To this end we focus on two representative examples of spectral densities: the long-tailed Lorentzian, and finite-ranged Gaussian—both expected to be encountered when using the qubit for nanoscale nuclear resonance imaging. We have found that, in contrast to Lorentz spectrum, for which the corrections to the standard spectroscopic formulas can easily be made negligible, the spectra with finite range are more challenging to reconstruct accurately. For Gaussian line shape of environmental spectral density, direct application of the standard dynamical-decoupling-based spectroscopy leads to erroneous attribution of long-tail behavior to the reconstructed spectrum. Fortunately, artifacts such as this, can be completely avoided with the simple extension to standard reconstruction method.
Combining dynamical decoupling with fault-tolerant quantum computation
International Nuclear Information System (INIS)
Ng, Hui Khoon; Preskill, John; Lidar, Daniel A.
2011-01-01
We study how dynamical decoupling (DD) pulse sequences can improve the reliability of quantum computers. We prove upper bounds on the accuracy of DD-protected quantum gates and derive sufficient conditions for DD-protected gates to outperform unprotected gates. Under suitable conditions, fault-tolerant quantum circuits constructed from DD-protected gates can tolerate stronger noise and have a lower overhead cost than fault-tolerant circuits constructed from unprotected gates. Our accuracy estimates depend on the dynamics of the bath that couples to the quantum computer and can be expressed either in terms of the operator norm of the bath's Hamiltonian or in terms of the power spectrum of bath correlations; we explain in particular how the performance of recursively generated concatenated pulse sequences can be analyzed from either viewpoint. Our results apply to Hamiltonian noise models with limited spatial correlations.
Dynamical-Decoupling-Based Quantum Sensing: Floquet Spectroscopy
Directory of Open Access Journals (Sweden)
J. E. Lang
2015-10-01
Full Text Available Sensing the internal dynamics of individual nuclear spins or clusters of nuclear spins has recently become possible by observing the coherence decay of a nearby electronic spin: the weak magnetic noise is amplified by a periodic, multipulse decoupling sequence. However, it remains challenging to robustly infer underlying atomic-scale structure from decoherence traces in all but the simplest cases. We introduce Floquet spectroscopy as a versatile paradigm for analysis of these experiments and argue that it offers a number of general advantages. In particular, this technique generalizes to more complex situations, offering physical insight in regimes of many-body dynamics, strong coupling, and pulses of finite duration. As there is no requirement for resonant driving, the proposed spectroscopic approach permits physical interpretation of striking, but overlooked, coherence decay features in terms of the form of the avoided crossings of the underlying quasienergy eigenspectrum. This is exemplified by a set of “diamond-shaped” features arising for transverse-field scans in the case of single-spin sensing by nitrogen-vacancy centers in diamond. We also investigate applications for donors in silicon, showing that the resulting tunable interaction strengths offer highly promising future sensors.
Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach
Directory of Open Access Journals (Sweden)
Simon Goddek
2016-07-01
Full Text Available The classical working principle of aquaponics is to provide nutrient-rich aquacultural water to a hydroponic plant culture unit, which in turn depurates the water that is returned to the aquaculture tanks. A known drawback is that a compromise away from optimal growing conditions for plants and fish must be achieved to produce both crops and fish in the same environmental conditions. The objective of this study was to develop a theoretical concept of a decoupled aquaponic system (DAPS, and predict water, nutrient (N and P, fish, sludge, and plant levels. This has been approached by developing a dynamic aquaponic system model, using inputs from data found in literature covering the fields of aquaculture, hydroponics, and sludge treatment. The outputs from the model showed the dependency of aquacultural water quality on the hydroponic evapotranspiration rate. This result can be explained by the fact that DAPS is based on one-way flows. These one-way flows results in accumulations of remineralized nutrients in the hydroponic component ensuring optimal conditions for the plants. The study also suggests to size the cultivation area based on P availability in the hydroponic component as P is an exhaustible resource and has been identified one of the main limiting factors for plant growth.
Feedforward control strategy for the state-decoupling Stand-alone UPS with LC output filter
DEFF Research Database (Denmark)
Lu, Jinghang; Savaghebi, Mehdi; Guerrero, Josep M.
2017-01-01
. In order to further increase the load current disturbance rejection capability of the state-decoupling in UPS system, a feedforward control strategy is proposed. In addition, the design principle for the current and voltage regulators are discussed. Simulation and experimental results are provided......In this paper, the disturbance rejection performance of the cascaded control strategy for UPS system is investigated. The comparison of closed loop system performance between conventional cascaded control (CCC) strategy and state-decoupling cascaded control (SDCC) strategy are further explored...
DEFF Research Database (Denmark)
Sokoler, Leo Emil; Standardi, Laura; Edlund, Kristian
2014-01-01
This paper presents a warm-started Dantzig–Wolfe decomposition algorithm tailored to economic model predictive control of dynamically decoupled subsystems. We formulate the constrained optimal control problem solved at each sampling instant as a linear program with state space constraints, input...... limits, input rate limits, and soft output limits. The objective function of the linear program is related directly to the cost of operating the subsystems, and the cost of violating the soft output constraints. Simulations for large-scale economic power dispatch problems show that the proposed algorithm...... is significantly faster than both state-of-the-art linear programming solvers, and a structure exploiting implementation of the alternating direction method of multipliers. It is also demonstrated that the control strategy presented in this paper can be tuned using a weighted ℓ1-regularization term...
Directory of Open Access Journals (Sweden)
Li Ke
2014-12-01
Full Text Available A large-scale high altitude environment simulation test cabin was developed to accurately control temperatures and pressures encountered at high altitudes. The system was developed to provide slope-tracking dynamic control of the temperature–pressure two-parameter and overcome the control difficulties inherent to a large inertia lag link with a complex control system which is composed of turbine refrigeration device, vacuum device and liquid nitrogen cooling device. The system includes multi-parameter decoupling of the cabin itself to avoid equipment damage of air refrigeration turbine caused by improper operation. Based on analysis of the dynamic characteristics and modeling for variations in temperature, pressure and rotation speed, an intelligent controller was implemented that includes decoupling and fuzzy arithmetic combined with an expert PID controller to control test parameters by decoupling and slope tracking control strategy. The control system employed centralized management in an open industrial ethernet architecture with an industrial computer at the core. The simulation and field debugging and running results show that this method can solve the problems of a poor anti-interference performance typical for a conventional PID and overshooting that can readily damage equipment. The steady-state characteristics meet the system requirements.
DEFF Research Database (Denmark)
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2011-01-01
In this paper, a circuit-level decoupling modulation strategy is proposed for the three-level (TL) neutral-point-clamped (NPC) inverters. With the proposed modulation scheme, the TL-NPC inverter can be decoupled into two three-level Buck converters in each defined operating section, which makes...
One-Shot Decoupling and Page Curves from a Dynamical Model for Black Hole Evaporation.
Brádler, Kamil; Adami, Christoph
2016-03-11
One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to Hawking radiation. An explicit numerical calculation of the discretized path integral of the S matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction. We argue that information transfer and the emergence of Page curves is a robust feature of any multilinear interaction Hamiltonian with a bounded spectrum.
Optimal pulse spacing for dynamical decoupling in the presence of a purely dephasing spin bath
International Nuclear Information System (INIS)
Ajoy, Ashok; Alvarez, Gonzalo A.; Suter, Dieter
2011-01-01
Maintaining quantum coherence is a crucial requirement for quantum computation; hence protecting quantum systems against their irreversible corruption due to environmental noise is an important open problem. Dynamical decoupling (DD) is an effective method for reducing decoherence with a low control overhead. It also plays an important role in quantum metrology, where, for instance, it is employed in multiparameter estimation. While a sequence of equidistant control pulses [the Carr-Purcell-Meiboom-Gill (CPMG) sequence] has been ubiquitously used for decoupling, Uhrig recently proposed that a nonequidistant pulse sequence [the Uhrig dynamic decoupling (UDD) sequence] may enhance DD performance, especially for systems where the spectral density of the environment has a sharp frequency cutoff. On the other hand, equidistant sequences outperform UDD for soft cutoffs. The relative advantage provided by UDD for intermediate regimes is not clear. In this paper, we analyze the relative DD performance in this regime experimentally, using solid-state nuclear magnetic resonance. Our system qubits are 13 C nuclear spins and the environment consists of a 1 H nuclear spin bath whose spectral density is close to a normal (Gaussian) distribution. We find that in the presence of such a bath, the CPMG sequence outperforms the UDD sequence. An analogy between dynamical decoupling and interference effects in optics provides an intuitive explanation as to why the CPMG sequence performs better than any nonequidistant DD sequence in the presence of this kind of environmental noise.
Frequency-agile gyrotron for electron decoupling and pulsed dynamic nuclear polarization
Scott, Faith J.; Saliba, Edward P.; Albert, Brice J.; Alaniva, Nicholas; Sesti, Erika L.; Gao, Chukun; Golota, Natalie C.; Choi, Eric J.; Jagtap, Anil P.; Wittmann, Johannes J.; Eckardt, Michael; Harneit, Wolfgang; Corzilius, Björn; Th. Sigurdsson, Snorri; Barnes, Alexander B.
2018-04-01
We describe a frequency-agile gyrotron which can generate frequency-chirped microwave pulses. An arbitrary waveform generator (AWG) within the NMR spectrometer controls the microwave frequency, enabling synchronized pulsed control of both electron and nuclear spins. We demonstrate that the acceleration of emitted electrons, and thus the microwave frequency, can be quickly changed by varying the anode voltage. This strategy results in much faster frequency response than can be achieved by changing the potential of the electron emitter, and does not require a custom triode electron gun. The gyrotron frequency can be swept with a rate of 20 MHz/μs over a 670 MHz bandwidth in a static magnetic field. We have already implemented time-domain electron decoupling with dynamic nuclear polarization (DNP) magic angle spinning (MAS) with this device. In this contribution, we show frequency-swept DNP enhancement profiles recorded without changing the NMR magnet or probe. The profile of endofullerenes exhibits a DNP profile with a <10 MHz linewidth, indicating that the device also has sufficient frequency stability, and therefore phase stability, to implement pulsed DNP mechanisms such as the frequency-swept solid effect. We describe schematics of the mechanical and vacuum construction of the device which includes a novel flanged sapphire window assembly. Finally, we discuss how commercially available continuous-wave gyrotrons can potentially be converted into similar frequency-agile high-power microwave sources.
Filter-design perspective applied to dynamical decoupling of a multi-qubit system
International Nuclear Information System (INIS)
Su Zhikun; Jiang Shaoji
2012-01-01
We employ the filter-design perspective and derive the filter functions according to nested Uhrig dynamical decoupling (NUDD) and symmetric dynamical decoupling (SDD) in the pure-dephasing spin-boson model with N qubits. The performances of NUDD and SDD are discussed in detail for a two-qubit system. The analysis shows that (i) SDD outperforms NUDD for the bath with a soft cutoff while NUDD approaches SDD as the cutoff becomes harder; (ii) if the qubits are coupled to a common reservoir, SDD helps to protect the decoherence-free subspace while NUDD destroys it; (iii) when the imperfect control pulses with finite width are considered, NUDD is affected in both the high-fidelity regime and coherence time regime while SDD is affected in the coherence time regime only. (paper)
Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences
International Nuclear Information System (INIS)
Mukhtar, Musawwadah; Soh, Wee Tee; Saw, Thuan Beng; Gong, Jiangbin
2010-01-01
Future quantum technologies rely heavily on good protection of quantum entanglement against environment-induced decoherence. A recent study showed that an extension of Uhrig's dynamical decoupling (UDD) sequence can (in theory) lock an arbitrary but known two-qubit entangled state to the Nth order using a sequence of N control pulses [Mukhtar et al., Phys. Rev. A 81, 012331 (2010)]. By nesting three layers of explicitly constructed UDD sequences, here we first consider the protection of unknown two-qubit states as superposition of two known basis states, without making assumptions of the system-environment coupling. It is found that the obtained decoherence suppression can be highly sensitive to the ordering of the three UDD layers and can be remarkably effective with the correct ordering. The detailed theoretical results are useful for general understanding of the nature of controlled quantum dynamics under nested UDD. As an extension of our three-layer UDD, it is finally pointed out that a completely unknown two-qubit state can be protected by nesting four layers of UDD sequences. This work indicates that when UDD is applicable (e.g., when the environment has a sharp frequency cutoff and when control pulses can be taken as instantaneous pulses), dynamical decoupling using nested UDD sequences is a powerful approach for entanglement protection.
Singh, Harpreet; Arvind, Dorai, Kavita
2018-02-01
We embarked upon the task of experimental protection of different classes of tripartite entangled states, namely, the maximally entangled Greenberger-Horne-Zeilinger (GHZ) and W states and the tripartite entangled state called the W W ¯ state, using dynamical decoupling. The states were created on a three-qubit NMR quantum information processor and allowed to evolve in the naturally noisy NMR environment. Tripartite entanglement was monitored at each time instant during state evolution, using negativity as an entanglement measure. It was found that the W state is most robust while the GHZ-type states are most fragile against the natural decoherence present in the NMR system. The W W ¯ state, which is in the GHZ class yet stores entanglement in a manner akin to the W state, surprisingly turned out to be more robust than the GHZ state. The experimental data were best modeled by considering the main noise channel to be an uncorrelated phase damping channel acting independently on each qubit, along with a generalized amplitude damping channel. Using dynamical decoupling, we were able to achieve a significant protection of entanglement for GHZ states. There was a marginal improvement in the state fidelity for the W state (which is already robust against natural system decoherence), while the W W ¯ state showed a significant improvement in fidelity and protection against decoherence.
Dynamical decoupling assisted acceleration of two-spin evolution in XY spin-chain environment
Energy Technology Data Exchange (ETDEWEB)
Wei, Yong-Bo; Zou, Jian [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Wang, Zhao-Ming [Department of Physics, Ocean University of China, Qingdao 266100 (China); Shao, Bin, E-mail: sbin610@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Li, Hai [School of Information and Electronic Engineering, Shandong Institute of Business and Technology, Yantai 264000 (China)
2016-01-28
We study the speed-up role of dynamical decoupling in an open system, which is modeled as two central spins coupled to their own XY spin-chain environment. We show that the fast bang–bang pulses can suppress the system evolution, which manifests the quantum Zeno effect. In contrast, with the increasing of the pulse interval time, the bang–bang pulses can enhance the decay of the quantum speed limit time and induce the speed-up process, which displays the quantum anti-Zeno effect. In addition, we show that the random pulses can also induce the speed-up of quantum evolution. - Highlights: • We propose a scheme to accelerate the dynamical evolution of central spins in an open system. • The quantum speed limit of central spins can be modulated by changing pulse frequency. • The random pulses can play the same role as the regular pulses do for small perturbation.
Energy Technology Data Exchange (ETDEWEB)
Papadopoulos, Alessandro Vittorio, E-mail: alessandro.papadopoulos@control.lth.se [Lund University, Department of Automatic Control (Sweden); Leva, Alberto, E-mail: alberto.leva@polimi.it [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria (Italy)
2015-06-15
The presence of different time scales in a dynamic model significantly hampers the efficiency of its simulation. In multibody systems the fact is particularly relevant, as the mentioned time scales may be very different, due, for example, to the coexistence of mechanical components controled by electronic drive units, and may also appear in conjunction with significant nonlinearities. This paper proposes a systematic technique, based on the principles of dynamic decoupling, to partition a model based on the time scales that are relevant for the particular simulation studies to be performed and as transparently as possible for the user. In accordance with said purpose, peculiar to the technique is its neat separation into two parts: a structural analysis of the model, which is general with respect to any possible simulation scenario, and a subsequent decoupled integration, which can conversely be (easily) tailored to the study at hand. Also, since the technique does not aim at reducing but rather at partitioning the model, the state space and the physical interpretation of the dynamic variables are inherently preserved. Moreover, the proposed analysis allows us to define some novel indices relative to the separability of the system, thereby extending the idea of “stiffness” in a way that is particularly keen to its use for the improvement of simulation efficiency, be the envisaged integration scheme monolithic, parallel, or even based on cosimulation. Finally, thanks to the way the analysis phase is conceived, the technique is naturally applicable to both linear and nonlinear models. The paper contains a methodological presentation of the proposed technique, which is related to alternatives available in the literature so as to evidence the peculiarities just sketched, and some application examples illustrating the achieved advantages and motivating the major design choice from an operational viewpoint.
Exploring the Dynamics of Decoupling and Recoupling in Corporate Responsibility Standardization
DEFF Research Database (Denmark)
Haack, Patrick; Martignoni, Dirk; Schoeneborn, Dennis
by the difficulty or impossibility of evaluation) stabilizes ceremonial adoption and thus impedes substantive adoption. This paper offers a dynamic view of adoption sequences and re-examines the role of opacity in promoting substantive adoption among multiple organizations within a given industry. Using a three......-state Markov chain model, we explore the boundary conditions under which initial opacity paired with an endogenous change towards transparency (characterized by the relative ease or possibility of evaluation) maximizes the overall number of substantive adoptions. We show that the hypocritical adoption...... of formal policies might prove instable and yield long-term institutional consequences, not only because of instability of decoupling within a single organization, but also because of sequence and endogeneity effects at the institutional field level. We illustrate our arguments by drawing on the case...
Cooper, R. F.
2010-12-01
Measurements of redox dynamics in silicate melts and glasses suggest that, for many compositions and for many external environments, the reaction proceeds and is rate-limited by the diffusive flux of divalent-cation network modifiers. Application of ion-backscattering spectrometry either (i) on oxidized or reduced melts (subsequently quenched before analysis) or (ii) on similarly reacted glasses, both of basalt-composition polymerization, demonstrates that the network modifiers move relative to the (first-order-rigid) aluminosilicate network. Thus, the textures associated with such reactions are often surprising, and frequently include metastable or unstable phases and/or spatial compositional differences. This response is only possible if the motion of cations can be decoupled from that of anions. In many cases, decoupling is accomplished by the presence in the melt/glass of transition-metal cations, whose heterovalency creates distortions in the electronic band structure resulting in electronic defects: electron “holes” in the valence band or electrons in the conduction band. (The prevalence of holes or electrons being a function of bulk chemistry and oxygen activity.) These electronic species make the melt/glass a “defect semiconductor.” Because (a) the critical issue in reaction dynamics is the transport coefficient (the product of species mobility and species concentration) and (b) the electronic species are many orders of magnitude more mobile than are the ions, very low concentrations of transition-metal ions are required for flux decoupling. For example, 0.04 at% Fe keeps a magnesium aluminosilicate melt/glass a defect semiconductor down to 800°C [Cook & Cooper, 2000]. Depending on composition, high-temperature melts can see ion species having a high-enough transport coefficient to allow decoupling, e.g., alkali cations in a basaltic melt [e.g., Pommier et al., 2010]. In this presentation, these ideas will be illustrated by examining redox dynamics
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.
Human hepatic carbohydrate metabolism. Dynamic observation using 13C MRS without proton decoupling
International Nuclear Information System (INIS)
Ikehira, H.; Obata, T.; Koga, M.; Yoshida, K.
1997-01-01
Purpose: Dynamic natural-abundance 13 C MR spectroscopy (MRS) studies without proton decoupling were performed in the human liver using commercial 1.5 T MR equipment. Material and methods: A single tuned custom-made circular surface coil with an OD of 20 cm operating at 16.04 MHz was used for the 13 C study. Seventy-five grams of glucose dissolved in water was administered for the natural-abundance 13 C-MRS dynamic study which lasted for approximately 40 to 60 min. Data acquisition was broken into 20-min and 1.7-min blocks. Localized proton shimming with a whole-body coil was performed with sufficient volume to include the observing area of the surface coil; the line width of the water signal was less than 20 Hz. Results and Conclusion: The glucose and glycogen spectra were clearly visible at 80 to 120 ppm after oral administration of the glucose solution. These data demonstrate that dynamic hepatic carbohydrate metabolism can be observed with commercially available MR equipment. Given that the human hepatic glycogen pool reaches maximum level within less than 10 min, this technique should provide a direct diagnosis of hepatic carbohydrate metabolic disorders. (orig.)
Dynamical decoupling sequences for multi-qubit dephasing suppression and long-time quantum memory
International Nuclear Information System (INIS)
Paz-Silva, Gerardo A; Lee, Seung-Woo; Green, Todd J; Viola, Lorenza
2016-01-01
We consider a class of multi-qubit dephasing models that combine classical noise sources and linear coupling to a bosonic environment, and are controlled by arbitrary sequences of dynamical decoupling pulses. Building on a general transfer filter-function framework for open-loop control, we provide an exact representation of the controlled dynamics for arbitrary stationary non-Gaussian classical and quantum noise statistics, with analytical expressions emerging when all dephasing sources are Gaussian. This exact characterization is used to establish two main results. First, we construct multi-qubit sequences that ensure maximum high-order error suppression in both the time and frequency domain and that can be exponentially more efficient than existing ones in terms of total pulse number. Next, we show how long-time multi-qubit storage may be achieved by meeting appropriate conditions for the emergence of a fidelity plateau under sequence repetition, thereby generalizing recent results for single-qubit memory under Gaussian dephasing. In both scenarios, the key step is to endow multi-qubit sequences with a suitable displacement anti-symmetry property, which is of independent interest for applications ranging from environment-assisted entanglement generation to multi-qubit noise spectroscopy protocols. (paper)
Schemes of detecting nuclear spin correlations by dynamical decoupling based quantum sensing
Ma, Wen-Long Ma; Liu, Ren-Bao
Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical decoupling (DD) enhanced diamond quantum sensing has enabled NMR of single nuclear spins and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the frequency fingerprints of target nuclear spins. Such schemes, however, cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear spin clusters. Here we show that the first limitation can be overcome by using wavefunction fingerprints of target nuclear spins, which is much more sensitive than the ''frequency fingerprints'' to weak hyperfine interaction between the targets and a sensor, while the second one can be overcome by a new design of two-dimensional DD sequences composed of two sets of periodic DD sequences with different periods, which can be independently set to match two different transition frequencies. Our schemes not only offer an approach to breaking the resolution limit set by ''frequency gradients'' in conventional MRI, but also provide a standard approach to correlation spectroscopy for single-molecule NMR.
International Nuclear Information System (INIS)
Alvarez, Gonzalo A.; Suter, Dieter; Ajoy, Ashok; Peng Xinhua
2010-01-01
Avoiding the loss of coherence of quantum mechanical states is an important prerequisite for quantum information processing. Dynamical decoupling (DD) is one of the most effective experimental methods for maintaining coherence, especially when one can access only the qubit system and not its environment (bath). It involves the application of pulses to the system whose net effect is a reversal of the system-environment interaction. In any real system, however, the environment is not static, and therefore the reversal of the system-environment interaction becomes imperfect if the spacing between refocusing pulses becomes comparable to or longer than the correlation time of the environment. The efficiency of the refocusing improves therefore if the spacing between the pulses is reduced. Here, we quantify the efficiency of different DD sequences in preserving different quantum states. We use 13 C nuclear spins as qubits and an environment of 1 H nuclear spins as the environment, which couples to the qubit via magnetic dipole-dipole couplings. Strong dipole-dipole couplings between the proton spins result in a rapidly fluctuating environment with a correlation time of the order of 100 μs. Our experimental results show that short delays between the pulses yield better performance if they are compared with the bath correlation time. However, as the pulse spacing becomes shorter than the bath correlation time, an optimum is reached. For even shorter delays, the pulse imperfections dominate over the decoherence losses and cause the quantum state to decay.
Zhang, Yajun; Chai, Tianyou; Wang, Hong; Wang, Dianhui; Chen, Xinkai
2018-06-01
Complex industrial processes are multivariable and generally exhibit strong coupling among their control loops with heavy nonlinear nature. These make it very difficult to obtain an accurate model. As a result, the conventional and data-driven control methods are difficult to apply. Using a twin-tank level control system as an example, a novel multivariable decoupling control algorithm with adaptive neural-fuzzy inference system (ANFIS)-based unmodeled dynamics (UD) compensation is proposed in this paper for a class of complex industrial processes. At first, a nonlinear multivariable decoupling controller with UD compensation is introduced. Different from the existing methods, the decomposition estimation algorithm using ANFIS is employed to estimate the UD, and the desired estimating and decoupling control effects are achieved. Second, the proposed method does not require the complicated switching mechanism which has been commonly used in the literature. This significantly simplifies the obtained decoupling algorithm and its realization. Third, based on some new lemmas and theorems, the conditions on the stability and convergence of the closed-loop system are analyzed to show the uniform boundedness of all the variables. This is then followed by the summary on experimental tests on a heavily coupled nonlinear twin-tank system that demonstrates the effectiveness and the practicability of the proposed method.
A dual voltage control strategy for single-phase PWM converters with power decoupling function
DEFF Research Database (Denmark)
Tang, Yi; Qin, Zian; Blaabjerg, Frede
2015-01-01
converter topology based on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling...... is therefore very sensitive to step load changes. Comprehensive simulation results and experimental results are presented to show the effectiveness of the proposed circuit and control algorithm....
DEFF Research Database (Denmark)
Rose, Jeremy; Schlichter, Bjarne Rerup
2013-01-01
the life of a major project and the complex demands of managing those fluctuations. We investigate evolving trust relationships in a longitudinal case analysis of a large integrated hospital system implementation for the Faroe Islands. Trust relationships suffered various breakdowns, but the project...... was able to recover and eventually meet its goals. Based on concepts from Giddens’ later work on modernity, we develop two approaches for managing dynamic trust relationships in implementation projects: decoupling and re-engaging....... in the project is contingent upon many factors, is likely to vary over time and should not be taken for granted. Previous studies have identified the relationship between trust and project outcomes and suggested trust-building strategies but have largely ignored the dynamic quality of trust relations through...
Directory of Open Access Journals (Sweden)
Yueling Wang
2013-01-01
Full Text Available A unique fuzzy self-tuning disturbance decoupling controller (FSDDC is designed for a serial-parallel hybrid humanoid arm (HHA to implement the throwing trajectory-tracking mission. Firstly, the dynamic model of the HHA is established and the input signal of the throwing process is obtained by studying the throwing process of human's arm. Secondly, the FSDDC, incorporating the disturbance decoupling controller (DDC and the fuzzy logic controller (FLC, is designed to ensure trajectory tracking of the HHA in the presence of uncertainties and disturbances. With the FSDDC method, the HHA system can be decoupled by actively estimating and rejecting the effects of both the internal plant dynamics and external disturbances. The self-tuning parameters are adapted online to improve the performance of the FSDDC; thus, it does not require detailed system parameters of the presented FSDDC. Finally, the controller introduced is compared with a PD controller which is commonly used for the robot manipulators control in industry. The effectiveness of the designed FSDDC is illustrated by simulations.
A dual voltage control strategy for single-phase PWM converters with power decoupling function
DEFF Research Database (Denmark)
Tang, Yi; Qin, Zian; Blaabjerg, Frede
2014-01-01
on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system...... of voltage control loop because the variation of dc-link voltage should be kept within an acceptable range during load transients. This is particularly important for systems with reduced dc-link capacitance because they are of lower energy capacity and very sensitive to step load changes. Simulation results...
DEFF Research Database (Denmark)
Ghoreishy, Hoda; Zhang, Zhe; Thomsen, Ole Cornelius
2012-01-01
In this paper, a modulation strategy based on the circuit-level decoupling concept is proposed and investigated for the three-level four-leg neutral-point-clamped (NPC) inverter,with the aim of delivering power to all sorts of loads, linear/nonlinear and balanced/unbalanced. By applying the propo......In this paper, a modulation strategy based on the circuit-level decoupling concept is proposed and investigated for the three-level four-leg neutral-point-clamped (NPC) inverter,with the aim of delivering power to all sorts of loads, linear/nonlinear and balanced/unbalanced. By applying...... the proposed modulation strategy, the four-leg NPC inverter can be decoupled into three three-level Buck converters in each defined operating section. This makes the controller design much simpler compared to the conventional four-leg NPC inverter controllers. Also, this technique can be implemented...
Energy Technology Data Exchange (ETDEWEB)
Popovic, D P; Stefanovic, M D [Nikola Tesla Inst., Belgrade (YU). Power System Dept.
1990-01-01
A simple, fast and reliable decoupled procedure for solving the network problems during short-term dynamic processes in power systems is presented. It is based on the Newton-Raphson method applied to the power balance equations, which include the effects of generator saliency and non-impedance loads, with further modifications resulting from the physical properties of the phenomena under study. The good convergence characteristics of the developed procedure are demonstrated, and a comparison is made with the traditional method based on the current equation and the triangularized admittance matrix, using the example of stability analysis of the Yugoslav power grid. (author).
Wang, Hongbin; Zhang, Yongqian; Gui, Shuqi; Zhang, Yong; Lu, Fuping; Deng, Yulin
2017-08-15
Comparisons across large numbers of samples are frequently necessary in quantitative proteomics. Many quantitative methods used in proteomics are based on stable isotope labeling, but most of these are only useful for comparing two samples. For up to eight samples, the iTRAQ labeling technique can be used. For greater numbers of samples, the label-free method has been used, but this method was criticized for low reproducibility and accuracy. An ingenious strategy has been introduced, comparing each sample against a 18 O-labeled reference sample that was created by pooling equal amounts of all samples. However, it is necessary to use proportion-known protein mixtures to investigate and evaluate this new strategy. Another problem for comparative proteomics of multiple samples is the poor coincidence and reproducibility in protein identification results across samples. In present study, a method combining 18 O-reference strategy and a quantitation and identification-decoupled strategy was investigated with proportion-known protein mixtures. The results obviously demonstrated that the 18 O-reference strategy had greater accuracy and reliability than other previously used comparison methods based on transferring comparison or label-free strategies. By the decoupling strategy, the quantification data acquired by LC-MS and the identification data acquired by LC-MS/MS are matched and correlated to identify differential expressed proteins, according to retention time and accurate mass. This strategy made protein identification possible for all samples using a single pooled sample, and therefore gave a good reproducibility in protein identification across multiple samples, and allowed for optimizing peptide identification separately so as to identify more proteins. Copyright © 2017 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Chia-Jung Tu
2016-09-01
Full Text Available Energy is a critical factor of economic growth, but the overuse of it results in global warming and climate change. Hence, energy efficiency improvement can help mitigate climate change and prevent economic losses or even ecological extinction. The data envelopment analysis (DEA approach has been extensively applied for energy efficiency estimation, but past studies of this estimation employ a static mode that does not consider consecutive periods and the carry-over effect. This study estimates energy efficiency under a weight-restricted dynamic DEA (WrD-DEA model, creates a weight-restricted dynamic energy efficiency (WrD-EE indicator, and discusses issues concerning the energy decoupling rate and decarbonization. We utilize members in the Group of Seven (G7 and BRICS (Brazil, China, India, Russia, and South Africa for our experimental observations. The main results herein are: (1 BRICS has larger room for improvement to achieve the standard ratio of the energy decoupling rate than the G7; (2 the G7 and BRICS do not converge to decarbonization; and (3 BRICS exhibits more rapid improvement on energy efficiency than the G7.
Scaling of dynamical decoupling for a single electron spin in nanodiamonds at room temperature
International Nuclear Information System (INIS)
Liu, Dong-Qi; Liu, Gang-Qin; Chang, Yan-Chun; Pan, Xin-Yu
2014-01-01
Overcoming the spin qubit decoherence is a challenge for quantum science and technology. We investigate the decoherence process in nanodiamonds by Carr–Purcell–Meiboom–Gill (CPMG) technique at room temperature. We find that the coherence time T 2 scales as n γ . The elongation effect of coherence time can be represented by a constant power of the number of pulses n. Considering the filter function of CPMG decoupling sequence as a δ function, the spectrum density of noise has been reconstructed directly from the coherence time measurements and a Lorentzian noise power spectrum model agrees well with the experiment. These results are helpful for the application of nanodiamonds to nanoscale magnetic imaging
Scaling of dynamical decoupling for a single electron spin in nanodiamonds at room temperature
Energy Technology Data Exchange (ETDEWEB)
Liu, Dong-Qi; Liu, Gang-Qin; Chang, Yan-Chun; Pan, Xin-Yu, E-mail: xypan@aphy.iphy.ac.cn
2014-01-01
Overcoming the spin qubit decoherence is a challenge for quantum science and technology. We investigate the decoherence process in nanodiamonds by Carr–Purcell–Meiboom–Gill (CPMG) technique at room temperature. We find that the coherence time T{sub 2} scales as n{sup γ}. The elongation effect of coherence time can be represented by a constant power of the number of pulses n. Considering the filter function of CPMG decoupling sequence as a δ function, the spectrum density of noise has been reconstructed directly from the coherence time measurements and a Lorentzian noise power spectrum model agrees well with the experiment. These results are helpful for the application of nanodiamonds to nanoscale magnetic imaging.
Shimer, Daniel W.; Lange, Arnold C.
1995-01-01
A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.
Shimer, D.W.; Lange, A.C.
1995-05-23
A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.
DEFF Research Database (Denmark)
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2013-01-01
inverters, but also reduces the switching loss of the inverter along with an inherent neutral point (NP) voltage control. Based on a circuit-level decoupling concept, the NPC inverter can be decoupled into two three-level Buck converters in every defined operating section, and thereby the controller design...... can be reduced by one third. In order to explain the operation of this topology properly, the decoupling principle including the driving signal synthesis and the NP potential variation are analyzed in detail in this paper. Finally the viability and performance of the proposed modulation scheme...
Wojnarowska, Z; Rams-Baron, M; Knapik-Kowalczuk, J; Połatyńska, A; Pochylski, M; Gapinski, J; Patkowski, A; Wlodarczyk, P; Paluch, M
2017-08-01
In this paper the relaxation dynamics of ionic glass-former acebutolol hydrochloride (ACB-HCl) is studied as a function of temperature and pressure by using dynamic light scattering and broadband dielectric spectroscopy. These unique experimental data provide the first direct evidence that the decoupling between the charge transport and structural relaxation exists in proton conductors over a wide T-P thermodynamic space, with the time scale of structural relaxation being constant at the liquid-glass transition (τ α = 1000 s). We demonstrate that the enhanced proton transport, being a combination of intermolecular H + hopping between cation and anion as well as tautomerization process within amide moiety of ACB molecule, results in a breakdown of the Stokes-Einstein relation at ambient and elevated pressure with the fractional exponent k being pressure dependent. The dT g /dP coefficient, stretching exponent β KWW and dynamic modulus E a /ΔV # were found to be the same regardless of the relaxation processes studied. This is in contrast to the apparent activation volume parameter that is different when charge transport and structural dynamics are considered. These experimental results together with theoretical considerations create new ideas to design efficient proton conductors for potential electrochemical applications.
Zhou, Yanguang; Gong, Xiaojing; Xu, Ben; Hu, Ming
2017-07-20
Thermoelectric (TE) materials manifest themselves to enable direct conversion of temperature differences to electric power and vice versa. Though remarkable advances have been achieved in the past decades for various TE systems, the energy conversion efficiency of TE devices, which is characterized by a dimensionless figure-of-merit (ZT = S 2 σT/(κ el + κ ph )), generally remains a poor factor that severely limits TE devices' competitiveness and range of employment. The bottleneck for substantially boosting the ZT coefficient lies in the strong interdependence of the physical parameters involved in electronic (S and σ, and κ el ) and phononic (κ ph ) transport. Herein, we propose a new strategy of incorporating nanotwinned structures to decouple electronic and phononic transport. Combining the new concept of nanotwinned structures with the previously widely used nanocrystalline approach, the power factor of the nanotwin-nanocrystalline Si heterostructures is enhanced by 120% compared to that of bulk crystalline Si, while the lattice thermal conductivity is reduced to a level well below the amorphous limit, yielding a theoretical limit of 0.52 and 0.9 for ZT coefficient at room temperature and 1100 K, respectively. This value is almost two orders of magnitude larger than that for bulk Si and twice that for polycrystalline Si. Even for the experimentally obtained nanotwin-nanocrystalline heterostructures (e.g. grain size of 5 nm), the ZT coefficient can be as high as 0.26 at room temperature and 0.7 at 1100 K, which is the highest ZT value among all Si-based bulk nanostructures found thus far. Such substantial improvement stems from two aspects: (1) the improvement in the power factor is caused due to an increase in the Seebeck coefficient (degeneracy of the band valley) and the enhancement of electrical conductivity (the reduction of the effective band mass) and (2) the significant reduction of the lattice thermal conductivity is mainly caused due to the
Song, Ya-Ju; Tan, Qing-Shou; Kuang, Le-Man
2017-03-08
We investigate the possibility to control quantum evolution speed of a single dephasing qubit for arbitrary initial states by the use of periodic dynamical decoupling (PDD) pulses. It is indicated that the quantum speed limit time (QSLT) is determined by initial and final quantum coherence of the qubit, as well as the non-Markovianity of the system under consideration during the evolution when the qubit is subjected to a zero-temperature Ohmic-like dephasing reservoir. It is shown that final quantum coherence of the qubit and the non-Markovianity of the system can be modulated by PDD pulses. Our results show that for arbitrary initial states of the dephasing qubit with non-vanishing quantum coherence, PDD pulses can be used to induce potential acceleration of the quantum evolution in the short-time regime, while PDD pulses can lead to potential speedup and slow down in the long-time regime. We demonstrate that the effect of PDD on the QSLT for the Ohmic or sub-Ohmic spectrum (Markovian reservoir) is much different from that for the super-Ohmic spectrum (non-Markovian reservoir).
Konow, Nicolai; Price, Samantha; Abom, Richard; Bellwood, David; Wainwright, Peter
2017-08-16
The diversity of fishes on coral reefs is influenced by the evolution of feeding innovations. For instance, the evolution of an intramandibular jaw joint has aided shifts to corallivory in Chaetodon butterflyfishes following their Miocene colonization of coral reefs. Today, over half of all Chaetodon species consume coral, easily the largest concentration of corallivores in any reef fish family. In contrast with Chaetodon , other chaetodontids, including the long-jawed bannerfishes, remain less intimately associated with coral and mainly consume other invertebrate prey. Here, we test (i) if intramandibular joint (IMJ) evolution in Chaetodon has accelerated feeding morphological diversification, and (ii) if cranial and post-cranial traits were affected similarly. We measured 19 cranial functional morphological traits, gut length and body elongation for 33 Indo-Pacific species. Comparisons of Brownian motion rate parameters revealed that cranial diversification was about four times slower in Chaetodon butterflyfishes with the IMJ than in other chaetodontids. However, the rate of gut length evolution was significantly faster in Chaetodon , with no group-differences for body elongation. The contrasting patterns of cranial and post-cranial morphological evolution stress the importance of comprehensive datasets in ecomorphology. The IMJ appears to enhance coral feeding ability in Chaetodon and represents a design breakthrough that facilitates this trophic strategy. Meanwhile, variation in gut anatomy probably reflects diversity in how coral tissues are procured and assimilated. Bannerfishes, by contrast, retain a relatively unspecialized gut for processing invertebrate prey, but have evolved some of the most extreme cranial mechanical innovations among bony fishes for procuring elusive prey. © 2017 The Author(s).
FRF decoupling of nonlinear systems
Kalaycıoğlu, Taner; Özgüven, H. Nevzat
2018-03-01
Structural decoupling problem, i.e. predicting dynamic behavior of a particular substructure from the knowledge of the dynamics of the coupled structure and the other substructure, has been well investigated for three decades and led to several decoupling methods. In spite of the inherent nonlinearities in a structural system in various forms such as clearances, friction and nonlinear stiffness, all decoupling studies are for linear systems. In this study, decoupling problem for nonlinear systems is addressed for the first time. A method, named as FRF Decoupling Method for Nonlinear Systems (FDM-NS), is proposed for calculating FRFs of a substructure decoupled from a coupled nonlinear structure where nonlinearity can be modeled as a single nonlinear element. Depending on where nonlinear element is, i.e., either in the known or unknown subsystem, or at the connection point, the formulation differs. The method requires relative displacement information between two end points of the nonlinear element, in addition to point and transfer FRFs at some points of the known subsystem. However, it is not necessary to excite the system from the unknown subsystem even when the nonlinear element is in that subsystem. The validation of FDM-NS is demonstrated with two different case studies using nonlinear lumped parameter systems. Finally, a nonlinear experimental test structure is used in order to show the real-life application and accuracy of FDM-NS.
Energy Technology Data Exchange (ETDEWEB)
Horn, M
1979-03-01
The relations between the economic development and energy consumption is explained and their complexity is pointed out. The development of the official energy prognoses since 1973 and the development of economic growth and energy consumption from 1951-1976 show that these two developments had been linked together during certain periods but that the coefficient of elasticity shows a falling trend in the long term. The parameters determining the relation between economic growth and energy consumption are discussed: energy prices, capacity load, investments and technological innovations. At the same time the limits of a possible decoupling are demonstrated.
Li, Ningzhi; Li, Shizhe; Shen, Jun
2017-06-01
In vivo 13C magnetic resonance spectroscopy (MRS) is a unique and effective tool for studying dynamic human brain metabolism and the cycling of neurotransmitters. One of the major technical challenges for in vivo 13C-MRS is the high radio frequency (RF) power necessary for heteronuclear decoupling. In the common practice of in vivo 13C-MRS, alkanyl carbons are detected in the spectra range of 10-65ppm. The amplitude of decoupling pulses has to be significantly greater than the large one-bond 1H-13C scalar coupling (1JCH=125-145 Hz). Two main proton decoupling methods have been developed: broadband stochastic decoupling and coherent composite or adiabatic pulse decoupling (e.g., WALTZ); the latter is widely used because of its efficiency and superb performance under inhomogeneous B1 field. Because the RF power required for proton decoupling increases quadratically with field strength, in vivo 13C-MRS using coherent decoupling is often limited to low magnetic fields (protons via weak long-range 1H-13C scalar couplings, which can be decoupled using low RF power broadband stochastic decoupling. Recently, the carboxylic/amide 13C-MRS technique using low power random RF heteronuclear decoupling was safely applied to human brain studies at 7T. Here, we review the two major decoupling methods and the carboxylic/amide 13C-MRS with low power decoupling strategy. Further decreases in RF power deposition by frequency-domain windowing and time-domain random under-sampling are also discussed. Low RF power decoupling opens the possibility of performing in vivo 13C experiments of human brain at very high magnetic fields (such as 11.7T), where signal-to-noise ratio as well as spatial and temporal spectral resolution are more favorable than lower fields.
A Decoupling Control Method for Shunt Hybrid Active Power Filter Based on Generalized Inverse System
Directory of Open Access Journals (Sweden)
Xin Li
2017-01-01
Full Text Available In this paper, a novel decoupling control method based on generalized inverse system is presented to solve the problem of SHAPF (Shunt Hybrid Active Power Filter possessing the characteristics of 2-input-2-output nonlinearity and strong coupling. Based on the analysis of operation principle, the mathematical model of SHAPF is firstly built, which is verified to be invertible using interactor algorithm; then the generalized inverse system of SHAPF is obtained to connect in series with the original system so that the composite system is decoupled under the generalized inverse system theory. The PI additional controller is finally designed to control the decoupled 1-order pseudolinear system to make it possible to adjust the performance of the subsystem. The simulation results demonstrated by MATLAB show that the presented generalized inverse system strategy can realise the dynamic decoupling of SHAPF. And the control system has fine dynamic and static performance.
Hedge Funds and Risk-Decoupling
DEFF Research Database (Denmark)
Ringe, Wolf-Georg
Negative risk-decoupling, otherwise known as empty voting, is a popular strategy amongst hedge funds and other activist investors. In short, it is the attempt to decouple the economic risk from the share’s ownership position, retaining in particular the voting right without risk. This paper uses ...
Directory of Open Access Journals (Sweden)
A. Solomon
2011-10-01
Full Text Available Observations suggest that processes maintaining subtropical and Arctic stratocumulus differ, due to the different environments in which they occur. For example, specific humidity inversions (specific humidity increasing with height are frequently observed to occur near cloud top coincident with temperature inversions in the Arctic, while they do not occur in the subtropics. In this study we use nested LES simulations of decoupled Arctic Mixed-Phase Stratocumulus (AMPS clouds observed during the DOE Atmospheric Radiation Measurement Program's Indirect and SemiDirect Aerosol Campaign (ISDAC to analyze budgets of water components, potential temperature, and turbulent kinetic energy. These analyses quantify the processes that maintain decoupled AMPS, including the role of humidity inversions. Key structural features include a shallow upper entrainment zone at cloud top that is located within the temperature and humidity inversions, a mixed layer driven by cloud-top cooling that extends from the base of the upper entrainment zone to below cloud base, and a lower entrainment zone at the base of the mixed layer. The surface layer below the lower entrainment zone is decoupled from the cloud mixed-layer system. Budget results show that cloud liquid water is maintained in the upper entrainment zone near cloud top (within a temperature and humidity inversion due to a down gradient transport of water vapor by turbulent fluxes into the cloud layer from above and direct condensation forced by radiative cooling. Liquid water is generated in the updraft portions of the mixed-layer eddies below cloud top by buoyant destabilization. These processes cause at least 20% of the cloud liquid water to extend into the inversion. The redistribution of water vapor from the top of the humidity inversion to its base maintains the cloud layer, while the mixed layer-entrainment zone system is continually losing total water. In this decoupled system, the humidity inversion is
Directory of Open Access Journals (Sweden)
Shanhui Liu
2013-01-01
Full Text Available This paper presents a new control methodology based on active disturbance rejection control (ADRC for designing the tension decoupling controller of the unwinding system in a gravure printing machine. The dynamic coupling can be actively estimated and compensated in real time, which makes feedback control an ideal approach to designing the decoupling controller of the unwinding system. This feature is unique to ADRC. In this study, a nonlinear mathematical model is established according to the working principle of the unwinding system. A decoupling model is also constructed to determine the order and decoupling plant of the unwinding system. Based on the order and decoupling plant, an ADRC decoupling control methodology is designed to enhance the tension stability in the unwinding system. The effectiveness and capability of the proposed methodology are verified through simulation and experiments. The results show that the proposed strategy not only realises a decoupling control for the unwinding system but also has an effective antidisturbance capability and is robust.
Decoupling structure and metallogenesis
International Nuclear Information System (INIS)
Tong Hangshou
1993-01-01
The decoupling structure is, at present, a hot spot for the study in geoscience. A study on the decoupling structure is not only of great theoretical significance, but also of more economic importance. The author briefly discusses the study of the decoupling structure in terms of its present status, implication, characteristics, formation mechanism and theoretical significance, in addition, with emphasis on the expounding of the decoupling structure over endogenic metallic deposits such as oil and gas, coal, gold, silver, copper, lead, zinc and iron etc. At last reconsideration is made on the ore control theory of the decoupling structure to the ore control structure in the uranium ore field in South China. The author proposes a superficial idea in order to provide a basis of geological structures for expanding old mining areas, opening up new areas(bases), and prospecting for large and rich uranium deposits
Livelihood strategies and dynamics in rural Cambodia
DEFF Research Database (Denmark)
Jiao, Xi; Pouliot, Mariéve; Walelign, Solomon Zena
2017-01-01
This paper addresses one of the major challenges in rural livelihood analysis to quantitatively examine the dynamics of household livelihood strategies. It investigates the interactions between livelihood assets, activities, and outcomes, and captures the dynamics of long-term changes......, for latent class cluster analysis and regression estimation. In this paper, livelihood strategies are quantified based on allocation of available resources, which overcomes the limitations of income-based analysis. Our study identifies five household livelihood strategies pursued in the study areas...... and their underlying factors. The study aims to identify the classification of rural livelihood strategies, their transitions and factors influencing these processes and changes. We employ the dynamic livelihood strategy framework, and use panel data for 2008 and 2012 covering 464 households in 15 villages in Cambodia...
Evolutionary dynamics on infinite strategy spaces
Oechssler, Jörg; Riedel, Frank
1998-01-01
The study of evolutionary dynamics was so far mainly restricted to finite strategy spaces. In this paper we show that this unsatisfying restriction is unnecessary. We specify a simple condition under which the continuous time replicator dynamics are well defined for the case of infinite strategy spaces. Furthermore, we provide new conditions for the stability of rest points and show that even strict equilibria may be unstable. Finally, we apply this general theory to a number of applications ...
Cepus, Elvis
This work focuses on the early impact response of textile armour systems. A relatively new data acquisition system, the Enhanced Laser Velocity Sensor (ELVS), was refined and used to generate a large database of results for a 5.57 mm diameter, 3 gram, non-deforming projectile impacting single-ply configurations of Ballistic Nylon, two weaves of Kevlar 129, and Zylon (PBO) over a range of velocities from 61 m/s to 248 m/s. In addition, one Kevlar 129 material was tested in configurations of 2, 3, 4, 8 and 16 plies over a range of strike velocities from 90 m/s to 481 m/s. ELVS results consisted of high-resolution timehistories of displacement, velocity and energy for each system tested. The strain wave velocity and ballistic performance of each system was also determined. Results taken from during the impact event were analysed up to just prior to the strain-wave rebounding from the boundary and returning to the impact point---effectively removing boundary influences. Regardless of system type, a constant rate of energy absorption within the pre-rebound timeframe was found to exist, which scales with the strike velocity to approximately the 8/3-power. Well-established single fibre theory was modified and applied to woven materials. It was assumed that three primary energy absorption mechanisms exist; elastic strain, in-plane kinetic and out-of-plane kinetic. This simple model yields the experimentally observed 8/3 exponent and parametrically predicts the difference between the different single-ply material systems, but underpredicts the observed behaviour by a factor of 2 and cannot address the performance reduction with increasing ply count. This combined experimental and analytical work confirms the long-held assumption that single fibre wave physics is applicable to multi-ply woven systems. More significantly, for the first time, it decouples material response from overall system response and provides the experimental tools and methodology required to analyse
Inventory classification based on decoupling points
Directory of Open Access Journals (Sweden)
Joakim Wikner
2015-01-01
Full Text Available The ideal state of continuous one-piece flow may never be achieved. Still the logistics manager can improve the flow by carefully positioning inventory to buffer against variations. Strategies such as lean, postponement, mass customization, and outsourcing all rely on strategic positioning of decoupling points to separate forecast-driven from customer-order-driven flows. Planning and scheduling of the flow are also based on classification of decoupling points as master scheduled or not. A comprehensive classification scheme for these types of decoupling points is introduced. The approach rests on identification of flows as being either demand based or supply based. The demand or supply is then combined with exogenous factors, classified as independent, or endogenous factors, classified as dependent. As a result, eight types of strategic as well as tactical decoupling points are identified resulting in a process-based framework for inventory classification that can be used for flow design.
Decoupling Responsible Management Education
DEFF Research Database (Denmark)
Rasche, Andreas; Gilbert, Dirk Ulrich
Business schools increasingly aim to embed corporate responsibility, sustainability, and ethics into their curricular and extracurricular activities. This paper examines under what conditions business schools may decouple the structural effects of their engagement in responsible management educat...
Catalytic Decoupling of Quantum Information
DEFF Research Database (Denmark)
Majenz, Christian; Berta, Mario; Dupuis, Frédéric
2017-01-01
The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence...... and quantum state merging, and leads to a resource theory of decoupling....
Buterakos, Donovan; Throckmorton, Robert E.; Das Sarma, S.
2018-01-01
In addition to magnetic field and electric charge noise adversely affecting spin-qubit operations, performing single-qubit gates on one of multiple coupled singlet-triplet qubits presents a new challenge: crosstalk, which is inevitable (and must be minimized) in any multiqubit quantum computing architecture. We develop a set of dynamically corrected pulse sequences that are designed to cancel the effects of both types of noise (i.e., field and charge) as well as crosstalk to leading order, and provide parameters for these corrected sequences for all 24 of the single-qubit Clifford gates. We then provide an estimate of the error as a function of the noise and capacitive coupling to compare the fidelity of our corrected gates to their uncorrected versions. Dynamical error correction protocols presented in this work are important for the next generation of singlet-triplet qubit devices where coupling among many qubits will become relevant.
DEFF Research Database (Denmark)
Duboc, Philippe Jean; von Stockar, U.; Villadsen, John
1998-01-01
The dynamic behavior of a continuous culture of Saccharomyces cerevisiae subjected to a sudden increase in the dilution rate has been successfully modelled for anaerobic growth on glucose, and for aerobic growth on acetate, on ethanol, and on glucose. The catabolism responded by an immediate jump...... identified in steady state continuous cultures or during batch experiments. Only the time constant of biosynthesis regeneration, tau(x), and the time constant of catabolic capacity regeneration, tau(cat), had to be identified during transient experiments. In most experiments 7, was around 3 h, and tau(cat...
Dynamic CDM strategies in an EHR environment.
Bieker, Michael; Bailey, Spencer
2012-02-01
A dynamic charge description master (CDM) integrates information from clinical ancillary systems into the charge-capture process, so an organization can reduce its reliance on the patient accounting system as the sole source of billing information. By leveraging the information from electronic ancillary systems, providers can eliminate the need for paper charge-capture forms and see increased accuracy and efficiency in the maintenance of billing information. Before embarking on a dynamic CDM strategy, organizations should first determine their goals for implementing an EHR system, include revenue cycle leaders on the EHR implementation team, and carefully weigh the pros and cons of CDM design decisions.
Optimal decoupling controllers revisited
Czech Academy of Sciences Publication Activity Database
Kučera, Vladimír
2013-01-01
Roč. 42, č. 1 (2013), s. 1-16 ISSN 0324-8569 R&D Projects: GA TA ČR(CZ) TE01020197 Institutional support: RVO:67985556 Keywords : linear systems * fractional representations * decoupling control lers * stabilizing control lers * optimal control lers Subject RIV: BC - Control Systems Theory
Energy Technology Data Exchange (ETDEWEB)
Wang, Shaobu; Huang, Renke; Huang, Zhenyu; Diao, Ruisheng
2016-06-03
The objective of this research work is to develop decoupled modulation control methods for damping inter-area oscillations with low frequencies, so the damping control can be more effective and easier to design with less interference among different oscillation modes in the power system. A signal-decoupling algorithm was developed that can enable separation of multiple oscillation frequency contents and extraction of a “pure” oscillation frequency mode that are fed into Power System Stabilizers (PSSs) as the modulation input signals. As a result, instead of introducing interferences between different oscillation modes from the traditional approaches, the output of the new PSS modulation control signal mainly affects only one oscillation mode of interest. The new decoupled modulation damping control algorithm has been successfully developed and tested on the standard IEEE 4-machine 2-area test system and a minniWECC system. The results are compared against traditional modulation controls, which demonstrates the validity and effectiveness of the newly-developed decoupled modulation damping control algorithm.
Decoupling Responsible Management Education
DEFF Research Database (Denmark)
Rasche, Andreas; Gilbert, Dirk Ulrich
2015-01-01
This article examines under what conditions business schools may decouple the structural effects of their engagement in responsible management education from actual organizational practices. We argue that schools may be unable to match rising institutional pressures to publicly commit to responsi......This article examines under what conditions business schools may decouple the structural effects of their engagement in responsible management education from actual organizational practices. We argue that schools may be unable to match rising institutional pressures to publicly commit...... to responsible management education with their limited internal capacity for change. Our analysis proposes that decoupling is likely if schools (a) are exposed to resource stringency, (b) face overt or covert resistance against change processes, (c) are confronted with competing institutional pressures, and (d......) perceive institutional demands as ambiguous. We discuss two implications of this proposition. On one hand, decoupling can cause dissonant legitimacy perceptions, leading to cynicism around responsible management education within business schools. On the other hand, a temporary inconsistency between talk...
International Nuclear Information System (INIS)
Wei, Xinyu; Wang, Pengfei; Zhao, Fuyu
2016-01-01
Highlights: • We establish a disperse dynamic model for AP1000 reactor core. • A digital PID control based on QDRNN is used to design a decoupling control system. • The decoupling performance is verified and discussed. • The decoupling control system is simulated under the load following operation. - Abstract: The control system of the AP1000 reactor core uses the mechanical shim (MSHIM) strategy, which includes a power control subsystem and an axial power distribution control subsystem. To address the strong coupling between the two subsystems, an interlock between the two subsystems is used, which can only alleviate but not eliminate the coupling. Therefore, sometimes the axial offset (AO) cannot be controlled tightly, and the flexibility of load-following operation is limited. Thus, the decoupling of the original AP1000 reactor core control system is the focus of this paper. First, a two-node disperse dynamic model is established for the AP1000 reactor core to use PID control. Then, a digital PID control system based on a quasi-diagonal recurrent neural network (QDRNN) is designed to decouple the original system. Finally, the decoupling of the control system is verified by the step signal and load-following condition. The results show that the designed control system can decouple the original system as expected and the AO can be controlled much more tightly. Moreover, the flexibility of the load following is increased.
Energy Technology Data Exchange (ETDEWEB)
Wei, Xinyu, E-mail: xyuwei@mail.xjtu.edu.cn; Wang, Pengfei, E-mail: pengfeixiaoli@yahoo.cn; Zhao, Fuyu, E-mail: fuyuzhao_xj@163.com
2016-08-01
Highlights: • We establish a disperse dynamic model for AP1000 reactor core. • A digital PID control based on QDRNN is used to design a decoupling control system. • The decoupling performance is verified and discussed. • The decoupling control system is simulated under the load following operation. - Abstract: The control system of the AP1000 reactor core uses the mechanical shim (MSHIM) strategy, which includes a power control subsystem and an axial power distribution control subsystem. To address the strong coupling between the two subsystems, an interlock between the two subsystems is used, which can only alleviate but not eliminate the coupling. Therefore, sometimes the axial offset (AO) cannot be controlled tightly, and the flexibility of load-following operation is limited. Thus, the decoupling of the original AP1000 reactor core control system is the focus of this paper. First, a two-node disperse dynamic model is established for the AP1000 reactor core to use PID control. Then, a digital PID control system based on a quasi-diagonal recurrent neural network (QDRNN) is designed to decouple the original system. Finally, the decoupling of the control system is verified by the step signal and load-following condition. The results show that the designed control system can decouple the original system as expected and the AO can be controlled much more tightly. Moreover, the flexibility of the load following is increased.
DECOUPLER DESIGN FOR AN INTERACTING TANKS SYSTEM
Directory of Open Access Journals (Sweden)
Duraid F. Ahmed
2013-05-01
Full Text Available The mathematical model forthe two interacting tanks system was derived and the dynamic behavior of thissystem was studied by introducing a step change in inlet flow rate. In thispaper, the analysis of the interaction loops between the controlled variable(liquid level and manipulated variable (inlet flow rate was carried out usingthe relative gain array. Also decoupling technique is applied to eliminate theeffect this interaction by design suitable decouplers for the system. Theresults show that the gain of each loop is cut in half when the opposite loopis closed and the gain of other loop changes sign when the opposite loop isclosed. The decoupling method show that the liquid level of tank one isconstant when the second inlet flow changes and to keep the liquid level oftank two constant the first inlet flow must be changed.
Dynamic Portfolio Strategy Using Clustering Approach.
Ren, Fei; Lu, Ya-Nan; Li, Sai-Ping; Jiang, Xiong-Fei; Zhong, Li-Xin; Qiu, Tian
2017-01-01
The problem of portfolio optimization is one of the most important issues in asset management. We here propose a new dynamic portfolio strategy based on the time-varying structures of MST networks in Chinese stock markets, where the market condition is further considered when using the optimal portfolios for investment. A portfolio strategy comprises two stages: First, select the portfolios by choosing central and peripheral stocks in the selection horizon using five topological parameters, namely degree, betweenness centrality, distance on degree criterion, distance on correlation criterion and distance on distance criterion. Second, use the portfolios for investment in the investment horizon. The optimal portfolio is chosen by comparing central and peripheral portfolios under different combinations of market conditions in the selection and investment horizons. Market conditions in our paper are identified by the ratios of the number of trading days with rising index to the total number of trading days, or the sum of the amplitudes of the trading days with rising index to the sum of the amplitudes of the total trading days. We find that central portfolios outperform peripheral portfolios when the market is under a drawup condition, or when the market is stable or drawup in the selection horizon and is under a stable condition in the investment horizon. We also find that peripheral portfolios gain more than central portfolios when the market is stable in the selection horizon and is drawdown in the investment horizon. Empirical tests are carried out based on the optimal portfolio strategy. Among all possible optimal portfolio strategies based on different parameters to select portfolios and different criteria to identify market conditions, 65% of our optimal portfolio strategies outperform the random strategy for the Shanghai A-Share market while the proportion is 70% for the Shenzhen A-Share market.
Dynamic Portfolio Strategy Using Clustering Approach.
Directory of Open Access Journals (Sweden)
Fei Ren
Full Text Available The problem of portfolio optimization is one of the most important issues in asset management. We here propose a new dynamic portfolio strategy based on the time-varying structures of MST networks in Chinese stock markets, where the market condition is further considered when using the optimal portfolios for investment. A portfolio strategy comprises two stages: First, select the portfolios by choosing central and peripheral stocks in the selection horizon using five topological parameters, namely degree, betweenness centrality, distance on degree criterion, distance on correlation criterion and distance on distance criterion. Second, use the portfolios for investment in the investment horizon. The optimal portfolio is chosen by comparing central and peripheral portfolios under different combinations of market conditions in the selection and investment horizons. Market conditions in our paper are identified by the ratios of the number of trading days with rising index to the total number of trading days, or the sum of the amplitudes of the trading days with rising index to the sum of the amplitudes of the total trading days. We find that central portfolios outperform peripheral portfolios when the market is under a drawup condition, or when the market is stable or drawup in the selection horizon and is under a stable condition in the investment horizon. We also find that peripheral portfolios gain more than central portfolios when the market is stable in the selection horizon and is drawdown in the investment horizon. Empirical tests are carried out based on the optimal portfolio strategy. Among all possible optimal portfolio strategies based on different parameters to select portfolios and different criteria to identify market conditions, 65% of our optimal portfolio strategies outperform the random strategy for the Shanghai A-Share market while the proportion is 70% for the Shenzhen A-Share market.
Geometrical method of decoupling
Directory of Open Access Journals (Sweden)
C. Baumgarten
2012-12-01
Full Text Available The computation of tunes and matched beam distributions are essential steps in the analysis of circular accelerators. If certain symmetries—like midplane symmetry—are present, then it is possible to treat the betatron motion in the horizontal, the vertical plane, and (under certain circumstances the longitudinal motion separately using the well-known Courant-Snyder theory, or to apply transformations that have been described previously as, for instance, the method of Teng and Edwards. In a preceding paper, it has been shown that this method requires a modification for the treatment of isochronous cyclotrons with non-negligible space charge forces. Unfortunately, the modification was numerically not as stable as desired and it was still unclear, if the extension would work for all conceivable cases. Hence, a systematic derivation of a more general treatment seemed advisable. In a second paper, the author suggested the use of real Dirac matrices as basic tools for coupled linear optics and gave a straightforward recipe to decouple positive definite Hamiltonians with imaginary eigenvalues. In this article this method is generalized and simplified in order to formulate a straightforward method to decouple Hamiltonian matrices with eigenvalues on the real and the imaginary axis. The decoupling of symplectic matrices which are exponentials of such Hamiltonian matrices can be deduced from this in a few steps. It is shown that this algebraic decoupling is closely related to a geometric “decoupling” by the orthogonalization of the vectors E[over →], B[over →], and P[over →], which were introduced with the so-called “electromechanical equivalence.” A mathematical analysis of the problem can be traced down to the task of finding a structure-preserving block diagonalization of symplectic or Hamiltonian matrices. Structure preservation means in this context that the (sequence of transformations must be symplectic and hence canonical. When
Virtual decoupling flight control via real-time trajectory synthesis and tracking
Zhang, Xuefu
The production of the General Aviation industry has declined in the past 25 years. Ironically, however, the increasing demand for air travel as a fast, safe, and high-quality mode of transportation has been far from satisfied. Addressing this demand shortfall with personal air transportation necessitates advanced systems for navigation, guidance, control, flight management, and flight traffic control. Among them, an effective decoupling flight control system will not only improve flight quality, safety, and simplicity, and increase air space usage, but also reduce expenses on pilot initial and current training, and thus expand the current market and explore new markets. Because of the formidable difficulties encountered in the actual decoupling of non-linear, time-variant, and highly coupled flight control systems through traditional approaches, a new approach, which essentially converts the decoupling problem into a real-time trajectory synthesis and tracking problem, is employed. Then, the converted problem is solved and a virtual decoupling effect is achieved. In this approach, a trajectory in inertial space can be predefined and dynamically modified based on the flight mission and the pilot's commands. A feedforward-feedback control architecture is constructed to guide the airplane along the trajectory as precisely as possible. Through this approach, the pilot has much simpler, virtually decoupled control of the airplane in terms of speed, flight path angle and horizontal radius of curvature. To verify and evaluate this approach, extensive computer simulation is performed. A great deal of test cases are designed for the flight control under different flight conditions. The simulation results show that our decoupling strategy is satisfactory and promising, and therefore the research can serve as a consolidated foundation for future practical applications.
Gauge symmetry from decoupling
Directory of Open Access Journals (Sweden)
C. Wetterich
2017-02-01
Full Text Available Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang–Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.
Comparative analysis of dynamic pricing strategies for managed lanes.
2015-06-01
The objective of this research is to investigate and compare the performances of different : dynamic pricing strategies for managed lanes facilities. These pricing strategies include real-time : traffic responsive methods, as well as refund options a...
Decoupling theorem in supersymmetric theories
Energy Technology Data Exchange (ETDEWEB)
Leon, J; Perez-Mercader, J; Sanchez, M F
1988-07-21
We introduce a superfield extension of Weisberger's method for decoupling calculations in multiscale field theories and generalize our previous method which does not require the computation of any Feynman diagram. We illustrate this for the two-scale Wess-Zumino model, showing explicitly how the decoupling takes place.
Decoupled Sliding Mode Control for a Novel 3-DOF Parallel Manipulator with Actuation Redundancy
Directory of Open Access Journals (Sweden)
Niu Xuemei
2015-05-01
Full Text Available This paper presents a decoupled nonsingular terminal sliding mode controller (DNTSMC for a novel 3-DOF parallel manipulator with actuation redundancy. According to kinematic analysis, the inverse dynamic model for a novel 3-DOF redundantly actuated parallel manipulator is formulated in the task space using Lagrangian formalism and decoupled into three entirely independent subsystems under generalized coordinates to significantly reduce system complexity. Based on the dynamic model, a decoupled sliding mode control strategy is proposed for the parallel manipulator; the idea behind this strategy is to design a nonsingular terminal sliding mode controller for each subsystem, which can drive states of three subsystems to the original equilibrium points simultaneously by two intermediate variables. Additionally, a RBF neural network is used to compensate the cross-coupling force and gravity to enhance the control precision. Simulation and experimental results show that the proposed DNTSMC can achieve better control performances compared with the conventional sliding mode controller (SMC and the DNTSMC without compensator.
Decoupling schemes for the SSC Collider
International Nuclear Information System (INIS)
Cai, Y.; Bourianoff, G.; Cole, B.; Meinke, R.; Peterson, J.; Pilat, F.; Stampke, S.; Syphers, M.; Talman, R.
1993-05-01
A decoupling system is designed for the SSC Collider. This system can accommodate three decoupling schemes by using 44 skew quadrupoles in the different configurations. Several decoupling schemes are studied and compared in this paper
Selective Regulator Decoupling and Organizations' Strategic Responses
Heese, Jonas; Krishnan, Ranjani; Moers, Frank
2016-01-01
Organizations often respond to institutional pressures by symbolically adopting policies and procedures but decoupling them from actual practice. Literature has examined why organizations decouple from regulatory pressures. In this study, we argue that decoupling occurs within regulatory agencies
Zhang, Ridong; Tao, Jili; Lu, Renquan; Jin, Qibing
2018-02-01
Modeling of distributed parameter systems is difficult because of their nonlinearity and infinite-dimensional characteristics. Based on principal component analysis (PCA), a hybrid modeling strategy that consists of a decoupled linear autoregressive exogenous (ARX) model and a nonlinear radial basis function (RBF) neural network model are proposed. The spatial-temporal output is first divided into a few dominant spatial basis functions and finite-dimensional temporal series by PCA. Then, a decoupled ARX model is designed to model the linear dynamics of the dominant modes of the time series. The nonlinear residual part is subsequently parameterized by RBFs, where genetic algorithm is utilized to optimize their hidden layer structure and the parameters. Finally, the nonlinear spatial-temporal dynamic system is obtained after the time/space reconstruction. Simulation results of a catalytic rod and a heat conduction equation demonstrate the effectiveness of the proposed strategy compared to several other methods.
van der Maas, H.L.J.; Newell, K.; Molenaar, P.C.M.
1998-01-01
Cognitive developmental psychology is faced with new developments in the mathematical theory of nonlinear dynamic systems and in psychometrics. This chapter addresses: the relation between the strategy concept in cognitive developmental psychology and the concept of attractor in nonlinear dynamic
A Fracture Decoupling Experiment
Stroujkova, A. F.; Bonner, J. L.; Leidig, M.; Ferris, A. N.; Kim, W.; Carnevale, M.; Rath, T.; Lewkowicz, J.
2012-12-01
Multiple observations made at the Semipalatinsk Test Site suggest that conducting nuclear tests in the fracture zones left by previous explosions results in decreased seismic amplitudes for the second nuclear tests (or "repeat shots"). Decreased seismic amplitudes reduce both the probability of detection and the seismically estimated yield of a "repeat shot". In order to define the physical mechanism responsible for the amplitude reduction and to quantify the degree of the amplitude reduction in fractured rocks, Weston Geophysical Corp., in collaboration with Columbia University's Lamont Doherty Earth Observatory, conducted a multi-phase Fracture Decoupling Experiment (FDE) in central New Hampshire. The FDE involved conducting explosions of various yields in the damage/fracture zones of previously detonated explosions. In order to quantify rock damage after the blasts we performed well logging and seismic cross-hole tomography studies of the source region. Significant seismic velocity reduction was observed around the source regions after the initial explosions. Seismic waves produced by the explosions were recorded at near-source and local seismic networks, as well as several regional stations throughout northern New England. Our analysis confirms frequency dependent seismic amplitude reduction for the repeat shots compared to the explosions in un-fractured rocks. The amplitude reduction is caused by pore closing and/or by frictional losses within the fractured media.
International Nuclear Information System (INIS)
Ravenal, E.C.
1988-01-01
This paper reports on the prospects of coupling and decoupling for extended deterrence. Thirty-eight years after the foundation of NATO, the defence of Western Europe still rests on the proposition that an American president will invite the destruction of US cities and the incineration of 100 million of its citizens to repel a Soviet incursion or resist a Soviet ultimatum in Western Europe. On its face, America's war plan---never denied by any president from Truman to Reagan, or by any Secretary of State from George Marshall to George Shultz---is the first use of nuclear weapons, if necessary, to defend Europe. Thus America threatens to turn local defeat into global holocaust. But under the surface, America's nuclear commitment to Europe is not so sure. The word that encapsulates this problem is coupling. Not the title of an Updike novel or an anthropological treatise by Margaret Mead, coupling is a term of art used by strategic analysts to connote the integrity of the chain of escalation, from conventional war in Europe, to theatre nuclear weapons, to the final use of America's ultimate strategic weapon
Fast Automated Decoupling at RHIC
Beebe-Wang, Joanne
2005-01-01
Coupling correction is essential for the operational performance of RHIC. The independence of the transverse degrees of freedom makes diagnostics and tune control easier, and it is advantageous to operate an accelerator close to the coupling resonance to minimize nearby nonlinear sidebands. An automated decoupling application has been developed at RHIC for coupling correction during routine operations. The application decouples RHIC globally by minimizing the tune separation through finding the optimal settings of two orthogonal skew quadrupole families. The program provides options of automatic, semi-automatic and manual decoupling operations. It accesses tune information from all RHIC tune measurement systems: the PLL (Phase Lock Loop), the high frequency Schottky system, and the tune meter. It also supplies tune and skew quadrupole scans, finding the minimum tune separation, display the real time results and interface with the RHIC control system. We summarize the capabilities of the decoupling application...
Calculation studies of a multi-layer decoupler system for a decoupled hydrogen moderator
International Nuclear Information System (INIS)
Ooi, M.; Kiyanagi, Y.
2001-01-01
We proposed a multi-layer decoupler as a method to improve pulse characteristics of emitted neutrons from a decoupled hydrogen moderator. Pulse shapes from a moderator with the multi layer-decoupler were compared with those with a traditional single layer decoupler. It was found that the multi-layer decoupler system gave better pulse characteristic with less decrease of peak intensity. (author)
Return models and dynamic asset allocation strategies
Shi, Wyanet Wen
2017-01-01
This thesis studies the design of optimal investment strategies. A strategy is considered optimal when it minimizes the variance of terminal portfolio wealth for a given level of expected terminal portfolio wealth, or equivalently, maximizes an investor's utility. We study this issue in two particular situations: when asset returns follow a continuous-time path-independent process, and when they follow a discrete-time path-dependent process. Continuous-time path-independent return mode...
Dynamic flow control strategies of vehicle SCR Urea Dosing System
Lin, Wei; Zhang, Youtong; Asif, Malik
2015-03-01
Selective Catalyst Reduction(SCR) Urea Dosing System(UDS) directly affects the system accuracy and the dynamic response performance of a vehicle. However, the UDS dynamic response is hard to keep up with the changes of the engine's operating conditions. That will lead to low NO X conversion efficiency or NH3 slip. In order to optimize the injection accuracy and the response speed of the UDS in dynamic conditions, an advanced control strategy based on an air-assisted volumetric UDS is presented. It covers the methods of flow compensation and switching working conditions. The strategy is authenticated on an UDS and tested in different dynamic conditions. The result shows that the control strategy discussed results in higher dynamic accuracy and faster dynamic response speed of UDS. The inject deviation range is improved from being between -8% and 10% to -4% and 2% and became more stable than before, and the dynamic response time was shortened from 200 ms to 150 ms. The ETC cycle result shows that after using the new strategy the NH3 emission is reduced by 60%, and the NO X emission remains almost unchanged. The trade-off between NO X conversion efficiency and NH3 slip is mitigated. The studied flow compensation and switching working conditions can improve the dynamic performance of the UDS significantly and make the UDS dynamic response keep up with the changes of the engine's operating conditions quickly.
Decoupling from international food safety standards
DEFF Research Database (Denmark)
Mercado, Geovana; Hjortsø, Carsten Nico; Honig, Benson
2018-01-01
rural producers who, grounded in culturally-embedded food safety conceptions, face difficulties in complying. We address this gap here through a multiple case study involving four public school feeding programs that source meals from local rural providers in the Bolivian Altiplan. Institutional logics...... in the market. These include: (1) partial adoption of formal rules; (2) selective adoption of convenient rules; and (3) ceremonial adoption to avoid compliance. Decoupling strategies allow local actors to largely disregard the formal food safety regulations while accommodating traditional cultural practices...
A Model of Dynamic Strategy-Making
DEFF Research Database (Denmark)
Andersen, Torben Juul; Hallin, Carina Antonia; Li, Xin
The organizational capacity to cope with unexpected changes remains a fundamental challenge in strategy as global competition and technological innovation increase environmental uncertainty. Conventional strategy-making is often conceived as a sequential linear process where we see it as a non......-linear interaction between top-down and bottom-up mechanisms dealing with multiple actions taken throughout the organization over time. It is driven by intension but with a flexible balance between centralized (planned) and decentralized (spontaneous) activities. We adopt the principles of complementary Yin......-Yang elements and Zhong Yong balance to explain the time bound interaction between these opposing yet complementary strategy-making mechanisms where tradeoffs and synergies are balanced across hierarchical levels....
Adaptive Strategies for Dynamic Pricing Agents
S. Ramezani (Sara); P.A.N. Bosman (Peter); J.A. La Poutré (Han)
2011-01-01
htmlabstractDynamic Pricing (DyP) is a form of Revenue Management in which the price of a (usually) perishable good is changed over time to increase revenue. It is an effective method that has become even more relevant and useful with the emergence of Internet firms and the possibility of readily
Cognitive Strategies for Learning from Static and Dynamic Visuals.
Lewalter, D.
2003-01-01
Studied the effects of including static or dynamic visuals in an expository text on a learning outcome and the use of learning strategies when working with these visuals. Results for 60 undergraduates for both types of illustration indicate different frequencies in the use of learning strategies relevant for the learning outcome. (SLD)
Decoupling Revenue from Energy Sales
International Nuclear Information System (INIS)
Potocnik, V.
2011-01-01
Energy sector based on the fossil fuels combustion has the largest greenhouse gases emissions, causing the actual climate change with numerous negative impacts. Therefore, different measures for the climate change mitigation are performed, mostly by increasing ENEF-energy efficiency (saving), and by substituting fossil fuels with renewable energy (RE), mainly with limited results. One of the most serious obstacles for implementation of these measures is an opposition of the energy utilities (power and natural gas), whose energy sales, revenue and profit are thus reduced. Consequently, new solutions are asked to decouple utilities revenues from energy sales. Decoupling has started in the US, where most states have at least one utility with some decoupling experience. California has pioneering role since 1982., with impressive results. (author)
DQ reference frame modeling and control of single-phase active power decoupling circuits
DEFF Research Database (Denmark)
Tang, Yi; Qin, Zian; Blaabjerg, Frede
2015-01-01
. This paper presents the dq synchronous reference frame modeling of single-phase power decoupling circuits and a complete model describing the dynamics of dc-link ripple voltage is presented. The proposed model is universal and valid for both inductive and capacitive decoupling circuits, and the input...... of decoupling circuits can be either dependent or independent of its front-end converters. Based on this model, a dq synchronous reference frame controller is designed which allows the decoupling circuit to operate in two different modes because of the circuit symmetry. Simulation and experimental results...... are presented to verify the effectiveness of the proposed modeling and control method....
'Glocalization' versus Notions of Decoupling
DEFF Research Database (Denmark)
Jakobsen, Michael
2011-01-01
Discussing modes of political and/or economic decoupling in an era of economic globalization seems almost contradictory as the dominating keywords in the latter are increasing integration, interdependency and harmonization. For example, when looking towards the political realm it seems problemati...
Cohen, M. J.; Douglass, R. L.; Martin, J. B.; Thomas, R. G.; Heffernan, J. B.; Foster, C. R.
2010-12-01
SRP is out of phase with observed synchronous variation in DO and nitrate, which reach their diel maximum (for DO) and minimum (for nitrate) between 14:00 and 16:00, and their reverse 12 hours later. SRP maxima are observed in the early afternoon (15:00-16:00) followed by rapid depletion to a minima between 23:00 and 01:00. We speculate that temporal decoupling of C and N from P assimilation reflects differences in their biochemical roles. Specifically, while N assimilation satisfies immediate requirements from the allocation of energy and C to construction of N-rich photosynthetic machinery (Chl a, Rubisco), P demand is primarily for ribosome construction which may be undertaken primarily during dark periods as an investment in future growth capacity, or may lag primary production due to high demand they place on internal energy stores whose availability may be greatest at the end of each day.
Generic and Brand Advertising Strategies in a Dynamic Duopoly
Frank M. Bass; Anand Krishnamoorthy; Ashutosh Prasad; Suresh P. Sethi
2005-01-01
To increase the sales of their products through advertising, firms must integrate their brand-advertising strategy for capturing market share from competitors and their generic-advertising strategy for increasing primary demand for the category. This paper examines whether, when, and how much brand advertising versus generic advertising should be done. Using differential game theory, optimal advertising decisions are obtained for a dynamic duopoly with symmetric or asymmetric competitors. We ...
Dynamic Investment Strategies and Leadership in Product Innovation
Dawid, H.; Keoula, M.Y.; Kopel, M.; Kort, Peter
2017-01-01
We employ a dynamic market model with endogenous creation of submarkets to study the optimal product innovation strategies of incumbent firms. Firms invest in production capacity and R&D knowledge stock, where the latter determines the hazard rate of innovation. We find that under Markov Perfect
Multidimensional (OLAP) Analysis for Designing Dynamic Learning Strategy
Rozeva, A.; Deliyska, B.
2010-10-01
Learning strategy in an intelligent learning system is generally elaborated on the basis of assessment of the following factors: learner's time for reaction, content of the learning object, amount of learning material in a learning object, learning object specification, e-learning medium and performance control. Current work proposes architecture for dynamic learning strategy design by implementing multidimensional analysis model of learning factors. The analysis model concerns on-line analytical processing (OLAP) of learner's data structured as multidimensional cube. Main components of the architecture are analysis agent for performing the OLAP operations on learner data cube, adaptation generator and knowledge selection agent for performing adaptive navigation in the learning object repository. The output of the analysis agent is involved in dynamic elaboration of learning strategy that fits best to learners profile and behavior. As a result an adaptive learning path for individual learner and for learner groups is generated.
Zhao, Jinsong; Wang, Zhipeng; Zhang, Chuanbi; Yang, Chifu; Bai, Wenjie; Zhao, Zining
2018-06-01
The shaking table based on electro-hydraulic servo parallel mechanism has the advantage of strong carrying capacity. However, the strong coupling caused by the eccentric load not only affects the degree of freedom space control precision, but also brings trouble to the system control. A novel decoupling control strategy is proposed, which is based on modal space to solve the coupling problem for parallel mechanism with eccentric load. The phenomenon of strong dynamic coupling among degree of freedom space is described by experiments, and its influence on control design is discussed. Considering the particularity of plane motion, the dynamic model is built by Lagrangian method to avoid complex calculations. The dynamic equations of the coupling physical space are transformed into the dynamic equations of the decoupling modal space by using the weighted orthogonality of the modal main mode with respect to mass matrix and stiffness matrix. In the modal space, the adjustments of the modal channels are independent of each other. Moreover, the paper discusses identical closed-loop dynamic characteristics of modal channels, which will realize decoupling for degree of freedom space, thus a modal space three-state feedback control is proposed to expand the frequency bandwidth of each modal channel for ensuring their near-identical responses in a larger frequency range. Experimental results show that the concept of modal space three-state feedback control proposed in this paper can effectively reduce the strong coupling problem of degree of freedom space channels, which verify the effectiveness of the proposed model space state feedback control strategy for improving the control performance of the electro-hydraulic servo plane redundant driving mechanism. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.
Blaen, P.; Riml, J.; Khamis, K.; Krause, S.
2017-12-01
Within river catchments across the world, headwater streams represent important sites of nutrient transformation and uptake due to their high rates of microbial community processing and relative abundance in the landscape. However, separating the combined influence of in-stream transport and reaction processes from the overall catchment response can be difficult due to spatio-temporal variability in nutrient and organic matter inputs, flow regimes, and reaction rates. Recent developments in optical sensor technologies enable high-frequency, in situ nutrient measurements, and thus provide opportunities for greater insights into in-stream processes. Here, we use in-stream observations of hourly nitrate (NO3-N), dissolved organic carbon (DOC) and dissolved oxygen (DO) measurements from paired in situ sensors that bound a 1 km headwater stream reach in a mixed-use catchment in central England. We employ a spectral approach to decompose (1) variances in solute loading from the surrounding landscape, and (2) variances in reach-scale in-stream nutrient transport and reaction processes. In addition, we estimate continuous rates of reach-scale NO3-N and DOC assimilation/dissimilation, ecosystem respiration and primary production. Comparison of these results over a range of hydrological conditions (baseflow, variable storm events) and timescales (event-based, diel, seasonal) facilitates new insights into the physical and biogeochemical processes that drive in-stream nutrient dynamics in headwater streams.
Long range personalized cancer treatment strategies incorporating evolutionary dynamics.
Yeang, Chen-Hsiang; Beckman, Robert A
2016-10-22
Current cancer precision medicine strategies match therapies to static consensus molecular properties of an individual's cancer, thus determining the next therapeutic maneuver. These strategies typically maintain a constant treatment while the cancer is not worsening. However, cancers feature complicated sub-clonal structure and dynamic evolution. We have recently shown, in a comprehensive simulation of two non-cross resistant therapies across a broad parameter space representing realistic tumors, that substantial improvement in cure rates and median survival can be obtained utilizing dynamic precision medicine strategies. These dynamic strategies explicitly consider intratumoral heterogeneity and evolutionary dynamics, including predicted future drug resistance states, and reevaluate optimal therapy every 45 days. However, the optimization is performed in single 45 day steps ("single-step optimization"). Herein we evaluate analogous strategies that think multiple therapeutic maneuvers ahead, considering potential outcomes at 5 steps ahead ("multi-step optimization") or 40 steps ahead ("adaptive long term optimization (ALTO)") when recommending the optimal therapy in each 45 day block, in simulations involving both 2 and 3 non-cross resistant therapies. We also evaluate an ALTO approach for situations where simultaneous combination therapy is not feasible ("Adaptive long term optimization: serial monotherapy only (ALTO-SMO)"). Simulations utilize populations of 764,000 and 1,700,000 virtual patients for 2 and 3 drug cases, respectively. Each virtual patient represents a unique clinical presentation including sizes of major and minor tumor subclones, growth rates, evolution rates, and drug sensitivities. While multi-step optimization and ALTO provide no significant average survival benefit, cure rates are significantly increased by ALTO. Furthermore, in the subset of individual virtual patients demonstrating clinically significant difference in outcome between
Anisotropic solutions by gravitational decoupling
Ovalle, J.; Casadio, R.; da Rocha, R.; Sotomayor, A.
2018-02-01
We investigate the extension of isotropic interior solutions for static self-gravitating systems to include the effects of anisotropic spherically symmetric gravitational sources by means of the gravitational decoupling realised via the minimal geometric deformation approach. In particular, the matching conditions at the surface of the star with the outer Schwarzschild space-time are studied in great detail, and we describe how to generate, from a single physically acceptable isotropic solution, new families of anisotropic solutions whose physical acceptability is also inherited from their isotropic parent.
Anisotropic solutions by gravitational decoupling
Energy Technology Data Exchange (ETDEWEB)
Ovalle, J. [Silesian University in Opava, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Opava (Czech Republic); Universidad Simon Bolivar, Departamento de Fisica, Caracas (Venezuela, Bolivarian Republic of); Casadio, R. [Alma Mater Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); Istituto Nazionale di Fisica Nucleare, Bologna (Italy); Rocha, R. da [Universidade Federal do ABC (UFABC), Centro de Matematica, Computacao e Cognicao, Santo Andre, SP (Brazil); Sotomayor, A. [Universidad de Antofagasta, Departamento de Matematicas, Antofagasta (Chile)
2018-02-15
We investigate the extension of isotropic interior solutions for static self-gravitating systems to include the effects of anisotropic spherically symmetric gravitational sources by means of the gravitational decoupling realised via the minimal geometric deformation approach. In particular, the matching conditions at the surface of the star with the outer Schwarzschild space-time are studied in great detail, and we describe how to generate, from a single physically acceptable isotropic solution, new families of anisotropic solutions whose physical acceptability is also inherited from their isotropic parent. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Tan, Kong Ooi; Meier, Beat H., E-mail: beme@ethz.ch, E-mail: maer@ethz.ch; Ernst, Matthias, E-mail: beme@ethz.ch, E-mail: maer@ethz.ch [Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland); Agarwal, Vipin [Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland); TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsinghi, Hyderabad 500 075 (India)
2016-09-07
We present a generalized theoretical framework that allows the approximate but rapid analysis of residual couplings of arbitrary decoupling sequences in solid-state NMR under magic-angle spinning conditions. It is a generalization of the tri-modal Floquet analysis of TPPM decoupling [Scholz et al., J. Chem. Phys. 130, 114510 (2009)] where three characteristic frequencies are used to describe the pulse sequence. Such an approach can be used to describe arbitrary periodic decoupling sequences that differ only in the magnitude of the Fourier coefficients of the interaction-frame transformation. It allows a ∼100 times faster calculation of second-order residual couplings as a function of pulse sequence parameters than full spin-dynamics simulations. By comparing the theoretical calculations with full numerical simulations, we show the potential of the new approach to examine the performance of decoupling sequences. We exemplify the usefulness of this framework by analyzing the performance of commonly used high-power decoupling sequences and low-power decoupling sequences such as amplitude-modulated XiX (AM-XiX) and its super-cycled variant SC-AM-XiX. In addition, the effect of chemical-shift offset is examined for both high- and low-power decoupling sequences. The results show that the cross-terms between the dipolar couplings are the main contributions to the line broadening when offset is present. We also show that the SC-AM-XIX shows a better offset compensation.
Tan, Kong Ooi; Agarwal, Vipin; Meier, Beat H; Ernst, Matthias
2016-09-07
We present a generalized theoretical framework that allows the approximate but rapid analysis of residual couplings of arbitrary decoupling sequences in solid-state NMR under magic-angle spinning conditions. It is a generalization of the tri-modal Floquet analysis of TPPM decoupling [Scholz et al., J. Chem. Phys. 130, 114510 (2009)] where three characteristic frequencies are used to describe the pulse sequence. Such an approach can be used to describe arbitrary periodic decoupling sequences that differ only in the magnitude of the Fourier coefficients of the interaction-frame transformation. It allows a ∼100 times faster calculation of second-order residual couplings as a function of pulse sequence parameters than full spin-dynamics simulations. By comparing the theoretical calculations with full numerical simulations, we show the potential of the new approach to examine the performance of decoupling sequences. We exemplify the usefulness of this framework by analyzing the performance of commonly used high-power decoupling sequences and low-power decoupling sequences such as amplitude-modulated XiX (AM-XiX) and its super-cycled variant SC-AM-XiX. In addition, the effect of chemical-shift offset is examined for both high- and low-power decoupling sequences. The results show that the cross-terms between the dipolar couplings are the main contributions to the line broadening when offset is present. We also show that the SC-AM-XIX shows a better offset compensation.
Interaction dynamics of multiple mobile robots with simple navigation strategies
Wang, P. K. C.
1989-01-01
The global dynamic behavior of multiple interacting autonomous mobile robots with simple navigation strategies is studied. Here, the effective spatial domain of each robot is taken to be a closed ball about its mass center. It is assumed that each robot has a specified cone of visibility such that interaction with other robots takes place only when they enter its visibility cone. Based on a particle model for the robots, various simple homing and collision-avoidance navigation strategies are derived. Then, an analysis of the dynamical behavior of the interacting robots in unbounded spatial domains is made. The article concludes with the results of computer simulations studies of two or more interacting robots.
Decoupling, situated cognition and immersion in art.
Reboul, Anne
2015-09-01
Situated cognition seems incompatible with strong decoupling, where representations are deployed in the absence of their targets and are not oriented toward physical action. Yet, in art consumption, the epitome of a strongly decoupled cognitive process, the artwork is a physical part of the environment and partly controls the perception of its target by the audience, leading to immersion. Hence, art consumption combines strong decoupling with situated cognition.
An uncoupling strategy for numerically solving the dynamic thermoelasticity equations
International Nuclear Information System (INIS)
Moura, C.A. de; Feijoo, R.A.
1981-01-01
The dynamic equations of coupled linear thermoelasticity are presented. A numerical algorithm which combines finite-element space approximation with a two-step time discretization in such a way as to reach significant computational savings is presented: It features a strategy for independently calculating the displacement and temperature fields through equations that nevertheless remain coupled. The scheme convergence was shown to be optimal and its machine performance, as ilustrated by some examples, fairly satisfactory. (Author) [pt
Capital Structure, Environmental Dynamism, Innovation Strategy, and Strategic Risk Management
DEFF Research Database (Denmark)
Juul Andersen, Torben
2005-01-01
Previous research found that capital structure affects performance when it is adapted to the level of environmental dynamism and pursuit of an innovation strategy. The current study reproduces some of these relationships in a more recent dataset but also identifies significant nuances across...... industrial environments. Analyses of a large cross sectional sample and various industry sub-samples suggest that other factors have influenced capital structure effects in recent years including flexibilities in multinational organization and effective strategic risk management capabilities....
FAST AUTOMATED DECOUPLING AT RHIC
International Nuclear Information System (INIS)
BEEBE-WANG, J.J.
2005-01-01
Coupling correction is essential for the operational performance of RHIC. The independence of the transverse degrees of freedom makes diagnostics and tune control easier, and it is advantageous to operate an accelerator close to the coupling resonance to minimize nearby nonlinear sidebands. An automated coupling correction application iDQmini has been developed for RHIC routine operations. The application decouples RHIC globally by minimizing the tune separation through finding the optimal settings of two orthogonal skew quadrupole families. The program iDQmini provides options of automatic, semi-automatic and manual decoupling operations. It accesses tune information from all RHIC tune measurement systems: the PLL (phase lock loop), the high frequency Schottky system and the tune meter. It also supplies tune and skew quadrupole scans, finding the minimum tune separation, display the real time results and interface with the RHIC control system. We summarize the capabilities of the coupling correction application iDQmini, and discuss the operational protections incorporated in the program
Dynamic strategy for sustainable business development: mania or hazard?
Directory of Open Access Journals (Sweden)
Jarmila Šebestová
2013-06-01
Full Text Available The main goal of this paper is to present a practical model of sustainability ratio. In this context, the study provides an analysis of theoretical literature sources in area of strategy evaluation and possible measurement of success. The purpose of presented research was to discover the impact of external business environment factors (based on previous PESTLE analysis on current strategic behavior in small and medium sized business area. The survey was conducted on SMEs in the Czech Republic in 2011 within own research project. The proposed model of sustainability ratio incorporates dynamic behavior and shows how manipulating certain items can alter outcomes in the strategic system in a predicable way. As a contribution to the literature, the paper highlights on the flexibility of business strategy types and which items are the most important for strategy making in an uncertain and turbulent environment.
Numerical simulations of slagging dynamics using a meshmeshless strategy
Energy Technology Data Exchange (ETDEWEB)
Losurdo, M.; Spliethoff, H. [Technische Universitaet Muenchen (Germany). Lehrstuhl fuer Energiesysteme
2009-07-01
In pulverized co-firing and gasification facilities such as coal and biomass power plants, ash deposition, fouling and slagging, may significantly affect heat exchange and gasification per-formance Deposit growth dramatically increases production loss and may lead to the shut-down of the facility. Computational Fluid Dynamics (CFD) calculations can be used as a valid 'non-intrusive' investigation tool in an efficient problem solving strategy. At TU Munich, an ongoing project aims to develop a dedicated numerical tool to monitor and predict deposition, deposit growth and slagging dynamics in pulverized solid fuel furnaces and gasifiers. A novel in-house code was developed to track solid particles and predict deposit growth and slag dynamics. The adopted numerical strategy uses a Mesh-Meshless approach combined with a Lagrangian particle tracking. Ash particles are tracked in a Lagrangian frame post-processing CFD gas phase results (RANS or LES). Growth and thermo-mechanical proper-ties of the deposit are simultaneously evaluated. Slag dynamics is computed by using a meshless approach: deposit mesh nodes are considered point-mass particles interacting only with mesh connected node-particle neighbours. Forces are modelled applying a visco-elastic model and calculated by means of a Galerking weight (kernel) function. The final goal is to mathematically describe both particle adhesion and slag dynamics applying visco-elastic models using a mesh-meshless approach aiming to investigate slag/slurry dynamics. Pre-liminary numerical results on one layer encourage further development on this subject. (orig.)
International Nuclear Information System (INIS)
Marumori, T.; Sakata, F.; Maskawa, T.; Une, T.; Hashimoto, Y.
1983-01-01
The main purpose of this paper is to develop a full quantum theory, which is capable by itself of determining a ''maximally-decoupled'' collective motion. The paper is divided into two parts. In the first part, the motivation and basic idea of the theory are explained, and the ''maximal-decoupling condition'' on the collective motion is formulated within the framework of the time-dependent Hartree-Fock theory, in a general form called the invariance principle of the (time-dependent) Schrodinger equation. In the second part, it is shown that when the author positively utilize the invariance principle, we can construct a full quantum theory of the ''maximally-decoupled'' collective motion. This quantum theory is shown to be a generalization of the kinematical boson-mapping theories so far developed, in such a way that the dynamical ''maximal-decoupling condition'' on the collective motion is automatically satisfied
Decoupled Access-Execute on ARM big.LITTLE
Weber, Anton
2016-01-01
Decoupled Access-Execute (DAE) presents a novel approach to improve power efficiency with a combination of compile-time transformations and Dynamic Voltage Frequency Scaling (DVFS). DAE splits regions of the program into two distinct phases: a memory-bound access phase and a compute-bound execute phase. DVFS is used to run the phases at different frequencies, thus conserving energy while caching data from main memory and performing computations at maximum performance. This project analyses th...
Strategy switching in the stabilization of unstable dynamics.
Directory of Open Access Journals (Sweden)
Jacopo Zenzeri
Full Text Available In order to understand mechanisms of strategy switching in the stabilization of unstable dynamics, this work investigates how human subjects learn to become skilled users of an underactuated bimanual tool in an unstable environment. The tool, which consists of a mass and two hand-held non-linear springs, is affected by a saddle-like force-field. The non-linearity of the springs allows the users to determine size and orientation of the tool stiffness ellipse, by using different patterns of bimanual coordination: minimal stiffness occurs when the two spring terminals are aligned and stiffness size grows by stretching them apart. Tool parameters were set such that minimal stiffness is insufficient to provide stable equilibrium whereas asymptotic stability can be achieved with sufficient stretching, although at the expense of greater effort. As a consequence, tool users have two possible strategies for stabilizing the mass in different regions of the workspace: 1 high stiffness feedforward strategy, aiming at asymptotic stability and 2 low stiffness positional feedback strategy aiming at bounded stability. The tool was simulated by a bimanual haptic robot with direct torque control of the motors. In a previous study we analyzed the behavior of naïve users and we found that they spontaneously clustered into two groups of approximately equal size. In this study we trained subjects to become expert users of both strategies in a discrete reaching task. Then we tested generalization capabilities and mechanism of strategy-switching by means of stabilization tasks which consist of tracking moving targets in the workspace. The uniqueness of the experimental setup is that it addresses the general problem of strategy-switching in an unstable environment, suggesting that complex behaviors cannot be explained in terms of a global optimization criterion but rather require the ability to switch between different sub-optimal mechanisms.
Curvature perturbations from dimensional decoupling
Giovannini, Massimo
2005-01-01
The scalar modes of the geometry induced by dimensional decoupling are investigated. In the context of the low energy string effective action, solutions can be found where the spatial part of the background geometry is the direct product of two maximally symmetric Euclidean manifolds whose related scale factors evolve at a dual rate so that the expanding dimensions first accelerate and then decelerate while the internal dimensions always contract. After introducing the perturbative treatment of the inhomogeneities, a class of five-dimensional geometries is discussed in detail. Quasi-normal modes of the system are derived and the numerical solution for the evolution of the metric inhomogeneities shows that the fluctuations of the internal dimensions provide a term that can be interpreted, in analogy with the well-known four-dimensional situation, as a non-adiabatic pressure density variation. Implications of this result are discussed with particular attention to string cosmological scenarios.
Disturbance Decoupling of Switched Linear Systems
Yurtseven, E.; Heemels, W.P.M.H.; Camlibel, M.K.
2010-01-01
In this paper we consider disturbance decoupling problems for switched linear systems. We will provide necessary and sufficient conditions for three different versions of disturbance decoupling, which differ based on which signals are considered to be the disturbance. In the first version the
Kinematically Decoupled Cores in Dwarf (Elliptical) Galaxies
Toloba, E.; Peletier, R. F.; Guhathakurta, P.; van de Ven, G.; Boissier, S.; Boselli, A.; Brok, M. d.; Falcón-Barroso, J.; Hensler, G.; Janz, J.; Laurikainen, E.; Lisker, T.; Paudel, S.; Ryś, A.; Salo, H.
An overview is given of what we know about the frequency of kinematically decoupled cores in dwarf elliptical galaxies. New observations show that kinematically decoupled cores happen just as often in dwarf elliptical as in ordinary early-type galaxies. This has important consequences for the
Evaluation of Electric Power Procurement Strategies by Stochastic Dynamic Programming
Saisho, Yuichi; Hayashi, Taketo; Fujii, Yasumasa; Yamaji, Kenji
In deregulated electricity markets, the role of a distribution company is to purchase electricity from the wholesale electricity market at randomly fluctuating prices and to provide it to its customers at a given fixed price. Therefore the company has to take risk stemming from the uncertainties of electricity prices and/or demand fluctuation instead of the customers. The way to avoid the risk is to make a bilateral contact with generating companies or install its own power generation facility. This entails the necessity to develop a certain method to make an optimal strategy for electric power procurement. In such a circumstance, this research has the purpose for proposing a mathematical method based on stochastic dynamic programming and additionally considering the characteristics of the start-up cost of electric power generation facility to evaluate strategies of combination of the bilateral contract and power auto-generation with its own facility for procuring electric power in deregulated electricity market. In the beginning we proposed two approaches to solve the stochastic dynamic programming, and they are a Monte Carlo simulation method and a finite difference method to derive the solution of a partial differential equation of the total procurement cost of electric power. Finally we discussed the influences of the price uncertainty on optimal strategies of power procurement.
Improving basic math skills through integrated dynamic representation strategies.
González-Castro, Paloma; Cueli, Marisol; Cabeza, Lourdes; Álvarez-García, David; Rodríguez, Celestino
2014-01-01
In this paper, we analyze the effectiveness of the Integrated Dynamic Representation strategy (IDR) to develop basic math skills. The study involved 72 students, aged between 6 and 8 years. We compared the development of informal basic skills (numbers, comparison, informal calculation, and informal concepts) and formal (conventionalisms, number facts, formal calculus, and formal concepts) in an experimental group (n = 35) where we applied the IDR strategy and in a Control group (n = 37) in order to identify the impact of the procedure. The experimental group improved significantly in all variables except for number facts and formal calculus. It can therefore be concluded that IDR favors the development of the skills more closely related to applied mathematics than those related to automatic mathematics and mental arithmetic.
Complexity Science Applications to Dynamic Trajectory Management: Research Strategies
Sawhill, Bruce; Herriot, James; Holmes, Bruce J.; Alexandrov, Natalia
2009-01-01
The promise of the Next Generation Air Transportation System (NextGen) is strongly tied to the concept of trajectory-based operations in the national airspace system. Existing efforts to develop trajectory management concepts are largely focused on individual trajectories, optimized independently, then de-conflicted among each other, and individually re-optimized, as possible. The benefits in capacity, fuel, and time are valuable, though perhaps could be greater through alternative strategies. The concept of agent-based trajectories offers a strategy for automation of simultaneous multiple trajectory management. The anticipated result of the strategy would be dynamic management of multiple trajectories with interacting and interdependent outcomes that satisfy multiple, conflicting constraints. These constraints would include the business case for operators, the capacity case for the Air Navigation Service Provider (ANSP), and the environmental case for noise and emissions. The benefits in capacity, fuel, and time might be improved over those possible under individual trajectory management approaches. The proposed approach relies on computational agent-based modeling (ABM), combinatorial mathematics, as well as application of "traffic physics" concepts to the challenge, and modeling and simulation capabilities. The proposed strategy could support transforming air traffic control from managing individual aircraft behaviors to managing systemic behavior of air traffic in the NAS. A system built on the approach could provide the ability to know when regions of airspace approach being "full," that is, having non-viable local solution space for optimizing trajectories in advance.
Adaptive sampling strategies with high-throughput molecular dynamics
Clementi, Cecilia
Despite recent significant hardware and software developments, the complete thermodynamic and kinetic characterization of large macromolecular complexes by molecular simulations still presents significant challenges. The high dimensionality of these systems and the complexity of the associated potential energy surfaces (creating multiple metastable regions connected by high free energy barriers) does not usually allow to adequately sample the relevant regions of their configurational space by means of a single, long Molecular Dynamics (MD) trajectory. Several different approaches have been proposed to tackle this sampling problem. We focus on the development of ensemble simulation strategies, where data from a large number of weakly coupled simulations are integrated to explore the configurational landscape of a complex system more efficiently. Ensemble methods are of increasing interest as the hardware roadmap is now mostly based on increasing core counts, rather than clock speeds. The main challenge in the development of an ensemble approach for efficient sampling is in the design of strategies to adaptively distribute the trajectories over the relevant regions of the systems' configurational space, without using any a priori information on the system global properties. We will discuss the definition of smart adaptive sampling approaches that can redirect computational resources towards unexplored yet relevant regions. Our approaches are based on new developments in dimensionality reduction for high dimensional dynamical systems, and optimal redistribution of resources. NSF CHE-1152344, NSF CHE-1265929, Welch Foundation C-1570.
Structural Decoupling and Disturbance Rejection in a Distillation Column
DEFF Research Database (Denmark)
Bahar, Mehrdad; Jantzen, Jan; Commault, C.
1996-01-01
Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references.......Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references....
Input saturation in nonlinear multivariable processes resolved by nonlinear decoupling
Directory of Open Access Journals (Sweden)
Jens G. Balchen
1995-04-01
Full Text Available A new method is presented for the resolution of the problem of input saturation in nonlinear multivariable process control by means of elementary nonlinear decoupling (END. Input saturation can have serious consequences particularly in multivariable control because it may lead to very undesirable system behaviour and quite often system instability. Many authors have searched for systematic techniques for designing multivariable control systems in which saturation may occur in any of the control variables (inputs, manipulated variables. No generally accepted method seems to have been presented so far which gives a solution in closed form. The method of elementary nonlinear decoupling (END can be applied directly to the case of saturation control variables by deriving as many control strategies as there are combinations of saturating control variables. The method is demonstrated by the multivariable control of a simulated Fluidized Catalytic Cracker (FCC with very convincing results.
Offering memorable patient experience through creative, dynamic marketing strategy
Raţiu, M; Purcărea, T
2008-01-01
Creative, dynamic strategies are the ones that identify new and better ways of uniquely offering the target customers what they want or need. A business can achieve competitive advantage if it chooses a marketing strategy that sets the business apart from anyone else. Healthcare services companies have to understand that the customer should be placed in the centre of all specific marketing operations. The brand message should reflect the focus on the patient. Healthcare products and services offered must represent exactly the solutions that customers expect. The touchpoints with the patients must be well mastered in order to convince them to accept the proposed solutions. Healthcare service providers must be capable to look beyond customer's behaviour or product and healthcare service aquisition. This will demand proactive and far–reaching changes, including focusing specifically on customer preference, quality, and technological interfaces; rewiring strategy to find new value from existing and unfamiliar sources; disintegrating and radically reassembling operational processes; and restructuring the organization to accommodate new typess of work and skill. PMID:20108466
Offering memorable patient experience through creative, dynamic marketing strategy.
Purcărea, Victor Lorín; Raţíu, Monica; Purcărea, Theodor; Davila, Carol
2008-01-01
Creative, dynamic strategies are the ones that identify new and better ways of uniquely offering the target customers what they want or need. A business can achieve competitive advantage if it chooses a marketing strategy that sets the business apart from anyone else. Healthcare services companies have to understand that the customer should be placed in the centre of all specific marketing operations. The brand message should reflect the focus on the patient. Healthcare products and services offered must represent exactly the solutions that customers expect. The touchpoints with the patients must be well mastered in order to convince them to accept the proposed solutions. Healthcare service providers must be capable to look beyond customer's behaviour or product and healthcare service aquisition. This will demand proactive and far-reaching changes, including focusing specifically on customer preference, quality, and technological interfaces; rewiring strategy to find new value from existing and unfamiliar sources: disintegrating and radically reassembling operational processes: and restructuring the organization to accommodate new types of work and skill.
DEFF Research Database (Denmark)
Qin, Zian; Tang, Yi; Loh, Poh Chiang
2015-01-01
studied, where the commercially available film capacitors, circuit topologies, and control strategies for active power decoupling are all taken into account. Then, an adaptive decoupling voltage control method is proposed to further improve the performance of dc decoupling in terms of efficiency...... and reliability. The feasibility and superiority of the identified solution for active power decoupling together with the proposed adaptive decoupling voltage control method are finally verified by both the experimental results obtained on a 2 kW single-phase inverter.......This paper presents the benchmark study of ac and dc active power decoupling circuits for second-order harmonic mitigation in kW-scale single-phase inverters. First of all, the best solutions of active power decoupling to achieve high efficiency and power density are identified and comprehensively...
DEFF Research Database (Denmark)
Qin, Zian; Tang, Yi; Loh, Poh Chiang
2016-01-01
efficiency and high power density is identified and comprehensively studied, and the commercially available film capacitors, the circuit topologies, and the control strategies adopted for active power decoupling are all taken into account. Then, an adaptive decoupling voltage control method is proposed...... to further improve the performance of dc decoupling in terms of efficiency and reliability. The feasibility and superiority of the identified solution for active power decoupling together with the proposed adaptive decoupling voltage control method are finally verified by both the simulation and experimental......This paper presents the benchmark study of ac and dc active power decoupling circuits for second order harmonic mitigation in kW scale single-phase inverters. First of all, a brief comparison of recently reported active power decoupling circuits is given, and the best solution that can achieve high...
Li-air batteries: Decouple to stabilize
Xu, Ji-Jing; Zhang, Xin-Bo
2017-09-01
The utilization of porous carbon cathodes in lithium-air batteries is hindered by their severe decomposition during battery cycling. Now, dual redox mediators are shown to decouple the complex electrochemical reactions at the cathode, avoiding cathode passivation and decomposition.
Optimal Dynamic Strategies for Index Tracking and Algorithmic Trading
Ward, Brian
In this thesis we study dynamic strategies for index tracking and algorithmic trading. Tracking problems have become ever more important in Financial Engineering as investors seek to precisely control their portfolio risks and exposures over different time horizons. This thesis analyzes various tracking problems and elucidates the tracking errors and strategies one can employ to minimize those errors and maximize profit. In Chapters 2 and 3, we study the empirical tracking properties of exchange traded funds (ETFs), leveraged ETFs (LETFs), and futures products related to spot gold and the Chicago Board Option Exchange (CBOE) Volatility Index (VIX), respectively. These two markets provide interesting and differing examples for understanding index tracking. We find that static strategies work well in the nonleveraged case for gold, but fail to track well in the corresponding leveraged case. For VIX, tracking via neither ETFs, nor futures\\ portfolios succeeds, even in the nonleveraged case. This motivates the need for dynamic strategies, some of which we construct in these two chapters and further expand on in Chapter 4. There, we analyze a framework for index tracking and risk exposure control through financial derivatives. We derive a tracking condition that restricts our exposure choices and also define a slippage process that characterizes the deviations from the index over longer horizons. The framework is applied to a number of models, for example, Black Scholes model and Heston model for equity index tracking, as well as the Square Root (SQR) model and the Concatenated Square Root (CSQR) model for VIX tracking. By specifying how each of these models fall into our framework, we are able to understand the tracking errors in each of these models. Finally, Chapter 5 analyzes a tracking problem of a different kind that arises in algorithmic trading: schedule following for optimal execution. We formulate and solve a stochastic control problem to obtain the optimal
Are CAP Decoupling Policies Really Production Neutral?
Katranidis, Stelios D.; Kotakou, Christina A.
2008-01-01
This paper examines the effects of decoupling policies on Greek cotton production. We estimate a system of cotton supply and input derived demand functions under the hypothesis that producers face uncertainty about prices. Using our estimation results we simulate the effects on cotton production under four alternative policy scenarios: the ‘Old’ CAP regime (i.e. the policy practiced until 2005), the Mid Term Review regime, a fully decoupled policy regime and a free trade-no policy scenario. O...
The sequence relay selection strategy based on stochastic dynamic programming
Zhu, Rui; Chen, Xihao; Huang, Yangchao
2017-07-01
Relay-assisted (RA) network with relay node selection is a kind of effective method to improve the channel capacity and convergence performance. However, most of the existing researches about the relay selection did not consider the statically channel state information and the selection cost. This shortage limited the performance and application of RA network in practical scenarios. In order to overcome this drawback, a sequence relay selection strategy (SRSS) was proposed. And the performance upper bound of SRSS was also analyzed in this paper. Furthermore, in order to make SRSS more practical, a novel threshold determination algorithm based on the stochastic dynamic program (SDP) was given to work with SRSS. Numerical results are also presented to exhibit the performance of SRSS with SDP.
Probabilistic models for access strategies to dynamic information elements
DEFF Research Database (Denmark)
Hansen, Martin Bøgsted; Olsen, Rasmus L.; Schwefel, Hans-Peter
In various network services (e.g., routing and instances of context-sensitive networking) remote access to dynamically changing information elements is a required functionality. Three fundamentally different strategies for such access are investigated in this paper: (1) a reactive approach...... initiated by the requesting entity, and two versions of proactive approaches in which the entity that contains the information element actively propagates its changes to potential requesters, either (2) periodically or (3) triggered by changes of the information element. This paper develops probabilistic...... for information elements spread over a large number of network nodes are provided, which allow to draw conclusions on scalability properties. The impact of different distribution types for the network delays as well as for the time between changes of the information element on the mismatch probability...
Learning predictive statistics from temporal sequences: Dynamics and strategies.
Wang, Rui; Shen, Yuan; Tino, Peter; Welchman, Andrew E; Kourtzi, Zoe
2017-10-01
Human behavior is guided by our expectations about the future. Often, we make predictions by monitoring how event sequences unfold, even though such sequences may appear incomprehensible. Event structures in the natural environment typically vary in complexity, from simple repetition to complex probabilistic combinations. How do we learn these structures? Here we investigate the dynamics of structure learning by tracking human responses to temporal sequences that change in structure unbeknownst to the participants. Participants were asked to predict the upcoming item following a probabilistic sequence of symbols. Using a Markov process, we created a family of sequences, from simple frequency statistics (e.g., some symbols are more probable than others) to context-based statistics (e.g., symbol probability is contingent on preceding symbols). We demonstrate the dynamics with which individuals adapt to changes in the environment's statistics-that is, they extract the behaviorally relevant structures to make predictions about upcoming events. Further, we show that this structure learning relates to individual decision strategy; faster learning of complex structures relates to selection of the most probable outcome in a given context (maximizing) rather than matching of the exact sequence statistics. Our findings provide evidence for alternate routes to learning of behaviorally relevant statistics that facilitate our ability to predict future events in variable environments.
Two-degrees-of-freedom piezo-driven fast steering mirror with cross-axis decoupling capability
Shao, Shubao; Tian, Zheng; Song, Siyang; Xu, Minglong
2018-05-01
Because mechanical cross coupling between its axes would lead to degradation of the scanning precision of a piezo-driven fast steering mirror (PFSM), a two-degrees-of-freedom (2-DoF) PFSM with a cross-axis decoupling capability, in which 2-DoF flexure hinges are used, is proposed in this work. The overall structure of the proposed PFSM is first introduced and then both static and dynamic models are established analytically; in addition, the decoupling mechanism is described in detail and the low dynamic cross coupling ratios that occur between the two DoFs are shown. Because of the decoupling property of the PFSM, the 2-DoF motion is treated as a combination of two independent one-degree-of-freedom (1-DoF) motions and two independent proportional-integral-derivative controllers are thus used separately in the control of the two DoFs. Based on this control strategy, experiments involving both 1-DoF trajectory tracking and 2-DoF trajectory tracking are implemented. The test results show that the proposed PFSM can achieve the tilt range of ±7 mrad for both axes with the low coupling ratios that are less than 2% (-34 dB), and the bandwidths of both axes are higher than 810 Hz; in addition, the maximal tracking full scale range errors for 1-DoF trajectory tracking and 2-DoF trajectory tracking are less than 0.2% and 1%, respectively, where the larger error of 2-DoF trajectory tracking is mainly caused by the remaining cross coupling between axes.
Decoupling Control Design for the Module Suspension Control System in Maglev Train
Directory of Open Access Journals (Sweden)
Guang He
2015-01-01
Full Text Available An engineering oriented decoupling control method for the module suspension system is proposed to solve the coupling issues of the two levitation units of the module in magnetic levitation (maglev train. According to the format of the system transfer matrix, a modified adjoint transfer matrix based decoupler is designed. Then, a compensated controller is obtained in the light of a desired close loop system performance. Optimization between the performance index and robustness index is also carried out to determine the controller parameters. However, due to the high orders and complexity of the obtained resultant controller, model reduction method is adopted to get a simplified controller with PID structure. Considering the modeling errors of the module suspension system as the uncertainties, experiments have been performed to obtain the weighting function of the system uncertainties. By using this, the robust stability of the decoupled module suspension control system is checked. Finally, the effectiveness of the proposed decoupling design method is validated by simulations and physical experiments. The results illustrate that the presented decoupling design can result in a satisfactory decoupling and better dynamic performance, especially promoting the reliability of the suspension control system in practical engineering application.
Equicontrollability and its application to model-following and decoupling.
Curran, R. T.
1971-01-01
Discussion of 'model following,' a term used to describe a class of problems characterized by having two dynamic systems, generically known as the 'plant' and the 'model,' it being required to find a controller to attach to the plant so as to make the resultant compensated system behave, in an input/output sense, in the same way as the model. The approach presented to the problem takes a structural point of view. The result is a complex but informative definition which solves the problem as posed. The application of both the algorithm and its basis, equicontrollability, to the decoupling problem is considered.
Multiple estimation channel decoupling and optimization method based on inverse system
Wu, Peng; Mu, Rongjun; Zhang, Xin; Deng, Yanpeng
2018-03-01
This paper addressed the intelligent autonomous navigation request of intelligent deformation missile, based on the intelligent deformation missile dynamics and kinematics modeling, navigation subsystem solution method and error modeling, and then focuses on the corresponding data fusion and decision fusion technology, decouples the sensitive channel of the filter input through the inverse system of design dynamics to reduce the influence of sudden change of the measurement information on the filter input. Then carrying out a series of simulation experiments, which verified the feasibility of the inverse system decoupling algorithm effectiveness.
The Heterogeneous Investment Horizon and Dynamic Strategies for Asset Allocation
Xiong, Heping; Xu, Yiheng; Xiao, Yi
This paper discusses the influence of the portfolio rebalancing strategy on the efficiency of long-term investment portfolios under the assumption of independent stationary distribution of returns. By comparing the efficient sets of the stochastic rebalancing strategy, the simple rebalancing strategy and the buy-and-hold strategy with specific data examples, we find that the stochastic rebalancing strategy is optimal, while the simple rebalancing strategy is of the lowest efficiency. In addition, the simple rebalancing strategy lowers the efficiency of the portfolio instead of improving it.
Premoderator optimization of decoupled hydrogen moderator
International Nuclear Information System (INIS)
Harada, Masahide; Teshigawara, Makoto; Kai, Tetsuya; Sakata, Hideaki; Watanabe, Noboru; Ikeda, Yujiro
2001-03-01
An optimization study on the premoderator, the reflector material choice and a length of the linear is carried out for the design of high performance decoupled hydrogen moderator. NMTC/JAM and MCNP-4C are used for the neutronics calculation. The result indicates that, assuming premoderator dimensions and decoupling energy is controlled, the decoupled hydrogen moderator with a premoderator can provide better pulse characteristics than that without the premoderator for a Be reflector. On the selection of the reflector material, it is clearly shown that Pb and Hg reflectors give merits in using the premoderator for higher intensity and reduction of energy deposition in moderator. It is also shown that a H 2 O premoderator provides a short tail while a D 2 O premoderator provides the high peak intensity. Minimum liner length is evaluated to be 20 cm from the viewpoint of neutronics. (author)
Decoupling interrelated parameters for designing high performance thermoelectric materials.
Xiao, Chong; Li, Zhou; Li, Kun; Huang, Pengcheng; Xie, Yi
2014-04-15
The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for
Deep-subwavelength Decoupling for MIMO Antennas in Mobile Handsets with Singular Medium.
Xu, Su; Zhang, Ming; Wen, Huailin; Wang, Jun
2017-09-22
Decreasing the mutual coupling between Multi-input Multi-output (MIMO) antenna elements in a mobile handset and achieving a high data rate is a challenging topic as the 5 th -generation (5G) communication age is coming. Conventional decoupling components for MIMO antennas have to be re-designed when the geometries or frequencies of antennas have any adjustment. In this paper, we report a novel metamaterial-based decoupling strategy for MIMO antennas in mobile handsets with wide applicability. The decoupling component is made of subwavelength metal/air layers, which can be treated as singular medium over a broad frequency band. The flexible applicable property of the decoupling strategy is verified with different antennas over different frequency bands with the same metamaterial decoupling element. Finally, 1/100-wavelength 10-dB isolation is demonstrated for a 24-element MIMO antenna in mobile handsets over the frequency band from 4.55 to 4.75 GHz.
Grimsrud, David Borkner
2015-01-01
Masteroppgave økonomi og administrasjon- Universitetet i Agder, 2015 This master thesis looks at unexpected volatility- and financial turbulence’s predictive ability, and exploit these measures of financial risk, together with volatility, to create three dynamic asset allocation strategies, and test if they can outperform a passive and naively diversified buy-and-hold strategy. The idea with the dynamic strategies is to increase the portfolio return by keeping the portfolio risk at a low a...
Computing Decoupled Residuals for Compact Disc Players
DEFF Research Database (Denmark)
Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle
2006-01-01
a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...
Shear Wave Generation by Decoupled and Partially Coupled Explosions
National Research Council Canada - National Science Library
Stevens, Jeffry L; Xu, Heming; Baker, G. E
2008-01-01
The objective of this project is to investigate the sources of shear wave generation by decoupled and partially coupled explosions, and the differences in shear wave generation between tamped and decoupled explosions...
DEFF Research Database (Denmark)
Federico, de Bosio; de Sousa Ribeiro, Luiz Antonio; Freijedo Fernandez, Francisco Daniel
2016-01-01
In stand-alone microgrids based on voltage source inverters state feedback coupling between the capacitor voltage and inductor current degrades significantly the dynamics performance of voltage and current regulators. The decoupling of the controlled states is proposed, considering the limitations...
Directory of Open Access Journals (Sweden)
Lu-Ning Liu
Full Text Available BACKGROUND: Photosynthetic organisms have developed multiple protective mechanisms to prevent photodamage in vivo under high-light conditions. Cyanobacteria and red algae use phycobilisomes (PBsomes as their major light-harvesting antennae complexes. The orange carotenoid protein in some cyanobacteria has been demonstrated to play roles in the photoprotective mechanism. The PBsome-itself-related energy dissipation mechanism is still unclear. METHODOLOGY/PRINCIPAL FINDINGS: Here, single-molecule spectroscopy is applied for the first time on the PBsomes of red alga Porphyridium cruentum, to detect the fluorescence emissions of phycoerythrins (PE and PBsome core complex simultaneously, and the real-time detection could greatly characterize the fluorescence dynamics of individual PBsomes in response to intense light. CONCLUSIONS/SIGNIFICANCE: Our data revealed that strong green-light can induce the fluorescence decrease of PBsome, as well as the fluorescence increase of PE at the first stage of photobleaching. It strongly indicated an energetic decoupling occurring between PE and its neighbor. The fluorescence of PE was subsequently observed to be decreased, showing that PE was photobleached when energy transfer in the PBsomes was disrupted. In contrast, the energetic decoupling was not observed in either the PBsomes fixed with glutaraldehyde, or the mutant PBsomes lacking B-PE and remaining b-PE. It was concluded that the energetic decoupling of the PBsomes occurs at the specific association between B-PE and b-PE within the PBsome rod. Assuming that the same process occurs also at the much lower physiological light intensities, such a decoupling process is proposed to be a strategy corresponding to PBsomes to prevent photodamage of the photosynthetic reaction centers. Finally, a novel photoprotective role of gamma-subunit-containing PE in red algae was discussed.
Self-organization through decoupling
Directory of Open Access Journals (Sweden)
Romar Correa
2000-01-01
Full Text Available In one line of research, the transition from Fordism to flexible specialisation is explained by the infeasibility of a mode of regulation that relied on central controls. According to another explanation, which we favour, the disintegration of vertically integrated production is unpredictable. The concept of self-organization is often recommended to model the transition from hierarchical organizational forms to flatter structures. Formally, a conditionally stable nonlinear system of differential equations is examined. In the first thesis, the characteristic roots with positive real parts play the role of ‘order’ parameters which can become unstable modes. The rest of the variables refer to stable modes. The strategy is to show that the stable modes can be expressed in terms of the unstable modes so that the former can be eliminated from the system. On the other hand, we provide a theorem showing that a coupled set of differential equations can become uncoupled and vice versa as an argument in favour of the second thesis. The path of evolution can turn both ways.
Porter's contribution to more general and dynamic strategy frameworks
F.A.J. van den Bosch (Frans)
1997-01-01
textabstractIntroduction. Understanding why firms are successful is a very basic question in strategy both from a practitioner and a research perspective. In the strategy and management literature, however, we are confronted with different analytical frameworks, applicable at different levels
Energy Technology Data Exchange (ETDEWEB)
Wang, F. J., E-mail: wangfujun@tju.edu.cn; Liang, C. M.; Tian, Y. L.; Zhao, X. Y.; Zhang, D. W. [Tianjin Key Laboratory of Equipment Design and Manufacturing Technology, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Zhang, H. J. [Tianjin Key Laboratory of Modern Mechatronics Equipment Technology, School of Mechanical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)
2015-12-15
This work presents the flexure-mechanism based decoupling design between high frequency piezoelectric ultrasonic transducers and their clamping connections to improve ultrasonic energy transmission efficiency. The ring, prismatic beam, and circular notched hinge based flanges were presented, and the crucial geometric dimensions of the transducers with the flexure decoupling flanges were determined. Finite element analysis (FEA) was carried out to investigate the dynamic characteristics of the transducers. Finally, experiments were conducted to examine and verify the effects of the proposed decoupling flanges. FEA and experimental results show that smaller frequency deviations and larger tip displacement amplitudes have been achieved by using the transducers with the flexure flanges compared with the transducer with a rigid ring-type flange, and thus the ultrasonic transmission efficiency can be improved through the flexure flanges.
D-FNN Based Modeling and BP Neural Network Decoupling Control of PVC Stripping Process
Directory of Open Access Journals (Sweden)
Shu-zhi Gao
2014-01-01
Full Text Available PVC stripping process is a kind of complicated industrial process with characteristics of highly nonlinear and time varying. Aiming at the problem of establishing the accurate mathematics model due to the multivariable coupling and big time delay, the dynamic fuzzy neural network (D-FNN is adopted to establish the PVC stripping process model based on the actual process operation datum. Then, the PVC stripping process is decoupled by the distributed neural network decoupling module to obtain two single-input-single-output (SISO subsystems (slurry flow to top tower temperature and steam flow to bottom tower temperature. Finally, the PID controller based on BP neural networks is used to control the decoupled PVC stripper system. Simulation results show the effectiveness of the proposed integrated intelligent control method.
Coupling Mechanism and Decoupled Suspension Control Model of a Half Car
Directory of Open Access Journals (Sweden)
Hailong Zhang
2016-01-01
Full Text Available A structure decoupling control strategy of half-car suspension is proposed to fully decouple the system into independent front and rear quarter-car suspensions in this paper. The coupling mechanism of half-car suspension is firstly revealed and formulated with coupled damping force (CDF in a linear function. Moreover, a novel dual dampers-based controllable quarter-car suspension structure is proposed to realize the independent control of pitch and vertical motions of the half car, in which a newly added controllable damper is suggested to be installed between the lower control arm and connection rod in conventional quarter-car suspension structure. The suggested damper constantly regulates the half-car pitch motion posture in a smooth and steady operation condition meantime achieving the expected completely structure decoupled control of the half-car suspension, by compensating the evolved CDF.
Decoupling control of steering and driving system for in-wheel-motor-drive electric vehicle
Zhang, Han; Zhao, Wanzhong
2018-02-01
To improve the maneuverability and stability of in-wheel-motor-drive electric vehicle, a control strategy based on nonlinear decoupling control method is proposed in this paper, realizing the coordinated control of the steering and driving system. At first, the nonlinear models of the in-wheel-motor-drive electric vehicle and its sub-system are constructed. Then the inverse system decoupling theory is applied to decompose the nonlinear system into several independent subsystems, which makes it possible to realize the coordinated control of each subsystem. Next, the μ-Synthesis theory is applied to eliminate the influence of model uncertainty, improving the stability, robustness and tracking performance of in-wheel-motor-drive electric vehicle. Simulation and experiment results and numerical analyses, based on the electric vehicle actuated by in-wheel-motors, prove that the proposed control method is effective to accomplish the decoupling control of the steering and driving system in both simulation and real practice.
Seretis, M.
2017-01-01
This report regards the development of a predictive control strategy for an automotive electrically-assisted Waste Heat Recovery System (eWHR) with preview information. In this system, the energy recovery is decoupled from the energy supply to the engine. For such dynamical systems with energy
Dynamic Commitment: Wargaming Projected Forces Against the QDR Defense Strategy
National Research Council Canada - National Science Library
Carter, Clarence
1997-01-01
.... The Dynamic Commitment Wargame Series informed participants regarding the expected future demand on forces, such that Services were better able to articulate the effect of the examined force options...
Arresting Strategy Based on Dynamic Criminal Networks Changing over Time
Directory of Open Access Journals (Sweden)
Junqing Yuan
2013-01-01
Full Text Available We investigate a sequence of dynamic criminal networks on a time series based on the dynamic network analysis (DNA. According to the change of networks’ structure, networks’ variation trend is analyzed to forecast its future structure. Finally, an optimal arresting time and priority list are designed based on our analysis. Better results can be expected than that based on social network analysis (SNA.
adaptation strategies of airline travel agencies to the dynamics of ...
African Journals Online (AJOL)
Bawa et al.
strategies airline travel agencies adopt to remain in business. Data for this paper was ... that in 2013, travel and tourism's total contribution to the global economy rose to ... reality of today's tourism industry as it has penetrated the decision.
An Integrative Model of Dynamic Strategy-Making
DEFF Research Database (Denmark)
Andersen, Torben Juul; Hallin, Carina Antonia; Li, Xin
. We adopt the frame of complementary Yin-Yang elements and Zhong Yong balance to explain the time bound interaction between these opposing yet complementary strategy-making mechanisms where tradeoffs and synergies are balanced across hierarchical levels. The model outlines how the interaction between......The organizational capacity to cope with unexpected changes remains a fundamental challenge in strategy as global competition and technological innovation increase environmental uncertainty. Whereas conventional strategy-making often is conceived as a sequential linear process, we see it as a non......-linear interaction between top-down and bottom-up mechanisms dealing with multiple actions taken throughout the organization over time. It is driven by intension but with a flexible balance between centralized (planned) and decentralized (spontaneous) activities where strategy formulation and implementation interact...
Multiple Antenna Systems with Inherently Decoupled Radiators
DEFF Research Database (Denmark)
Pelosi, Mauro; Knudsen, Mikael B.; Pedersen, Gert Frølund
2012-01-01
In multiple antenna systems mutual coupling needs to be minimized. We propose an alternative novel decoupling technique, investigating several multiple antenna configurations for small handsets through measurements and numerical simulations. The influence of different novel designs on performance...... metrics such as total loss, antenna isolation and envelope correlation coefficient are investigated. By varying antenna impedance bandwidth and antenna location with respect to the handset, both Planar Inverted F Antenna (PIFA) and Inverted F Antennas (IFA) were investigated in different UMTS frequency...
Decoupling of charm beyond leading order
Knechtli, Francesco; Korzec, Tomasz; Leder, Björn; Moir, Graham
2017-01-01
We study the effective theory of decoupling of a charm quark at low energies. We do this by simulating a model, QCD with two mass-degenerate charm quarks. At leading order the effective theory is a pure gauge theory. By computing ratios of hadronic scales we have direct access to the power corrections in the effective theory. We show that these corrections follow the expected leading behavior, which is quadratic in the inverse charm quark mass.
Delayed Antiwindup Control Using a Decoupling Structure
Directory of Open Access Journals (Sweden)
Huawei Zhu
2013-01-01
Full Text Available This paper investigates the antiwindup (AW control problem for plants with input saturation. The AW compensator is not activated as soon as input saturation occurs as usual. A delayed decoupling structure is first proposed. Then, appropriate linear matrix inequalities (LMIs are developed to determine a plant-order AW compensator. Effectiveness of the presented AW technique is illustrated by a fighter aircraft model.
Motion Estimation and Compensation Strategies in Dynamic Computerized Tomography
Hahn, Bernadette N.
2017-12-01
A main challenge in computerized tomography consists in imaging moving objects. Temporal changes during the measuring process lead to inconsistent data sets, and applying standard reconstruction techniques causes motion artefacts which can severely impose a reliable diagnostics. Therefore, novel reconstruction techniques are required which compensate for the dynamic behavior. This article builds on recent results from a microlocal analysis of the dynamic setting, which enable us to formulate efficient analytic motion compensation algorithms for contour extraction. Since these methods require information about the dynamic behavior, we further introduce a motion estimation approach which determines parameters of affine and certain non-affine deformations directly from measured motion-corrupted Radon-data. Our methods are illustrated with numerical examples for both types of motion.
An extension of the classification of evolutionary singular strategies in Adaptive Dynamics
Boldin, Barbara; Diekmann, Odo
2014-01-01
The existing classification of evolutionarily singular strategies in Adaptive Dynamics (Geritz et al. in Evol Ecol 12:35–57, 1998; Metz et al. in Stochastic and spatial structures of dynamical systems, pp 183–231, 1996) assumes an invasion exponent that is differentiable twice as a function of both
A digital strategy for manometer dynamic enhancement. [for wind tunnel monitoring
Stoughton, J. W.
1978-01-01
Application of digital signal processing techniques to improve the non-linear dynamic characteristics of a sonar-type mercury manometer is described. The dynamic enhancement strategy quasi-linearizes the manometer characteristics and improves the effective bandwidth in the context of a wind-tunnel pressure regulation system. Model identification data and real-time hybrid simulation data demonstrate feasibility of approach.
Time-Varying Combinations of Bayesian Dynamic Models and Equity Momentum Strategies
N. Basturk (Nalan); S. Grassi (Stefano); L.F. Hoogerheide (Lennart); H.K. van Dijk (Herman)
2016-01-01
markdownabstractA novel dynamic asset-allocation approach is proposed where portfolios as well as portfolio strategies are updated at every decision period based on their past performance. For modeling, a general class of models is specified that combines a dynamic factor and a vector autoregressive
Decision support for dynamic greenhouse climate control strategies
Körner, O.; Straten, van G.
2008-01-01
Earlier, different dynamic greenhouse climate regimes were designed with various aims as energy saving, biocide reduction or reduction of chemical growth retardants that are used for quality improvement. The aim of this research was to create a decision support tool in order to decide at which week
N.F. Höning (Nicolas); J.A. La Poutré (Han); F. Lopes; Z. Vale; J. Sousa; H. Coelho
2013-01-01
htmlabstractDemand response is a crucial mechanism for flattening of peak loads. For its implementation, we not only require consumers who react to price changes, but also intelligent strategies to select prices. We propose a parametrised meta-strategy for dynamic pricing and identify suitable
A dynamic replication management strategy in distributed GIS
Pan, Shaoming; Xiong, Lian; Xu, Zhengquan; Chong, Yanwen; Meng, Qingxiang
2018-03-01
Replication strategy is one of effective solutions to meet the requirement of service response time by preparing data in advance to avoid the delay of reading data from disks. This paper presents a brand-new method to create copies considering the selection of replicas set, the number of copies for each replica and the placement strategy of all copies. First, the popularities of all data are computed considering both the historical access records and the timeliness of the records. Then, replica set can be selected based on their recent popularities. Also, an enhanced Q-value scheme is proposed to assign the number of copies for each replica. Finally, a reasonable copies placement strategy is designed to meet the requirement of load balance. In addition, we present several experiments that compare the proposed method with techniques that use other replication management strategies. The results show that the proposed model has better performance than other algorithms in all respects. Moreover, the experiments based on different parameters also demonstrated the effectiveness and adaptability of the proposed algorithm.
Adaptation strategies of airline travel agencies to the dynamics of ...
African Journals Online (AJOL)
The role of airline travel agencies in a changing operational environment depends on their ability to adapt and survive in the airline travel industry. This paper examines the adaptation strategies airline travel agencies adopt to remain in business. Data for this paper was obtained through multi-stage sampling system that ...
Argumentation as a Strategy for Conceptual Learning of Dynamics
Eskin, Handan; Ogan-Bekiroglu, Feral
2013-01-01
Researchers have emphasized the importance of promoting argumentation in science classrooms for various reasons. However, the study of argumentation is still a young field and more research needs to be carried out on the tools and pedagogical strategies that can assist teachers and students in both the construction and evaluation of scientific…
Optimal Dynamic Advertising Strategy Under Age-Specific Market Segmentation
Krastev, Vladimir
2011-12-01
We consider the model proposed by Faggian and Grosset for determining the advertising efforts and goodwill in the long run of a company under age segmentation of consumers. Reducing this model to optimal control sub problems we find the optimal advertising strategy and goodwill.
Biotechnology Patenting in the BRICS Countries: Strategies and Dynamics.
Streltsova, Ekaterina; Linton, Jonathan D
2018-01-05
The BRICS countries (Brazil, Russia, India, China, South Africa) account for 25% of global biotechnology patents. To understand the current and future landscape of the domain, it is important to better understand the capacity of these contributors. Here, we consider the thematic priorities, strategies, and key players of the BRICS countries in biotechnology patenting. Copyright © 2017 Elsevier Ltd. All rights reserved.
Decoupling, re-Engaging: managing trust relationships in implementation projects
DEFF Research Database (Denmark)
Rose, Jeremy; Schlichter, Bjarne Rerup
2012-01-01
, and the complex demands of managing those fluctuations. We investigate evolving trust relationships in a longitudinal case analysis of a large Integrated Hospital System implementation for the Faroe Islands. Trust relationships suffered various breakdowns, but the project was able to recover and eventually meet...... its goals. Based on concepts from Giddens’ later work on modernity, we develop two approaches for managing dynamic trust relationships in implementation projects: decoupling and re-engaging.......An important aspect of the successful implementation of large information systems (such as ERP systems) is trust. These implementations impact the legitimate interests of many groups of stakeholders, and trust is a critical factor for success. Trust in the project is contingent upon many factors...
Decoupled simulations of offshore wind turbines with reduced rotor loads and aerodynamic damping
Directory of Open Access Journals (Sweden)
S. Schafhirt
2018-02-01
Full Text Available Decoupled load simulations are a computationally efficient method to perform a dynamic analysis of an offshore wind turbine. Modelling the dynamic interactions between rotor and support structure, especially the damping caused by the rotating rotor, is of importance, since it influences the structural response significantly and has a major impact on estimating fatigue lifetime. Linear damping is usually used for this purpose, but experimentally and analytically derived formulas to calculate an aerodynamic damping ratio often show discrepancies to measurement and simulation data. In this study decoupled simulation methods with reduced and full rotor loads are compared to an integrated simulation. The accuracy of decoupled methods is evaluated and an optimization is performed to obtain aerodynamic damping ratios for different wind speeds that provide the best results with respect to variance and equivalent fatigue loads at distinct output locations. Results show that aerodynamic damping is not linear, but it is possible to match desired output using decoupled models. Moreover, damping ratios obtained from the empirical study suggest that aerodynamic damping increases for higher wind speeds.
Decoupled Simulation Method For Incremental Sheet Metal Forming
International Nuclear Information System (INIS)
Sebastiani, G.; Brosius, A.; Tekkaya, A. E.; Homberg, W.; Kleiner, M.
2007-01-01
Within the scope of this article a decoupling algorithm to reduce computing time in Finite Element Analyses of incremental forming processes will be investigated. Based on the given position of the small forming zone, the presented algorithm aims at separating a Finite Element Model in an elastic and an elasto-plastic deformation zone. Including the elastic response of the structure by means of model simplifications, the costly iteration in the elasto-plastic zone can be restricted to the small forming zone and to few supporting elements in order to reduce computation time. Since the forming zone moves along the specimen, an update of both, forming zone with elastic boundary and supporting structure, is needed after several increments.The presented paper discusses the algorithmic implementation of the approach and introduces several strategies to implement the denoted elastic boundary condition at the boundary of the plastic forming zone
The Dynamic Evaluation of Enterprise's Strategy Based on Rough Set Theory
Institute of Scientific and Technical Information of China (English)
刘恒江; 陈继祥
2003-01-01
This paper presents dynamic evaluation of enterprise's strategy which is suitable for dealing with the complex and dynamic problems of strategic evaluation. Rough Set Theory is a powerful mathematical tool to handle vagueness and uncertainty of dynamic evaluation. By the application of Rough Set Theory, this paper computes the significance and weights of each evaluation criterion and helps to lay evaluation emphasis on the main and effective criteria. From the reduced decision table,evaluators can get decision rules Which direct them to give judgment or suggestion of strategy. The whole evaluation process is decided by data, so the results are certain and reasonable.
Exploitation Strategies of Cabin and Galley Thermal Dynamics
Schlabe, Daniel; Zimmer, Dirk; Pollok, Alexander
2017-01-01
The thermal inertia of aircraft cabins and galleys is significant for commercial aircraft. The aircraft cabin is controlled by the Environment Control System (ECS) to reach, among other targets, a prescribed temperature. By allowing a temperature band of ± 2 K instead of a fixed temperature, it is possible to use this thermal dynamic of the cabin as energy storage. This storage can then be used to reduce electrical peak power, increase efficiency of the ECS, reduce thermal cooling peak power...
An optimal strategy for functional mapping of dynamic trait loci.
Jin, Tianbo; Li, Jiahan; Guo, Ying; Zhou, Xiaojing; Yang, Runqing; Wu, Rongling
2010-02-01
As an emerging powerful approach for mapping quantitative trait loci (QTLs) responsible for dynamic traits, functional mapping models the time-dependent mean vector with biologically meaningful equations and are likely to generate biologically relevant and interpretable results. Given the autocorrelation nature of a dynamic trait, functional mapping needs the implementation of the models for the structure of the covariance matrix. In this article, we have provided a comprehensive set of approaches for modelling the covariance structure and incorporated each of these approaches into the framework of functional mapping. The Bayesian information criterion (BIC) values are used as a model selection criterion to choose the optimal combination of the submodels for the mean vector and covariance structure. In an example for leaf age growth from a rice molecular genetic project, the best submodel combination was found between the Gaussian model for the correlation structure, power equation of order 1 for the variance and the power curve for the mean vector. Under this combination, several significant QTLs for leaf age growth trajectories were detected on different chromosomes. Our model can be well used to study the genetic architecture of dynamic traits of agricultural values.
Decoupling mechanisms-paying for conservation
Energy Technology Data Exchange (ETDEWEB)
Cross, P.S.
1993-07-15
In 1988, the National Association of Regulatory Utility Commissioners issued a policy statement that said [open quotes]ratemaking practices should align utilities' pursuit of profit with least-cost planning.[close quotes] This policy coincided with then-current thinkingg at a number of state commissions about the much-touted goal of encouraging utilities to invest in conservation, or demand-side management (DSM) programs, rather than in generating resources to meet system load requirements. Besides utility concerns about recovering conservation program investments, regulators also notices a built-in [open quotes]disincentive[close quotes] to investment in the traditional ratemaking format: If profit is tied to sales, then utilities will always shy away from aggressively promoting conservation. Or so the thinkin went. [open quotes]Decoupling mechanisms[close quotes] were born to remove this disincentive. A number of states have implemented these mechanisms, while several others are investigating the issue. One chief drawback of the mechanisms is that if sales go down, rates go up to cover the shortfall. (Of course, rates go down if sales exceed forecasted levels.) A major problem has been that rate increases have occurred at exactly the wrong time, during economic slowdowns when utilities are struggling to retain price-sensitive customers and residential ratepayers are least likely to bear with quiet stoicism the burden placed on family budgets. Decoupling is seen by some as a step backwards in the move to competitive regulatory reforms that seek to encourage utilities to behave like free-market companies. Indeed, the newest decoupling mechanisms face serious challenge.
Vehicle systems: coupled and interactive dynamics analysis
Vantsevich, Vladimir V.
2014-11-01
This article formulates a new direction in vehicle dynamics, described as coupled and interactive vehicle system dynamics. Formalised procedures and analysis of case studies are presented. An analytical consideration, which explains the physics of coupled system dynamics and its consequences for dynamics of a vehicle, is given for several sets of systems including: (i) driveline and suspension of a 6×6 truck, (ii) a brake mechanism and a limited slip differential of a drive axle and (iii) a 4×4 vehicle steering system and driveline system. The article introduces a formal procedure to turn coupled system dynamics into interactive dynamics of systems. A new research direction in interactive dynamics of an active steering and a hybrid-electric power transmitting unit is presented and analysed to control power distribution between the drive axles of a 4×4 vehicle. A control strategy integrates energy efficiency and lateral dynamics by decoupling dynamics of the two systems thus forming their interactive dynamics.
Open string decoupling and tachyon condensation
International Nuclear Information System (INIS)
Chalmers, G.
2001-01-01
The amplitudes in perturbative open string theory are examined as functions of the tachyon condensate parameter. The boundary state formalism demonstrates the decoupling of the open string modes at the non-perturbative minima of the tachyon potential via a degeneration of open world-sheets and identifies an independence of the coupling constants g s and g YM at general values of the tachyon condensate. The closed sector is generated at the quantum level; it is also generated at the classical level through the condensation of the propagating open string modes on the D-brane degrees of freedom.
Global Decoupling on the RHIC Ramp
Luo, Yun; Della Penna, Al; Fischer, Wolfram; Laster, Jonathan S; Marusic, Al; Pilat, Fulvia Caterina; Roser, Thomas; Trbojevic, Dejan
2005-01-01
The global betatron decoupling on the ramp is an important issue for the operation of the Relativistic Heavy Ion Collider (RHIC). In the polarized proton run, the betatron tunes are required to keep almost constant on the ramp to avoid spin resonance line crossing and the beam polarization loss. Some possible correction schemes on the ramp, like three-ramp correction, the coupling amplitude modulation and the coupling phase modulaxtion, have been found. The principles of these schemes are shortly reviewed and compared. Operational results of their applications on the RHIC ramps are given.
New modelling strategy for IRIS dynamic response simulation
International Nuclear Information System (INIS)
Cammi, A.; Ricotti, M. E.; Casella, F.; Schiavo, F.
2004-01-01
The pressurized light water cooled, medium power (1000 MWt) IRIS (International Reactor Innovative and Secure) has been under development for four years by an international consortium of over 21 organizations from ten countries. The plant conceptual design was completed in 2001 and the preliminary design is nearing completion. The pre-application licensing process with NRC started in October, 2002 and IRIS is one of the designs considered by US utilities as part of the ESP (Early Site Permit) process. In this paper the development of an adequate modeling and simulation tool for Dynamics and Control tasks is presented. The key features of the developed simulator are: a) Modularity: the system model is built by connecting the models of its components, which are written independently of their boundary conditions; b) Openness: the code of each component model is clearly readable and close to the original equations and easily customised by the experienced user; c) Efficiency: the simulation code is fast; d) Tool support: the simulation tool is based on reliable, tested and well-documented software. To achieve these objectives, the Modelica language was used as a basis for the development of the simulator. The Modelica language is the results of recent advances in the field of object-oriented, multi-physics, dynamic system modelling. The language definition is open-source and it has already been successfully adopted in several industrial fields. To provide the required capabilities for the analysis, specific models for nuclear reactor components have been developed, to be applied for the dynamic simulation of the IRIS integral reactor, albeit keeping general validity for PWR plants. The following Modelica models have been written to satisfy the IRIS modelling requirements and are presented in this paper: neutronics point kinetic, fuel heat transfer, control rods model, including the innovative internal drive mechanism type, and a once-through type steam generator, thus
Using of dynamic strategy model in innovation process
Directory of Open Access Journals (Sweden)
Monika Chobotová
2013-01-01
Full Text Available This paper incorporates a new scenario method which can use for formulate innovation strategy. The purpose of scenario is not to identify the most likely future, but to create a map of uncertainty — to acknowledge and examine the visible and hidden forces that directed toward the unknown future of a firm. Scenarios are used for capture a range of possibilities, good and bad, expected and surprising. They are designed to stretch our thinking about emerging changes and the opportunities and threats that may occur in the future. Scenario allows us to weigh our choices more carefully when making short-term and long-term strategic decisions.
A dynamic routing strategy with limited buffer on scale-free network
Wang, Yufei; Liu, Feng
2016-04-01
In this paper, we propose an integrated routing strategy based on global static topology information and local dynamic data packet queue lengths to improve the transmission efficiency of scale-free networks. The proposed routing strategy is a combination of a global static routing strategy (based on the shortest path algorithm) and local dynamic queue length management, in which, instead of using an infinite buffer, the queue length of each node i in the proposed routing strategy is limited by a critical queue length Qic. When the network traffic is lower and the queue length of each node i is shorter than its critical queue length Qic, it forwards packets according to the global routing table. With increasing network traffic, when the buffers of the nodes with higher degree are full, they do not receive packets due to their limited buffers and the packets have to be delivered to the nodes with lower degree. The global static routing strategy can shorten the transmission time that it takes a packet to reach its destination, and the local limited queue length can balance the network traffic. The optimal critical queue lengths of nodes have been analysed. Simulation results show that the proposed routing strategy can get better performance than that of the global static strategy based on topology, and almost the same performance as that of the global dynamic routing strategy with less complexity.
Judo strategy. The competitive dynamics of Internet time.
Yoffie, D B; Cusumano, M A
1999-01-01
Competition on the Internet is creating fierce battles between industry giants and small-scale start-ups. Smart start-ups can avoid those conflicts by moving quickly to uncontested ground and, when that's no longer possible, turning dominant players' strengths against them. The authors call this competitive approach judo strategy. They use the Netscape-Microsoft battles to illustrate the three main principles of judo strategy: rapid movement, flexibility, and leverage. In the early part of the browser wars, for instance, Netscape applied the principle of rapid movement by being the first company to offer a free stand-alone browser. This allowed Netscape to build market share fast and to set the market standard. Flexibility became a critical factor later in the browser wars. In December 1995, when Microsoft announced that it would "embrace and extend" competitors' Internet successes, Netscape failed to give way in the face of superior strength. Instead it squared off against Microsoft and even turned down numerous opportunities to craft deep partnerships with other companies. The result was that Netscape lost deal after deal when competing with Microsoft for common distribution channels. Netscape applied the principle of leverage by using Microsoft's strengths against it. Taking advantage of Microsoft's determination to convert the world to Windows or Windows NT, Netscape made its software compatible with existing UNIX systems. While it is true that these principles can't replace basic execution, say the authors, without speed, flexibility, and leverage, very few companies can compete successfully on Internet time.
Migration strategy affects avian influenza dynamics in mallards (Anas platyrhynchos).
Takekawa, John Y.; Hill, Nichola J.; Ackerman, Joshua T.; Herring, Garth; Hobson, Keith; Cardona, Carol J.; Runstadler, Jonathan; Boyce, Walter M.
2012-01-01
Studies of pathogen transmission typically overlook that wildlife hosts can include both migrant and resident populations when attempting to model circulation. Through the application of stable isotopes in flight feathers, we estimated the migration strategy of mallards (Anas platyrhynchos) occurring on California wintering grounds. Our study demonstrates that mallards- a principal host of avian influenza virus (AIV) in nature, contribute differently to virus gene flow depending on migration strategy. No difference in AIV prevalence was detected between resident (9.6%), intermediate-distance (9.6%) and long-distance migrants (7.4%). Viral diversity among the three groups was also comparable, possibly owing to viral pool mixing when birds converge at wetlands during winter. However, migrants and residents contributed differently to the virus gene pool at wintering wetlands. Migrants introduced virus from northern breeding grounds (Alaska and the NW Pacific Rim) into the wintering population, facilitating gene flow at continental scales, but circulation of imported virus appeared to be limited. In contrast, resident mallards acted as AIV reservoirs facilitating year-round circulation of limited subtypes (i.e. H5N2) at lower latitudes. This study supports a model of virus exchange in temperate regions driven by the convergence of wild birds with separate geographic origins and exposure histories.
Lai, Lei-Jie; Gu, Guo-Ying; Zhu, Li-Min
2012-04-01
This paper presents a novel decoupled two degrees of freedom (2-DOF) translational parallel micro-positioning stage. The stage consists of a monolithic compliant mechanism driven by two piezoelectric actuators. The end-effector of the stage is connected to the base by four independent kinematic limbs. Two types of compound flexure module are serially connected to provide 2-DOF for each limb. The compound flexure modules and mirror symmetric distribution of the four limbs significantly reduce the input and output cross couplings and the parasitic motions. Based on the stiffness matrix method, static and dynamic models are constructed and optimal design is performed under certain constraints. The finite element analysis results are then given to validate the design model and a prototype of the XY stage is fabricated for performance tests. Open-loop tests show that maximum static and dynamic cross couplings between the two linear motions are below 0.5% and -45 dB, which are low enough to utilize the single-input-single-out control strategies. Finally, according to the identified dynamic model, an inversion-based feedforward controller in conjunction with a proportional-integral-derivative controller is applied to compensate for the nonlinearities and uncertainties. The experimental results show that good positioning and tracking performances are achieved, which verifies the effectiveness of the proposed mechanism and controller design. The resonant frequencies of the loaded stage at 2 kg and 5 kg are 105 Hz and 68 Hz, respectively. Therefore, the performance of the stage is reasonably good in term of a 200 N load capacity. © 2012 American Institute of Physics
A dynamic switching strategy for air-conditioning systems operated in light-thermal-load conditions
International Nuclear Information System (INIS)
Lin, Jin-Long; Yeh, T.-J.; Hwang, Wei-Yang
2009-01-01
Recently, modern air-conditioners have begun to incorporate variable-speed compressors and variable-opening expansion valves, together with feedback control to improve the performance and energy efficiency. However, for the compressor there usually exists a low-speed limit below which its speed can not be continuously modulated unless it is completely turned off. When the air-conditioning system is operated in light-thermal-load conditions, the low-speed limit causes the compressor to run in an on-off manner which can significantly degrade the performance and efficiency. In this paper, a dynamic switching strategy is proposed for such scenarios. The strategy is basically an integration of a cascading control structure, an intuitive switching strategy, and a dynamic compensator. While the control structure provides the nominal performance, the intuitive switching strategy and the dynamic compensator together can account for the compressor's low-speed limitation. Theoretical analysis reveals that when the output matrix of the dynamic compensator is chosen properly, the proposed strategy can effectively reduce the output error caused by the on-off operation of the compressor. Experiments also demonstrate that the proposed strategy can simultaneously provide better regulation for the indoor temperature and improve the energy efficiency at steady state.
Optorsim: A Grid Simulator for Studying Dynamic Data Replication Strategies
Bell, William H; Millar, A Paul; Capozza, Luigi; Stockinger, Kurt; Zini, Floriano
2003-01-01
Computational grids process large, computationally intensive problems on small data sets. In contrast, data grids process large computational problems that in turn require evaluating, mining and producing large amounts of data. Replication, creating geographically disparate identical copies of data, is regarded as one of the major optimization techniques for reducing data access costs. In this paper, several replication algorithms are discussed. These algorithms were studied using the Grid simulator: OptorSim. OptorSim provides a modular framework within which optimization strategies can be studied under different Grid configurations. The goal is to explore the stability and transient behaviour of selected optimization techniques. We detail the design and implementation of OptorSim and analyze various replication algorithms based on different Grid workloads.
Cross-modal decoupling in temporal attention.
Mühlberg, Stefanie; Oriolo, Giovanni; Soto-Faraco, Salvador
2014-06-01
Prior studies have repeatedly reported behavioural benefits to events occurring at attended, compared to unattended, points in time. It has been suggested that, as for spatial orienting, temporal orienting of attention spreads across sensory modalities in a synergistic fashion. However, the consequences of cross-modal temporal orienting of attention remain poorly understood. One challenge is that the passage of time leads to an increase in event predictability throughout a trial, thus making it difficult to interpret possible effects (or lack thereof). Here we used a design that avoids complete temporal predictability to investigate whether attending to a sensory modality (vision or touch) at a point in time confers beneficial access to events in the other, non-attended, sensory modality (touch or vision, respectively). In contrast to previous studies and to what happens with spatial attention, we found that events in one (unattended) modality do not automatically benefit from happening at the time point when another modality is expected. Instead, it seems that attention can be deployed in time with relative independence for different sensory modalities. Based on these findings, we argue that temporal orienting of attention can be cross-modally decoupled in order to flexibly react according to the environmental demands, and that the efficiency of this selective decoupling unfolds in time. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.
Decoupled Multicamera Sensing for Flexible View Generation
Directory of Open Access Journals (Sweden)
Vivek K. Singh
2016-01-01
Full Text Available Any sensing paradigm has three important components, namely, the actor, the sensor, and the environment. Traditionally, the sensors have been attached to either the actor or the environment. This restricts the kind of sensing that can be undertaken. We study a newer decoupled sensing paradigm, which separates the sensors from both the actor and the environment and tremendously increases the flexibility with which the scenes can be viewed. For example, instead of showing just one view, “how the environment sees the actor” or “how the actor sees the environment,” a viewer can choose to see either one or both of these views and even choose to see the scene from any desired position in any desired direction. We describe a methodology using mobile autonomous sensors to undertake such decoupled sensing and study the feasible number as well as the placement of such sensors. Also, we describe how the sensors can coordinate their movements around a moving actor so as to continue capturing the required views with minimum overall cost. The practical results obtained demonstrate the viability of the proposed approach.
Superior MR images with electronically tuned and decoupled surface coils
International Nuclear Information System (INIS)
Ingwersen, H.; Freisen, L.; Friedrich, A.; Kess, H.; Krause, N.; Meissner, R.; Popp, W.
1987-01-01
In order to gain free positioning of surface coils in linearly polarized transmitting coils, it is absolutely necessary to electronically decouple both coils. For circularly polarized transmitting coils, decoupling is necessary in any case. In addition to the decoupling circuit automatic electronic tuning of the surface coils is used to gain the bast ratio of signal to noise. This combination of electronically decoupling and tuning of the surface coils yields intrinsic patient safety concerning local power deposition as well as free positioning and easy handling at the same time. Block diagrams, circuit schemes, and MR images obtained with several different surface coils are shown
Decoupling of Solid 4He Layers under the Superfluid Overlayer
Ishibashi, Kenji; Hiraide, Jo; Taniguchi, Junko; Suzuki, Masaru
2018-03-01
It has been reported that in a large oscillation amplitude, the mass decoupling of multilayer 4He films adsorbed on graphite results from the depinning of the second solid atomic layer. This decoupling suddenly vanishes below a certain low temperature TD due to the cancellation of mass decoupling by the superfluid counterflow of the the overylayer. We studied the relaxation of the depinned state at various temperatures, after reduction of oscillation amplitude below TD . It was found that above the superfluid transition temperature the mass decoupling revives with a relaxation time of several 100 s. It strongly supports that the depinned state of the second solid atomic layer remains underneath the superfluid overlayer.
Directory of Open Access Journals (Sweden)
Lei Wang
2017-01-01
Full Text Available In real-world manufacturing systems, production scheduling systems are often implemented under random or dynamic events like machine failure, unexpected processing times, stochastic arrival of the urgent orders, cancellation of the orders, and so on. These dynamic events will lead the initial scheduling scheme to be nonoptimal and/or infeasible. Hence, appropriate dynamic rescheduling approaches are needed to overcome the dynamic events. In this paper, we propose a dynamic rescheduling method based on variable interval rescheduling strategy (VIRS to deal with the dynamic flexible job shop scheduling problem considering machine failure, urgent job arrival, and job damage as disruptions. On the other hand, an improved genetic algorithm (GA is proposed for minimizing makespan. In our improved GA, a mix of random initialization population by combining initialization machine and initialization operation with random initialization is designed for generating high-quality initial population. In addition, the elitist strategy (ES and improved population diversity strategy (IPDS are used to avoid falling into the local optimal solution. Experimental results for static and several dynamic events in the FJSP show that our method is feasible and effective.
Peña, Daniel; Contreras, María José; Shih, Pei Chun; Santacreu, José
2008-05-01
When individuals perform spatial tasks, individual differences emerge in accuracy and speed as well as in the response patterns used to cope with the task. The purpose of this study is to identify, through empirical criteria, the different response patterns or strategies used by individuals when performing the dynamic spatial task presented in the Spatial Orientation Dynamic Test-Revised (SODT-R). Results show that participants can be classified according to their response patterns. Three different ways of solving a task are described, and their relation to (a) performance factors (response latency, response frequency, and invested time) and (b) ability tests (analytical reasoning, verbal reasoning, and spatial estimation) are investigated. Sex differences in response patterns and performance are also analyzed. It is found that the frequency with which men and women employ each one of the strategies described here, is different and statistically significant. Thus, employed strategy plays an important role when interpreting sex differences on dynamic spatial tasks.
DEFF Research Database (Denmark)
Yao, Wenli; Loh, Poh Chiang; Tang, Yi
2016-01-01
dc capacitor to realize power decoupling, but the conventional power decoupling control scheme for this half-bridge circuit is developed with equal storage capacitances, which may vary in practice and degrade the ac and dc performance. The intention of this paper is to quantify ac and dc...... imperfections when storage mismatch occurs, which may break the standard requirement such as IEEE 1547. As a consequence, a robust control scheme is then proposed for half-bridge circuit, which realized power decoupling by generating second order harmonic voltage on the split dc decoupling capacitor instead...
Complex dynamics of the generic and brand advertising strategies in duopoly
International Nuclear Information System (INIS)
Qi Jie; Ding Yongsheng; Chen Liang
2008-01-01
By using the optimal profit adjusting strategies, a dynamic advertising competition model in duopoly is extended from Krishnamurthy's static model. Both generic and brand effects for advertising are considered. This model can create complex bifurcating and chaotic behavior for the generic advertising efforts, which lead to chaotic dynamics for the brand advertising and even for the whole system. The asymptotic properties of the symmetric system and the asymmetric system are also investigated, which reflect interactions between the two firms' advertising strategies and relationships between the brand and the generic advertising expenditures
Complex dynamics of the generic and brand advertising strategies in duopoly
Energy Technology Data Exchange (ETDEWEB)
Qi Jie [College of Information Sciences and Technology, Donghua University, Shanghai 200051 (China)], E-mail: jieqi@dhu.edu.cn; Ding Yongsheng [College of Information Sciences and Technology, Donghua University, Shanghai 200051 (China)], E-mail: ysding@dhu.edu.cn; Chen Liang [College of Information Sciences and Technology, Donghua University, Shanghai 200051 (China)
2008-04-15
By using the optimal profit adjusting strategies, a dynamic advertising competition model in duopoly is extended from Krishnamurthy's static model. Both generic and brand effects for advertising are considered. This model can create complex bifurcating and chaotic behavior for the generic advertising efforts, which lead to chaotic dynamics for the brand advertising and even for the whole system. The asymptotic properties of the symmetric system and the asymmetric system are also investigated, which reflect interactions between the two firms' advertising strategies and relationships between the brand and the generic advertising expenditures.
Adaptive Control Based Harvesting Strategy for a Predator-Prey Dynamical System.
Sen, Moitri; Simha, Ashutosh; Raha, Soumyendu
2018-04-23
This paper deals with designing a harvesting control strategy for a predator-prey dynamical system, with parametric uncertainties and exogenous disturbances. A feedback control law for the harvesting rate of the predator is formulated such that the population dynamics is asymptotically stabilized at a positive operating point, while maintaining a positive, steady state harvesting rate. The hierarchical block strict feedback structure of the dynamics is exploited in designing a backstepping control law, based on Lyapunov theory. In order to account for unknown parameters, an adaptive control strategy has been proposed in which the control law depends on an adaptive variable which tracks the unknown parameter. Further, a switching component has been incorporated to robustify the control performance against bounded disturbances. Proofs have been provided to show that the proposed adaptive control strategy ensures asymptotic stability of the dynamics at a desired operating point, as well as exact parameter learning in the disturbance-free case and learning with bounded error in the disturbance prone case. The dynamics, with uncertainty in the death rate of the predator, subjected to a bounded disturbance has been simulated with the proposed control strategy.
Dynamic Protective Control Strategy for Distributed Generation System with Fixed-speed Wind Turbines
Institute of Scientific and Technical Information of China (English)
2012-01-01
The characteristics of induction generator based fixed-speed wind turbines （FSWT） are investigated. The impacts of different execution time in protective operations are studied under different fauit duration and various wind velocity situations, e.g. , FSWT stabilities of load shedding in distribution systems. Based on this research, a dynamic protective control strategy for a distributed generation system （DGS） with FSWT is proposed. Finally, simulation results demonstrate the effectiveness of the strategy.
Decoupling of CO2 emissions and GDP
Directory of Open Access Journals (Sweden)
Yves Rocha de Salles Lima
2016-12-01
Full Text Available The objetive of this work is to analyze the variation of CO2 emissions and GDP per capita throughout the years and identify the possible interaction between them. For this purpose, data from the International Energy Agency was collected on two countries, Brazil and the one with the highest GDP worldwide, the United States. Thus, the results showed that CO2 emissions have been following the country’s economic growth for many years. However, these two indicators have started to decouple in the US in 2007 while in Brazil the same happened in 2011. Furthermore, projections for CO2 emissions are made until 2040, considering 6 probable scenarios. These projections showed that even if the oil price decreases, the emissions will not be significantly affected as long as the economic growth does not decelerate.
Gauge hierarchy, decoupling, and heavy particle effects
International Nuclear Information System (INIS)
Yao, York-Peng
1981-01-01
This chapter examines the problems of a large gauge hierarchy and decoupling in theories with spontaneously broken symmetry. Attempts to show, with regard to all orders in the loop expansion, that: once a proper identification is made of the light particles and of the heavy particles at the tree level, then such a division will be maintained order by order in the loop expansion without the necessity of fine tuning; there is a local renormalizable effective Lagrangian, composed of light fields only, which can be used to reproduce all the one light particle irreducible Green's functions; and a set of renormalization group equations can be written down, wherein one stays in the lower energy region to correlate the two sets of parameters in the full and the effective light theories. The appendix gives an algebraic rearrangement method which can be efficiently used to calculate the muon effects on the electron anomalous magnetic moment
Development and test of decoupler for ICRF antenna in EAST
Energy Technology Data Exchange (ETDEWEB)
Chen, Gen, E-mail: chengen@ipp.ac.cn; Mao, Yuzhou; Zhao, Yanping; Yuan, Shuai; Zhang, Xinjun; Qing, Chengming
2016-06-15
Highlights: • The mechanism of decoupler for ICRF antenna is proposed. • Three candidate assembly positions for the decouper can be used. • The performance relies on the ohmic dissipation and the assembly position of decoupler. - Abstract: Ion Cyclotron Range of Frequency (ICRF) heating has been adopted in EAST tokamak as one of main auxiliary heating methods. The ICRF antenna usually consists of multiple launching elements because of limited port and space of tokamak device. Mutual coupling between straps has been observed in previous EAST ICRF current drive experiments. Due to adverse effects of such mutual coupling, many issues induced by cross power cannot be ignored, such as power imbalance in feed lines, high voltage standing wave ratio (VSWR), and etc. To restrain such mutual coupling, A device named decoupler was developed and tested in EAST ICRF system. According to the admittance matrix of load, three assembly positions (oscillation position, optimum position, and smooth position) along transmission line for the decoupler were taken into account and tested. The test results showed that ohmic dissipation in decoupler could not be neglected, which partly influenced the decoupling performance. The oscillation position and optimum position could restrain such adverse effects of ohmic dissipation and showed good decoupling performance. However, they cannot ensure the steady operation during H-mod due to the load variation. Finally, the smooth position has been adopted for EAST I port antenna because of steady decoupling performance comprised with engineering error and load resilience, which sincerely enhance the capability of system operation.
Adaptive decoupled power control method for inverter connected DG
DEFF Research Database (Denmark)
Sun, Xiaofeng; Tian, Yanjun; Chen, Zhe
2014-01-01
an adaptive droop control method based on online evaluation of power decouple matrix for inverter connected distributed generations in distribution system. Traditional decoupled power control is simply based on line impedance parameter, but the load characteristics also cause the power coupling, and alter...
Optimal Temporal Decoupling in Task Scheduling with Preferences
Endhoven, L.; Klos, T.B.; Witteveen, C.
2011-01-01
Multi-agent planning and scheduling concerns finding a joint plan to achieve some set of common goals with several independent agents each aiming to find a plan or schedule for their part of the goals. To avoid conflicts in these individual plans or schedules decoupling is used. Such a decoupling
A new strategy for transient stability using augmented generator control and local dynamic braking
Energy Technology Data Exchange (ETDEWEB)
Dorsey, J; Jiang, H; Habetler, T [Georgia Inst. of Tech., Atlanta, GA (United States); Qu, Z [University of Central Florida, Orlando, FL (United States)
1994-12-31
A decentralized automatic control strategy for significantly improving the transient stability of a large power system is introduced. The strategy combines local dynamic braking and a straightforward augmentation of the existing turbine / governor control system that uses only local feedback. The brake resistor, which employs thick film, metal oxide technology, has no inductance and is of very low resistance, allowing its use during fault to show a generator`s acceleration. Simulation results using the 39 Bus New England system show that the strategy dramatically increases the global stability of a power system. (author) 15 refs., 7 figs., 1 tab.
Is Decoupling GDP Growth from Environmental Impact Possible?
Ward, James D; Sutton, Paul C; Werner, Adrian D; Costanza, Robert; Mohr, Steve H; Simmons, Craig T
2016-01-01
The argument that human society can decouple economic growth-defined as growth in Gross Domestic Product (GDP)-from growth in environmental impacts is appealing. If such decoupling is possible, it means that GDP growth is a sustainable societal goal. Here we show that the decoupling concept can be interpreted using an easily understood model of economic growth and environmental impact. The simple model is compared to historical data and modelled projections to demonstrate that growth in GDP ultimately cannot be decoupled from growth in material and energy use. It is therefore misleading to develop growth-oriented policy around the expectation that decoupling is possible. We also note that GDP is increasingly seen as a poor proxy for societal wellbeing. GDP growth is therefore a questionable societal goal. Society can sustainably improve wellbeing, including the wellbeing of its natural assets, but only by discarding GDP growth as the goal in favor of more comprehensive measures of societal wellbeing.
Reverse-time Migration in Tilted Transversely Isotropic Media with Decoupled Equations
Zhan, Ge
2012-12-01
benefit in cost saving of the new scheme, 2D and 3D RTM examples using the hybrid solution to the decoupled P-wave equation are carried out, and respective runtimes are listed and compared. Computation examples show that the hybrid strategy demands less computation time and is faster than using the pseudospectral method alone. Furthermore, this new hybrid TTI RTM algorithm is less computationally expensive than the FD solution to the conventional TTI coupled equations but more stable.
Poverty alleviation strategies in eastern China lead to critical ecological dynamics.
Zhang, Ke; Dearing, John A; Dawson, Terence P; Dong, Xuhui; Yang, Xiangdong; Zhang, Weiguo
2015-02-15
Poverty alleviation linked to agricultural intensification has been achieved in many regions but there is often only limited understanding of the impacts on ecological dynamics. A central need is to observe long term changes in regulating and supporting services as the basis for assessing the likelihood of sustainable agriculture or ecological collapse. We show how the analyses of 55 time-series of social, economic and ecological conditions can provide an evolutionary perspective for the modern Lower Yangtze River Basin region since the 1950s with powerful insights about the sustainability of modern ecosystem services. Increasing trends in provisioning ecosystem services within the region over the past 60 years reflect economic growth and successful poverty alleviation but are paralleled by steep losses in a range of regulating ecosystem services mainly since the 1980s. Increasing connectedness across the social and ecological domains after 1985 points to a greater uniformity in the drivers of the rural economy. Regime shifts and heightened levels of variability since the 1970s in local ecosystem services indicate progressive loss of resilience across the region. Of special concern are water quality services that have already passed critical transitions in several areas. Viewed collectively, our results suggest that the regional social-ecological system passed a tipping point in the late 1970s and is now in a transient phase heading towards a new steady state. However, the long-term relationship between economic growth and ecological degradation shows no sign of decoupling as demanded by the need to reverse an unsustainable trajectory. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.
Teunter, Ruud H.; Haneveld, Willem K. Klein
2008-01-01
We study inventory systems with two demand classes (critical and non-critical), Poisson demand and backordering. We analyze dynamic rationing strategies where the number of items reserved for critical demand depends on the remaining time until the next order arrives. Different from results in the
Static and Dynamic Pricing Strategies in a Closed-Loop Supply Chain with Reference Quality Effects
Directory of Open Access Journals (Sweden)
Zhichao Zhang
2018-01-01
Full Text Available Remanufacturing of returned products has been increasingly recognized in industries as an effective approach to face environmental responsibility, government regulations, and increased awareness of consumers. In this paper, we address a closed-loop supply chain (CLSC in which the manufacturer produces the brand-new products, as well as the remanufactured goods while the retailer sells these products to customers. We consider several different scenarios: the manufacturer and the retailer adopt a steady-state price or a dynamic price with reference quality effects in a centralized case; either, neither or both the manufacturer and the retailer price dynamically with reference quality effects, respectively, in a decentralized model. We solve the problem with the retailer recycling the sold copies and deduce the optimal pricing strategies while the manufacturer in charge of recovering the used items in such a CLSC. The result shows that dynamic pricing strategies are much more profitable for the supply chain and its members when compared with pricing statically; the dynamic pricing strategies with time-varying quality characterized by reference quality are more suited to a long-term and cooperative closed-loop supply chain. Moreover, the optimal recycling fraction relies on the recovery cost coefficient and proves to be uniform despite adopting a dynamic price and quality in all distinct cases.
Tomicic, Alemka; Martínez, Claudio; Pérez, J Carola; Hollenstein, Tom; Angulo, Salvador; Gerstmann, Adam; Barroux, Isabelle; Krause, Mariane
2015-01-01
This study seeks to provide evidence of the dynamics associated with the configurations of discourse-voice regulatory strategies in patient-therapist interactions in relevant episodes within psychotherapeutic sessions. Its central assumption is that discourses manifest themselves differently in terms of their prosodic characteristics according to their regulatory functions in a system of interactions. The association between discourse and vocal quality in patients and therapists was analyzed in a sample of 153 relevant episodes taken from 164 sessions of five psychotherapies using the state space grid (SSG) method, a graphical tool based on the dynamic systems theory (DST). The results showed eight recurrent and stable discourse-voice regulatory strategies of the patients and three of the therapists. Also, four specific groups of these discourse-voice strategies were identified. The latter were interpreted as regulatory configurations, that is to say, as emergent self-organized groups of discourse-voice regulatory strategies constituting specific interactional systems. Both regulatory strategies and their configurations differed between two types of relevant episodes: Change Episodes and Rupture Episodes. As a whole, these results support the assumption that speaking and listening, as dimensions of the interaction that takes place during therapeutic conversation, occur at different levels. The study not only shows that these dimensions are dependent on each other, but also that they function as a complex and dynamic whole in therapeutic dialog, generating relational offers which allow the patient and the therapist to regulate each other and shape the psychotherapeutic process that characterizes each type of relevant episode.
Dynamic performance analysis of permanent magnet contactor with a flux-weakening control strategy
Wang, Xianbing; Lin, Heyun; Fang, Shuhua; Jin, Ping; Wang, Junhua; Ho, S. L.
2011-04-01
A new flux-weakening control strategy for permanent magnet contactors is proposed. By matching the dynamic attraction force and the antiforce, the terminal velocity and collision energy of the movable iron in the closing process are significantly reduced. The movable iron displacement is estimated by detecting the closing voltage and current with the proposed control. A dynamic mathematical model is also established under four kinds of excitation scenarios. The attraction force and flux linkage are predicted by finite element method and the dynamics of the closing process is simulated using the 4th-order Runge-Kutta algorithm. Experiments are carried out on a 250A prototype with an intelligent control unit to verify the proposed control strategy.
Nygren, T E
1997-09-01
It is well documented that the way a static choice task is "framed" can dramatically alter choice behavior, often leading to observable preference reversals. This framing effect appears to result from perceived changes in the nature or location of a person's initial reference point, but it is not clear how framing effects might generalize to performance on dynamic decision making tasks that are characterized by high workload, time constraints, risk, or stress. A study was conducted to examine the hypothesis that framing can introduce affective components to the decision making process and can influence, either favorably (positive frame) or adversely (negative frame), the implementation and use of decision making strategies in dynamic high-workload environments. Results indicated that negative frame participants were significantly impaired in developing and employing a simple optimal decision strategy relative to a positive frame group. Discussion focuses on implications of these results for models of dynamic decision making.
Design and evaluation of dynamic replication strategies for a high-performance data grid
International Nuclear Information System (INIS)
Ranganathan, K.; Foster, I.
2001-01-01
Physics experiments that generate large amounts of data need to be able to share it with researchers around the world. High performance grids facilitate the distribution of such data to geographically remote places. Dynamic replication can be used as a technique to reduce bandwidth consumption and access latency in accessing these huge amounts of data. The authors describe a simulation framework that we have developed to model a grid scenario, which enables comparative studies of alternative dynamic replication strategies. The authors present preliminary results obtained with this simulator, in which we evaluate the performance of six different replication strategies for three different kinds of access patterns. The simulation results show that the best strategy has significant savings in latency and bandwidth consumption if the access patterns contain a moderate amount of geographical locality
DEFF Research Database (Denmark)
Dorn, Jochen
on Forex, interest rates and commodities. If an investor positions himself on the (volatility) market within a long/short trading framework, he typically bets on a traditional mispricing arbitrage. However as this corresponds to a call spread with equal exercise prices, this strategy alone would...
More or less-On the influence of labelling strategies to infer cell population dynamics.
Gabel, Michael; Regoes, Roland R; Graw, Frederik
2017-01-01
The adoptive transfer of labelled cell populations has been an essential tool to determine and quantify cellular dynamics. The experimental methods to label and track cells over time range from fluorescent dyes over congenic markers towards single-cell labelling techniques, such as genetic barcodes. While these methods have been widely used to quantify cell differentiation and division dynamics, the extent to which the applied labelling strategy actually affects the quantification of the dynamics has not been determined so far. This is especially important in situations where measurements can only be obtained at a single time point, as e.g. due to organ harvest. To this end, we studied the appropriateness of various labelling strategies as characterised by the number of different labels and the initial number of cells per label to quantify cellular dynamics. We simulated adoptive transfer experiments in systems of various complexity that assumed either homoeostatic cellular turnover or cell expansion dynamics involving various steps of cell differentiation and proliferation. Re-sampling cells at a single time point, we determined the ability of different labelling strategies to recover the underlying kinetics. Our results indicate that cell transition and expansion rates are differently affected by experimental shortcomings, such as loss of cells during transfer or sampling, dependent on the labelling strategy used. Furthermore, uniformly distributed labels in the transferred population generally lead to more robust and less biased results than non-equal label sizes. In addition, our analysis indicates that certain labelling approaches incorporate a systematic bias for the identification of complex cell expansion dynamics.
More or less-On the influence of labelling strategies to infer cell population dynamics.
Directory of Open Access Journals (Sweden)
Michael Gabel
Full Text Available The adoptive transfer of labelled cell populations has been an essential tool to determine and quantify cellular dynamics. The experimental methods to label and track cells over time range from fluorescent dyes over congenic markers towards single-cell labelling techniques, such as genetic barcodes. While these methods have been widely used to quantify cell differentiation and division dynamics, the extent to which the applied labelling strategy actually affects the quantification of the dynamics has not been determined so far. This is especially important in situations where measurements can only be obtained at a single time point, as e.g. due to organ harvest. To this end, we studied the appropriateness of various labelling strategies as characterised by the number of different labels and the initial number of cells per label to quantify cellular dynamics. We simulated adoptive transfer experiments in systems of various complexity that assumed either homoeostatic cellular turnover or cell expansion dynamics involving various steps of cell differentiation and proliferation. Re-sampling cells at a single time point, we determined the ability of different labelling strategies to recover the underlying kinetics. Our results indicate that cell transition and expansion rates are differently affected by experimental shortcomings, such as loss of cells during transfer or sampling, dependent on the labelling strategy used. Furthermore, uniformly distributed labels in the transferred population generally lead to more robust and less biased results than non-equal label sizes. In addition, our analysis indicates that certain labelling approaches incorporate a systematic bias for the identification of complex cell expansion dynamics.
Maintenance grouping strategy for multi-component systems with dynamic contexts
International Nuclear Information System (INIS)
Vu, Hai Canh; Do, Phuc; Barros, Anne; Bérenguer, Christophe
2014-01-01
This paper presents a dynamic maintenance grouping strategy for multi-component systems with both “positive” and “negative” economic dependencies. Positive dependencies are commonly due to setup cost whereas negative dependencies are related to shutdown cost. Actually, grouping maintenance activities can save part of the setup cost, but can also in the same time increase the shutdown cost. Until now, both types of dependencies have been jointly taken into account only for simple system structures as pure series. The first aim of this paper is to investigate the case of systems with any combination of basic structures (series, parallel or k-out-of n structures). A cost model and a heuristic optimization scheme are proposed since the optimization of maintenance grouping strategy for such multi-component systems leads to a NP-complete problem. Then the second objective is to propose a finite horizon (dynamic) model in order to optimize online the maintenance strategy in the presence of dynamic contexts (change of the environment, the working condition, the production process, etc). A numerical example of a 16-component system is finally introduced to illustrate the use and the advantages of the proposed approach in the maintenance optimization framework. - Highlights: • A dynamic grouping maintenance strategy for complex structure systems is proposed. • Impacts of the system structure on grouping maintenance are investigated. • A grouping approach based on the rolling horizon and GA algorithm is proposed. • Different dynamic contexts and their impacts on grouping maintenance are studied. • The proposed approach can help to update the maintenance planning in dynamic contexts
Effect of vaccination strategies on the dynamic behavior of epidemic spreading and vaccine coverage
International Nuclear Information System (INIS)
Cai, Chao-Ran; Wu, Zhi-Xi; Guan, Jian-Yue
2014-01-01
The transmission of infectious, yet vaccine-preventable, diseases is a typical complex social phenomenon, where the increasing level of vaccine update in the population helps to inhibit the epidemic spreading, which in turn, however, discourages more people to participate in vaccination campaigns, due to the “externality effect” raised by vaccination. We herein study the impact of vaccination strategies, pure, continuous (rather than adopt vaccination definitely, the individuals choose to taking vaccine with some probabilities), or continuous with randomly mutation, on the vaccination dynamics with a spatial susceptible-vaccinated-infected-recovered (SVIR) epidemiological model. By means of extensive Monte-Carlo simulations, we show that there is a crossover behavior of the final vaccine coverage between the pure-strategy case and the continuous-strategy case, and remarkably, both the final vaccination level and epidemic size in the continuous-strategy case are less than them in the pure-strategy case when vaccination is cheap. We explain this phenomenon by analyzing the organization process of the individuals in the continuous-strategy case in the equilibrium. Our results are robust to the SVIR dynamics defined on other spatial networks, like the Erdős–Rényi and Barabási–Albert networks
Reactive power and voltage control strategy based on dynamic and adaptive segment for DG inverter
Zhai, Jianwei; Lin, Xiaoming; Zhang, Yongjun
2018-03-01
The inverter of distributed generation (DG) can support reactive power to help solve the problem of out-of-limit voltage in active distribution network (ADN). Therefore, a reactive voltage control strategy based on dynamic and adaptive segment for DG inverter is put forward to actively control voltage in this paper. The proposed strategy adjusts the segmented voltage threshold of Q(U) droop curve dynamically and adaptively according to the voltage of grid-connected point and the power direction of adjacent downstream line. And then the reactive power reference of DG inverter can be got through modified Q(U) control strategy. The reactive power of inverter is controlled to trace the reference value. The proposed control strategy can not only control the local voltage of grid-connected point but also help to maintain voltage within qualified range considering the terminal voltage of distribution feeder and the reactive support for adjacent downstream DG. The scheme using the proposed strategy is compared with the scheme without the reactive support of DG inverter and the scheme using the Q(U) control strategy with constant segmented voltage threshold. The simulation results suggest that the proposed method has a significant improvement on solving the problem of out-of-limit voltage, restraining voltage variation and improving voltage quality.
A Dynamically Focusing Cochlear Implant Strategy Can Improve Vowel Identification in Noise.
Arenberg, Julie G; Parkinson, Wendy S; Litvak, Leonid; Chen, Chen; Kreft, Heather A; Oxenham, Andrew J
2018-03-09
The standard, monopolar (MP) electrode configuration used in commercially available cochlear implants (CI) creates a broad electrical field, which can lead to unwanted channel interactions. Use of more focused configurations, such as tripolar and phased array, has led to mixed results for improving speech understanding. The purpose of the present study was to assess the efficacy of a physiologically inspired configuration called dynamic focusing, using focused tripolar stimulation at low levels and less focused stimulation at high levels. Dynamic focusing may better mimic cochlear excitation patterns in normal acoustic hearing, while reducing the current levels necessary to achieve sufficient loudness at high levels. Twenty postlingually deafened adult CI users participated in the study. Speech perception was assessed in quiet and in a four-talker babble background noise. Speech stimuli were closed-set spondees in noise, and medial vowels at 50 and 60 dB SPL in quiet and in noise. The signal to noise ratio was adjusted individually such that performance was between 40 and 60% correct with the MP strategy. Subjects were fitted with three experimental strategies matched for pulse duration, pulse rate, filter settings, and loudness on a channel-by-channel basis. The strategies included 14 channels programmed in MP, fixed partial tripolar (σ = 0.8), and dynamic partial tripolar (σ at 0.8 at threshold and 0.5 at the most comfortable level). Fifteen minutes of listening experience was provided with each strategy before testing. Sound quality ratings were also obtained. Speech perception performance for vowel identification in quiet at 50 and 60 dB SPL and for spondees in noise was similar for the three tested strategies. However, performance on vowel identification in noise was significantly better for listeners using the dynamic focusing strategy. Sound quality ratings were similar for the three strategies. Some subjects obtained more benefit than others, with some
Exploring the dynamics of financial markets: from stock prices to strategy returns
International Nuclear Information System (INIS)
Borland, Lisa
2016-01-01
Exploring the dynamics of financial time-series is an exciting and interesting challenge because of the many truly complex interactions that underly the price formation process. In this contribution we describe some of the anomalous statistical features of such time-series and review models of the price dynamics both across time and across the universe of stocks. In particular we discuss a non-Gaussian statistical feedback process of stock returns which we have developed over the past years with the particular application of option pricing. We then discuss a cooperative model for the correlations of stock dynamics which has its roots in the field of synergetics, where numerical simulations and comparisons with real data are presented. Finally we present summarized results of an empirical analysis probing the dynamics of actual trading strategy return streams.
Ninomiya, Hitoshi; Nanerikawa, Susumu
Public procurement system such as Overall-Evaluation dynamically has been changed on local public works in Japan. However some characteristics of Bidding-Strategy and procurement system have not enough clarified. This paper attempt to analysis for a syatem dynamics and mechanisum of Overall-Evaluation by developing new simulation model focused on Bidding-Strategy, to propose some improvement scenario.
Credit Rating via Dynamic Slack-Based Measure And It´s Optimal Investment Strategy
Directory of Open Access Journals (Sweden)
A. Delavarkhalafi
2015-01-01
Full Text Available In this paper we check the credit rating of firms applied for a loan. In this regard we introduce a model, named Dynamic Slack-Based Measure (DSBM for measuring credit rating of applicant companies. Selection of financial ratios that represent the financial state of a company -in the best possible way- is one of the most challenging parts of any credit rating analysis. At first, ranking needs to identify the appropriate variables. Therefore we introduce five financial variables to provide a ranking. As noted above, we assess the performance of these firms. Then we introduce the dynamic model of SBM and theorems, also we discuss the overall structure of DSBM. Then we will present the implementation and the simulation model. After that, we propose a stochastic controlled dynamic system model to express the optimal strategy. Banks expect companies selected with DSBM model, act in accordance with this strategy. This stochastic dynamic system is originated from the balance sheets of firms applying for a loan. Finally we evaluate the performance of the system and strategy problem.
Decoupling of heavy quarks in quantum chromodynamics
International Nuclear Information System (INIS)
Bernreuther, W.
1983-01-01
Decoupling of heavy quarks in quantum chromodynamics (QCD) defined by mass-independent renormalization is investigated. The structure of the relations between the parameters of f flavour QCD below a heavy-quark threshold is discussed to all orders in the loop expansion, and the relations are computed to two-loop approximation for the minimal subtraction schemes (MS) and to one-loop approximation for some Weinberg schemes. These matching relations can be used to systematically determine the renormalization group (RG)-invariant parameters of the effective theory in terms of the RG-invariant parameters of the theory which includes the heavy quark, or vice versa. For MS scheme the connection between Λ/sub f/-1 and Λ/sub f/ to two and three loops is given as well as the two-loop connection between the RG-invariant mass parameters of the f-1 and f flavour theory. The effect of heavy quarks on the evolution of the QCQ coupling is of significance for present QCD phenomenology based on next-to-leading-order perturbation theory. This is illustrated with a few examples within the MS scheme
Hedge Funds and Risk-Decoupling
DEFF Research Database (Denmark)
Ringe, Georg
2013-01-01
The law must remain adaptive and responsive to the constantly changing challenges of our society and our business life. One of the most pressing challenges of the past years is the emergence of alternative investment funds, in particular hedge funds, which masterfully exploit the traditional cate...... to the traditional market expectations of shareholders. Based on the insight developed from these policy perspectives, this article develops regulatory reform proposals, particularly with regard to the EU context.......The law must remain adaptive and responsive to the constantly changing challenges of our society and our business life. One of the most pressing challenges of the past years is the emergence of alternative investment funds, in particular hedge funds, which masterfully exploit the traditional...... theoretical perspectives are used as an analytical framework to examine the vast challenges of risk-decoupling: (1) a classical agency costs approach; (2) an information costs perspective; and (3) a view from corporate finance. This Article argues that shareholders with hedged risk exposure do not correspond...
International Nuclear Information System (INIS)
Sutrisno; Widowati; Solikhin
2016-01-01
In this paper, we propose a mathematical model in stochastic dynamic optimization form to determine the optimal strategy for an integrated single product inventory control problem and supplier selection problem where the demand and purchasing cost parameters are random. For each time period, by using the proposed model, we decide the optimal supplier and calculate the optimal product volume purchased from the optimal supplier so that the inventory level will be located at some point as close as possible to the reference point with minimal cost. We use stochastic dynamic programming to solve this problem and give several numerical experiments to evaluate the model. From the results, for each time period, the proposed model was generated the optimal supplier and the inventory level was tracked the reference point well. (paper)
Berchoux, Tristan; Hutton, Craig; Watmough, Gary; Amoako Johnson, Fiifi; Atkinson, Peter
2017-04-01
With population increase and the urbanisation of rural areas, land scarcity is one of the biggest challenges now faced by communities in agrarian societies. At the household level, loss of land can be due to physical processes such as erosion, to social constraints such as inheritance, or to financial constraints such as loan reimbursement or the need of cash. For rural households, whose livelihoods are mainly based on agriculture, a decrease in the area of land cultivated can have significant consequences on their livelihood strategies, thus on their livelihood outcomes. However, it is still unclear how changes in cultivated area and agricultural productivity influence households' livelihood systems, including community capitals and households' livelihood strategies. This study aims to answer this gap by combining together earth observation from space, national census and participatory qualitative data into a community-wise analysis of the relationships between land cover dynamics, variability in agricultural production and livelihood activities. Its overarching aim is to investigate how land cover dynamics relates to changes in livelihood strategies and livelihood capitals. The study demonstrates that a change in land cover influences livelihood activities differently depending on the community capitals that households have access to. One significant aspect of integrating land dynamics with livelihood activities is its capacity to provide insights on the relationships between climate, agriculture, livelihood dynamics and rural development. More broadly, it gives policymakers new methods to characterise livelihood dynamics, thus to monitor some of the key Sustainable Development Goals: food security (SDG2), employment dynamics (SDG8), inequalities (SDG10) and sustainability of communities (SDG11).
The dynamics of a Beddington-type system with impulsive control strategy
International Nuclear Information System (INIS)
Li Zhenqing; Wang Weiming; Wang Hailing
2006-01-01
In this paper, by using the theories and methods of ecology and ordinary differential equation, a prey-predator system with Beddington-type functional response and impulsive control strategy is established. Conditions for the system to be extinct are given by using the theories of impulsive equation and small amplitude perturbation skills. It is proved that the system is permanent via the method of comparison involving multiple Liapunov functions. Furthermore, by using the method of numerical simulation, the influence of the impulsive control strategy on the inherent oscillation are investigated, which shows rich dynamics, such as period doubling bifurcation, crises, symmetry-breaking pitchfork bifurcations, chaotic bands, quasi-periodic oscillation, narrow periodic window, wide periodic window, period-halving bifurcation, etc. That will be useful for study of the dynamic complexity of ecosystems
A Dynamic Simulation Model of Organizational Culture and Business Strategy Effects on Performance
Trivellas, Panagiotis; Reklitis, Panagiotis; Konstantopoulos, Nikolaos
2007-12-01
In the past two decades, organizational culture literature has gained tremendous interest for both academic and practitioners. This is based not only on the suggestion that culture is related to performance, but also on the view that it is subject of direct managerial control and manipulation to the desired direction. In the present paper, we adopt Competing Values Framework (CVF) to operationalise organizational culture and Porter's typology to conceptualize business strategy (cost leadership, innovative and marketing differentiation, and focus). Although simulation of social events is a quite difficult task, since there are so many considerations (not all well understood) involved, in the present study we developed a dynamic model to simulate the organizational culture and strategy effects on financial performance. Data obtained from a six-year survey in the banking sector of a European developing economy was used for the proposed dynamic model development.
Supercritical water gasification with decoupled pressure and heat transfer modules
Dibble, Robert W.; Ng, Kim Choon; Sarathy, Mani
2017-01-01
decouples the function of containing high pressure from the high temperature function. The present invention allows the heat transfer function to be conducted independently from the pressure transfer function such that the system equipment can be designed
Studies of spatial decoupling in heterogeneous LMFBR critical assemblies
International Nuclear Information System (INIS)
Brumbach, S.B.; Goin, R.W.; Carpenter, S.G.
1984-01-01
Recent measurements at the Zero Power Plutonium Reactor have studied the spatial decoupling in large, heterogeneous assemblies. These assemblies exhibited a significantly greater degree of decoupling than previous homogeneous assemblies of similar size. The flux distributions in these heterogeneous assemblies were very sensitive reactivity perturbations, and perturbed flux distributions were achieved relatively slowly. Decoupling was investigated using rod-drop, boron-oscillator and noise-coherence techniques which emphasized different times following the perturbations. Reactivity changes could be measured by analyzing the power history from a single detector using inverse kinetics methods with the assumption of an instantaneous efficiency change for the detector. For assemblies more decoupled than ZPPR-13, the instantaneous efficiency change assumption begins to be invalid
Efficiency of Decoupled Farm Programs under Distortionary Taxation
GianCarlo Moschini; Paolo Sckokai
1994-01-01
When lump-sum taxation is not feasible, decoupled transfers to farmers (which require raising government revenue) will entail welfare loss somewhere in the economy. Assuming the government's objective is to assure a given welfare level for farmers, we show that when decoupling is possible, free trade is always superior to some tariff protection for a small country, even under Distortionary taxation. As expected, for a large country there is scope for an optimal tariff policy that improves the...
Directory of Open Access Journals (Sweden)
Alemka eTomicic
2015-04-01
Full Text Available This study seeks to provide evidence of the dynamics associated with the configurations of discourse-voice regulatory strategies in patient-therapist interactions in relevant episodes within psychotherapeutic sessions. Its central assumption is that discourses manifest themselves differently in terms of their prosodic characteristics according to their regulatory functions in a system of interactions. The association between discourse and vocal quality in patients and therapists was analyzed in a sample of 153 relevant episodes taken from 164 sessions of five psychotherapies using the State Space Grid (SSG method, a graphical tool based on the Dynamic Systems Theory (DST. The results showed eight recurrent and stable discourse-voice regulatory strategies of the patients and three of the therapists. Also, four specific groups of these discourse-voice strategies were identified. The latter were interpreted as regulatory configurations, that is to say, as emergent self-organized groups of discourse-voice regulatory strategies constituting specific interactional systems. Both regulatory strategies and their configurations differed between two types of relevant episodes: Change Episodes and Rupture Episodes. As a whole, these results support the assumption that speaking and listening, as dimensions of the interaction that takes place during therapeutic conversation, occur at different levels. The study not only shows that these dimensions are dependent on each other, but also that they function as a complex and dynamic whole in therapeutic dialogue, generating relational offers which allow the patient and the therapist to regulate each other and shape the psychotherapeutic process that characterizes each type of relevant episode.
Effects of fundamentals acquisition and strategy switch on stock price dynamics
Wu, Songtao; He, Jianmin; Li, Shouwei
2018-02-01
An agent-based artificial stock market is developed to simulate trading behavior of investors. In the market, acquisition and employment of information about fundamentals and strategy switch are investigated to explain stock price dynamics. Investors could obtain the information from both market and neighbors resided on their social networks. Depending on information status and performances of different strategies, an informed investor may switch to the strategy of fundamentalist. This in turn affects the information acquisition process, since fundamentalists are more inclined to search and spread the information than chartists. Further investigation into price dynamics generated from three typical networks, i.e. regular lattice, small-world network and random graph, are conducted after general relation between network structures and price dynamics is revealed. In each network, integrated effects of different combinations of information efficiency and switch intensity are investigated. Results have shown that, along with increasing switch intensity, market and social information efficiency play different roles in the formation of price distortion, standard deviation and kurtosis of returns.
Energy Technology Data Exchange (ETDEWEB)
Azar, Christian; Holmberg, John; Karlsson, Sten [Chalmers Univ. of Tech., Goeteborg (SE). Physical Resource Theory] [and others
2002-05-01
There are widespread demands in society for a dematerialization or decoupling of economic growth from environmental impact. Calls are being made for eco-efficiency and/or an improvement of resource efficiency by a factor of 10. At the same time, some analysts claim there is an environmental Kuznet's curve that supposedly implies a fall in environmental pressure, as we get richer. An improvement in the environmental situation has already been observed in many cases, but there are also many areas where the situation is deteriorating. The purpose of this report is to summarize some key trends of energy and material use over time in both developing and developed countries. We have focused on Sweden, the EU, Japan and the USA as well as China, India and Brazil. The main findings in this paper can be summarized as follows: Absolute emissions of CO{sub 2} have been increasing in most countries and periods studied. Some countries have experienced periods with constant or even falling emissions, but this is the exception rather than the rule, and it has been triggered by oil crises or economic recessions. In order to stabilize atmospheric CO{sub 2} concentrations, CO{sub 2} emissions have to be decoupled much more rapidly than has been the case in the past, and it is extremely unlikely that this will happen by itself. There was some decoupling of CO{sub 2} emissions from GDP in the major economies of the world from 1970 to 1998 in the EU, Japan and the US as well as in some major developing countries such as China, although India actually increased its emissions over GDP by 1.4 per cent/yr over this period. The drop in CO{sub 2} intensity has been prompted by some decoupling of energy from GDP and CO{sub 2} from energy, the latter being a consequence of an increased use of natural gas and nuclear power. In the South, fossil CO 2 per energy tends to increase from rather low levels. With industrialization, the proportion of biomass drops and the proportion of fossil
Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach
Goddek, Simon; Espinal, Carlos; Delaide, Boris; Jijakli, Mohamed; Schmautz, Zala; Wuertz, Sven; Keesman, Karel
2016-01-01
The classical working principle of aquaponics is to provide nutrient-rich aquacultural water to a hydroponic plant culture unit, which in turn depurates the water that is returned to the aquaculture tanks. A known drawback is that a compromise away from optimal growing conditions for plants and fish
Dynamic route guidance strategy in a two-route pedestrian-vehicle mixed traffic flow system
Liu, Mianfang; Xiong, Shengwu; Li, Bixiang
2016-05-01
With the rapid development of transportation, traffic questions have become the major issue for social, economic and environmental aspects. Especially, during serious emergencies, it is very important to alleviate road traffic congestion and improve the efficiency of evacuation to reduce casualties, and addressing these problems has been a major task for the agencies responsible in recent decades. Advanced road guidance strategies have been developed for homogeneous traffic flows, or to reduce traffic congestion and enhance the road capacity in a symmetric two-route scenario. However, feedback strategies have rarely been considered for pedestrian-vehicle mixed traffic flows with variable velocities and sizes in an asymmetric multi-route traffic system, which is a common phenomenon in many developing countries. In this study, we propose a weighted road occupancy feedback strategy (WROFS) for pedestrian-vehicle mixed traffic flows, which considers the system equilibrium to ease traffic congestion. In order to more realistic simulating the behavior of mixed traffic objects, the paper adopted a refined and dynamic cellular automaton model (RDPV_CA model) as the update mechanism for pedestrian-vehicle mixed traffic flow. Moreover, a bounded rational threshold control was introduced into the feedback strategy to avoid some negative effect of delayed information and reduce. Based on comparisons with the two previously proposed strategies, the simulation results obtained in a pedestrian-vehicle traffic flow scenario demonstrated that the proposed strategy with a bounded rational threshold was more effective and system equilibrium, system stability were reached.
Inflation Protected Investment Strategies
Directory of Open Access Journals (Sweden)
Mirco Mahlstedt
2016-03-01
Full Text Available In this paper, a dynamic inflation-protected investment strategy is presented, which is based on traditional asset classes and Markov-switching models. Different stock market, as well as inflation regimes are identified, and within those regimes, the inflation hedging potential of stocks, bonds, real estate, commodities and gold are investigated. Within each regime, we determine optimal investment portfolios driven by the investment idea of protection from losses due to changing inflation if inflation is rising or high, but decoupling the performance from inflation if inflation is low. The results clearly indicate that these asset classes behave differently in different stock market and inflation regimes. Whereas in the long-run, we agree with the general opinion in the literature that stocks and bonds are a suitable hedge against inflation, we observe for short time horizons that the hedging potential of each asset class, especially of real estate and commodities, depend strongly on the state of the current market environment. Thus, our approach provides a possible explanation for different statements in the literature regarding the inflation hedging properties of these asset classes. A dynamic inflation-protected investment strategy is developed, which combines inflation protection and upside potential. This strategy outperforms standard buy-and-hold strategies, as well as the well-known 1 N -portfolio.
Efficiency Evaluation of Strategies for Dynamic Management of Wireless Sensor Networks
Directory of Open Access Journals (Sweden)
Andrea Verônica González
2017-01-01
Full Text Available This paper presents and evaluates dynamic management strategies to improve efficiency in event-triggered wireless sensor networks. We are considering mobility, where nodes move themselves to maximize the coverage, and load balancing state-of-the-art techniques, by which the number of nodes sensing the same area is reduced. To explore mobility, we present a simple method by which nodes can dynamically reorganize themselves based on the force fields approach of mobile robotics. Firstly, the strategies are evaluated separately through experiments with different network configurations and, afterwards, a joint evaluation has been conducted to observe the impact of mobility on the efficiency of load balancing techniques. We show that mobile nodes significantly contribute to keeping the coverage as nodes die in mesh and powerfully improving it in random deployments. Load balancing techniques achieve important results, increasing lifetime and the number of sensed events. However, in random deployments, these techniques lose efficiency and become unsuitable strategies. Combining these strategies with mobility, we observe that PS-based technique keeps its contribution in mesh and random deployments, as well as improving its performance for not so dense networks. Ant-based technique when combined with mobile nodes loses performance significantly in mesh and keeps its good performance in random deployed and less dense networks.
Modular Estimation Strategy of Vehicle Dynamic Parameters for Motion Control Applications
Directory of Open Access Journals (Sweden)
Rawash Mustafa
2018-01-01
Full Text Available The presence of motion control or active safety systems in vehicles have become increasingly important for improving vehicle performance and handling and negotiating dangerous driving situations. The performance of such systems would be improved if combined with knowledge of vehicle dynamic parameters. Since some of these parameters are difficult to measure, due to technical or economic reasons, estimation of those parameters might be the only practical alternative. In this paper, an estimation strategy of important vehicle dynamic parameters, pertaining to motion control applications, is presented. The estimation strategy is of a modular structure such that each module is concerned with estimating a single vehicle parameter. Parameters estimated include: longitudinal, lateral, and vertical tire forces – longitudinal velocity – vehicle mass. The advantage of this strategy is its independence of tire parameters or wear, road surface condition, and vehicle mass variation. Also, because of its modular structure, each module could be later updated or exchanged for a more effective one. Results from simulations on a 14-DOF vehicle model are provided here to validate the strategy and show its robustness and accuracy.
Two-Stage Dynamic Pricing and Advertising Strategies for Online Video Services
Directory of Open Access Journals (Sweden)
Zhi Li
2017-01-01
Full Text Available As the demands for online video services increase intensively, the selection of business models has drawn the great attention of online providers. Among them, pay-per-view mode and advertising mode are two important resource modes, where the reasonable fee charge and suitable volume of ads need to be determined. This paper establishes an analytical framework studying the optimal dynamic pricing and advertising strategies for online providers; it shows how the strategies are influenced by the videos available time and the viewers’ emotional factor. We create the two-stage strategy of revenue models involving a single fee mode and a mixed fee-free mode and find out the optimal fee charge and advertising level of online video services. According to the results, the optimal video price and ads volume dynamically vary over time. The viewer’s aversion level to advertising has direct effects on both the volume of ads and the number of viewers who have selected low-quality content. The optimal volume of ads decreases with the increase of ads-aversion coefficient, while increasing as the quality of videos increases. The results also indicate that, in the long run, a pure fee mode or free mode is the optimal strategy for online providers.
A Dynamic Optimization Strategy for the Operation of Large Scale Seawater Reverses Osmosis System
Directory of Open Access Journals (Sweden)
Aipeng Jiang
2014-01-01
Full Text Available In this work, an efficient strategy was proposed for efficient solution of the dynamic model of SWRO system. Since the dynamic model is formulated by a set of differential-algebraic equations, simultaneous strategies based on collocations on finite element were used to transform the DAOP into large scale nonlinear programming problem named Opt2. Then, simulation of RO process and storage tanks was carried element by element and step by step with fixed control variables. All the obtained values of these variables then were used as the initial value for the optimal solution of SWRO system. Finally, in order to accelerate the computing efficiency and at the same time to keep enough accuracy for the solution of Opt2, a simple but efficient finite element refinement rule was used to reduce the scale of Opt2. The proposed strategy was applied to a large scale SWRO system with 8 RO plants and 4 storage tanks as case study. Computing result shows that the proposed strategy is quite effective for optimal operation of the large scale SWRO system; the optimal problem can be successfully solved within decades of iterations and several minutes when load and other operating parameters fluctuate.
Complex dynamics and bifurcation analysis of host–parasitoid models with impulsive control strategy
International Nuclear Information System (INIS)
Yang, Jin; Tang, Sanyi; Tan, Yuanshun
2016-01-01
Highlights: • We develop novel host-parasitoid models with impulsive control strategy. • The effects of key parameters on the successful control have been addressed. • The complex dynamics and related biological significance are investigated. • The results between two types of host-parasitoid models have been discussed. - Abstract: In this paper, we propose and analyse two type host–parasitoid models with integrated pest management (IPM) interventions as impulsive control strategies. For fixed pulsed model, the threshold condition for the global stability of the host-eradication periodic solution is provided, and the effects of key parameters including the impulsive period, proportionate killing rate, instantaneous search rate, releasing constant, survival rate and the proportionate release rate on the threshold condition are discussed. Then latin hypercube sampling /partial rank correlation coefficients are used to carry out sensitivity analyses to determine the significance of each parameters. Further, bifurcation analyses are presented and the results show that coexistence of attractors existed for a wide range of parameters, and the switch-like transitions among these attractors indicate that varying dosages and frequencies of insecticide applications and numbers of parasitoid released are crucial for IPM strategy. For unfixed pulsed model, the results show that this model exists very complex dynamics and the host population can be controlled below ET, and it implies that the modelling methods are helpful for improving optimal strategies to design appropriate IPM.
Ding, Fei; Liu, Yun; Li, Yong
In this paper, a new model of opinion formation within the framework of evolutionary game theory is presented. The model simulates strategic situations when people are in opinion discussion. Heterogeneous agents adjust their behaviors to the environment during discussions, and their interacting strategies evolve together with opinions. In the proposed game, we take into account payoff discount to join a discussion, and the situation that people might drop out of an unpromising game. Analytical and emulational results show that evolution of opinion and strategy always tend to converge, with utility threshold, memory length, and decision uncertainty parameters influencing the convergence time. The model displays different dynamical regimes when we set differently the rule when people are at a loss in strategy.
Research on verification and validation strategy of detonation fluid dynamics code of LAD2D
Wang, R. L.; Liang, X.; Liu, X. Z.
2017-07-01
The verification and validation (V&V) is an important approach in the software quality assurance of code in complex engineering application. Reasonable and efficient V&V strategy can achieve twice the result with half the effort. This article introduces the software-Lagrangian adaptive hydrodynamics code in 2D space (LAD2D), which is self-developed software in detonation CFD with plastic-elastic structure. The V&V strategy of this detonation CFD code is presented based on the foundation of V&V methodology for scientific software. The basic framework of the module verification and the function validation is proposed, composing the detonation fluid dynamics model V&V strategy of LAD2D.
Research on Control Strategy of Free-Piston Stirling Power Generating System
Directory of Open Access Journals (Sweden)
Jigui Zheng
2017-10-01
Full Text Available As a clean and fuel adaptive alternative power plant, the Stirling power generating system has drawn attention of experts and scholars in the energy field. In practical application, the instability of free-piston Stirling power generating system caused by abrupt load change is an inevitable problem. Thus, methods to improve the output frequency response and stability of the free-piston Stirling power generating system are necessary. The model of free-piston Stirling power generating system is built by isothermal analysis firstly, and the initial control strategy based on given voltage system is put forward. To further improve the performance of power system, a current feedback decoupling control strategy is proposed, and the mathematical model is established. The influence of full decoupled quadrature-direct (d-q axis currents is analyzed with respect to the output voltage adjusting time and fluctuation amplitude under the variations of piston displacement and output load. The simulation results show that the system performance is significantly improved, but the dynamic regulation lags caused by the decoupled current control still exist. To solve this problem and improve the performance of decoupled-state feedback current control that relies on parameter accuracy, internal model control based on sliding mode (IMC-SM current decoupling control strategy is proposed, the system model is established, and then the performance of voltage ripple in generating mode is improved. Finally, the test bench is built, and the steady state and transient voltage control performances are tested. The feasibility and priority of the control strategy is verified by experiment and simulation results.
"Sometimes, I feel a bit decoupled"
DEFF Research Database (Denmark)
Nortvig, Anne Mette
2015-01-01
. These categories were developed with respect to the ways the teaching strategies include or relate to the e-learning space in the physical part of the videoconference classroom. The study found a distancing strategy which was employed in order to focus activities in the physical classroom and keep......This paper is about videoconference interaction and teaching strategies. On the basis of participant observation and detailed video analyses of videoconference teaching, this paper lists three different categories that were employed in a professional bachelor’s programme in physiotherapy...... the videoconference space at a distance; an appendixing strategy which linked the e-learning space to the physical one by the use of specific technology, communication form and time; and an annexing strategy which related to both the physical space and the e-learners’ space and coupled the two spaces by very frequent...
Guan, Xiangmin; Zhang, Xuejun; Wei, Jian; Hwang, Inseok; Zhu, Yanbo; Cai, Kaiquan
2016-07-01
Conflict avoidance plays a crucial role in guaranteeing the safety and efficiency of the air traffic management system. Recently, the strategic conflict avoidance (SCA) problem has attracted more and more attention. Taking into consideration the large-scale flight planning in a global view, SCA can be formulated as a large-scale combinatorial optimisation problem with complex constraints and tight couplings between variables, which is difficult to solve. In this paper, an SCA approach based on the cooperative coevolution algorithm combined with a new decomposition strategy is proposed to prevent the premature convergence and improve the search capability. The flights are divided into several groups using the new grouping strategy, referred to as the dynamic grouping strategy, which takes full advantage of the prior knowledge of the problem to better deal with the tight couplings among flights through maximising the chance of putting flights with conflicts in the same group, compared with existing grouping strategies. Then, a tuned genetic algorithm (GA) is applied to different groups simultaneously to resolve conflicts. Finally, the high-quality solutions are obtained through cooperation between different groups based on cooperative coevolution. Simulation results using real flight data from the China air route network and daily flight plans demonstrate that the proposed algorithm can reduce the number of conflicts and the average delay effectively, outperforming existing approaches including GAs, the memetic algorithm, and the cooperative coevolution algorithms with different well-known grouping strategies.
Coupled vs. decoupled boundary layers in VOCALS-REx
Directory of Open Access Journals (Sweden)
C. R. Jones
2011-07-01
Full Text Available We analyze the extent of subtropical stratocumulus-capped boundary layer decoupling and its relation to other boundary-layer characteristics and forcings using aircraft observations from VOCALS-REx along a swath of the subtropical southeast Pacific Ocean running west 1600 km from the coast of Northern Chile. We develop two complementary and consistent measures of decoupling. The first is based on boundary layer moisture and temperature stratification in flight profiles from near the surface to above the capping inversion, and the second is based the difference between the lifted condensation level (LCL and a mean lidar-derived cloud base measured on flight legs at 150 m altitude. Most flights took place during early-mid morning, well before the peak in insolation-induced decoupling.
We find that the boundary layer is typically shallower, drier, and well mixed near the shore, and tends to deepen, decouple, and produce more drizzle further offshore to the west. Decoupling is strongly correlated to the "mixed layer cloud thickness", defined as the difference between the capping inversion height and the LCL; other factors such as wind speed, cloud droplet concentration, and inversion thermodynamic jumps have little additional explanatory power. The results are broadly consistent with the deepening-warming theory of decoupling.
In the deeper boundary layers observed well offshore, there was frequently nearly 100 % boundary-layer cloud cover despite pronounced decoupling. The cloud cover was more strongly correlated to a κ parameter related to the inversion jumps of humidity and temperature, though the exact functional relation is slightly different than found in prior large-eddy simulation studies.
The role of grazer predation strategies in the dynamics of consumer-resource based ecological models
Cropp, Roger; Moroz, Irene; Norbury, John
2017-07-01
We analyse a simple plankton system to provide a heuristic for more complex models such as Dynamic Green Ocean Models (DGOMs). Zooplankton foraging is either by generalist grazers that consume whatever they bump into or specialist grazers that actively seek particular prey. The zooplankton may further be classified as either facultative grazers that can survive on any of their prey or obligate grazers that depend on the presence of specific prey. A key result is that different prey dependencies can result in dramatically different impacts of grazing strategies on system outcomes. The grazing strategy can determine whether a system with obligate grazers will be stable, have regular, predictable cycles or be chaotic. Conversely, whether facultative zooplankton functioned as specialist or generalist grazers makes no qualitative difference to the dynamics of the system. These results demonstrate that the effect of different grazing strategies can be critically dependent on the grazer's dependency on specific prey. Great care must be taken when choosing functional forms for population interactions in DGOMs, particularly in scenarios such as climate change where parameters such as mortality and growth coefficients may change. A robust theoretical framework supporting model development and analysis is key to understanding how such choices can affect model properties and hence predictions.
Energy Technology Data Exchange (ETDEWEB)
Rouse, M.J.
2000-07-01
The demand for corporate responsiveness to environmental and social concerns, more specifically the requirement for public participation/consultation with stakeholders is, according to industry insiders, one of the most pressing changes for the oil industry. For this study, data on a public consultation process involving Syncrude Canada Limited, Alberta Environmental Protection, and the Alberta Energy and Utilities Board was collected through a combination of public hearing transcripts, participant observation, interview methodologies and reports. >From the perspective of organizational strategy, stakeholder relations, institutional theory and organizational cultures, the author investigated the public consultation process. Strategic action was the central theme to emerge through the findings. Positioning strategies influenced by stakeholder status from the organization's viewpoint and stakeholder relationships informed by the network of stakeholder relationships are included in stakeholder dynamics. The management of organizational culture and the creation of an institutional field to generate and maintain values across the relational field of focal organizations, and reduce costs and conflicts, are included in strategic outcomes. The elaboration and extension of components of stakeholder and institutional theories are part of further results, as well as an integrated understanding of the dynamic interconnectedness of organizational cultures, strategies and stakeholders in an environmental public consultation process.
State Feedback Decoupling with In-Loop Lead Compensator in Stand-Alone VSIs
DEFF Research Database (Denmark)
Federico, de Bosio; Pastorelli, Michele; de Sousa Ribeiro, Luiz Antonio
2016-01-01
The performance of current and voltage regulators during transients and steady-state is of primary concern for power converters intended for stand-alone applications. Dynamics performance and command tracking capability are enhanced by actively decoupling the controlled states variables. To further...... widen the current loop bandwidth while still preserving a well-damped system a lead compensator structure on the forward loop is proposed. A 3 kHz bandwidth with 0.707 damping factor is achieved for the inner current controller. Accordingly, also the voltage regulator bandwidth can be widen, thus...
Evaluating Decoupling Process in OECD Countries: Case Study of Turkey
An, Nazan; Şengün Ucal, Meltem; Kurnaz, M. Levent
2017-04-01
Climate change is at the top of the present and future problems facing humanity. Climate change is now largely attributed to human activities and economic activities are the source of human activities that cause climate change by creating pressure on the environment. Providing the sustainability of resources for the future seems possible by reducing the pressure of these economic activities on the environment. Given the increasing population pressure and growth-focused economies, it is possible to say that achieving decoupling is not so easy on a global basis. It is known that there are some problems in developing countries especially in terms of accessing reliable data in transition and implementation process of decoupling. Developed countries' decoupling practices and proper calculation methods can also be a guide for developing countries. In this study, we tried to calculate the comparative decoupling index for OECD countries and Turkey in terms of data suitability, and we showed the differences between them. We tried to indicate the level of decoupling (weak, stable, strong) for each country. We think that the comparison of Turkey can be an example in terms of developing countries. Acknowledgement: This research has been supported by Bogazici University Research Fund Grant Number 12220.
A dynamic re-partitioning strategy based on the distribution of key in Spark
Zhang, Tianyu; Lian, Xin
2018-05-01
Spark is a memory-based distributed data processing framework, has the ability of processing massive data and becomes a focus in Big Data. But the performance of Spark Shuffle depends on the distribution of data. The naive Hash partition function of Spark can not guarantee load balancing when data is skewed. The time of job is affected by the node which has more data to process. In order to handle this problem, dynamic sampling is used. In the process of task execution, histogram is used to count the key frequency distribution of each node, and then generate the global key frequency distribution. After analyzing the distribution of key, load balance of data partition is achieved. Results show that the Dynamic Re-Partitioning function is better than the default Hash partition, Fine Partition and the Balanced-Schedule strategy, it can reduce the execution time of the task and improve the efficiency of the whole cluster.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Gyro's fault diagnosis plays a critical role in inertia navigation systems for higher reliability and precision. A new fault diagnosis strategy based on the statistical parameter analysis (SPA) and support vector machine(SVM) classification model was proposed for dynamically tuned gyroscopes (DTG). The SPA, a kind of time domain analysis approach, was introduced to compute a set of statistical parameters of vibration signal as the state features of DTG, with which the SVM model, a novel learning machine based on statistical learning theory (SLT), was applied and constructed to train and identify the working state of DTG. The experimental results verify that the proposed diagnostic strategy can simply and effectively extract the state features of DTG, and it outperforms the radial-basis function (RBF) neural network based diagnostic method and can more reliably and accurately diagnose the working state of DTG.
International Nuclear Information System (INIS)
Zhao-Bing, Liu; Hua-Guang, Zhang; Qiu-Ye, Sun
2010-01-01
This paper considers the global stability of controlling an uncertain complex network to a homogeneous trajectory of the uncoupled system by a local pinning control strategy. Several sufficient conditions are derived to guarantee the network synchronisation by investigating the relationship among pinning synchronisation, network topology, and coupling strength. Also, some fundamental and yet challenging problems in the pinning control of complex networks are discussed: (1) what nodes should be selected as pinned candidates? (2) How many nodes are needed to be pinned for a fixed coupling strength? Furthermore, an adaptive pinning control scheme is developed. In order to achieve synchronisation of an uncertain complex network, the adaptive tuning strategy of either the coupling strength or the control gain is utilised. As an illustrative example, a network with the Lorenz system as node self-dynamics is simulated to verify the efficacy of theoretical results. (general)
Are Human and Natural Systems Decoupling?
Ehrlich, P. R.; Ehrlich, A. H.
2012-12-01
trivial financial problems currently facing rich nations. Financial coverage in the media is massive compared to, say, the news that Earth's coral reefs are now beyond saving. Or consider the utter failure of most social scientists to come to grips with the inability of civilization to develop mechanisms to deal with global environmental problems, or of the persistence of an economic system based on unrealistic academic models and the preposterous notion that growth can continue forever. Whether mutually beneficial human-nature coupling can be restored in time is an open question. Doubtless grassroots action would be required, as well as new institutions/mechanisms for coordinating bottom-up and top-down efforts. There are many hopeful small-scale recoupling efforts such as the Natural Capital Project (http://www.naturalcapitalproject.org/) to protect biodiversity and ecosystem services, deployment of renewable energy systems in many countries, and work to unite academics and civil society in developing the necessary foresight intelligence, as in the Millennium Alliance for Humanity and the Biosphere (MAHB - http://mahb.stanford.edu/). Bottom-up efforts such as Occupy Wall Street (http://occupywallst.org/), the Movement to Solve the Climate Crisis (http://www.350.org/), and many other civil society groups are gaining some traction. But time is short, and in our view decoupling is winning.
International Nuclear Information System (INIS)
Porteus, E.
1982-01-01
The study of infinite-horizon nonstationary dynamic programs using the operator approach is continued. The point of view here differs slightly from that taken by others, in that Denardo's local income function is not used as a starting point. Infinite-horizon values are defined as limits of finite-horizon values, as the horizons get long. Two important conditions of an earlier paper are weakened, yet the optimality equations, the optimality criterion, and the existence of optimal ''structured'' strategies are still obtained
Directory of Open Access Journals (Sweden)
Lorenzo Peppoloni
Full Text Available The Strength-Dexterity (SD test measures the ability of the pulps of the thumb and index finger to compress a compliant and slender spring prone to buckling at low forces (<3N. We know that factors such as aging and neurodegenerative conditions bring deteriorating physiological changes (e.g., at the level of motor cortex, cerebellum, and basal ganglia, which lead to an overall loss of dexterous ability. However, little is known about how these changes reflect upon the dynamics of the underlying biological system. The spring-hand system exhibits nonlinear dynamical behavior and here we characterize the dynamical behavior of the phase portraits using attractor reconstruction. Thirty participants performed the SD test: 10 young adults, 10 older adults, and 10 older adults with Parkinson's disease (PD. We used delayed embedding of the applied force to reconstruct its attractor. We characterized the distribution of points of the phase portraits by their density (number of distant points and interquartile range and geometric features (trajectory length and size. We find phase portraits from older adults exhibit more distant points (p = 0.028 than young adults and participants with PD have larger interquartile ranges (p = 0.001, trajectory lengths (p = 0.005, and size (p = 0.003 than their healthy counterparts. The increased size of the phase portraits with healthy aging suggests a change in the dynamical properties of the system, which may represent a weakening of the neural control strategy. In contrast, the distortion of the attractor in PD suggests a fundamental change in the underlying biological system, and disruption of the neural control strategy. This ability to detect differences in the biological mechanisms of dexterity in healthy and pathological aging provides a simple means to assess their disruption in neurodegenerative conditions and justifies further studies to understand the link with the physiological changes.
Ueno, Kazuhide; Angell, C Austen
2011-12-08
To support a new interpretation of the origin of the dynamic heterogeneity observed pervasively in fragile liquids as they approach their glass transition temperatures T(g), we demonstrate that the introduction of ~2 nm structural inhomogeneities into a homogeneous glass former leads to a decoupling of diffusion from viscosity similar to that observed during the cooling of orthoterphenyl (OTP) below T(A,) where Arrhenius behavior is lost. Further, the decoupling effect grows stronger as temperature decreases (and viscosity increases). The liquid is cresol, and the ~2 nm inhomogeneities are cresol-soluble asymmetric derivatized tetrasiloxy-based (polyhedral oligomeric silsesquioxane (POSS)) molecules. The decoupling is the phenomenon predicted by Onsager in discussing the approach to a liquid-liquid phase separation with decreasing temperature. In the present case the observations support the notion of a polyamorphic transition in fragile liquids that is hidden below the glass transition. A similar decoupling can be expected as a globular protein is dissolved in dilute aqueous solutions or in protic ionic liquids. © 2011 American Chemical Society
Decoupled Closed-Form Solution for Humanoid Lower Limb Kinematics
Directory of Open Access Journals (Sweden)
Alejandro Said
2015-01-01
Full Text Available This paper presents an explicit, omnidirectional, analytical, and decoupled closed-form solution for the lower limb kinematics of the humanoid robot NAO. The paper starts by decoupling the position and orientation analysis from the overall Denavit-Hartenberg (DH transformation matrices. Here, the joint activation sequence for the DH matrices is based on the geometry of a triangle. Furthermore, the implementation of a forward and a reversed kinematic analysis for the support and swing phase equations is developed to avoid matrix inversion. The allocation of constant transformations allows the position and orientation end-coordinate systems to be aligned with each other. Also, the redefinition of the DH transformations and the use of constraints allow decoupling the shared DOF between the legs and the torso. Finally, a geometric approach to avoid the singularities during the walking process is indicated. Numerical data is presented along with an experimental implementation to prove the validity of the analytical results.
Introduction to geometric nonlinear control; Linearization, observability, decoupling
Energy Technology Data Exchange (ETDEWEB)
Respondek, W [Laboratoire de Mathematiques, INSA de Rouen (France)
2002-07-15
These notes are devoted to the problems of linearization, observability, and decoupling of nonlinear control systems. Together with notes of Bronislaw Jakubczyk in the same volume, they form an introduction to geometric methods in nonlinear control theory. In the first part we discuss equivalence of control systems. We consider various aspects of the problem: state-space and feedback equivalence, local and global equivalence, equivalence to linear and partially linear systems. In the second part we present the notion of observability and give a geometric rank condition for local observability and an algebraic characterization of local observability. We discuss unm observability, decompositions of non-observable systems, and properties of generic observable systems. In the third part we introduce the notion of invariant distributions and discuss disturbance decoupling and input-output decoupling. Many concepts and results are illustrated with examples. (author)
M. Pieterse-Bloem (Mary); W.F.C. Verschoor (Willem); Z. Qian (Zhaowen); R.C.J. Zwinkels (Remco)
2017-01-01
textabstractIn this paper, we propose a dynamic portfolio strategy for European corporate bonds based on a two-factor pricing model. We introduce a strategy in which we forecast both future factors as well as bonds' future exposure to these factor. Using a unique dataset that is representative for
A closer look at non-decoupling D-Terms
Staub, Florian
2016-01-01
Non-Decoupling D-Terms are an attractive possibility to enhance the tree-level mass of the standard model like Higgs boson in supersymmetric models. We discuss here for the case of a new Abelian gauge group two effects usually neglected in literature: (i) the size of the additional radiative corrections to the Higgs mass due to the presence of the new gauge coupling, and (ii) the impact of gauge kinetic mixing. It is shown that both effects reduce to some extent the positive effect of the non-decoupling D-terms on the Higgs mass.
A closer look at non-decoupling D-terms
Directory of Open Access Journals (Sweden)
Florian Staub
2016-07-01
Full Text Available Non-decoupling D-terms are an attractive possibility to enhance the tree-level mass of the standard model like Higgs boson in supersymmetric models. We discuss here for the case of a new Abelian gauge group two effects usually neglected in literature: (i the size of the additional radiative corrections to the Higgs mass due to the presence of the new gauge coupling, and (ii the impact of gauge kinetic mixing. It is shown that both effects reduce to some extent the positive effect of the non-decoupling D-terms on the Higgs mass.
Late kinetic decoupling of light magnetic dipole dark matter
International Nuclear Information System (INIS)
Gondolo, Paolo; Kadota, Kenji
2016-01-01
We study the kinetic decoupling of light (≲10 GeV) magnetic dipole dark matter (DM). We find that present bounds from collider, direct DM searches, and structure formation allow magnetic dipole DM to remain in thermal equilibrium with the early universe plasma until as late as the electron-positron annihilation epoch. This late kinetic decoupling leads to a minimal mass for the earliest dark protohalos of thousands of solar masses, in contrast to the conventional weak scale DM scenario where they are of order 10 −6 solar masses.
Dynamical principles of cell-cycle arrest: Reversible, irreversible, and mixed strategies
Pfeuty, Benjamin
2012-08-01
Living cells often alternate between proliferating and nonproliferating states as part of individual or collective strategies to adapt to complex and changing environments. To this aim, they have evolved a biochemical regulatory network enabling them to switch between cell-division cycles (i.e., oscillatory state) and cell-cycle arrests (i.e., steady state) in response to extracellular cues. This can be achieved by means of a variety of bifurcation mechanisms that potentially give rise to qualitatively distinct cell-cycle arrest properties. In this paper, we study the dynamics of a minimal biochemical network model in which a cell-division oscillator and a differentiation switch mutually antagonize. We identify the existence of three biologically plausible bifurcation scenarios organized around a codimension-four swallowtail-homoclinic singularity. As a result, the model exhibits a broad repertoire of cell-cycle arrest properties in terms of reversibility of these arrests, tunability of interdivision time, and ability to track time-varying signals. This dynamic versatility would explain the diversity of cell-cycle arrest strategies developed in different living species and functional contexts.
Competitive marketing strategies: tools for enhancing value in the dynamic world of business
Directory of Open Access Journals (Sweden)
Ph. D. Kehinde Oladele Joseph
2011-05-01
Full Text Available Developing solid competitive marketing strategies in order to contribute towards long-term sustainable success, has become imperative today for every success driven organization. The paper examines a number of Competitive Strategies, whitch have become string tools for enhancing value in the Nigerian Telecommunication industry.Thr objectives of the paper among others are to (iExamine whether there is any relationship between the use ao competitive marketing strategies and business success and(ii Find out whether the various competitive marketing strategies used by Nigerian telecommunication firms have effects on rival companies, among others.The paper uses survey method with two hypotheses stated in the null form, with structured questionnaire,which were,distributed among the sampled respondents who are secondary school teachers in Lagos, Ogun, and Oyo states of Nigeria.Results were analyzed with the aid of correlation test statistics.Findings show that there is significant positive relationship between the use of competitive Marketing Strategies and Business Success.Finding also reveals that the various Competitive Strategiea used by players have effects on other competitors. The paper makesvarious policy recommendtions,which operators in the Nigerian Telecomunication Industry will find useful, if faithfully implemented. These include the need for firms to constantly engage in research to meet the changing needs of their esteemed Customers. Companies must identify where they could have competitive advantage over their Competitors and that Companies must render quality Service and try to constantly improve their offers in the face of changing market Dynamics, amongst others.
Dynamic strategy and sustainable business development: lessons learned from the crisis
Directory of Open Access Journals (Sweden)
Jarmila Šebestová
2013-01-01
Full Text Available Each adaptation in business is an impulse to change and may cause unexpected behaviour inside or outside the company. This article aims to present an innovative thinking bond and investment success in overcoming the crisis, based on the results of the research carried out. From knowledge of current methods of management and business management services in general it can be inferred that the enterprise can develop an open system that is capable of rapidly adapting to positive and negative external influences. Which interactions support the dynamics and adaptability of the strategy in a positive way? As a contribution to the literature, the paper will highlight which elements have the biggest influence on the flexibility of business and which items are the most important for sustainable behaviour in an uncertain and turbulent environment. In this survey (twice observed groups, the main aim is to identify the effect of investment on innovation, strategy preparation and the relationship between financial ratios and company performance. The survey of this study was conducted with owners and managers of small and medium size businesses in the Czech Republic (under 250 employees operating between the years 2007–2012. The main goal of this paper is, based on the literature review, to provide a practical model of adaptation. Research methodology, analyses results and research models will take place in the second section. The results of the analyses will be discussed and recommendations will be provided in the last section. The QRBITS analysis is presented as a special tool for analyzing the business environment and resources. Finally, a model of dynamic entrepreneurship is presented as a combination of factors which generate the final effectiveness of strategy implementation.
Investment Strategy on the Zagreb Stock Exchange Based on Dynamic DEA
Directory of Open Access Journals (Sweden)
Tihana Škrinjarić
2014-04-01
Full Text Available Nowadays, there is a growing interest in the application of quantitative methods in portfolio management, as the results of their application can be used as guidelines for managing a successful investment portfolio, i.e., a portfolio that outperforms the market. This paper deals with the Data Envelopment Analysis (DEA approach and a Dynamic Slacks-Based Measure as a method of forming a portfolio which would predominantly outperform the market. In order to test the strategy, data on stocks listed on the Zagreb Stock Exchange were gathered for the period April 2009 – June 2012. Using the quarterly returns, standard deviations and coefficients of skewness as links, a dynamic slacks-based measure approach was applied to evaluate the relative efficiency of stocks in each quarter. The findings indicate that a portfolio based on the results of the optimization beats the market in terms of both returns and risk. This is the first implementation of the dynamic DEA model in stock trading. The results suggest that it is superior to basic DEA models.
Search strategy in a complex and dynamic environment (the Indian Ocean case)
Loire, Sophie; Arbabi, Hassan; Clary, Patrick; Ivic, Stefan; Crnjaric-Zic, Nelida; Macesic, Senka; Crnkovic, Bojan; Mezic, Igor; UCSB Team; Rijeka Team
2014-11-01
The disappearance of Malaysia Airlines Flight 370 (MH370) in the early morning hours of 8 March 2014 has exposed the disconcerting lack of efficient methods for identifying where to look and how to look for missing objects in a complex and dynamic environment. The search area for plane debris is a remote part of the Indian Ocean. Searches, of the lawnmower type, have been unsuccessful so far. Lagrangian kinematics of mesoscale features are visible in hypergraph maps of the Indian Ocean surface currents. Without a precise knowledge of the crash site, these maps give an estimate of the time evolution of any initial distribution of plane debris and permits the design of a search strategy. The Dynamic Spectral Multiscale Coverage search algorithm is modified to search a spatial distribution of targets that is evolving with time following the dynamic of ocean surface currents. Trajectories are generated for multiple search agents such that their spatial coverage converges to the target distribution. Central to this DSMC algorithm is a metric for the ergodicity.
Dynamic electro-thermal modeling of all-vanadium redox flow battery with forced cooling strategies
International Nuclear Information System (INIS)
Wei, Zhongbao; Zhao, Jiyun; Xiong, Binyu
2014-01-01
Highlights: • A dynamic electro-thermal model is proposed for VRB with forced cooling. • The Foster network is adopted to model the battery cooling process. • Both the electrolyte temperature and terminal voltage can be accurately predicted. • The flow rate of electrolyte and coolant significantly impact battery performance. - Abstract: The present study focuses on the dynamic electro-thermal modeling for the all-vanadium redox flow battery (VRB) with forced cooling strategies. The Foster network is adopted to dynamically model the heat dissipation of VRB with heat exchangers. The parameters of Foster network are extracted by fitting the step response of it to the results of linearized CFD model. Then a complete electro-thermal model is proposed by coupling the heat generation model, Foster network and electrical model. Results show that the established model has nearly the same accuracy with the nonlinear CFD model in electrolyte temperature prediction but drastically improves the computational efficiency. The modeled terminal voltage is also benchmarked with the experimental data under different current densities. The electrolyte temperature is found to be significantly influenced by the flow rate of coolant. As compared, although the electrolyte flow rate has unremarkable impact on electrolyte temperature, its effect on system pressure drop and battery efficiency is significant. Increasing the electrolyte flow rate improves the coulombic efficiency, voltage efficiency and energy efficiency simultaneously but at the expense of higher pump power demanded. An optimal flow rate exists for each operating condition to maximize the system efficiency
Application of optimal control strategies to HIV-malaria co-infection dynamics
Fatmawati; Windarto; Hanif, Lathifah
2018-03-01
This paper presents a mathematical model of HIV and malaria co-infection transmission dynamics. Optimal control strategies such as malaria preventive, anti-malaria and antiretroviral (ARV) treatments are considered into the model to reduce the co-infection. First, we studied the existence and stability of equilibria of the presented model without control variables. The model has four equilibria, namely the disease-free equilibrium, the HIV endemic equilibrium, the malaria endemic equilibrium, and the co-infection equilibrium. We also obtain two basic reproduction ratios corresponding to the diseases. It was found that the disease-free equilibrium is locally asymptotically stable whenever their respective basic reproduction numbers are less than one. We also conducted a sensitivity analysis to determine the dominant factor controlling the transmission. sic reproduction numbers are less than one. We also conducted a sensitivity analysis to determine the dominant factor controlling the transmission. Then, the optimal control theory for the model was derived analytically by using Pontryagin Maximum Principle. Numerical simulations of the optimal control strategies are also performed to illustrate the results. From the numerical results, we conclude that the best strategy is to combine the malaria prevention and ARV treatments in order to reduce malaria and HIV co-infection populations.
Application of a New Dynamic Heating System Model Using a Range of Common Control Strategies
Directory of Open Access Journals (Sweden)
Joshua Fong
2016-06-01
Full Text Available This research investigates the overall heating energy consumptions using various control strategies, secondary heat emitters, and primary plant for a building. Previous research has successfully demonstrated that a dynamic distributed heat emitter model embedded within a simplified third-order lumped parameter building model is capable of achieving improved results when compared to other commercially available modelling tools. With the enhanced ability to capture transient effects of emitter thermal capacity, this research studies the influence of control strategies and primary plant configurations on the rate of energy consumption of a heating system. Four alternative control strategies are investigated: zone feedback; weather-compensated; a combination of both of these methods; and thermostatic control. The plant alternative configurations consist of conventional boilers, biomass boilers, and heat pumps supporting radiator heating and underfloor heating. The performance of the model is tested on a primary school building and can be applied to any residential or commercial building with a heating system. Results show that the new methods reported offer greater detail and rigor in the conduct of building energy modelling.
Dynamic Modeling Strategy for Flow Regime Transition in Gas-Liquid Two-Phase Flows
Directory of Open Access Journals (Sweden)
Xia Wang
2012-12-01
Full Text Available In modeling gas-liquid two-phase flows, the concept of flow regimes has been widely used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are flow regime dependent. Current nuclear reactor safety analysis codes, such as RELAP5, classify flow regimes using flow regime maps or transition criteria that were developed for steady-state, fully-developed flows. As two-phase flows are dynamic in nature, it is important to model the flow regime transitions dynamically to more accurately predict the two-phase flows. The present work aims to develop a dynamic modeling strategy to determine flow regimes in gas-liquid two-phase flows through introduction of interfacial area transport equations (IATEs within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation of the interfacial area, fluid particle (bubble or liquid droplet disintegration, boiling and evaporation, and the destruction of the interfacial area, fluid particle coalescence and condensation. For flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shapes, namely group-1 and group-2 bubbles. A preliminary approach to dynamically identify the flow regimes is discussed, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration. The flow regime predicted with this method shows good agreement with the experimental observations.
Natural relations and Appelquist-Carazzone decoupling theorem
International Nuclear Information System (INIS)
Grzadkowski, B.; Krawczyk, P.; Pokorski, S.
1984-01-01
It is pointed out that in some cases violation of the Appelquist-Carazzone decoupling theorem in spontaneously broken gauge theories is related to the presence in such theories of the so-called natural zeroth-order relations. In this context heavy-fermion effects in the Glashow-Salam-Weinberg model are discussed
Decoupled systems on trial: Eliminating bottlenecks to improve aquaponic processes.
Directory of Open Access Journals (Sweden)
Hendrik Monsees
Full Text Available In classical aquaponics (coupled aquaponic systems, 1-loop systems the production of fish in recirculating aquaculture systems (RAS and plants in hydroponics are combined in a single loop, entailing systemic compromises on the optimal production parameters (e.g. pH. Recently presented decoupled aquaponics (2-loop systems have been awarded for eliminating major bottlenecks. In a pilot study, production in an innovative decoupled aquaponic system was compared with a coupled system and, as a control, a conventional RAS, assessing growth parameters of fish (FCR, SGR and plants over an experimental period of 5 months. Soluble nutrients (NO3--N, NO2--N, NH4+-N, PO43-, K+, Ca2+, Mg2+, SO42-, Cl2- and Fe2+, elemental composition of plants, fish and sludge (N, P, K, Ca, Mg, Na, C, abiotic factors (temperature, pH, oxygen, and conductivity, fertilizer and water consumption were determined. Fruit yield was 36% higher in decoupled aquaponics and pH and fertilizer management was more effective, whereas fish production was comparable in both systems. The results of this pilot study clearly illustrate the main advantages of decoupled, two-loop aquaponics and demonstrate how bottlenecks commonly encountered in coupled aquaponics can be managed to promote application in aquaculture.
Decoupled systems on trial: Eliminating bottlenecks to improve aquaponic processes.
Monsees, Hendrik; Kloas, Werner; Wuertz, Sven
2017-01-01
In classical aquaponics (coupled aquaponic systems, 1-loop systems) the production of fish in recirculating aquaculture systems (RAS) and plants in hydroponics are combined in a single loop, entailing systemic compromises on the optimal production parameters (e.g. pH). Recently presented decoupled aquaponics (2-loop systems) have been awarded for eliminating major bottlenecks. In a pilot study, production in an innovative decoupled aquaponic system was compared with a coupled system and, as a control, a conventional RAS, assessing growth parameters of fish (FCR, SGR) and plants over an experimental period of 5 months. Soluble nutrients (NO3--N, NO2--N, NH4+-N, PO43-, K+, Ca2+, Mg2+, SO42-, Cl2- and Fe2+), elemental composition of plants, fish and sludge (N, P, K, Ca, Mg, Na, C), abiotic factors (temperature, pH, oxygen, and conductivity), fertilizer and water consumption were determined. Fruit yield was 36% higher in decoupled aquaponics and pH and fertilizer management was more effective, whereas fish production was comparable in both systems. The results of this pilot study clearly illustrate the main advantages of decoupled, two-loop aquaponics and demonstrate how bottlenecks commonly encountered in coupled aquaponics can be managed to promote application in aquaculture.
Non-decoupling of heavy scalars in cosmology
Hardeman, Sjoerd Reimer
2012-01-01
The theory describing physics at the highest energy scales likely contains extra dimensions, whose internal degrees of freedom result in many massive field and particles. At accelerator experiments these fields and particles generally decouple from the low energy physics. However, in cosmology
Do 'green' taxes work? Decoupling environmental pressures and economic growth
DEFF Research Database (Denmark)
Andersen, Mikael Skou
2005-01-01
This essay intends to shed light on whether environmental taxation can help to decouple environmental pressures from economic growth, a policy outcome widely desired and particularly pressing in the context of climate change where radical measures are needed to curb CO2 build up....
Decoupling among CSR policies, programs, and impacts : An empirical study
Graafland, Johan; Smid, Hugo
2016-01-01
There are relatively few empirical studies on the impacts of corporate social responsibility (CSR) policies and programs. This article addresses the research gap by analyzing the incidence of, and the conditions that affect, decoupling (defined as divergence) among CSR policies, implementation of
Active power decoupling with reduced converter stress for single ...
Indian Academy of Sciences (India)
SUJATA BHOWMICK
Department of Electronic Systems Engineering, Indian Institute of Science, ... Single phase; double-frequency ripple; active power decoupling; reduced stress; ... sation of renewable energy sources (e.g., PV), potential ... In standard grid connected DC/AC H-bridge configuration, ..... solar inverter with reduced-size dc link.
A decoupling approach to classical data transmission over quantum channels
DEFF Research Database (Denmark)
Dupont-Dupuis, Fréderic; Szehr, Oleg; Tomamichel, Marco
2014-01-01
be solved this way, one of the most basic coding problems remains impervious to a direct application of this method, sending classical information through a quantum channel. We will show that this problem can, in fact, be solved using decoupling ideas, specifically by proving a dequantizing theorem, which...
State policy change: Revenue decoupling in the electricity market
McNeil, Kytson L.
The study seeks to answer the question, why are states adopting revenue decoupling in the electricity market, by investigating the relationship between policy adoption and attributes of the electricity market, the structure of the state utility commissions, and the political climate of the state. The study examines the period 1978-2008. Two econometric models, the marginal risk set model and the conditional risk set model, are estimated to predict the influence of covariates on the probability of the state adopting revenue decoupling in the electricity market. The models are both variants of the Cox proportional hazard model and use different underlying assumptions about the nature of adoption of revenue decoupling and when the states are considered to be at risk of adoption. Results suggest that market attributes, such as the source of electricity generation in the state, state energy intensity, and the distribution of non-public and public utilities, significantly influence the adoption of the policy. Also, the method of selecting commissioners and the party affiliation of elected officials in the state are important factors. The study concludes by suggestions to improve the implementation and evaluation of revenue decoupling in the electricity markets.
Pagano, Alessandro; Pluchinotta, Irene; Giordano, Raffaele; Vurro, Michele
2016-04-01
Resilience has recently become a key concept, and a crucial paradigm in the analysis of the impacts of natural disasters, mainly concerning Lifeline Systems (LS). Indeed, the traditional risk management approaches require a precise knowledge of all potential hazards and a full understanding of the interconnections among different infrastructures, based on past events and trends analysis. Nevertheless, due to the inner complexity of LS, their interconnectedness and the dynamic context in which they operate (i.e. technology, economy and society), it is difficult to gain a complete comprehension of the processes influencing vulnerabilities and threats. Therefore, resilience thinking addresses the complexities of large integrated systems and the uncertainty of future threats, emphasizing the absorbing, adapting and responsive behavior of the system. Resilience thinking approaches are focused on the capability of the system to deal with the unforeseeable. The increasing awareness of the role played by LS, has led governmental agencies and institutions to develop resilience management strategies. Risk prone areas, such as cities, are highly dependent on infrastructures providing essential services that support societal functions, safety, economic prosperity and quality of life. Among the LS, drinking water supply is critical for supporting citizens during emergency and recovery, since a disruption could have a range of serious societal impacts. A very well-known method to assess LS resilience is the TOSE approach. The most interesting feature of this approach is the integration of four dimensions: Technical, Organizational, Social and Economic. Such issues are all concurrent to the resilience level of an infrastructural system, and should be therefore quantitatively assessed. Several researches underlined that the lack of integration among the different dimensions, composing the resilience concept, may contribute to a mismanagement of LS in case of natural disasters
Directory of Open Access Journals (Sweden)
Febriyanto
2015-08-01
Full Text Available This research is conducted to examine the influence of market attractiveness and dynamic capability on strategic competitive response through overall logistics strategies of logistics service providers LSPs. Involving 266 LSPs SEM-LISREL is applied to test the hypotheses. The findings reveal that the market attractiveness and the dynamic capability positively affect the overall logistics strategy. Additionally the market attractiveness and the dynamic capability positively affect the strategic competitive response. Indirectly the market attractiveness and the dynamic capability positively affect the performance through strategic competitive response of LSPs. Obviously overall logistics strategy strengthen the influence of both market attractiveness and dynamic capability on strategic competitive response. There are five alternatives to optimize the overall logistics strategy of LSPs market intensification integration focus collaboration and strengthening value proposition. The involvement of overall logistics strategy as mediating variable is new paradigm in the strategic management discourses especially in logistics industry. Further research needs to be performed by involving the size of business as control variable and LSPs perception on Governments policies.
Unmasking decoupling: Redefining the Resource Intensity of the Economy.
Bithas, Kostas; Kalimeris, Panos
2018-04-01
Interest in investigating the complex link between resources and developments has revived recently following studies which support striking "dematerialized" growth over the last hundred years or so. This so-called decoupling effect is defined as the declining quantity of resources required for producing one unit of GDP. Decoupling studies adopt aggregate GDP as the measure of the outcome of the economy. However, this outcome is contributed by the total population which differs over time and between countries. A valid comparison should use a comparable, standardized indicator that adjusts for population size. GDP per capita, the income index, defines in monetary terms the ultimate outcome of the economy and is adopted by international organizations as the standard index for comparing economies. The income index approximates, in monetary terms, the welfare produced by the economic system and enjoyed by individuals. Recently developed alternative indexes of welfare lack broad data coverage and have limited empirical application as yet. For this reason and for ensuring direct comparison with the standard decoupling estimates, our study remains within the monetary context. The present paper re-evaluates the resources-economy link from the perspective of "the resources required for the production of one unit of GDP per capita (Income)" and hence evaluates the efficiency of turning resources into the actual outcome of the economic system. Our estimates suggest that the dependence of global economic growth on natural resources has increased by over 60% in the last 110years (1900-2009), contrasting with the prevailing decoupling estimates which suggest a reduction by 63%. We find that the actual decoupling, which began in the mid-1970s in post-industrial economies, is counterbalanced by the intensified resource intensity of several developing economies. Accordingly, in the pursuit of sustainability, the dematerialization target needs to be more clearly incorporated into
JACoW Decoupling CERN accelerators
Dworak, Andrzej
2018-01-01
The accelerator complex at CERN is a living system. Accelerators are being dismantled, upgraded or change their purpose. New accelerators are built. The changes do not happen overnight, but when they happen they may require profound changes across the handling systems. Central timings (CT), responsible for sequencing and synchronization of accelerators, are good examples of such systems. This paper shows how over the past twenty years the changes and new requirements influenced the evolution of the CTs. It describes experience gained from using the Central Beam and Cycle Manager (CBCM) CT model, for strongly coupled accelerators, and how it led to a design of a new Dynamic Beam Negotiation (DBN) model for the AD and ELENA accelerators, which reduces the coupling, increasing accelerator independence. The paper ends with an idea how to merge strong points of both models in order to create a single generic system able to efficiently handle all CERN accelerators and provide more beam time to experiments and LHC.
Li, Ping; Jiang, Li Jun; Bagci, Hakan
2017-01-01
In this paper, a discontinuous Galerkin time-domain (DGTD) method is developed to analyze the power-ground planes taking into account the decoupling capacitors. In the presence of decoupling capacitors, the whole physical system can be split
Dynamic Modeling and Control Strategy Optimization for a Hybrid Electric Tracked Vehicle
Directory of Open Access Journals (Sweden)
Hong Wang
2015-01-01
Full Text Available A new hybrid electric tracked bulldozer composed of an engine generator, two driving motors, and an ultracapacitor is put forward, which can provide high efficiencies and less fuel consumption comparing with traditional ones. This paper first presents the terramechanics of this hybrid electric tracked bulldozer. The driving dynamics for this tracked bulldozer is then analyzed. After that, based on analyzing the working characteristics of the engine, generator, and driving motors, the power train system model and control strategy optimization is established by using MATLAB/Simulink and OPTIMUS software. Simulation is performed under a representative working condition, and the results demonstrate that fuel economy of the HETV can be significantly improved.
DEFF Research Database (Denmark)
Andersen, Maj Munch; Sandén, Björn A.; Palmberg, Christopher
This project analyzes Nordic trends in the development and industrial uptake of green nanotechno-logy in construction. The project applies an evolutionary economic perspective in analyzing the innovation dynamics and firm strategies in the window value chains in three Nordic countries, Denmark......, Finland and Sweden. Hence the project investigates two pervasive parallel market trends: The emergence of the green market and the emergence of nanotechnology. The analysis investigates how a traditional economic sector such as the construction sector reacts to such major trends. Conclusions are multiple...... of nanotechnology in the construction sector in the Nordic countries we do find quite a high number of nanotech applications in the Nordic window chains. Eco-innovation is influencing strongly on the nanotech development. We see several examples of nano-enabled smart, multifunctional green solutions in the Nordic...
DEFF Research Database (Denmark)
Andersen, Maj Munch
2010-01-01
This project analyzes Nordic trends in the development and industrial uptake of green nanotechno-logy in construction. The project applies an evolutionary economic perspective in analyzing the innovation dynamics and firm strategies in the window value chains in three Nordic countries, Denmark......, Finland and Sweden. Hence the project investigates two pervasive parallel market trends: The emergence of the green market and the emergence of nanotechnology. The analysis investigates how a traditional economic sector such as the construction sector reacts to such major trends. Conclusions are multiple...... of nanotechnology in the construction sector in the Nordic countries we do find quite a high number of nanotech applications in the Nordic window chains. Eco-innovation is influencing strongly on the nanotech development. We see several examples of nano-enabled smart, multifunctional green solutions in the Nordic...
Energy Technology Data Exchange (ETDEWEB)
Breazeale, K. [ed.; Isaak, D.T.; Yamaguchi, N.; Fridley, D.; Johnson, C.; Long, S.
1993-12-01
This report in the Hawaii Energy Strategy Project examines world and regional fossil energy dynamics. The topics of the report include fossil energy characteristics, the world oil industry including reserves, production, consumption, exporters, importers, refining, products and their uses, history and trends in the global oil market and the Asia-Pacific market; world gas industry including reserves, production, consumption, exporters, importers, processing, gas-based products, international gas market and the emerging Asia-Pacific gas market; the world coal industry including reserves, classification and quality, utilization, transportation, pricing, world coal market, Asia-Pacific coal outlook, trends in Europe and the Americas; and environmental trends affecting fossil fuels. 132 figs., 46 tabs.
International Nuclear Information System (INIS)
Ciborowski, J.; Dixon, G.; Foote, L.; Liber, K.; Smits, J.
2010-01-01
This abstract provided details of the Carbon Dynamics, Food Web Structure and Reclamation Strategies in Athabasca Oil Sands Wetlands (CFRAW) program, a collaboration between oil sands industry partners and university laboratories. CFRAW researchers are investigating the effects of mine tailings and process waters on the development, health, and function of wetland communities in post-mining landscapes. The aim of the program is to accurately predict how quickly the reclaimed wetlands will approach conditions seen in reference wetland systems. The program is also examining the effects of hydrocarbons as a surrogate source of carbon after they are metabolized by bacteria. The biological uptake, pathways, and movement through the food web of materials used by the biota in constructed wetlands are also being studied. Flux estimates will be used to determine if wetlands amended with peat will maintain their productivity. A conceptual model of carbon pathways and budgets is also being developed.
Hoyos Velasco, Fredy Edimer; García, Nicolás Toro; Garcés Gómez, Yeison Alberto
In this paper, the output voltage of a buck power converter is controlled by means of a quasi-sliding scheme. The Fixed Point Inducting Control (FPIC) technique is used for the control design, based on the Zero Average Dynamics (ZAD) strategy, including load estimation by means of the Least Mean Squares (LMS) method. The control scheme is tested in a Rapid Control Prototyping (RCP) system based on Digital Signal Processing (DSP) for dSPACE platform. The closed loop system shows adequate performance. The experimental and simulation results match. The main contribution of this paper is to introduce the load estimator by means of LMS, to make ZAD and FPIC control feasible in load variation conditions. In addition, comparison results for controlled buck converter with SMC, PID and ZAD-FPIC control techniques are shown.
Directory of Open Access Journals (Sweden)
Guitao Zhang
2014-01-01
Full Text Available The advertisement can increase the consumers demand; therefore it is one of the most important marketing strategies in the operations management of enterprises. This paper aims to analyze the impact of advertising investment on a discrete dynamic supply chain network which consists of suppliers, manufactures, retailers, and demand markets associated at different tiers under random demand. The impact of advertising investment will last several planning periods besides the current period due to delay effect. Based on noncooperative game theory, variational inequality, and Lagrange dual theory, the optimal economic behaviors of the suppliers, the manufactures, the retailers, and the consumers in the demand markets are modeled. In turn, the supply chain network equilibrium model is proposed and computed by modified project contraction algorithm with fixed step. The effectiveness of the model is illustrated by numerical examples, and managerial insights are obtained through the analysis of advertising investment in multiple periods and advertising delay effect among different periods.
Vortex-strings in N=2 SQCD and bulk-string decoupling
Gerchkovitz, Efrat; Karasik, Avner
2018-02-01
We study vortex-strings in four-dimensional N=2 supersymmetric SU( N c ) × U(1) gauge theories with N f hypermultiplets in the fundamental representation of SU( N c ) and general U(1) charges. If N f > N c , the vacuum is not gapped and the low-energy theory contains both the vacuum massless excitations and the string zero-modes. The question we address in this work is whether the vacuum and the string moduli decouple at low energies, allowing a description of the low-energy dynamics in terms of a two-dimensional theory on the string worldsheet. We find a simple condition controlling the bulk-string coupling: if there exist two flavors such that the product of their U(1) charge difference with the magnetic flux carried by the string configuration is not an integer multiple of 2 π, the string has zero-modes that decay slower than 1 /r, where r is the radial distance from the string core. These modes are coupled to the vacuum massless excitations even at low energies. If, however, all such products are integer multiples of 2 π, long-range modes of this type do not exist and the string moduli decouple from the bulk at low energies. This condition turns out to coincide with the condition of trivial Aharonov-Bohm phases for the particles in the spectrum. In addition to a derivation of the bulk-string decoupling criterion using classical analysis of the string zero-modes, we provide a non-perturbative derivation of the criterion, which uses supersymmetric localization techniques.
Novel type of chimera spiral waves arising from decoupling of a diffusible component
Energy Technology Data Exchange (ETDEWEB)
Tang, Xiaodong; Yang, Tao; Liu, Yang; Zhao, Yuemin; Gao, Qingyu, E-mail: epstein@brandeis.edu, E-mail: gaoqy@cumt.edu.cn [College of Chemical Engineering, China University of Mining and Technology, Xuzhou 221008 (China); Epstein, Irving R., E-mail: epstein@brandeis.edu, E-mail: gaoqy@cumt.edu.cn [Department of Chemistry and Volen Center for Complex Systems, MS 015, Brandeis University, Waltham, Massachusetts 02454-9110 (United States)
2014-07-14
Spiral waves composed of coherent traveling waves surrounding a core containing stochastically distributed stationary areas are found in numerical simulations of a three-variable reaction-diffusion system with one diffusible species. In the spiral core, diffusion of this component (w) mediates transitions between dynamic states of the subsystem formed by the other two components, whose dynamics is more rapid than that of w. Diffusive coupling between adjacent sites can be “on” or “off” depending on the subsystem state. The incoherent structures in the spiral core are produced by this decoupling of the slow diffusive component from the fast non-diffusing subsystem. The phase diagram reveals that the region of incoherent behavior in chimera spirals grows drastically, leading to modulation and breakup of the spirals, in the transition zones between 1{sup n-1} and 1{sup n} local mixed-mode oscillations.
Decoupled electron and phonon transports in hexagonal boron nitride-silicene bilayer heterostructure
Energy Technology Data Exchange (ETDEWEB)
Cai, Yongqing; Pei, Qing-Xiang, E-mail: peiqx@ihpc.a-star.edu.sg, E-mail: zhangg@ihpc.a-star.edu.sg; Zhang, Gang, E-mail: peiqx@ihpc.a-star.edu.sg, E-mail: zhangg@ihpc.a-star.edu.sg; Zhang, Yong-Wei [Institute of High Performance Computing, A*STAR, Singapore 138632 (Singapore)
2016-02-14
Calculations based on the density functional theory and empirical molecular dynamics are performed to investigate interlayer interaction, electronic structure and thermal transport of a bilayer heterostructure consisting of silicene and hexagonal boron nitride (h-BN). In this heterostructure, the two layers are found to interact weakly via a non-covalent binding. As a result, the Dirac cone of silicene is preserved with the Dirac cone point being located exactly at the Fermi level, and only a small amount of electrons are transferred from h-BN to silicene, suggesting that silicene dominates the electronic transport. Molecular dynamics calculation results demonstrate that the heat current along h-BN is six times of that along silicene, suggesting that h-BN dominates the thermal transport. This decoupled role of h-BN and silicene in thermal and electronic transport suggests that the BN-silicene bilayer heterostructure is promising for thermoelectric applications.
Sustainable Strategies for the Dynamic Equilibrium of the Urban Stream, Cheonggyecheon
Seo, D.; Kwon, Y.
2018-04-01
Cheonggyecheon, which had been transformed into a 14-lane urban highway and a large underground sewer system, was finally converted back to an urban stream again. Its transformation has been praised as a successful example of urban downtown regeneration and beautification. It is, however, obvious that there have not been prudent ecological considerations since the project’s principal goals were to provide public recreational use and achieve maximum flood control capacity via the use of embankments. For a healthier and sustainable stream environment, Cheonggyecheon should be ecologically re-restored again, based on a dynamic equilibrium model. It must primarily establish a corridor of vegetation, an aquatic transitional zone, and install constructed wetlands nearby which support the water source. The upper streams of Cheonggyecheon should be further restored and supply natural waters. Furthermore, there ultimately needs to be de-channelization for hydrological sustainability. This would vary from merely increasing the sinuosity to thoroughly reconstruct a naturalized stream. Complete dynamic equilibrium of Cheonggyecheon can be accomplished through more fundamental sustainable strategies.
A Self-adaptive Dynamic Evaluation Model for Diabetes Mellitus, Based on Evolutionary Strategies
Directory of Open Access Journals (Sweden)
An-Jiang Lu
2016-03-01
Full Text Available In order to evaluate diabetes mellitus objectively and accurately, this paper builds a self-adaptive dynamic evaluation model for diabetes mellitus, based on evolutionary strategies. First of all, on the basis of a formalized description of the evolutionary process of diabetes syndromes, using a state transition function, it judges whether a disease is evolutionary, through an excitation parameter. It then, provides evidence for the rebuilding of the evaluation index system. After that, by abstracting and rebuilding the composition of evaluation indexes, it makes use of a heuristic algorithm to determine the composition of the evolved evaluation index set of diabetes mellitus, It then, calculates the weight of each index in the evolved evaluation index set of diabetes mellitus by building a dependency matrix and realizes the self-adaptive dynamic evaluation of diabetes mellitus under an evolutionary environment. Using this evaluation model, it is possible to, quantify all kinds of diagnoses and treatment experiences of diabetes and finally to adopt ideal diagnoses and treatment measures for different patients with diabetics.
Rural settlements dynamics and the prospects of densification strategy in rural Bangladesh.
Alam, A F M Ashraful; Asad, Rumana; Enamul Kabir, Md
2016-01-01
Given the year on year decrease of rural farmland and various forms of land degradation through the intrusion of non-farm land uses, the government of Bangladesh has drafted the agrarian reform strategies, primarily to protect the agricultural land from encroachment, conversion, and indiscriminate use. The draft Agricultural Land Protection and Land Use Bill since its inception in 2011 is facing serious uncertainties of implementation due to its borrowed nature from the developed contexts and inadequacy to recognize the local complexities. With a particular focus on the densification component of the draft bill, a semester-long design studio was conducted in consultation with the existing villagers to explore the practicability of the draft bill in the villages of Tetultala and Chhoygharia in the south-western coastal Bangladesh. The findings from the two villages hint that in Bangladesh, the unique and evolving nature of rural settlements dynamics that are disintegrating the rural society from farming practices and the farmland, thereby, unsettling the traditional village-morphology. The settlements dynamics vary from those of the western context; hence, there is an emerging need to build locally situated knowledge towards a feasible rural land reform.
Stochastic win-stay-lose-shift strategy with dynamic aspirations in evolutionary social dilemmas
Amaral, Marco A.; Wardil, Lucas; Perc, Matjaž; da Silva, Jafferson K. L.
2016-09-01
In times of plenty expectations rise, just as in times of crisis they fall. This can be mathematically described as a win-stay-lose-shift strategy with dynamic aspiration levels, where individuals aspire to be as wealthy as their average neighbor. Here we investigate this model in the realm of evolutionary social dilemmas on the square lattice and scale-free networks. By using the master equation and Monte Carlo simulations, we find that cooperators coexist with defectors in the whole phase diagram, even at high temptations to defect. We study the microscopic mechanism that is responsible for the striking persistence of cooperative behavior and find that cooperation spreads through second-order neighbors, rather than by means of network reciprocity that dominates in imitation-based models. For the square lattice the master equation can be solved analytically in the large temperature limit of the Fermi function, while for other cases the resulting differential equations must be solved numerically. Either way, we find good qualitative agreement with the Monte Carlo simulation results. Our analysis also reveals that the evolutionary outcomes are to a large degree independent of the network topology, including the number of neighbors that are considered for payoff determination on lattices, which further corroborates the local character of the microscopic dynamics. Unlike large-scale spatial patterns that typically emerge due to network reciprocity, here local checkerboard-like patterns remain virtually unaffected by differences in the macroscopic properties of the interaction network.
Sun, Shuhua; Chen, Huaizhong
2017-10-01
[Correction Notice: An Erratum for this article was reported in Vol 102(10) of Journal of Applied Psychology (see record 2017-34254-001). In the article, Table 1 contained a formatting error. Correlation coefficient values in the last four cells of column 6 were misplaced with correlation coefficient values in the last four cells of column 7. All versions of this article have been corrected.] We conduct a theory-driven empirical investigation on whether political behavior, as a coping strategy to perceived organizational politics, creates resource trade-offs in moderating the relationship between perceived organizational politics and task performance. Drawing on conservation of resources theory, we hypothesize that political behavior mitigates the adverse effect of perceived organizational politics on task performance via psychological empowerment, yet exacerbates its adverse effect on task performance via emotional exhaustion. Three-wave multisource data from a sample of 222 employees and their 75 supervisors were collected for hypothesis testing. Findings supported our hypotheses. Our study enhances understandings of the complex resource dynamics of using political behavior to cope with perceived organizational politics and highlights the need to move stress-coping research from a focus on the stress-buffering effect of coping on outcomes to a focus on the underlying competing resource dynamics. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
Energy Technology Data Exchange (ETDEWEB)
Valdes-Abellan, J.; Jiménez-Martínez, J.; Candela, L.; Tamoh, K.
2015-07-01
Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a first measure. For this purpose, the control of volumetric water content, θ, and pressure head, h, is required. This study adopted two types of monitoring strategies in the same experimental plot to control θ and h in the vadose zone: i) non-automatic and more time-consuming; ii) automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic). Goodness-of-fit results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of θ and h, but with slight differences in computed annual drainage (711 mm and 774 mm). Soil hydraulic properties were inversely estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, θs, and the n and α van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic data acquisition as data variability was lower and accuracy was higher. (Author)
Nanaeda, Kimihiro; Mueller, Fabian; Brouwer, Jacob; Samuelsen, Scott
Operating strategies of solid oxide fuel cell (SOFC) combined heat and power (CHP) systems are developed and evaluated from a utility, and end-user perspective using a fully integrated SOFC-CHP system dynamic model that resolves the physical states, thermal integration and overall efficiency of the system. The model can be modified for any SOFC-CHP system, but the present analysis is applied to a hotel in southern California based on measured electric and heating loads. Analysis indicates that combined heat and power systems can be operated to benefit both the end-users and the utility, providing more efficient electric generation as well as grid ancillary services, namely dispatchable urban power. Design and operating strategies considered in the paper include optimal sizing of the fuel cell, thermal energy storage to dispatch heat, and operating the fuel cell to provide flexible grid power. Analysis results indicate that with a 13.1% average increase in price-of-electricity (POE), the system can provide the grid with a 50% operating range of dispatchable urban power at an overall thermal efficiency of 80%. This grid-support operating mode increases the operational flexibility of the SOFC-CHP system, which may make the technology an important utility asset for accommodating the increased penetration of intermittent renewable power.
International Nuclear Information System (INIS)
Mohamed, A.H.
2008-01-01
In recent years, state based functional diagnostic systems have gained a growing attention among the model based diagnostic systems. They have been used to diagnose the new faults of the complex systems. On the other hand, a main point considered against it is its subjective, and the inability of reusing the knowledge gathered from one engineer by others. Different methods have been' suggested to solve these problems. In the same way, the suggested functional diagnostic system introduces the uses of Dynamic Master Logic Diagram (DMLD) modeling strategy for the functional diagnostic systems. DMLD has proven its power as a good modeling strategy. It can model the functions of the system's components in terms of a set of defined primitives for the domain of applications. However, the suggested system can use the DMLD technique to model the small functions of the system according to the defined primitives of its domain. So, the modeling process of the system is relatively invariant from one modeler to another. Also, the functions defined can be reused by other users in the domain for solving different problems. Besides, it can deal with the complex system in a flexible manner. Thus, the proposed system can improve the performance of the state based functional diagnostic systems. It can be applied for a wide area of the complex systems. It has been applied for a fluid system as a case of the real-time systems. The suggested system has proved its success as a powerful practical state based functional diagnostic system
Directory of Open Access Journals (Sweden)
Javier Valdes-Abellan
2015-03-01
Full Text Available Abstract Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a first measure. For this purpose, the control of volumetric water content, θ, and pressure head, h, is required. This study adopted two types of monitoring strategies in the same experimental plot to control θ and h in the vadose zone: i non-automatic and more time-consuming; ii automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic. Goodness-of-fit results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of θ and h, but with slight differences in computed annual drainage (711 mm and 774 mm. Soil hydraulic properties were inversely estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, θs, and the n and α van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic data acquisition as data variability was lower and accuracy was higher.
Watershed-based point sources permitting strategy and dynamic permit-trading analysis.
Ning, Shu-Kuang; Chang, Ni-Bin
2007-09-01
Permit-trading policy in a total maximum daily load (TMDL) program may provide an additional avenue to produce environmental benefit, which closely approximates what would be achieved through a command and control approach, with relatively lower costs. One of the important considerations that might affect the effective trading mechanism is to determine the dynamic transaction prices and trading ratios in response to seasonal changes of assimilative capacity in the river. Advanced studies associated with multi-temporal spatially varied trading ratios among point sources to manage water pollution hold considerable potential for industries and policy makers alike. This paper aims to present an integrated simulation and optimization analysis for generating spatially varied trading ratios and evaluating seasonal transaction prices accordingly. It is designed to configure a permit-trading structure basin-wide and provide decision makers with a wealth of cost-effective, technology-oriented, risk-informed, and community-based management strategies. The case study, seamlessly integrating a QUAL2E simulation model with an optimal waste load allocation (WLA) scheme in a designated TMDL study area, helps understand the complexity of varying environmental resources values over space and time. The pollutants of concern in this region, which are eligible for trading, mainly include both biochemical oxygen demand (BOD) and ammonia-nitrogen (NH3-N). The problem solution, as a consequence, suggests an array of waste load reduction targets in a well-defined WLA scheme and exhibits a dynamic permit-trading framework among different sub-watersheds in the study area. Research findings gained in this paper may extend to any transferable dynamic-discharge permit (TDDP) program worldwide.
Seasonal Dynamics of Water Use Strategy of Two Salix Shrubs in Alpine Sandy Land, Tibetan Plateau.
Zhu, Yajuan; Wang, Guojie; Li, Renqiang
2016-01-01
Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land.
Effects of rewiring strategies on information spreading in complex dynamic networks
Ally, Abdulla F.; Zhang, Ning
2018-04-01
Recent advances in networks and communication services have attracted much interest to understand information spreading in social networks. Consequently, numerous studies have been devoted to provide effective and accurate models for mimicking information spreading. However, knowledge on how to spread information faster and more widely remains a contentious issue. Yet, most existing works are based on static networks which limit the reality of dynamism of entities that participate in information spreading. Using the SIR epidemic model, this study explores and compares effects of two rewiring models (Fermi-Dirac and Linear functions) on information spreading in scale free and small world networks. Our results show that for all the rewiring strategies, the spreading influence replenishes with time but stabilizes in a steady state at later time-steps. This means that information spreading takes-off during the initial spreading steps, after which the spreading prevalence settles toward its equilibrium, with majority of the population having recovered and thus, no longer affecting the spreading. Meanwhile, rewiring strategy based on Fermi-Dirac distribution function in one way or another impedes the spreading process, however, the structure of the networks mimic the spreading, even with a low spreading rate. The worst case can be when the spreading rate is extremely small. The results emphasize that despite a big role of such networks in mimicking the spreading, the role of the parameters cannot be simply ignored. Apparently, the probability of giant degree neighbors being informed grows much faster with the rewiring strategy of linear function compared to that of Fermi-Dirac distribution function. Clearly, rewiring model based on linear function generates the fastest spreading across the networks. Therefore, if we are interested in speeding up the spreading process in stochastic modeling, linear function may play a pivotal role.
Decoupling the Arrhenius equation via mechanochemistry.
Andersen, Joel M; Mack, James
2017-08-01
Mechanochemistry continues to reveal new possibilities in chemistry including the opportunity for "greening" reactions. Nevertheless, a clear understanding of the energetic transformations within mechanochemical systems remains elusive. We employed a uniquely modified ball mill and strategically chosen Diels-Alder reactions to evaluate the role of several ball-milling variables. This revealed three different energetic regions that we believe are defining characteristics of most, if not all, mechanochemical reactors. Relative to the locations of a given ball mill's regions, activation energy determines whether a reaction is energetically easy (Region I), challenging (Region II), or unreasonable (Region III) in a given timeframe. It is in Region II, that great sensitivity to mechanochemical conditions such as vial material and oscillation frequency emerge. Our unique modifications granted control of reaction vessel temperature, which in turn allowed control of the locations of Regions I, II, and III for our mill. Taken together, these results suggest envisioning vibratory mills (and likely other mechanochemical methodologies) as molecular-collision facilitating devices that act upon molecules occupying a thermally-derived energy distribution. This unifies ball-milling energetics with solution-reaction energetics via a common tie to the Arrhenius equation, but gives mechanochemistry the unique opportunity to influence either half of the equation. In light of this, we discuss a strategy for translating solvent-based reaction conditions to ball milling conditions. Lastly, we posit that the extra control via frequency factor grants mechanochemistry the potential for greater selectivity than conventional solution reactions.
A Cognitive Modeling Approach to Strategy Formation in Dynamic Decision Making
Directory of Open Access Journals (Sweden)
Sabine Prezenski
2017-08-01
Full Text Available Decision-making is a high-level cognitive process based on cognitive processes like perception, attention, and memory. Real-life situations require series of decisions to be made, with each decision depending on previous feedback from a potentially changing environment. To gain a better understanding of the underlying processes of dynamic decision-making, we applied the method of cognitive modeling on a complex rule-based category learning task. Here, participants first needed to identify the conjunction of two rules that defined a target category and later adapt to a reversal of feedback contingencies. We developed an ACT-R model for the core aspects of this dynamic decision-making task. An important aim of our model was that it provides a general account of how such tasks are solved and, with minor changes, is applicable to other stimulus materials. The model was implemented as a mixture of an exemplar-based and a rule-based approach which incorporates perceptual-motor and metacognitive aspects as well. The model solves the categorization task by first trying out one-feature strategies and then, as a result of repeated negative feedback, switching to two-feature strategies. Overall, this model solves the task in a similar way as participants do, including generally successful initial learning as well as reversal learning after the change of feedback contingencies. Moreover, the fact that not all participants were successful in the two learning phases is also reflected in the modeling data. However, we found a larger variance and a lower overall performance of the modeling data as compared to the human data which may relate to perceptual preferences or additional knowledge and rules applied by the participants. In a next step, these aspects could be implemented in the model for a better overall fit. In view of the large interindividual differences in decision performance between participants, additional information about the underlying
A Cognitive Modeling Approach to Strategy Formation in Dynamic Decision Making.
Prezenski, Sabine; Brechmann, André; Wolff, Susann; Russwinkel, Nele
2017-01-01
Decision-making is a high-level cognitive process based on cognitive processes like perception, attention, and memory. Real-life situations require series of decisions to be made, with each decision depending on previous feedback from a potentially changing environment. To gain a better understanding of the underlying processes of dynamic decision-making, we applied the method of cognitive modeling on a complex rule-based category learning task. Here, participants first needed to identify the conjunction of two rules that defined a target category and later adapt to a reversal of feedback contingencies. We developed an ACT-R model for the core aspects of this dynamic decision-making task. An important aim of our model was that it provides a general account of how such tasks are solved and, with minor changes, is applicable to other stimulus materials. The model was implemented as a mixture of an exemplar-based and a rule-based approach which incorporates perceptual-motor and metacognitive aspects as well. The model solves the categorization task by first trying out one-feature strategies and then, as a result of repeated negative feedback, switching to two-feature strategies. Overall, this model solves the task in a similar way as participants do, including generally successful initial learning as well as reversal learning after the change of feedback contingencies. Moreover, the fact that not all participants were successful in the two learning phases is also reflected in the modeling data. However, we found a larger variance and a lower overall performance of the modeling data as compared to the human data which may relate to perceptual preferences or additional knowledge and rules applied by the participants. In a next step, these aspects could be implemented in the model for a better overall fit. In view of the large interindividual differences in decision performance between participants, additional information about the underlying cognitive processes from
Chen, Qian; Liu, Guohai; Xu, Dezhi; Xu, Liang; Xu, Gaohong; Aamir, Nazir
2018-05-01
This paper proposes a new decoupled control for a five-phase in-wheel fault-tolerant permanent magnet (IW-FTPM) motor drive, in which radial basis function neural network inverse (RBF-NNI) and internal model control (IMC) are combined. The RBF-NNI system is introduced into original system to construct a pseudo-linear system, and IMC is used as a robust controller. Hence, the newly proposed control system incorporates the merits of the IMC and RBF-NNI methods. In order to verify the proposed strategy, an IW-FTPM motor drive is designed based on dSPACE real-time control platform. Then, the experimental results are offered to verify that the d-axis current and the rotor speed are successfully decoupled. Besides, the proposed motor drive exhibits strong robustness even under load torque disturbance.
Lara-Cabrera, Raúl; Cotta, Carlos; Fernández Leiva, Antonio J.
2013-01-01
This work presents a procedural content generation system that uses an evolutionary algorithm in order to generate interesting maps for a real-time strategy game, called Planet Wars. Interestingness is here captured by the dynamism of games (i.e., the extent to which they are action-packed). We consider two different approaches to measure the dynamism of the games resulting from these generated maps, one based on fluctuations in the resources controlled by either player and another one based ...
Lim, J. T.; Gold, H. J.; Wilkerson, G. G.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)
1989-01-01
We describe the application of a strategy for conducting a sensitivity analysis for a complex dynamic model. The procedure involves preliminary screening of parameter sensitivities by numerical estimation of linear sensitivity coefficients, followed by generation of a response surface based on Monte Carlo simulation. Application is to a physiological model of the vegetative growth of soybean plants. The analysis provides insights as to the relative importance of certain physiological processes in controlling plant growth. Advantages and disadvantages of the strategy are discussed.
Adner, Ron; Zemsky, Peter
2003-01-01
We develop a novel approach to the dynamics of business strategy that is grounded in an explicit treatment of consumer choice when technologies improve over time. We address the evolution of market boundaries, resource rents and competitive positions by adapting models of competition with differentiated products. Our model is consistent with the central strategy assertion that competitive interactions are governed by superior value creation and competitive advantage. More importantly, it show...
System dynamics analysis of strategies to reduce energy use in aluminum-intensive sectors
Energy Technology Data Exchange (ETDEWEB)
Hanes, Rebecca J.; Nicholson, Scott; 25-29 June 2017, Carpenter, Alberta
2017-07-13
Aluminum is one of the most widely used materials in industry, with applications in buildings, vehicles, aircraft, and consumer products. Its ubiquity is also on the rise: aluminum is beginning to supplant steel in lightweight vehicles and aircraft, and is used in many green or LEED-certified buildings. Although aluminum tends to be highly recycled, particularly by manufacturers of aluminum products, the sector as a whole is still far from a closed system. As a result, the increase in aluminum consumption also means an increase in primary aluminum production-an energy-intensive process-and an increase in consumption of the raw material bauxite, which in the U.S. is almost entirely imported. Our objectives for this study are to identify and analyze aluminum sector technologies and practices that reduce the energy required to manufacture aluminum products and reduce U.S. dependence on imported aluminum and bauxite. To accomplish these objectives, we will develop a system dynamics (SD) model of aluminum production, use and recycling in key application areas, including aerospace, ground vehicles and consumer products. The model will cover the entire aluminum supply chain as it exists in the U.S., from bauxite importing and refining, to the manufacture of products, to the product use phase and end-of-life processing steps. Aluminum flows throughout the model will be determined by the annual domestic demand for each application area as well as demand projections that extend to 2030. Energy consumption will be tracked based on the flows of aluminum through each step of the supply chain. Using the SD model, we will evaluate several technologies and practices that have the potential to reduce energy consumption and reliance on imported bauxite. These include implementation of advanced primary aluminum production technologies, increased recycling within and between application areas, increased material efficiency and increased product lifetimes. Each of these strategies
Kempel, Robert W.; Mcneill, Walter E.; Gilyard, Glenn B.; Maine, Trindel A.
1988-01-01
The NASA Ames Research Center developed an oblique-wing research plane from NASA's digital fly-by-wire airplane. Oblique-wing airplanes show large cross-coupling in control and dynamic behavior which is not present on conventional symmetric airplanes and must be compensated for to obtain acceptable handling qualities. The large vertical motion simulator at NASA Ames-Moffett was used in the piloted evaluation of a proposed flight control system designed to provide decoupled handling qualities. Five discrete flight conditions were evaluated ranging from low altitude subsonic Mach numbers to moderate altitude supersonic Mach numbers. The flight control system was effective in generally decoupling the airplane. However, all participating pilots objected to the high levels of lateral acceleration encountered in pitch maneuvers. In addition, the pilots were more critical of left turns (in the direction of the trailing wingtip when skewed) than they were of right turns due to the tendency to be rolled into the left turns and out of the right turns. Asymmetric side force as a function of angle of attack was the primary cause of lateral acceleration in pitch. Along with the lateral acceleration in pitch, variation of rolling and yawing moments as functions of angle of attack caused the tendency to roll into left turns and out of right turns.
Wang, Tianqiong; Riti, Joshua Sunday; Shu, Yang
2018-05-08
The adoption and ratification of relevant policies, particularly the household enrolment system metamorphosis in China, led to rising urbanization growth. As the leading developing economy, China has experienced a drastic and rapid increase in the rate of urbanization, energy use, economic growth and greenhouse gas (GHG) pollution for the past 30 years. The knowledge of the dynamic interrelationships among these trends has a plethora of implications ranging from demographic, energy, and environmental and sustainable development policies. This study analyzes the role of urbanization in decoupling GHG emissions, energy, and income in China while considering the critical contribution of energy use. As a contribution to the extant body of literature, the present research introduces a new phenomenon called "the environmental urbanization Kuznets curve" (EUKC), which shows that at the early stage of urbanization, the environment degrades however, after a threshold point the technique effects surface and environmental degradation reduces with rise in urbanization. Applying the autoregressive distributed lag model and the vector error correction model, the paper finds the presence of inverted U-shaped curve between urbanization and GHG emission of CO 2 , while the same hypothesis cannot be found between income and GHG emission of CO 2 . Energy use in all the models contributes to GHG emission of CO 2 . In decoupling greenhouse gas emissions, urbanization, energy, and income, articulated and well-implemented energy and urbanization policies should be considered.
DECOUPLING CONTROL OF TITO SYSTEM SUPPORTED BY DOMINANT POLE PLACEMENT METHOD
Directory of Open Access Journals (Sweden)
Novak N. Nedić
2017-08-01
Full Text Available Appropriate approach to the nature of systems is a significant precondition for its successful control. An always actual issue of its mutual coupling is considered in this paper. A multivariable system with two-inputs and two-outputs (TITO is in the focus here. The dominant pole placement method is used in trying to tune the PID controllers that should support the decoupling control. The aim is to determine parameters of the PID controllers which, in combination with decoupler, can obtain a good dynamical behavior of the system. Therefore, this kind of the centralized analytically obtained controller is used for object control. Another goal is to simplify the tuning procedure of PID controllers and enlarge the possibility for introducing the given approach into practice. But the research results indicate that the proposed procedure leads to the usage of P controllers because they enable the best performances for the considered object. Also, it is noticed that some differences from the usual rules in selection of the dominant poles gives better results. The research is supported by simulations and, therefore, the proposed method effectiveness, regarding the system behavior quality, is presented on several examples.
A Two-Layer Gene Circuit for Decoupling Cell Growth from Metabolite Production.
Lo, Tat-Ming; Chng, Si Hui; Teo, Wei Suong; Cho, Han-Saem; Chang, Matthew Wook
2016-08-01
We present a synthetic gene circuit for decoupling cell growth from metabolite production through autonomous regulation of enzymatic pathways by integrated modules that sense nutrient and substrate. The two-layer circuit allows Escherichia coli to selectively utilize target substrates in a mixed pool; channel metabolic resources to growth by delaying enzymatic conversion until nutrient depletion; and activate, terminate, and re-activate conversion upon substrate availability. We developed two versions of controller, both of which have glucose nutrient sensors but differ in their substrate-sensing modules. One controller is specific for hydroxycinnamic acid and the other for oleic acid. Our hydroxycinnamic acid controller lowered metabolic stress 2-fold and increased the growth rate 2-fold and productivity 5-fold, whereas our oleic acid controller lowered metabolic stress 2-fold and increased the growth rate 1.3-fold and productivity 2.4-fold. These results demonstrate the potential for engineering strategies that decouple growth and production to make bio-based production more economical and sustainable. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
Reliability-based optimal structural design by the decoupling approach
International Nuclear Information System (INIS)
Royset, J.O.; Der Kiureghian, A.; Polak, E.
2001-01-01
A decoupling approach for solving optimal structural design problems involving reliability terms in the objective function, the constraint set or both is discussed and extended. The approach employs a reformulation of each problem, in which reliability terms are replaced by deterministic functions. The reformulated problems can be solved by existing semi-infinite optimization algorithms and computational reliability methods. It is shown that the reformulated problems produce solutions that are identical to those of the original problems when the limit-state functions defining the reliability problem are affine. For nonaffine limit-state functions, approximate solutions are obtained by solving series of reformulated problems. An important advantage of the approach is that the required reliability and optimization calculations are completely decoupled, thus allowing flexibility in the choice of the optimization algorithm and the reliability computation method
Decoupling Suspension Controller Based on Magnetic Flux Feedback
Directory of Open Access Journals (Sweden)
Wenqing Zhang
2013-01-01
Full Text Available The suspension module control system model has been established based on MIMO (multiple input and multiple output state feedback linearization. We have completed decoupling between double suspension points, and the new decoupling method has been applied to CMS04 magnetic suspension vehicle in national mid-low-speed maglev experiment field of Tangshan city in China. Double suspension system model is very accurate for investigating stability property of maglev control system. When magnetic flux signal is taken back to the suspension control system, the suspension module’s antijamming capacity for resisting suspension load variety has been proved. Also, the external force interference has been enhanced. As a result, the robustness and stability properties of double-electromagnet suspension control system have been enhanced.
Power decoupling method for single phase differential buck converter
DEFF Research Database (Denmark)
Yao, Wenli; Tang, Yi; Zhang, Xiaobin
2015-01-01
inverter to improve the dc link power quality, and an improved active power decoupling method is proposed to achieve ripple power reduction for both AC-DC and DC-AC conversions. The ripple energy storage is realized by the filter capacitors, which are connected between the output terminal and the negative...... generation technique is proposed to provide accurate ripple power compensation, and closed-loop controllers are also designed based on small signal models. The effectiveness of this power decoupling method is verified by detailed simulation studies as well as laboratory prototype experimental results....... dc bus. By properly controlling the differential mode voltage of the capacitors, it is possible to transfer desired energy between the DC port and AC port. The common mode voltage is controlled in such a way that the ripple power on the dc side will be reduced. Furthermore, an autonomous reference...
Principle of Global Decoupling with Coupling Angle Modulation
Luo, Yun; Pilat, Fulvia Caterina; Roser, Thomas; Trbojevic, Dejan
2005-01-01
The global betatron decoupling on the ramp is an important issue for the operation of the Relativistic Heavy Ion Collider (RHIC). A new scheme coupling phase modulation is found. It introduces a rotating extra coupling into the coupled machine to detect the residual coupling. The eigentune responses are measured with a high resolution phase lock loop (PLL) system. From the minimum and maximum tune splits, the correction strengths are given. The time period occupied by one coupling phase modulation is less than 10 seconds. So it is a very promising solution for the global decoupling on the ramp. In this article the principle of the coupling phase modulation is given. The simulation with the smooth accelerator model is also done. The practical issues concerning its applications are discussed.
Maximizing biodiversity co-benefits under REDD+: a decoupled approach
International Nuclear Information System (INIS)
Potts, Matthew D; Kelley, Lisa C; Doll, Hannah M
2013-01-01
Current debates on biodiversity co-benefits under REDD+ are marked by considerable ambiguity and contention. Nevertheless, REDD+ continues to represent one of the most important opportunities for global biodiversity conservation, and the question of how best to achieve biodiversity co-benefits remains an important one. Thus far, most biodiversity conservation in the context of REDD+ is predicated on the notion that services are co-located on a landscape. In contrast, this letter argues that decoupling biodiversity and carbon services on a landscape through national-level planning is a better approach to biodiversity conservation under REDD+. We discuss the fundamental ecological differences between the two services and use principles of resource economics to demonstrate that a decoupled approach will be more efficient, more flexible, and better able to mobilize sufficient finance for biodiversity conservation than a coupled approach. (letter)
Decoupling suspension controller based on magnetic flux feedback.
Zhang, Wenqing; Li, Jie; Zhang, Kun; Cui, Peng
2013-01-01
The suspension module control system model has been established based on MIMO (multiple input and multiple output) state feedback linearization. We have completed decoupling between double suspension points, and the new decoupling method has been applied to CMS04 magnetic suspension vehicle in national mid-low-speed maglev experiment field of Tangshan city in China. Double suspension system model is very accurate for investigating stability property of maglev control system. When magnetic flux signal is taken back to the suspension control system, the suspension module's antijamming capacity for resisting suspension load variety has been proved. Also, the external force interference has been enhanced. As a result, the robustness and stability properties of double-electromagnet suspension control system have been enhanced.
A Fully Symmetric and Completely Decoupled MEMS-SOI Gyroscope
Directory of Open Access Journals (Sweden)
Abdelhameed SHARAF
2011-04-01
Full Text Available This paper introduces a novel MEMS gyroscope that is capable of exciting the drive mode differentially. The structure also decouples the drive and sense modes via an intermediate mass and decoupling beams. Both drive and sense modes are fully differential enabling control over the zero-rate-output for the former and maximizing output sensitivity using a bridge circuit for the latter. Further, the structure is fully symmetric about the x- and y- axes which results in minimizing the temperature sensitivity problem. Complete analytical analysis based on the equations of motion was performed and verified using two commercially available finite element software packages. Results from both methods are in good agreement. The analysis of the sensor shows an electrical sensitivity of 1.14 (mV/(º/s. The gyroscope was fabricated using single mask and deep reactive ion etching. The measurement of the resonance frequency performed showing a good agreement with the analytical and numerical analysis.
Power corrections from decoupling of the charm quark
Knechtli, Francesco; Korzec, Tomasz; Leder, Björn; Moir, Graham; Alpha Collaboration
2017-11-01
Decoupling of heavy quarks at low energies can be described by means of an effective theory as shown by S. Weinberg in Ref. [1]. We study the decoupling of the charm quark by lattice simulations. We simulate a model, QCD with two degenerate charm quarks. In this case the leading order term in the effective theory is a pure gauge theory. The higher order terms are proportional to inverse powers of the charm quark mass M starting at M-2. Ratios of hadronic scales are equal to their value in the pure gauge theory up to power corrections. We show, by precise measurements of ratios of scales defined from the Wilson flow, that these corrections are very small and that they can be described by a term proportional to M-2 down to masses in the region of the charm quark mass.
Maximizing biodiversity co-benefits under REDD+: a decoupled approach
Potts, Matthew D.; Kelley, Lisa C.; Doll, Hannah M.
2013-06-01
Current debates on biodiversity co-benefits under REDD+ are marked by considerable ambiguity and contention. Nevertheless, REDD+ continues to represent one of the most important opportunities for global biodiversity conservation, and the question of how best to achieve biodiversity co-benefits remains an important one. Thus far, most biodiversity conservation in the context of REDD+ is predicated on the notion that services are co-located on a landscape. In contrast, this letter argues that decoupling biodiversity and carbon services on a landscape through national-level planning is a better approach to biodiversity conservation under REDD+. We discuss the fundamental ecological differences between the two services and use principles of resource economics to demonstrate that a decoupled approach will be more efficient, more flexible, and better able to mobilize sufficient finance for biodiversity conservation than a coupled approach.
Cladding technique for development of Ag-In-Cd decoupler
International Nuclear Information System (INIS)
Teshigawara, M.; Harada, M.; Saito, S.; Kikuchi, K.; Kogawa, H.; Ikeda, Y.; Kawai, M.; Kurishita, H.; Konashi, K.
2005-01-01
To develop a Ag (silver)-In (indium)-Cd (cadmium) alloy decoupler, a method is needed to bond the decoupler between two plates of the Al alloy (A6061-T6). We found that a better HIP condition was temperature, pressure and holding time at 803 K, 100 MPa and 1 h, respectively, for small test pieces (φ 22 mm in diam. x 5 mm in height). Especially, a sandwich case (a Ag-In plate with thickness of 0.5 mm between two Ag-Cd plates with thickness of 1.25 mm) gave easier (or better) bonding results. Though a hardened layer is found in the bonding layer, the rupture strength of the bonding layer is more than 30 MPa, which is higher than the design stress in our application
Decoupling Subtraction Conserving Full Gauge Symmetries : Particles and Fields
Noriyasu, OHTSUBO; Hideo, MIYATA; Department of Phycics, Kanazawa Technical College; Department of Information Science, Kanazawa Institute of Technolgy
1984-01-01
A new subtraction scheme (^^^) which realizes the decoupling and conserves the symmetries of full gauge group simultaneously, is proposed. One particle irreducible Green's functions subtracted by ^^^ reveal the effective low energy symmetries at -p^2≪M^2 and the full symmetries at -p^2≫M^2, where M denotes a heavy mass. Also discussed are conditions in order to carry out ^^^ under two-loop approximation.
Asia’s decoupling: fact, forecast or fiction?
Lillie Lam; James Yetman
2013-01-01
Standard measures of real economic co-movement between Asia-Pacific economies and those elsewhere had been observed to follow a downward trend, leading some commentators to suggest that the region was decoupling. However, this process reversed in response to the International Financial Crisis, and co-movement increased to historically high levels for some economies. We examine co-movement patterns and show that these are very sensitive to changes in macroeconomic volatility over time. Control...
Decoupled numerical simulation of a solid fuel fired retort boiler
International Nuclear Information System (INIS)
Ryfa, Arkadiusz; Buczynski, Rafal; Chabinski, Michal; Szlek, Andrzej; Bialecki, Ryszard A.
2014-01-01
The paper deals with numerical simulation of the retort boiler fired with solid fuel. Such constructions are very popular for heating systems and their development is mostly based on the designer experience. The simulations have been done in ANSYS/Fluent package and involved two numerical models. The former deals with a fixed-bed combustion of the solid fuel and free-board gas combustion. Solid fuel combustion is based on the coal kinetic parameters. This model encompasses chemical reactions, radiative heat transfer and turbulence. Coal properties have been defined with user defined functions. The latter model describes flow of water inside a water jacked that surrounds the combustion chamber and flue gas ducts. The novelty of the proposed approach is separating of the combustion simulation from the water flow. Such approach allows for reducing the number of degrees of freedom and thus lowering the necessary numerical effort. Decoupling combustion from water flow requires defining interface boundary condition. As this boundary condition is unknown it is adjusted iteratively. The results of the numerical simulation have been successfully validated against measurement data. - Highlights: • New decoupled modelling of small scale boiler is proposed. • Fixed-bed combustion model based on kinetic parameters is introduced. • Decoupling reduced the complexity of the model and computational time. • Simple and computationally inexpensive coupling algorithm is proposed. • Model is successfully validated against measurements
Quantifying the ice-albedo feedback through decoupling
Kravitz, B.; Rasch, P. J.
2017-12-01
The ice-albedo feedback involves numerous individual components, whereby warming induces sea ice melt, inducing reduced surface albedo, inducing increased surface shortwave absorption, causing further warming. Here we attempt to quantify the sea ice albedo feedback using an analogue of the "partial radiative perturbation" method, but where the governing mechanisms are directly decoupled in a climate model. As an example, we can isolate the insulating effects of sea ice on surface energy and moisture fluxes by allowing sea ice thickness to change but fixing Arctic surface albedo, or vice versa. Here we present results from such idealized simulations using the Community Earth System Model in which individual components are successively fixed, effectively decoupling the ice-albedo feedback loop. We isolate the different components of this feedback, including temperature change, sea ice extent/thickness, and air-sea exchange of heat and moisture. We explore the interactions between these different components, as well as the strengths of the total feedback in the decoupled feedback loop, to quantify contributions from individual pieces. We also quantify the non-additivity of the effects of the components as a means of investigating the dominant sources of nonlinearity in the ice-albedo feedback.
Yuan, Zhiyou; Liu, Weixing; Niu, Shuli; Wan, Shiqiang
2007-10-01
Numerous studies have examined the effects of climatic factors on the distribution of C(3) and C(4) grasses in various regions throughout the world, but the role of seasonal fluctuations in temperature, precipitation and soil N availability in regulating growth and competition of these two functional types is still not well understood. This report is about the effects of seasonality of soil N availability and competition on plant N dynamics and N-use strategies of one C(3) (Leymus chinensis) and one C(4) (Chloris virgata) grass species. Leymus chinensis and C. virgata, two grass species native to the temperate steppe in northern China, were planted in a monoculture and a mixture under three different N seasonal availabilities: an average model (AM) with N evenly distributed over the growing season; a one-peak model (OM) with more N in summer than in spring and autumn; and a two-peak model (TM) with more N in spring and autumn than in summer. The results showed that the altered N seasonality changed plant N concentration, with the highest value of L. chinensis under the OM treatment and C. virgata under the TM treatment, respectively. N seasonality also affected plant N content, N productivity and N-resorption efficiency and proficiency in both the C(3) and C(4) species. Interspecific competition influenced N-use and resorption efficiency in both the C(3) and C(4) species, with higher N-use and resorption efficiency in the mixture than in monoculture. The C(4) grass had higher N-use efficiency than the C(3) grass due to its higher N productivity, irrespective of the N treatment or competition. The observations suggest that N-use strategies in the C(3) and C(4) species used in the study were closely related to seasonal dynamics of N supply and competition. N seasonality might be involved in the growth and temporal niche separation between C(3) and C(4) species observed in the natural ecosystems.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Xiaodong, E-mail: xiaodong.zhang@beg.utexas.edu [Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78713 (United States); Huang, Gordon [Institute of Energy, Environment and Sustainable Communities, University of Regina, Regina, Saskatchewan S4S 0A2 (Canada)
2013-02-15
Highlights: ► A dynamic stochastic possibilistic multiobjective programming model is developed. ► Greenhouse gas emission control is considered. ► Three planning scenarios are analyzed and compared. ► Optimal decision schemes under three scenarios and different p{sub i} levels are obtained. ► Tradeoffs between economics and environment are reflected. -- Abstract: Greenhouse gas (GHG) emissions from municipal solid waste (MSW) management facilities have become a serious environmental issue. In MSW management, not only economic objectives but also environmental objectives should be considered simultaneously. In this study, a dynamic stochastic possibilistic multiobjective programming (DSPMP) model is developed for supporting MSW management and associated GHG emission control. The DSPMP model improves upon the existing waste management optimization methods through incorporation of fuzzy possibilistic programming and chance-constrained programming into a general mixed-integer multiobjective linear programming (MOP) framework where various uncertainties expressed as fuzzy possibility distributions and probability distributions can be effectively reflected. Two conflicting objectives are integrally considered, including minimization of total system cost and minimization of total GHG emissions from waste management facilities. Three planning scenarios are analyzed and compared, representing different preferences of the decision makers for economic development and environmental-impact (i.e. GHG-emission) issues in integrated MSW management. Optimal decision schemes under three scenarios and different p{sub i} levels (representing the probability that the constraints would be violated) are generated for planning waste flow allocation and facility capacity expansions as well as GHG emission control. The results indicate that economic and environmental tradeoffs can be effectively reflected through the proposed DSPMP model. The generated decision variables can help
Modulation of actin dynamics as potential macrophage subtype-targeting anti-tumour strategy.
Pergola, Carlo; Schubert, Katrin; Pace, Simona; Ziereisen, Jana; Nikels, Felix; Scherer, Olga; Hüttel, Stephan; Zahler, Stefan; Vollmar, Angelika M; Weinigel, Christina; Rummler, Silke; Müller, Rolf; Raasch, Martin; Mosig, Alexander; Koeberle, Andreas; Werz, Oliver
2017-01-30
Tumour-associated macrophages mainly comprise immunosuppressive M2 phenotypes that promote tumour progression besides anti-tumoural M1 subsets. Selective depletion or reprogramming of M2 may represent an innovative anti-cancer strategy. The actin cytoskeleton is central for cellular homeostasis and is targeted for anti-cancer chemotherapy. Here, we show that targeting G-actin nucleation using chondramide A (ChA) predominantly depletes human M2 while promoting the tumour-suppressive M1 phenotype. ChA reduced the viability of M2, with minor effects on M1, but increased tumour necrosis factor (TNF)α release from M1. Interestingly, ChA caused rapid disruption of dynamic F-actin filaments and polymerization of G-actin, followed by reduction of cell size, binucleation and cell division, without cellular collapse. In M1, but not in M2, ChA caused marked activation of SAPK/JNK and NFκB, with slight or no effects on Akt, STAT-1/-3, ERK-1/2, and p38 MAPK, seemingly accounting for the better survival of M1 and TNFα secretion. In a microfluidically-supported human tumour biochip model, circulating ChA-treated M1 markedly reduced tumour cell viability through enhanced release of TNFα. Together, ChA may cause an anti-tumoural microenvironment by depletion of M2 and activation of M1, suggesting induction of G-actin nucleation as potential strategy to target tumour-associated macrophages in addition to neoplastic cells.
Dimas Pristovani, R.; Raden Sanggar, D.; Dadet, Pramadihanto.
2018-04-01
Push recovery is one of humanbehaviorwhich is a strategy to defend the body from anexternal force in any environment. This paper describes push recovery strategy which usesMIMO decoupled control system method. The dynamics system uses aquasi-dynamic system based on triple linear inverted pendulum model (TLIPM). The analysis of TLIPMuses zero moment point (ZMP) calculation from ZMP simplification in last research. By using this simplification of dynamics system, the control design can be simplified into 3 serial SISOwith known and uncertain disturbance models in each inverted pendulum. Each pendulum has different plan to damp the external force effect. In this experiment, PID controller (closed- loop)is used to arrange the damp characteristic.The experiment result shows thatwhen using push recovery control strategy (closed-loop control) is about 85.71% whilewithout using push recovery control strategy (open-loop control) it is about 28.57%.
Directory of Open Access Journals (Sweden)
Shouzhao Sheng
2015-09-01
Full Text Available The aerodynamic parameters of ducted fan micro aerial vehicles (MAVs are difficult and expensive to precisely measure and are, therefore, not available in most cases. Furthermore, the actuator dynamics with risks of potentially destabilizing the overall system are important but often neglected consideration factors in the control system design of ducted fan MAVs. This paper presents a near-hover adaptive attitude control strategy of a prototype ducted fan MAV with actuator dynamics and without any prior information about the behavior of the MAV. The proposed strategy consists of an online parameter estimation algorithm and an adaptive gain scheduling algorithm, with the former accommodating parametric uncertainties, and the latter approximately eliminating the coupling among axes and guaranteeing the control quality of the MAV. The effectiveness of the proposed strategy is verified numerically and experimentally.
Zhang, Xiaodong; Huang, Gordon
2013-02-15
Greenhouse gas (GHG) emissions from municipal solid waste (MSW) management facilities have become a serious environmental issue. In MSW management, not only economic objectives but also environmental objectives should be considered simultaneously. In this study, a dynamic stochastic possibilistic multiobjective programming (DSPMP) model is developed for supporting MSW management and associated GHG emission control. The DSPMP model improves upon the existing waste management optimization methods through incorporation of fuzzy possibilistic programming and chance-constrained programming into a general mixed-integer multiobjective linear programming (MOP) framework where various uncertainties expressed as fuzzy possibility distributions and probability distributions can be effectively reflected. Two conflicting objectives are integrally considered, including minimization of total system cost and minimization of total GHG emissions from waste management facilities. Three planning scenarios are analyzed and compared, representing different preferences of the decision makers for economic development and environmental-impact (i.e. GHG-emission) issues in integrated MSW management. Optimal decision schemes under three scenarios and different p(i) levels (representing the probability that the constraints would be violated) are generated for planning waste flow allocation and facility capacity expansions as well as GHG emission control. The results indicate that economic and environmental tradeoffs can be effectively reflected through the proposed DSPMP model. The generated decision variables can help the decision makers justify and/or adjust their waste management strategies based on their implicit knowledge and preferences. Copyright © 2012 Elsevier B.V. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Lyle G. Roybal; Robert F Jeffers
2013-07-01
The United States electric power grid is the most complex and expansive control system in the world. Local generation control occurs at individual units based on response time and unit economics, larger regional control coordinates unit response to error conditions, and high level large-area regional control is ultimately administered by a network of humans guided by economic and resiliency related factors. Under normal operating conditions, the grid is a relatively slow moving entity that exhibits high inertia to outside stimuli, and behaves along repeatable diurnal and seasonal patterns. However, that paradigm is quickly changing because of the increasing implementation of renewable generation sources. Renewable generators by nature cannot be tightly controlled or scheduled. They appear like a negative load to the system with all of the variability associated with load on a larger scale. Also, grid-reactive loads (i.e. smart devices) can alter their consumption based on price or demand rules adding more variability to system behavior. This paper demonstrates how a systems dynamic modeling approach capable of operating over multiple time scales, can provide valuable insight into developing new “smart-grid” control strategies and devices needed to accommodate renewable generation and regulate the frequency of the grid.
Dynamics of the European refining and petrochemical industry. Strategies, structure and change
International Nuclear Information System (INIS)
Steenbakkers, K.
1997-01-01
The changes in the market position of producers engaged in the oil refining and basic petrochemical industry on the Western European market are the central theme of this book. Analysis of this reshuffling process among these actors is conducted on three levels. First, research is carried out at the level of world regions. In order to understand the reorganization of oil refining and basic petrochemical production in Western Europe, it is necessary to explore the recent aggregate dynamics of these activities on a global scale. Second, the differences in strategic behaviour are exanuned at the level of groups of market participants, namely the major oil companies, the chemical companies, the state-owned companies from both consumer and producer countries, and the independents. Finally, the investment/disinvestment decisions in the Western European oil refining and basic petrochemical industry are investigated at the level of the individual firm. Particular emphasis is placed upon explaining why companies active in the sectors under study have followed different strategies, although they have been confronted with similar adverse market conditions in Western Europe during the last decades. 341 refs
Gower, Drew B.; Dell'Angelo, Jampel; McCord, Paul F.; Caylor, Kelly K.; Evans, Tom P.
2016-11-01
In dryland environments, characterized by low and frequently variable rainfall, smallholder farmers must take crop water sensitivity into account along with other characteristics like seed availability and market price when deciding what to plant. In this paper we use the results of surveys conducted among smallholders located near Mount Kenya to identify clusters of farmers devoting different fractions of their land to subsistence and market crops. Additionally, we explore the tradeoffs between water-insensitive but low-value subsistence crops and a water-sensitive but high-value market crop using a numerical model that simulates soil moisture dynamics and crop production over multiple growing seasons. The cluster analysis shows that most farmers prefer to plant either only subsistence crops or only market crops, with a minority choosing to plant substantial fractions of both. The model output suggests that the value a farmer places on a successful growing season, a measure of risk aversion, plays a large role in whether the farmer chooses a subsistence or market crop strategy. Furthermore, access to irrigation, makes market crops more appealing, even to very risk-averse farmers. We then conclude that the observed clustering may result from different levels of risk aversion and access to irrigation.
Directory of Open Access Journals (Sweden)
J Lesitha Jeeva Kumari
Full Text Available Subunit reassociation in mucin 1, a breast cancer tumor marker, is reported as one of the critical factors for its cytoplasmic activation. Inhibition of its heterodimeric association would therefore result in loss of its function and alter disease progression. The present study aimed at evaluating peptide inhibitor designing strategies that may serve as antagonist against this receptor-ligand alliance. Several peptides and their derivatives were designed based on native residues, subunit interface, hydrogen bonding and secondary structure. Docking studies with the peptides were carried on the receptor subunit and their binding affinities were evaluated using steered molecular dynamics simulation and umbrella sampling. Our results showed that among all the different classes of peptides evaluated, the receptor based peptide showed the highest binding affinity. This result was concurrent with the experimental observation that the receptor-ligand alliance in mucin 1 is highly specific. Our results also show that peptide ligand against this subunit association is only stabilized through native residue inter-protein interaction irrespective of the peptide structure, peptide length and number of hydrogen bonds. Consistency in binding affinity, pull force and free energy barrier was observed with only the receptor derived peptides which resulted in favorable interprotein interactions at the interface. Several observations were made and discussed which will eventually lead to designing efficient peptide inhibitors against mucin 1 heterodimeric subunit reassociation.
Yuan, Hongping; Chini, Abdol R; Lu, Yujie; Shen, Liyin
2012-03-01
During the past few decades, construction and demolition (C&D) waste has received increasing attention from construction practitioners and researchers worldwide. A plethora of research regarding C&D waste management has been published in various academic journals. However, it has been determined that existing studies with respect to C&D waste reduction are mainly carried out from a static perspective, without considering the dynamic and interdependent nature of the whole waste reduction system. This might lead to misunderstanding about the actual effect of implementing any waste reduction strategies. Therefore, this research proposes a model that can serve as a decision support tool for projecting C&D waste reduction in line with the waste management situation of a given construction project, and more importantly, as a platform for simulating effects of various management strategies on C&D waste reduction. The research is conducted using system dynamics methodology, which is a systematic approach that deals with the complexity - interrelationships and dynamics - of any social, economic and managerial system. The dynamic model integrates major variables that affect C&D waste reduction. In this paper, seven causal loop diagrams that can deepen understanding about the feedback relationships underlying C&D waste reduction system are firstly presented. Then a stock-flow diagram is formulated by using software for system dynamics modeling. Finally, a case study is used to illustrate the validation and application of the proposed model. Results of the case study not only built confidence in the model so that it can be used for quantitative analysis, but also assessed and compared the effect of three designed policy scenarios on C&D waste reduction. One major contribution of this study is the development of a dynamic model for evaluating C&D waste reduction strategies under various scenarios, so that best management strategies could be identified before being implemented
Thompson, William H.; Fransson, Peter
2015-01-01
When studying brain connectivity using fMRI, signal intensity time-series are typically correlated with each other in time to compute estimates of the degree of interaction between different brain regions and/or networks. In the static connectivity case, the problem of defining which connections that should be considered significant in the analysis can be addressed in a rather straightforward manner by a statistical thresholding that is based on the magnitude of the correlation coefficients. More recently, interest has come to focus on the dynamical aspects of brain connectivity and the problem of deciding which brain connections that are to be considered relevant in the context of dynamical changes in connectivity provides further options. Since we, in the dynamical case, are interested in changes in connectivity over time, the variance of the correlation time-series becomes a relevant parameter. In this study, we discuss the relationship between the mean and variance of brain connectivity time-series and show that by studying the relation between them, two conceptually different strategies to analyze dynamic functional brain connectivity become available. Using resting-state fMRI data from a cohort of 46 subjects, we show that the mean of fMRI connectivity time-series scales negatively with its variance. This finding leads to the suggestion that magnitude- versus variance-based thresholding strategies will induce different results in studies of dynamic functional brain connectivity. Our assertion is exemplified by showing that the magnitude-based strategy is more sensitive to within-resting-state network (RSN) connectivity compared to between-RSN connectivity whereas the opposite holds true for a variance-based analysis strategy. The implications of our findings for dynamical functional brain connectivity studies are discussed. PMID:26236216
Thompson, William H; Fransson, Peter
2015-01-01
When studying brain connectivity using fMRI, signal intensity time-series are typically correlated with each other in time to compute estimates of the degree of interaction between different brain regions and/or networks. In the static connectivity case, the problem of defining which connections that should be considered significant in the analysis can be addressed in a rather straightforward manner by a statistical thresholding that is based on the magnitude of the correlation coefficients. More recently, interest has come to focus on the dynamical aspects of brain connectivity and the problem of deciding which brain connections that are to be considered relevant in the context of dynamical changes in connectivity provides further options. Since we, in the dynamical case, are interested in changes in connectivity over time, the variance of the correlation time-series becomes a relevant parameter. In this study, we discuss the relationship between the mean and variance of brain connectivity time-series and show that by studying the relation between them, two conceptually different strategies to analyze dynamic functional brain connectivity become available. Using resting-state fMRI data from a cohort of 46 subjects, we show that the mean of fMRI connectivity time-series scales negatively with its variance. This finding leads to the suggestion that magnitude- versus variance-based thresholding strategies will induce different results in studies of dynamic functional brain connectivity. Our assertion is exemplified by showing that the magnitude-based strategy is more sensitive to within-resting-state network (RSN) connectivity compared to between-RSN connectivity whereas the opposite holds true for a variance-based analysis strategy. The implications of our findings for dynamical functional brain connectivity studies are discussed.
The Situated HKB Model: how sensorimotor spatial coupling can alter oscillatory brain dynamics
Directory of Open Access Journals (Sweden)
Miguel eAguilera
2013-08-01
Full Text Available Despite the increase both of dynamic and embodied/situated approaches in cognitive science, there is still little research on how coordination dynamics under a closed sensorimotor loop might induce qualitatively different patterns of neural oscillations compared to those found in isolated systems. We take as a departure point the HKB model, a generic model for dynamic coordination between two oscillatory components, which has proven useful for a vast range of applications in cognitive science and whose dynamical properties are well understood. In order to explore the properties of this model under closed sensorimotor conditions we present what we call the situated HKB model: a robotic model that performs a gradient climbing task and whose "brain" is modelled by the HKB equation. We solve the differential equations that define the agent-environment coupling for increasing values of the agent's sensitivity (sensor gain, finding different behavioural strategies. These results are compared with two different models: a decoupled HKB with no sensory input and a passively-coupled HKB that is also decoupled but receives a structured input generated by a situated agent. We can precisely quantify and qualitatively describe how the properties of the system, when studied in coupled conditions, radically change in a manner that cannot be deduced from the decoupled HKB models alone. We also present the notion of neurodynamic signature as the dynamic pattern that correlates with a specific behaviour and we show how only a situated agent can display this signature compared to an agent that simply receives the exact same sensory input.To our knowledge, this is the first analytical solution of the HKB equation in a sensorimotor loop and qualitative and quantitative analytic comparison of spatially coupled vs. decoupled oscillatory controllers. Finally, we discuss the limitations and possible generalization of our model to contemporary neuroscience and philosophy
The situated HKB model: how sensorimotor spatial coupling can alter oscillatory brain dynamics
Aguilera, Miguel; Bedia, Manuel G.; Santos, Bruno A.; Barandiaran, Xabier E.
2013-01-01
Despite the increase of both dynamic and embodied/situated approaches in cognitive science, there is still little research on how coordination dynamics under a closed sensorimotor loop might induce qualitatively different patterns of neural oscillations compared to those found in isolated systems. We take as a departure point the Haken-Kelso-Bunz (HKB) model, a generic model for dynamic coordination between two oscillatory components, which has proven useful for a vast range of applications in cognitive science and whose dynamical properties are well understood. In order to explore the properties of this model under closed sensorimotor conditions we present what we call the situated HKB model: a robotic model that performs a gradient climbing task and whose “brain” is modeled by the HKB equation. We solve the differential equations that define the agent-environment coupling for increasing values of the agent's sensitivity (sensor gain), finding different behavioral strategies. These results are compared with two different models: a decoupled HKB with no sensory input and a passively-coupled HKB that is also decoupled but receives a structured input generated by a situated agent. We can precisely quantify and qualitatively describe how the properties of the system, when studied in coupled conditions, radically change in a manner that cannot be deduced from the decoupled HKB models alone. We also present the notion of neurodynamic signature as the dynamic pattern that correlates with a specific behavior and we show how only a situated agent can display this signature compared to an agent that simply receives the exact same sensory input. To our knowledge, this is the first analytical solution of the HKB equation in a sensorimotor loop and qualitative and quantitative analytic comparison of spatially coupled vs. decoupled oscillatory controllers. Finally, we discuss the limitations and possible generalization of our model to contemporary neuroscience and
Static balancing of a spatial six-degree-of-freedom decoupling parallel mechanism
International Nuclear Information System (INIS)
Gao, Taoran Liu; Zhao, Xianchao; Qi, Chenkun
2014-01-01
The static balancing of a spatial 6-degree-of-freedom (6-DoF) decoupling parallel mechanism is discussed in this paper. Two traditional approaches (using counterweights and the springs) are used to statically balance the mechanism. Due to the existence of their shortcomings, a hybrid approach is proposed based on the static balancing of the mechanism. The main feature of this mechanism is that the 3-DoF rotating part can be static balancing itself, which means that its mass has no effect on the gravity balancing of the system, for any configuration of the mechanism, so the rotating part can be considered as a whole and the calculation is simplified. Finally, examples and dynamic analysis corresponding to the three balancing methods are given to illustrate the results.
Directory of Open Access Journals (Sweden)
Eric Dumonteil
2017-09-01
Full Text Available The Monte Carlo criticality simulation of decoupled systems, as for instance in large reactor cores, has been a challenging issue for a long time. In particular, due to limited computer time resources, the number of neutrons simulated per generation is still many order of magnitudes below realistic statistics, even during the start-up phases of reactors. This limited number of neutrons triggers a strong clustering effect of the neutron population that affects Monte Carlo tallies. Below a certain threshold, not only is the variance affected but also the estimation of the eigenvectors. In this paper we will build a time-dependent diffusion equation that takes into account both spatial correlations and population control (fixed number of neutrons along generations. We will show that its solution obeys a traveling wave dynamic, and we will discuss the mechanism that explains this biasing of local tallies whenever leakage boundary conditions are applied to the system.
International Nuclear Information System (INIS)
Abdel-Halim, H.A.
2005-01-01
evaporation is a proven method for a treatment of liquid radioactive wastes providing both good decontamination and high concentration . in a radioactive waste treatment plant, an evaporator is used to reduce the volume of medium radioactive liquid waste arising from different applications of nuclear industries. the control system objective is to limit the composition of the liquid waste at a prescribed value. for the safe operation, without damaging the installed equipment, a good control for the evaporator operating pressure and the level of liquid waste inside the separator part has been required. evaporator equipment is a complex process, which is a multivariable, nonlinear and has many disturbances. therefore, design a control strategy for the evaporator is bit difficult. the solution method is based on system decoupling eliminating the parasite interactions between input-output pairing variables and converting multi-inputs multi-outputs (MIMO) system to several single-inputs single-outputs (SISO) systems
Avdievich, Nikolai I; Giapitzakis, Ioannis-Angelos; Pfrommer, Andreas; Henning, Anke
2018-02-01
To improve the decoupling of a transceiver human head phased array at ultra-high fields (UHF, ≥ 7T) and to optimize its transmit (Tx) and receive (Rx) performance, a single-row eight-element (1 × 8) tight-fit transceiver overlapped loop array was developed and constructed. Overlapping the loops increases the RF field penetration depth but can compromise decoupling by generating substantial mutual resistance. Based on analytical modeling, we optimized the loop geometry and relative positioning to simultaneously minimize the resistive and inductive coupling and constructed a 9.4T eight-loop transceiver head phased array decoupled entirely by overlapping loops. We demonstrated that both the magnetic and electric coupling between adjacent loops is compensated at the same time by overlapping and nearly perfect decoupling (below -30 dB) can be obtained without additional decoupling strategies. Tx-efficiency and SNR of the overlapped array outperformed that of a common UHF gapped array of similar dimensions. Parallel Rx-performance was also not compromised due to overlapping the loops. As a proof of concept we developed and constructed a 9.4T (400 MHz) overlapped transceiver head array based on results of the analytical modeling. We demonstrated that at UHF overlapping loops not only provides excellent decoupling but also improves both Tx- and Rx-performance. Magn Reson Med 79:1200-1211, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.
International Nuclear Information System (INIS)
Yuan Hongping; Chini, Abdol R.; Lu Yujie; Shen Liyin
2012-01-01
Highlights: ► We proposes a model for projecting C and D waste reduction of construction projects. ► The model can simulate effects of various management strategies on waste reduction. ► The model integrates all essential variables that affect C and D waste reduction. ► By using the model, best strategies could be identified before being implemented. - Abstract: During the past few decades, construction and demolition (C and D) waste has received increasing attention from construction practitioners and researchers worldwide. A plethora of research regarding C and D waste management has been published in various academic journals. However, it has been determined that existing studies with respect to C and D waste reduction are mainly carried out from a static perspective, without considering the dynamic and interdependent nature of the whole waste reduction system. This might lead to misunderstanding about the actual effect of implementing any waste reduction strategies. Therefore, this research proposes a model that can serve as a decision support tool for projecting C and D waste reduction in line with the waste management situation of a given construction project, and more importantly, as a platform for simulating effects of various management strategies on C and D waste reduction. The research is conducted using system dynamics methodology, which is a systematic approach that deals with the complexity – interrelationships and dynamics – of any social, economic and managerial system. The dynamic model integrates major variables that affect C and D waste reduction. In this paper, seven causal loop diagrams that can deepen understanding about the feedback relationships underlying C and D waste reduction system are firstly presented. Then a stock-flow diagram is formulated by using software for system dynamics modeling. Finally, a case study is used to illustrate the validation and application of the proposed model. Results of the case study not only
Löbel, Swantje; Rydin, Håkan
2009-09-01
Host trees for obligate epiphytes are dynamic patches that emerge, grow and fall, and metacommunity diversity critically depends on efficient dispersal. Even though species that disperse by large asexual diaspores are strongly dispersal limited, asexual dispersal is common. The stronger dispersal limitation of asexually reproducing species compared to species reproducing sexually via small spores may be compensated by higher growth rates, lower sensitivity to habitat conditions, higher competitive ability or younger reproductive age. We compared growth and reproduction of different groups of epiphytic bryophytes with contrasting dispersal (asexual vs. sexual) and life history strategies (colonists, short- and long-lived shuttle species, perennial stayers) in an old-growth forest stand in the boreo-nemoral region in eastern Sweden. No differences were seen in relative growth rates between asexual and sexual species. Long-lived shuttles had lower growth rates than colonists and perennial stayers. Most groups grew best at intermediate bark pH. Interactions with other epiphytes had a small, often positive effect on growth. Neither differences in sensitivity of growth to habitat conditions nor differences in competitive abilities among species groups were found. Habitat conditions, however, influenced the production of sporophytes, but not of asexual diaspores. Presence of sporophytes negatively affected growth, whereas presence of asexual diaspores did not. Sexual species had to reach a certain colony size before starting to reproduce, whereas no such threshold existed for asexual reproduction. The results indicate that the epiphyte metacommunity is structured by two main trade-offs: dispersal distance vs. reproductive age, and dispersal distance vs. sensitivity to habitat quality. There seems to be a trade-off between growth and sexual reproduction, but not asexual. Trade-offs in species traits may be shaped by conflicting selection pressures imposed by habitat
Dynamic simulation of crime perpetration and reporting to examine community intervention strategies.
Yonas, Michael A; Burke, Jessica G; Brown, Shawn T; Borrebach, Jeffrey D; Garland, Richard; Burke, Donald S; Grefenstette, John J
2013-10-01
To develop a conceptual computational agent-based model (ABM) to explore community-wide versus spatially focused crime reporting interventions to reduce community crime perpetrated by youth. Agents within the model represent individual residents and interact on a two-dimensional grid representing an abstract nonempirically grounded community setting. Juvenile agents are assigned initial random probabilities of perpetrating a crime and adults are assigned random probabilities of witnessing and reporting crimes. The agents' behavioral probabilities modify depending on the individual's experience with criminal behavior and punishment, and exposure to community crime interventions. Cost-effectiveness analyses assessed the impact of activating different percentages of adults to increase reporting and reduce community crime activity. Community-wide interventions were compared with spatially focused interventions, in which activated adults were focused in areas of highest crime prevalence. The ABM suggests that both community-wide and spatially focused interventions can be effective in reducing overall offenses, but their relative effectiveness may depend on the intensity and cost of the interventions. Although spatially focused intervention yielded localized reductions in crimes, such interventions were shown to move crime to nearby communities. Community-wide interventions can achieve larger reductions in overall community crime offenses than spatially focused interventions, as long as sufficient resources are available. The ABM demonstrates that community-wide and spatially focused crime strategies produce unique intervention dynamics influencing juvenile crime behaviors through the decisions and actions of community adults. It shows how such models might be used to investigate community-supported crime intervention programs by integrating community input and expertise and provides a simulated setting for assessing dimensions of cost comparison and intervention effect
Control strategies for DC motors driving rotor dynamic systems through resonance
Bisoi, Alfa; Samantaray, A. K.; Bhattacharyya, Ranjan
2017-12-01
Rotor dynamic systems require considerably higher power/torque to accelerate through the structural resonance. However, most sources of mechanical power are non-ideal, i.e., they can only provide a limited amount of power. If there is insufficient power to overcome the resonance then the rotor speed may get caught at resonance and the persistent high vibrations can damage the machine. Various proposed solutions to this problem deal with modifications to the mechanical structure and active/semi-active control of structural parameters. This article proposes modification to the prime mover so that peak available power is delivered exactly at the structural resonance frequency. The limited power/non-ideal prime mover considered in this article is a direct current (DC) motor and the structural resonance happens due to forcing from an eccentric rotor disk and vibrations of a flexible weakly damped foundation. Various control strategies to modify the torque-speed characteristics of permanent magnet, shunt and series wound DC motors to promote escape through resonance are considered. Also, the characteristic curves for rotor/motor speed versus the DC supply voltage are obtained for the considered DC motor types from which the unattainable steady angular speeds and the speed jumps due to Sommerfeld effect are computed. Transient simulations are performed using bond graph models for this multi-energy domain (here, electro-mechanical) system. It is shown that a switched control permitting to switch between shunt and series DC motor configurations gives better regulation over the power delivery at the resonant frequency as well as super-critical operating speeds in the neighborhood of structural resonance.
Method for decoupling error correction from privacy amplification
Energy Technology Data Exchange (ETDEWEB)
Lo, Hoi-Kwong [Department of Electrical and Computer Engineering and Department of Physics, University of Toronto, 10 King' s College Road, Toronto, Ontario, Canada, M5S 3G4 (Canada)
2003-04-01
In a standard quantum key distribution (QKD) scheme such as BB84, two procedures, error correction and privacy amplification, are applied to extract a final secure key from a raw key generated from quantum transmission. To simplify the study of protocols, it is commonly assumed that the two procedures can be decoupled from each other. While such a decoupling assumption may be valid for individual attacks, it is actually unproven in the context of ultimate or unconditional security, which is the Holy Grail of quantum cryptography. In particular, this means that the application of standard efficient two-way error-correction protocols like Cascade is not proven to be unconditionally secure. Here, I provide the first proof of such a decoupling principle in the context of unconditional security. The method requires Alice and Bob to share some initial secret string and use it to encrypt their communications in the error correction stage using one-time-pad encryption. Consequently, I prove the unconditional security of the interactive Cascade protocol proposed by Brassard and Salvail for error correction and modified by one-time-pad encryption of the error syndrome, followed by the random matrix protocol for privacy amplification. This is an efficient protocol in terms of both computational power and key generation rate. My proof uses the entanglement purification approach to security proofs of QKD. The proof applies to all adaptive symmetric methods for error correction, which cover all existing methods proposed for BB84. In terms of the net key generation rate, the new method is as efficient as the standard Shor-Preskill proof.
Method for decoupling error correction from privacy amplification
International Nuclear Information System (INIS)
Lo, Hoi-Kwong
2003-01-01
In a standard quantum key distribution (QKD) scheme such as BB84, two procedures, error correction and privacy amplification, are applied to extract a final secure key from a raw key generated from quantum transmission. To simplify the study of protocols, it is commonly assumed that the two procedures can be decoupled from each other. While such a decoupling assumption may be valid for individual attacks, it is actually unproven in the context of ultimate or unconditional security, which is the Holy Grail of quantum cryptography. In particular, this means that the application of standard efficient two-way error-correction protocols like Cascade is not proven to be unconditionally secure. Here, I provide the first proof of such a decoupling principle in the context of unconditional security. The method requires Alice and Bob to share some initial secret string and use it to encrypt their communications in the error correction stage using one-time-pad encryption. Consequently, I prove the unconditional security of the interactive Cascade protocol proposed by Brassard and Salvail for error correction and modified by one-time-pad encryption of the error syndrome, followed by the random matrix protocol for privacy amplification. This is an efficient protocol in terms of both computational power and key generation rate. My proof uses the entanglement purification approach to security proofs of QKD. The proof applies to all adaptive symmetric methods for error correction, which cover all existing methods proposed for BB84. In terms of the net key generation rate, the new method is as efficient as the standard Shor-Preskill proof
Luo, Yugong; Chen, Tao; Li, Keqiang
2015-12-01
The paper presents a novel active distance control strategy for intelligent hybrid electric vehicles (IHEV) with the purpose of guaranteeing an optimal performance in view of the driving functions, optimum safety, fuel economy and ride comfort. Considering the complexity of driving situations, the objects of safety and ride comfort are decoupled from that of fuel economy, and a hierarchical control architecture is adopted to improve the real-time performance and the adaptability. The hierarchical control structure consists of four layers: active distance control object determination, comprehensive driving and braking torque calculation, comprehensive torque distribution and torque coordination. The safety distance control and the emergency stop algorithms are designed to achieve the safety and ride comfort goals. The optimal rule-based energy management algorithm of the hybrid electric system is developed to improve the fuel economy. The torque coordination control strategy is proposed to regulate engine torque, motor torque and hydraulic braking torque to improve the ride comfort. This strategy is verified by simulation and experiment using a forward simulation platform and a prototype vehicle. The results show that the novel control strategy can achieve the integrated and coordinated control of its multiple subsystems, which guarantees top performance of the driving functions and optimum safety, fuel economy and ride comfort.
Simple-decoupling treatment of high-Tc superconductors
International Nuclear Information System (INIS)
Misawa, S.
1992-01-01
The t-J model is examined within the framework of the Hubbard-I-type decoupling method of the Green's functions and by using the Fukuyama's expression for Hall coefficient R H . The superconducting transition temperature T c and the normal-state R H at finite temperature are calculated as functions of doping-fraction δ. The obtained results are symmetrical with respect to hole- and electron-doping. In the small hole-doping case, the extended s-wave state is favorable, and the behaviors of T c and R H as functions of δ are qualitatively in agreement with the experimental results. (orig.)
A decoupled power flow algorithm using particle swarm optimization technique
International Nuclear Information System (INIS)
Acharjee, P.; Goswami, S.K.
2009-01-01
A robust, nondivergent power flow method has been developed using the particle swarm optimization (PSO) technique. The decoupling properties between the power system quantities have been exploited in developing the power flow algorithm. The speed of the power flow algorithm has been improved using a simple perturbation technique. The basic power flow algorithm and the improvement scheme have been designed to retain the simplicity of the evolutionary approach. The power flow is rugged, can determine the critical loading conditions and also can handle the flexible alternating current transmission system (FACTS) devices efficiently. Test results on standard test systems show that the proposed method can find the solution when the standard power flows fail.
Electric field-decoupled electroosmotic pump for microfluidic devices.
Liu, Shaorong; Pu, Qiaosheng; Lu, Joann J
2003-09-26
An electric field-free electroosmotic pump has been constructed and its pumping rate has been measured under various experimental conditions. The key component of the pump is an ion-exchange membrane grounding joint that serves two major functions: (i) to maintain fluid continuity between pump channels and microfluidic conduit and (ii) to ground the solution in the microfluidic channel at the joint through an external electrode, and hence to decouple the electric field applied to the pump channels from the rest of the microfluidic system. A theoretical model has been developed to calculate the pumping rates and its validity has been demonstrated.
Supercritical water gasification with decoupled pressure and heat transfer modules
Dibble, Robert
2017-09-14
The present invention discloses a system and method for supercritical water gasification (SCWG) of biomass materials wherein the system includes a SCWG reactor and a plurality of heat exchangers located within a shared pressurized vessel, which decouples the function of containing high pressure from the high temperature function. The present invention allows the heat transfer function to be conducted independently from the pressure transfer function such that the system equipment can be designed and fabricated in manner that would support commercial scaled-up SCWG operations. By using heat exchangers coupled to the reactor in a series configuration, significant efficiencies are achieved by the present invention SCWG system over prior known SCWG systems.
Directory of Open Access Journals (Sweden)
Jens G. Balchen
1984-10-01
Full Text Available The problem of systematic derivation of a quasi-dynamic optimal control strategy for a non-linear dynamic process based upon a non-quadratic objective function is investigated. The wellknown LQG-control algorithm does not lead to an optimal solution when the process disturbances have non-zero mean. The relationships between the proposed control algorithm and LQG-control are presented. The problem of how to constrain process variables by means of 'penalty' - terms in the objective function is dealt with separately.
Qiu, J. P.; Niu, D. X.
Micro-grid is one of the key technologies of the future energy supplies. Take economic planning. reliability, and environmental protection of micro grid as a basis for the analysis of multi-strategy objective programming problems for micro grid which contains wind power, solar power, and battery and micro gas turbine. Establish the mathematical model of each power generation characteristics and energy dissipation. and change micro grid planning multi-objective function under different operating strategies to a single objective model based on AHP method. Example analysis shows that in combination with dynamic ant mixed genetic algorithm can get the optimal power output of this model.
Combining household income and asset data to identify livelihood strategies and their dynamics
DEFF Research Database (Denmark)
Walelign, Solomon Zena; Pouliot, Mariéve; Larsen, Helle Overgaard
2017-01-01
Current approaches to identifying and describing rural livelihood strategies, and household movements between strategies over time, in developing countries are imprecise. Here we: (i) present a new statistical quantitative approach combining income and asset data to identify household activity...... of livelihood strategies and household movements between strategies over time than using only income or asset data. Most households changed livelihood strategy at least once over the two three-year periods. A common pathway out of poverty included an intermediate step during which households accumulate assets...
DEFF Research Database (Denmark)
Shaker Barikhan, Subhi; Wörgötter, Florentin; Manoonpong, Poramate
2014-01-01
, and their interactions during body and leg movements through the environment. Based on this concept, we present here an artificial bio-inspired walking system. Its intralimb coordination is formed by multiple decoupled CPGs while its interlimb coordination is attained by the interactions between body dynamics...... and the environment through local sensory feedback of each leg. Simulation results show that this bio-inspired approach generates self-organizing emergent locomotion allowing the robot to adaptively form regular patterns, to stably walk while pushing an object with its front legs or performing multiple stepping...
Directory of Open Access Journals (Sweden)
Shunyi Li
2013-01-01
Full Text Available A predator-prey system with generalized group defense and impulsive control strategy is investigated. By using Floquet theorem and small amplitude perturbation skills, a local asymptotically stable prey-eradication periodic solution is obtained when the impulsive period is less than some critical value. Otherwise, the system is permanent if the impulsive period is larger than the critical value. By using bifurcation theory, we show the existence and stability of positive periodic solution when the pest eradication lost its stability. Numerical examples show that the system considered has more complicated dynamics, including (1 high-order quasiperiodic and periodic oscillation, (2 period-doubling and halving bifurcation, (3 nonunique dynamics (meaning that several attractors coexist, and (4 chaos and attractor crisis. Further, the importance of the impulsive period, the released amount of mature predators and the degree of group defense effect are discussed. Finally, the biological implications of the results and the impulsive control strategy are discussed.
E072/ST-HM - A dynamic maintenance strategie to meet the requirements of the LHC installation
Böttcher, O
2003-01-01
The new ST-HM contract E072 for the maintenance of transport and handling equipment is designed to obtain the high operating reliability as required for the LHC installation and to respect the situation of limited resources at CERN at the same time. The contract is based on a dynamic maintenance strategy. It contains a flexible maintenance contingent that is essential to prepare the equipment for extremely important and critical utilization phases that will come up during the LHC installation...
Li, Jing; Wu, Huayi; Yang, Chaowei; Wong, David W.; Xie, Jibo
2011-09-01
Geoscientists build dynamic models to simulate various natural phenomena for a better understanding of our planet. Interactive visualizations of these geoscience models and their outputs through virtual globes on the Internet can help the public understand the dynamic phenomena related to the Earth more intuitively. However, challenges arise when the volume of four-dimensional data (4D), 3D in space plus time, is huge for rendering. Datasets loaded from geographically distributed data servers require synchronization between ingesting and rendering data. Also the visualization capability of display clients varies significantly in such an online visualization environment; some may not have high-end graphic cards. To enhance the efficiency of visualizing dynamic volumetric data in virtual globes, this paper proposes a systematic framework, in which an octree-based multiresolution data structure is implemented to organize time series 3D geospatial data to be used in virtual globe environments. This framework includes a view-dependent continuous level of detail (LOD) strategy formulated as a synchronized part of the virtual globe rendering process. Through the octree-based data retrieval process, the LOD strategy enables the rendering of the 4D simulation at a consistent and acceptable frame rate. To demonstrate the capabilities of this framework, data of a simulated dust storm event are rendered in World Wind, an open source virtual globe. The rendering performances with and without the octree-based LOD strategy are compared. The experimental results show that using the proposed data structure and processing strategy significantly enhances the visualization performance when rendering dynamic geospatial phenomena in virtual globes.
Private quantum decoupling and secure disposal of information
International Nuclear Information System (INIS)
Buscemi, Francesco
2009-01-01
Given a bipartite system, correlations between its subsystems can be understood as the information that each one carries about the other. In order to give a model-independent description of secure information disposal, we propose the paradigm of private quantum decoupling, corresponding to locally reducing correlations in a given bipartite quantum state without transferring them to the environment. In this framework, the concept of private local randomness naturally arises as a resource, and total correlations are divided into eliminable and ineliminable ones. We prove upper and lower bounds on the quantity of ineliminable correlations present in an arbitrary bipartite state, and show that, in tripartite pure states, ineliminable correlations satisfy a monogamy constraint, making apparent their quantum nature. A relation with entanglement theory is provided by showing that ineliminable correlations constitute an entanglement parameter. In the limit of infinitely many copies of the initial state provided, we compute the regularized ineliminable correlations to be measured by the coherent information, which is thus equipped with a new operational interpretation. In particular, our results imply that two subsystems can be privately decoupled if their joint state is separable.
Decoupling - past trends and prospects for the future
International Nuclear Information System (INIS)
Azar, Christian; Holmberg, John; Karlsson, Sten
2002-05-01
There are widespread demands in society for a de materialization or decoupling of economic growth from environmental impact. Calls are being made for eco-efficiency and/or an improvement of resource efficiency by a factor of 10. At the same time, some analysts claim there is an environmental Kuznet's curve that supposedly implies a fall in environmental pressure, as we get richer. An improvement in the environmental situation has already been observed in many cases, but there are also many areas where the situation is deteriorating. The purpose of this report is to summarize some key trends of energy and material use over time in both developing and developed countries. We have focused on Sweden, the EU, Japan and the USA as well as China, India and Brazil. The main findings in this paper can be summarized as follows: Absolute emissions of CO 2 have been increasing in most countries and periods studied. Some countries have experienced periods with constant or even falling emissions, but this is the exception rather than the rule, and it has been triggered by oil crises or economic recessions. In order to stabilize atmospheric CO 2 concentrations, CO 2 emissions have to be decoupled much more rapidly than has been the case in the past, and it is extremely unlikely that this will happen by itself. There was some decoupling of CO 2 emissions from GDP in the major economies of the world from 1970 to 1998 in the EU, Japan and the US as well as in some major developing countries such as China, although India actually increased its emissions over GDP by 1.4 per cent/yr over this period. The drop in CO 2 intensity has been prompted by some decoupling of energy from GDP and CO 2 from energy, the latter being a consequence of an increased use of natural gas and nuclear power. In the South, fossil CO 2 per energy tends to increase from rather low levels. With industrialization, the proportion of biomass drops and the proportion of fossil energy rises in the energy supply mix
SKATE: a docking program that decouples systematic sampling from scoring.
Feng, Jianwen A; Marshall, Garland R
2010-11-15
SKATE is a docking prototype that decouples systematic sampling from scoring. This novel approach removes any interdependence between sampling and scoring functions to achieve better sampling and, thus, improves docking accuracy. SKATE systematically samples a ligand's conformational, rotational and translational degrees of freedom, as constrained by a receptor pocket, to find sterically allowed poses. Efficient systematic sampling is achieved by pruning the combinatorial tree using aggregate assembly, discriminant analysis, adaptive sampling, radial sampling, and clustering. Because systematic sampling is decoupled from scoring, the poses generated by SKATE can be ranked by any published, or in-house, scoring function. To test the performance of SKATE, ligands from the Asetex/CDCC set, the Surflex set, and the Vertex set, a total of 266 complexes, were redocked to their respective receptors. The results show that SKATE was able to sample poses within 2 A RMSD of the native structure for 98, 95, and 98% of the cases in the Astex/CDCC, Surflex, and Vertex sets, respectively. Cross-docking accuracy of SKATE was also assessed by docking 10 ligands to thymidine kinase and 73 ligands to cyclin-dependent kinase. 2010 Wiley Periodicals, Inc.
Visualizing decoupling in nanocrystalline alloys: A FORC-temperature analysis
Rivas, M.; Martínez-García, J. C.; Gorria, P.
2016-02-01
Devitrifying ferromagnetic amorphous precursors in the adequate conditions may give rise to disordered assemblies of densely packed nanocrystals with extraordinary magnetic softness well explained by the exchange coupling among multiple crystallites. Whether the magnetic exchange interaction is produced by direct contact or mediated by the intergranular amorphous matrix has a strong influence on the behaviour of the system above room temperature. Multi-phase amorphous-nanocrystalline systems dramatically harden when approaching the amorphous Curie temperature (TC) due to the hard grains decoupling. The study of the thermally induced decoupling of nanosized crystallites embedded in an amorphous matrix has been performed in this work by the first-order reversal curves (FORCs) analysis. We selected a Fe-rich amorphous alloy with TC = 330 K, in order to follow the evolution of the FORC diagrams obtained below and above such temperature in samples with different percentages of nanocrystalline phase. The existence of up to four regions exhibiting unlike magnetic behaviours is unambiguously determined from the temperature evolution of the FORC.
Anthropocene Dialogues: Decoupling Economic Prosperity from Carbon Emissions
Tewksbury, J.; Kohm, K.
2017-12-01
Anthropocene magazine is a new science magazine produced by Future Earth. Its mission is to bring together the world's leading scientists, technologists, and creatives to explore on-the-ground stories of sustainability science in action. For AGU 2017, Anthropocene magazine will stage an "Anthropocene Dialogue" based on its July 2017 issue. Anthropocene Dialogues are panel discussions about the successes and challenges of transformative science-policy collaborations by leading science journalists, researchers, and practitioners. The focus of this dialogue is: What are the scientific and technological innovations that drive the decarbonization of economies—from plugging artificial intelligence into electrical grids to new experiments in solar geoengineering. Panelist include: Robert Jackson of the Global Carbon Project discussing the historic decoupling of carbon emissions from GDP, Oliver Morton of The Economist speaking on how geoengineering can be a key element of a decoupling process; Robinson Meyer of The Atlantic outlining a coal "retirement plan" based on supply side economics; Wayt Gibbs of Scientific American tackling the quintessential question, How much energy will the world need? and Mark Harris of IEEE Spectrum looking at new experiments in artificial intelligence that could pull fossil fuels out of electrical grids, factories, data centers, and transit systems. For more information on these stories, visit: anthropocenemagazine.org/in-print/. Free sample copies of the magazine will be available at the session.
Energy Technology Data Exchange (ETDEWEB)
Chen, Qifang; Wang, Fei; Hodge, Bri-Mathias; Zhang, Jianhua; Li, Zhigang; Shafie-Khah, Miadreza; Catalao, Joao P. S.
2017-11-01
A real-time price (RTP)-based automatic demand response (ADR) strategy for PV-assisted electric vehicle (EV) Charging Station (PVCS) without vehicle to grid is proposed. The charging process is modeled as a dynamic linear program instead of the normal day-ahead and real-time regulation strategy, to capture the advantages of both global and real-time optimization. Different from conventional price forecasting algorithms, a dynamic price vector formation model is proposed based on a clustering algorithm to form an RTP vector for a particular day. A dynamic feasible energy demand region (DFEDR) model considering grid voltage profiles is designed to calculate the lower and upper bounds. A deduction method is proposed to deal with the unknown information of future intervals, such as the actual stochastic arrival and departure times of EVs, which make the DFEDR model suitable for global optimization. Finally, both the comparative cases articulate the advantages of the developed methods and the validity in reducing electricity costs, mitigating peak charging demand, and improving PV self-consumption of the proposed strategy are verified through simulation scenarios.
Effects of decoupling of carbon dioxide emission by Chinese nonferrous metals industry
International Nuclear Information System (INIS)
Ren Shenggang; Hu Zhen
2012-01-01
We adopted the refined Laspeyres index approach to explore the impacts of industry scale, energy mix, energy intensity and utility mix on the total carbon dioxide emissions from the Chinese nonferrous metals industry for the period 1996–2008. In addition, we calculated the trend of decoupling effects in nonferrous metals industry in China by presenting a theoretical framework for decoupling. As the results suggest, Chinese nonferrous metals industry has gone through four decoupling stages: strong negative decoupling stage (1996–1998), weak decoupling stage (1999–2000), expensive negative decoupling stage (2001–2003) and weak decoupling stage (2004–2008). We have analyzed the reasons for each phase. Generally speaking, the rapid growth of the industry is the most important factor responsible for the increase of CO 2 emissions, and the change in energy mix was mainly due to the increased proportion of electric energy consumption that has contributed to the increase of CO 2 emissions. Reduction of energy intensity has contributed significantly to emissions decrease, and the utility mix effect has also contributed to the emission decrease to some extent. - Highlights: ► We calculate the decoupling effects of CO 2 from Chinese nonferrous metals industry. ► Results demonstrate that the industry has gone through four decoupling stages. ► The output effect is most important for the increase of CO 2 emissions. ► Reduction of energy intensity has contributed significantly to emissions decrease.
Decoupled Scheme for Time-Dependent Natural Convection Problem II: Time Semidiscreteness
Directory of Open Access Journals (Sweden)
Tong Zhang
2014-01-01
stability and the corresponding optimal error estimates are presented. Furthermore, a decoupled numerical scheme is proposed by decoupling the nonlinear terms via temporal extrapolation; optimal error estimates are established. Finally, some numerical results are provided to verify the performances of the developed algorithms. Compared with the coupled numerical scheme, the decoupled algorithm not only keeps good accuracy but also saves a lot of computational cost. Both theoretical analysis and numerical experiments show the efficiency and effectiveness of the decoupled method for time-dependent natural convection problem.
Gray, A. B.
2017-12-01
Watersheds with sufficient monitoring data have been predominantly found to display nonstationary suspended sediment dynamics, whereby the relationship between suspended sediment concentration and discharge changes over time. Despite the importance of suspended sediment as a keystone of geophysical and biochemical processes, and as a primary mediator of water quality, stationary behavior remains largely assumed in the context of these applications. This study presents an investigation into the time dependent behavior of small mountainous rivers draining the coastal ranges of the western continental US over interannual to interdecadal time scales. Of the 250+ small coastal (drainage area systems. Temporal patterns of non-stationary behavior provided some evidence for spatial coherence, which may be related to synoptic hydro-metrological patterns and regional scale changes in land use patterns. However, the results also highlight the complex, integrative nature of watershed scale fluvial suspended sediment dynamics. This underscores the need for in-depth, forensic approaches for initial processes identification, which require long term, high resolution monitoring efforts in order to adequately inform management. The societal implications of nonstationary sediment dynamics and their controls were further explored through the case of California, USA, where over 150 impairment listings have resulted in more than 50 sediment TMDLs, only 3 of which are flux based - none of which account for non-stationary behavior.
The dynamic complexity of a three-species Beddington-type food chain with impulsive control strategy
International Nuclear Information System (INIS)
Wang Weiming; Wang Hailing; Li Zhenqing
2007-01-01
In this paper, by using theories and methods of ecology and ordinary differential equation, the dynamics complexity of a prey-predator system with Beddington-type functional response and impulsive control strategy is established. Conditions for the system to be extinct are given by using the Floquet theory of impulsive equation and small amplitude perturbation skills. Furthermore, by using the method of numerical simulation with the international software Maple, the influence of the impulsive perturbations on the inherent oscillation is investigated, which shows rich dynamics, such as quasi-periodic oscillation, narrow periodic window, wide periodic window, chaotic bands, period doubling bifurcation, symmetry-breaking pitchfork bifurcation, period-halving bifurcation and crises, etc. The numerical results indicate that computer simulation is a useful method for studying the complex dynamic systems
International Nuclear Information System (INIS)
Ciborowski, J.J.; Dixon, G.; Foote, L.; Liber, K.; Smits, J.E.
2007-01-01
The remediation and ecology of oilsands constructed wetlands was discussed with reference to a project known as the Carbon dynamics, Food web structure and Reclamation strategies in Athabasca oil sands Wetlands (CFRAW). This joint project between 7 mining partners and 5 universities documents how tailings in constructed wetlands modify maturation leading to natural conditions in a reclaimed landscape. Since wetlands are expected to make up 20-50 per cent of the final reclamation landscape of areas surface mined for oil sands in northeastern Alberta, the project focuses on how quickly wetlands amended with reclamation materials approach the conditions seen in reference wetland systems. This study provided a conceptual model of carbon pathways and budgets to evaluate how the allocation of carbon among compartments changes as newly formed wetlands mature in the boreal system. It is likely that succession and community development will accelerate if constructed wetlands are supplemented with stockpiled peat or topsoil. The bitumens and naphthenic acids found in wetlands constructed with mine tailings materials are initially toxic, but may ultimately serve as an alternate source of carbon once they degrade or are metabolized by bacteria. This study evaluated the sources, biological uptake, pathways, and movement through the food web of materials used by the biota in constructed wetlands, with particular reference to how productivity of new wetlands is maintained. Net ecosystem productivity is being monitored along with rates of organic carbon accumulation from microbial, algal, and macrophyte production, and influx of outside materials. The rates of leaf litter breakdown and microbial respiration are also being monitored to determine how constituents speed or slow food web processes of young and older wetlands. Carbon and nitrogen stable isotope measurements indicate which sources are incorporated into the food web as wetlands age, and how this influences community
DEFF Research Database (Denmark)
Faria, Lourenco; Andersen, Maj Munch
2017-01-01
analysis using patent data from 1965 to 2012. Our findings suggest a process of co-evolution of firms' strategies and indicate that strong sectoral-specific patterns of eco-innovation are present in this sector from the mid-2000s onwards. For fuel cells technologies, however, we observe the formation......This paper sheds light on some important but underestimated elements of green industrial dynamics: the evolution of firms' eco-innovation strategies and activities within a sector. While eco-innovation sectoral case studies have taken place before, our analysis is distinct in investigating the rate......, direction and extent of eco-innovation in the automotive sector, represented here by the main automakers, in order to identify possibly sectoral-specific patterns in firms' strategies, as opposed to divergent strategic behaviors, grounded on evolutionary economic theory. We conduct a two-step empirical...
Directory of Open Access Journals (Sweden)
Amores Ernesto
2017-06-01
Full Text Available Alkaline water electrolysis powered by renewable energy sources is one of the most promising strategies for environmentally friendly hydrogen production. However, wind and solar energy sources are highly dependent on weather conditions. As a result, power fluctuations affect the electrolyzer and cause several negative effects. Considering these limiting effects which reduce the water electrolysis efficiency, a novel operation strategy is proposed in this study. It is based on pumping the electrolyte according to the current density supplied by a solar PV module, in order to achieve the suitable fluid dynamics conditions in an electrolysis cell. To this aim, a mathematical model including the influence of electrode-membrane distance, temperature and electrolyte flow rate has been developed and used as optimization tool. The obtained results confirm the convenience of the selected strategy, especially when the electrolyzer is powered by renewable energies.
Directory of Open Access Journals (Sweden)
Rui Wang
2015-01-01
Full Text Available Obstacle avoidance is a key performance of mobile robots. However, its experimental verification is rather difficult, due to the probabilistic behaviors of both the robots and the obstacles. This paper presents the Markov Decision Process based probabilistic formal models for three obstacle-avoidance strategies of a mobile robot in an uncertain dynamic environment. The models are employed to make analyses in PRISM, and the correctness of the analysis results is verified by MATLAB simulations. Finally, the minimum time and the energy consumption are determined by further analyses in PRISM, which prove to be useful in finding the optimal strategy. The present work provides a foundation for the probabilistic formal verification of more complicated obstacle-avoidance strategies.
Konstantopoulos, Nikolaos; Trivellas, Panagiotis; Reklitis, Panagiotis
2007-12-01
According to many researchers of organizational theory, a great number of problems encountered by the manufacturing firms are due to their failure to foster innovative behaviour by aligning business strategy and structure. From this point of view, the fit between strategy and structure is essential in order to facilitate firms' innovative behaviour. In the present paper, we adopt Porter's typology to operationalise business strategy (cost leadership, innovative and marketing differentiation, and focus). Organizational structure is built on four dimensions (centralization, formalization, complexity and employees' initiatives to implement new ideas). Innovativeness is measured as product innovation, process and technological innovation. This study provides the necessary theoretical framework for the development of a dynamic simulation method, although the simulation of social events is a quite difficult task, considering that there are so many alternatives (not all well understood).
Jibson, Randall W.; Jibson, Matthew W.
2003-01-01
Landslides typically cause a large proportion of earthquake damage, and the ability to predict slope performance during earthquakes is important for many types of seismic-hazard analysis and for the design of engineered slopes. Newmark's method for modeling a landslide as a rigid-plastic block sliding on an inclined plane provides a useful method for predicting approximate landslide displacements. Newmark's method estimates the displacement of a potential landslide block as it is subjected to earthquake shaking from a specific strong-motion record (earthquake acceleration-time history). A modification of Newmark's method, decoupled analysis, allows modeling landslides that are not assumed to be rigid blocks. This open-file report is available on CD-ROM and contains Java programs intended to facilitate performing both rigorous and simplified Newmark sliding-block analysis and a simplified model of decoupled analysis. For rigorous analysis, 2160 strong-motion records from 29 earthquakes are included along with a search interface for selecting records based on a wide variety of record properties. Utilities are available that allow users to add their own records to the program and use them for conducting Newmark analyses. Also included is a document containing detailed information about how to use Newmark's method to model dynamic slope performance. This program will run on any platform that supports the Java Runtime Environment (JRE) version 1.3, including Windows, Mac OSX, Linux, Solaris, etc. A minimum of 64 MB of available RAM is needed, and the fully installed program requires 400 MB of disk space.
Edelbring, Samuel; Wahlström, Rolf
2016-04-23
Students' self-regulated learning becomes essential with increased use of exploratory web-based activities such as virtual patients (VPs). The purpose was to investigate the interplay between students' self-regulated learning strategies and perceived benefit in VP learning activities. A cross-sectional study (n = 150) comparing students' study strategies and perceived benefit of a virtual patient learning activity in a clinical clerkship preparatory course. Teacher regulation varied among three settings and was classified from shared to strong. These settings were compared regarding their respective relations between regulation strategies and perceived benefit of the virtual patient activity. Self-regulation learning strategy was generally associated with perceived benefit of the VP activities (rho 0.27, p strategies can increase the value of flexible web-based learning resources to students.
Decoupled Implementation of New-Wave Land Reforms
DEFF Research Database (Denmark)
Pedersen, Rasmus Hundsbæk
2012-01-01
Decentralisation is a key element in the new wave of land reforms that have been introduced in sub-Saharan Africa. However, not much research has been carried out into their implementation at the local level. Consequently, reforms are described in old-fashioned terms. Through comparative case stu...... the local level as a part of the land administration structure.......Decentralisation is a key element in the new wave of land reforms that have been introduced in sub-Saharan Africa. However, not much research has been carried out into their implementation at the local level. Consequently, reforms are described in old-fashioned terms. Through comparative case...... studies in Tanzania, this article unpacks implementation as a process consisting of multiple administrative layers and potential actors. It concludes that implementation is slow and uneven due to the decoupling of layers within the formal land administration. Greater attention should be directed towards...
TALE proteins search DNA using a rotationally decoupled mechanism.
Cuculis, Luke; Abil, Zhanar; Zhao, Huimin; Schroeder, Charles M
2016-10-01
Transcription activator-like effector (TALE) proteins are a class of programmable DNA-binding proteins used extensively for gene editing. Despite recent progress, however, little is known about their sequence search mechanism. Here, we use single-molecule experiments to study TALE search along DNA. Our results show that TALEs utilize a rotationally decoupled mechanism for nonspecific search, despite remaining associated with DNA templates during the search process. Our results suggest that the protein helical structure enables TALEs to adopt a loosely wrapped conformation around DNA templates during nonspecific search, facilitating rapid one-dimensional (1D) diffusion under a range of solution conditions. Furthermore, this model is consistent with a previously reported two-state mechanism for TALE search that allows these proteins to overcome the search speed-stability paradox. Taken together, our results suggest that TALE search is unique among the broad class of sequence-specific DNA-binding proteins and supports efficient 1D search along DNA.
Magnetic decoupling of ferromagnetic metals through a graphene spacer
Energy Technology Data Exchange (ETDEWEB)
Grimaldi, I.; Papagno, M. [Dipartimento di Fisica, Universitá della Calabria, Arcavacata di Rende (CS), 87036 (Italy); Ferrari, L. [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Roma I-00133 (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy); Sheverdyaeva, P.M.; Mahatha, S.K. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy); Pacilé, D., E-mail: daniela.pacile@fis.unical.it [Dipartimento di Fisica, Universitá della Calabria, Arcavacata di Rende (CS), 87036 (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy); Carbone, C. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy)
2017-03-15
We study the magnetic coupling between different ferromagnetic metals (FMs) across a graphene (G) layer, and the role of graphene as a thin covalent spacer. Starting with G grown on a FM substrate (Ni or Co), we deposited on top at room temperature several FM metals (Fe, Ni, Co). By measuring the dichroic effect of 3p photoemission lines we detect the magnetization of the substrate and the sign of the exchange coupling in FM overlayer at room temperature. We show that the G layer magnetically decouples the FM metals. - Highlights: • The magnetic coupling between ferromagnets mediated by graphene is studied. • To this end, the linear dichroic effect in 3p photoemission lines is employed. • For selected junctions no magnetic coupling is attained through graphene. • Graphene inhibits the magnetic alignment that normally occurs between ferromagnets.
Artificial electron acceptors decouple archaeal methane oxidation from sulfate reduction.
Scheller, Silvan; Yu, Hang; Chadwick, Grayson L; McGlynn, Shawn E; Orphan, Victoria J
2016-02-12
The oxidation of methane with sulfate is an important microbial metabolism in the global carbon cycle. In marine methane seeps, this process is mediated by consortia of anaerobic methanotrophic archaea (ANME) that live in syntrophy with sulfate-reducing bacteria (SRB). The underlying interdependencies within this uncultured symbiotic partnership are poorly understood. We used a combination of rate measurements and single-cell stable isotope probing to demonstrate that ANME in deep-sea sediments can be catabolically and anabolically decoupled from their syntrophic SRB partners using soluble artificial oxidants. The ANME still sustain high rates of methane oxidation in the absence of sulfate as the terminal oxidant, lending support to the hypothesis that interspecies extracellular electron transfer is the syntrophic mechanism for the anaerobic oxidation of methane. Copyright © 2016, American Association for the Advancement of Science.
ECONOMIC GROWTH AND AIR POLLUTION IN THECZECHREPUBLIC: DECOUPLING CURVES
Directory of Open Access Journals (Sweden)
Petr Šauer
2012-07-01
Full Text Available The decoupling curve, together with the Environmental Kuznets Curve, has beenrecognized as one of the important indicators showing relations betweeneconomic growth and environmental degradation/pollution. Many boththeoreticaland empirical studies have been published on it. Our paper brings models whichinvestigate relations between the economic growth per capita and selectedindicators of air pollution in theCzechRepublic. The analysis tried to go beforethe year 1990, despite the difficulties when dealing with different macroeconomicindicators published during the socialist period and those introduced after thetransition to a market economy. The results might be somehow surprising forthose dealing only with data generated after the year 1990: it is possible todiscover the turning points for some of the airborne pollutants already in the1980s.
The effective gravitational decoupling between dark matter and the CMB
Voruz, Luc; Tram, Thomas
2014-01-01
We present a detailed and self-contained analytical derivation of the evolution of sub-horizon cosmological perturbations before decoupling, based on previous work by S. Weinberg. These solutions are valid in the minimal LCDM scenario, to first order in perturbation theory, in the tight-coupling limit and neglecting neutrino shear stress. We compare them to exact numerical solutions computed by a Boltzmann code, and we find the two to be in very good agreement. The analytic solutions show explicitly that CDM and the baryon-photon fluid effectively behave as separate self-gravitating fluids until the epoch of baryon drag. This in turn leads to the surprising conclusion that the CMB is much less sensitive to the clustering properties of minimally coupled Dark Matter models than what would be naively expected.
Global coupling and decoupling of the APS storage ring
Energy Technology Data Exchange (ETDEWEB)
Chae, Y.C.; Liu, J.; Teng, L.C.
1993-07-01
This paper describes a study of controlling the coupling between the horizontal and the vertical betatron oscillations in the 7-GeV Advanced Photon Source (APS) storage ring. First, we investigate the strengthening of coupling using two families of skew quadrupoles. Twenty skew quadrupoles are arranged in the 40 sectors of the storage ring and powered in such a way so as to generate both quadrature components of the required 21st harmonic. The numerical results from tracking a single particle are presented for the various configurations of skew quadrupoles. Second, we describe the global decoupling procedure to minimize the unwanted coupling effects. These are mainly due to the random roll errors of normal quadruples. It is shown that even with the rather large rms roll error of 2 mrad, the coupling effects can be compensated for with 20 skew quadrupoles each having maximum strength one order of magnitude lower than the typical normal quadrupole strength.
Directory of Open Access Journals (Sweden)
Laurent Coudeville
Full Text Available BACKGROUND: Prior economic evaluations of adult and adolescent vaccination strategies against pertussis have reached disparate conclusions. Using static approaches only, previous studies failed to analytically include the indirect benefits derived from herd immunity as well as the impact of vaccination on the evolution of disease incidence over time. METHODS: We assessed the impact of different pertussis vaccination strategies using a dynamic compartmental model able to consider pertussis transmission. We then combined the results with economic data to estimate the relative cost-effectiveness of pertussis immunization strategies for adolescents and adults in the US. The analysis compares combinations of programs targeting adolescents, parents of newborns (i.e. cocoon strategy, or adults of various ages. RESULTS: In the absence of adolescent or adult vaccination, pertussis incidence among adults is predicted to more than double in 20 years. Implementing an adult program in addition to childhood and adolescent vaccination either based on 1 a cocoon strategy and a single booster dose or 2 a decennial routine vaccination would maintain a low level of pertussis incidence in the long run for all age groups (respectively 30 and 20 cases per 100,000 person years. These strategies would also result in significant reductions of pertussis costs (between -77% and -80% including additional vaccination costs. The cocoon strategy complemented by a single booster dose is the most cost-effective one, whereas the decennial adult vaccination is slightly more effective in the long run. CONCLUSIONS: By providing a high level of disease control, the implementation of an adult vaccination program against pertussis appears to be highly cost-effective and often cost-saving.
Bartolini, R.
2016-01-01
This paper introduces the most recent achievements in the control of nonlinear dynamics in electron synchrotron light sources, with special attention to diffraction limited storage rings. Guidelines for the design and optimization of the magnetic lattice are reviewed and discussed.
Martinez, N.
2016-09-06
Water and protein dynamics on a nanometer scale were measured by quasi-elastic neutron scattering in the piezophile archaeon Thermococcus barophilus and the closely related pressure-sensitive Thermococcus kodakarensis, at 0.1 and 40 MPa. We show that cells of the pressure sensitive organism exhibit higher intrinsic stability. Both the hydration water dynamics and the fast protein and lipid dynamics are reduced under pressure. In contrast, the proteome of T. barophilus is more pressure sensitive than that of T. kodakarensis. The diffusion coefficient of hydration water is reduced, while the fast protein and lipid dynamics are slightly enhanced with increasing pressure. These findings show that the coupling between hydration water and cellular constituents might not be simply a master-slave relationship. We propose that the high flexibility of the T. barophilus proteome associated with reduced hydration water may be the keys to the molecular adaptation of the cells to high hydrostatic pressure.
Martinez, N.; Michoud, Gregoire; Cario, A.; Ollivier, J.; Franzetti, B.; Jebbar, M.; Oger, P.; Peters, J.
2016-01-01
Water and protein dynamics on a nanometer scale were measured by quasi-elastic neutron scattering in the piezophile archaeon Thermococcus barophilus and the closely related pressure-sensitive Thermococcus kodakarensis, at 0.1 and 40 MPa. We show that cells of the pressure sensitive organism exhibit higher intrinsic stability. Both the hydration water dynamics and the fast protein and lipid dynamics are reduced under pressure. In contrast, the proteome of T. barophilus is more pressure sensitive than that of T. kodakarensis. The diffusion coefficient of hydration water is reduced, while the fast protein and lipid dynamics are slightly enhanced with increasing pressure. These findings show that the coupling between hydration water and cellular constituents might not be simply a master-slave relationship. We propose that the high flexibility of the T. barophilus proteome associated with reduced hydration water may be the keys to the molecular adaptation of the cells to high hydrostatic pressure.
Directory of Open Access Journals (Sweden)
Hui Li
2014-04-01
Full Text Available Three-motor synchronous coordination system is a MI-MO nonlinear and complex control system. And it often works in poor working condition. Advanced control strategies are required to improve the control performance of the system and to achieve the decoupling between main motor speed and tension. Cerebellar Model Articulation Controller coupled with Active Disturbance Rejection Control (CMAC-ADRC control strategy is proposed. The speed of the main motor and tensions between two motors is decoupled by extended state observer (ESO in ADRC. ESO in ADRC is used to compensate internal and external disturbances of the system online. And the anti interference of the system is improved by ESO. And the same time the control model is optimized. Feedforward control is implemented by the adoption of CMAC neural network controller. And control precision of the system is improved in reason of CMAC. The overshoot of the system can be reduced without affecting the dynamic response of the system by the use of CMAC-ADRC. The simulation results show that: the CMAC- ADRC control strategy is better than the traditional PID control strategy. And CMAC-ADRC control strategy can achieve the decoupling between speed and tension. The control system using CMAC-ADRC have strong anti-interference ability and small regulate time and small overshoot. The magnitude of the system response incited by the interference using CMAC-ADRC is smaller than the system using conventional PID control 6.43 %. And the recovery time of the system with CMAC-ADRC is shorter than the system with traditional PID control 0.18 seconds. And the triangular wave tracking error of the system with CMAC-ADRC is smaller than the system with conventional PID control 0.24 rad/min. Thus the CMAC-ADRC control strategy is a good control strategy and is able to fit three-motor synchronous coordinated control.
Surfing on sandy beaches: an efficient strategy to flourish in a highly dynamic environment?
Vanagt, T.; Merckx, B.; Vincx, M.; Degraer, S.
2007-01-01
The gastropod Olivella semistriata is a dominant surfer on exposed, intermediate beaches in the tropical part of the East-Pacific. The impact of the swash dynamics on the feeding behaviour of the species was studied in order to improve the understanding of the swash zonation pattern of O. semistriata, and its general success on beaches. The feeding activity of dense patch of Olivella semistriata was monitored for 5 to 15 min, while simultaneously noting the swash dynamics. Feeding time and fe...
Power-optimal force decoupling in a hybrid linear reluctance motor
Overboom, T.T.; Smeets, J.P.C.; Jansen, J.W.; Lomonova, E.A.; Mavrudieva, D.
2015-01-01
This paper concerns the power-optimal decoupling of the propulsion and normal force created by a hybrid linear reluctance motor. The intrinsic limitations to the decoupling is addressed by the visualizing each force component with a quadric surface in the Euclidean space which is spanned by the
Improved Decoupling for 13C coil Arrays Using Non-Conventional Matching and Preamplifier Impedance
DEFF Research Database (Denmark)
Sanchez, Juan Diego; Johansen, Daniel Højrup; Hansen, Rie Beck
In this study, we describe a method to obtain improved preamplifier decoupling for receive-only coils. The method relies on the better decoupling obtained when coils are matched to an impedance higher than 50 . Preamplifiers with inductive imaginary impedance and low real impedance, increase...
Efficient decoupling schemes with bounded controls based on Eulerian orthogonal arrays
International Nuclear Information System (INIS)
Wocjan, Pawel
2006-01-01
The task of decoupling, i.e., removing unwanted internal couplings of a quantum system and its couplings to an environment, plays an important role in quantum control theory. There are many efficient decoupling schemes based on combinatorial concepts such as orthogonal arrays, difference schemes, and Hadamard matrices. So far these combinatorial decoupling schemes have relied on the ability to effect sequences of instantaneous, arbitrarily strong control Hamiltonians (bang-bang controls). To overcome the shortcomings of bang-bang control, Viola and Knill proposed a method called 'Eulerian decoupling' that allows the use of bounded-strength controls for decoupling. However, their method was not directly designed to take advantage of the local structure of internal couplings and couplings to an environment that typically occur in multipartite quantum systems. In this paper we define a combinatorial structure called Eulerian orthogonal array. It merges the desirable properties of orthogonal arrays and Eulerian cycles in Cayley graphs (that are the basis of Eulerian decoupling). We show that this structure gives rise to decoupling schemes with bounded-strength control Hamiltonians that can be used to remove both internal couplings and couplings to an environment of a multipartite quantum system. Furthermore, we show how to construct Eulerian orthogonal arrays having good parameters in order to obtain efficient decoupling schemes
Directory of Open Access Journals (Sweden)
Zhenzhen Lei
2017-01-01
Full Text Available The driving pattern has an important influence on the parameter optimization of the energy management strategy (EMS for hybrid electric vehicles (HEVs. A new algorithm using simulated annealing particle swarm optimization (SA-PSO is proposed for parameter optimization of both the power system and control strategy of HEVs based on multiple driving cycles in order to realize the minimum fuel consumption without impairing the dynamic performance. Furthermore, taking the unknown of the actual driving cycle into consideration, an optimization method of the dynamic EMS based on driving pattern recognition is proposed in this paper. The simulation verifications for the optimized EMS based on multiple driving cycles and driving pattern recognition are carried out using Matlab/Simulink platform. The results show that compared with the original EMS, the former strategy reduces the fuel consumption by 4.36% and the latter one reduces the fuel consumption by 11.68%. A road test on the prototype vehicle is conducted and the effectiveness of the proposed EMS is validated by the test data.
Directory of Open Access Journals (Sweden)
Wim Munters
2018-01-01
Full Text Available In wind farms, wakes originating from upstream turbines cause reduced energy extraction and increased loading variability in downstream rows. The prospect of mitigating these detrimental effects through coordinated controllers at the wind-farm level has fueled a multitude of research efforts in wind-farm control. The main strategies in wind-farm control are to influence the velocity deficits in the wake by deviating from locally optimal axial induction setpoints on the one hand, and steering wakes away from downstream rows through yaw misalignment on the other hand. The current work investigates dynamic induction and yaw control of individual turbines for wind-farm power maximization in large-eddy simulations. To this end, receding-horizon optimal control techniques combined with continuous adjoint gradient evaluations are used. We study a 4 × 4 aligned wind farm, and find that for this farm layout yaw control is more effective than induction control, both for uniform and turbulent inflow conditions. Analysis of optimal yaw controls leads to the definition of two simplified yaw control strategies, in which wake meandering and wake redirection are exploited respectively. Furthermore it is found that dynamic yawing provides significant benefits over static yaw control in turbulent flow environments, whereas this is not the case for uniform inflow. Finally, the potential of combining overinductive axial induction control with yaw control is shown, with power gains that approximate the sum of those achieved by each control strategy separately.
Boyi Xiao; Huazhong Lu; Hailin Wang; Jiageng Ruan; Nong Zhang
2017-01-01
A regenerative braking system and hydraulic braking system are used in conjunction in the majority of electric vehicles worldwide. We propose a new regenerative braking distribution strategy that is based on multi-input fuzzy control logic while considering the influences of the battery’s state of charge, the brake strength and the motor speed. To verify the braking performance and recovery economy, this strategy was applied to a battery electric vehicle model and compared with two other impr...
Directory of Open Access Journals (Sweden)
Boyi Xiao
2017-11-01
Full Text Available A regenerative braking system and hydraulic braking system are used in conjunction in the majority of electric vehicles worldwide. We propose a new regenerative braking distribution strategy that is based on multi-input fuzzy control logic while considering the influences of the battery’s state of charge, the brake strength and the motor speed. To verify the braking performance and recovery economy, this strategy was applied to a battery electric vehicle model and compared with two other improved regenerative braking strategies. The performance simulation was performed using standard driving cycles (NEDC, LA92, and JP1015 and a real-world-based urban cycle in China. The tested braking strategies satisfied the general safety requirements of Europe (as specified in ECE-13H, and the emergency braking scenario and economic potential were tested. The simulation results demonstrated the differences in the braking force distribution performance of these three regenerative braking strategies, the feasibility of the braking methods for the proposed driving cycles and the energy economic potential of the three strategies.
Decoupling Economic Growth From Carbon Dioxide Emissions in the EU Countries
Directory of Open Access Journals (Sweden)
Mariola Piłatowska
2018-03-01
Full Text Available This paper aims to look at the long-run equilibrium relationship between CO2 emissions and economic growth (the EKC hypothesis in an asymmetric framework using the non-linear threshold cointegration. In order to avoid the problem of omitted variables bias, the dynamic relationship between pollutant emissions, economic development and energy consumption are also examined (the extended EKC model. The research hypothesis is that the economic growth decouples from CO2 emissions growth, i.e. the EKC hypothesis holds. The empirical study is carried out for the European Union countries (EU-14 divided into three groups depending on a category of knowledge-advanced economies in order to explain the differences in the dynamic linkage between CO2 emissions and economic growth, as well as in the energy consumption impact on this cointegrating relationship. We have found that the EKC hypothesis is valid for the most high-level and some middle-level knowledge advanced economies. The addition of energy consumption to the standard EKC model has improved the results in terms of the presence of linear or threshold cointegration for all low-level knowledge based economies. Moreover, the causality pattern between CO2 emissions and income has changed after energy consumption adding to the EKC model and some similarities are found in the countries belonging to the same category of knowledge-advanced economies
A novel hybrid actuation mechanism based XY nanopositioning stage with totally decoupled kinematics
Zhu, Wu-Le; Zhu, Zhiwei; Guo, Ping; Ju, Bing-Feng
2018-01-01
This paper reports the design, analysis and testing of a parallel two degree-of-freedom piezo-actuated compliant stage for XY nanopositioning by introducing an innovative hybrid actuation mechanism. It mainly features the combination of two Scott-Russell and a half-bridge mechanisms for double-stage displacement amplification as well as moving direction modulation. By adopting the leaf-type double parallelogram (LTDP) structures at both input and output ends of the hybrid mechanism, the lateral stiffness and dynamic characteristics are significantly improved while the parasitic motions are greatly eliminated. The XY nanopositioning stage is constructed with two orthogonally configured hybrid mechanisms along with the LTDP mechanisms for totally decoupled kinematics at both input and output ends. An analytical model was established to describe the complete elastic deformation behavior of the stage, with further verification through the finite element simulation. Finally, experiments were implemented to comprehensively evaluate both the static and dynamic performances of the proposed stage. Closed-loop control of the piezoelectric actuators (PEA) by integrating strain gauges was also conducted to effectively eliminate the nonlinear hysteresis of the stage.
Energy Company strategies in the dynamic EU Energy Market (1995-2007)
International Nuclear Information System (INIS)
Van den Heuvel, S.; De Jong, J.; Van der Linde, C.; Sherwood, D.
2010-05-01
Generally, companies adapt their strategies to a changing environment, a process that often moves faster than the implementation of new policy measures. These strategic reactions are often taken to mitigate risks and to secure a strong position in an increasingly competitive market. Such responses interact with the main policy priorities. It is therefore interesting to understand the interaction between company strategies and policy priorities and to assess whether synergies can be found and whether strategies and policy objectives can be aligned. This study concentrates on gas and electricity companies in Europe's largest markets. The structure of the paper is as follows. Chapter 2 introduces the major changes that have taken place and that have formed the basis of the EU's new energy policy priorities. Chapter 3 presents the strategic responses that followed these major trends. In Chapter 4, specific strategies that companies developed to deal with the changing environment are highlighted and illustrated with examples. Chapter 5 discusses the alignment of company strategies and policy objectives and presents a number of policy recommendations to make use of the companies for reaching policy targets. The final chapter provides the conclusion. A number of appendices are included to provide background to the analyses.
Trabucchi, Stefano; Casella, Francesco; Maioli, Tommaso; Elsido, Cristina; Franzini, Davide; Ramond, Mathieu
2017-06-01
Concentrated Solar Power plants (CSP) coupled with thermal storage have the potential to guarantee both flexible and continuous energy production, thus being competitive with conventional fossil fuel and hydro power plants, in terms of dispatchability and provision of ancillary services. Hence, the plant equipment and control design have to be focused on flexible operation on one hand, and on plant safety concerning the molten salt freezing on the other hand. The PreFlexMS European project aims to introduce a molten salt Once-Through Steam Generator (OTSG) within a Rankine cycle based power unit, a technology that has greater flexibility potential if compared to steam drum boilers, currently used in CSP plants. The dynamic modelling and simulation from the early design stages is, thus, of paramount importance, to assess the plant dynamic behavior and controllability, and to predict the achievable closed-loop dynamic performance, potentially saving money and time during the detailed design, construction and commissioning phases. The present paper reports the main results of the analysis carried out during the first part of the project, regarding the system analysis and control design. In particular, two different control systems have been studied and tested with the plant dynamic model: a decentralized control strategy based on PI controllers and a Linear Model Predictive Control (LMPC).
Directory of Open Access Journals (Sweden)
Imam Wahyudi
2013-04-01
Full Text Available Firm’s strategic orientation involves synchronizing environmental dynamics, corporate strategy and capital structure in order to achieve firm performance targets. The co-alignment model used successfully in the hospitality industry might be used in a wider context as a framework in explain- ing these relationships simultaneously. Using the data of public firms in Indonesia during the pe- riod of 1996-2010, we found that co-alignment model can be implemented in property and real estate industry as well as in hospitality industry.
International Nuclear Information System (INIS)
Jahedi, G.; Ardehali, M.M.
2012-01-01
Highlights: ► In HVAC systems, temperature and relative humidity are coupled and dynamic mathematical models are non-linear. ► A wavelet-based ANN is used in series with an infinite impulse response filter for self tuning of PD controller. ► Energy consumption is evaluated for a decoupled bi-linear HVAC system with variable air volume and variable water flow. ► Substantial enhancement in energy efficiency is realized, when the gain coefficients of PD controllers are tuned adaptively. - Abstract: Control methodologies could lower energy demand and consumption of heating, ventilating and air conditioning (HVAC) systems and, simultaneously, achieve better comfort conditions. However, the application of classical controllers is unsatisfactory as HVAC systems are non-linear and the control variables such as temperature and relative humidity (RH) inside the thermal zone are coupled. The objective of this study is to develop and simulate a wavelet-based artificial neural network (WNN) for self tuning of a proportional-derivative (PD) controller for a decoupled bi-linear HVAC system with variable air volume and variable water flow responsible for controlling temperature and RH of a thermal zone, where thermal comfort and energy consumption of the system are evaluated. To achieve the objective, a WNN is used in series with an infinite impulse response (IIR) filter for faster and more accurate identification of system dynamics, as needed for on-line use and off-line batch mode training. The WNN-IIR algorithm is used for self-tuning of two PD controllers for temperature and RH. The simulation results show that the WNN-IIR controller performance is superior, as compared with classical PD controller. The enhancement in efficiency of the HVAC system is accomplished due to substantially lower consumption of energy during the transient operation, when the gain coefficients of PD controllers are tuned in an adaptive manner, as the steady state setpoints for temperature and
Short Term Strategies for a Dynamic Multi-Period Routing Problem
Angelelli, E.; Bianchessi, N.; Mansini, R.; Speranza, M. G.
2009-01-01
We consider a Dynamic Multi-Period Routing Problem (DMPRP) faced by a company which deals with on-line pick-up requests and has to serve them by a fleet of uncapacitated vehicles over a finite time horizon. When a request is issued, a deadline of a given number of days d ≤ 2 is associated to it: if
Graaf, J. van der; Segers, P.C.J.; Verhoeven, L.T.W.
2015-01-01
A dynamic assessment tool was developed and validated using Mokken scale analysis to assess the extent to which kindergartners are able to construct unconfounded experiments, an essential part of scientific reasoning. Scientific reasoning is one of the learning processes happening within science
Jongejans, E.
2004-01-01
This study aims to contribute to the knowledge of how plants respond to adverse influences of intensified land use. In particular, attention was paid to the ways in which life history strategies change in order to buffer environmental variation, and which important parts of the life cycle are
The development of small cities has been adopted as the main strategy to make full use of extra labor in the rural areas of China. The ecological and economic consequences of this development will affect over 100 million people and change the organization of agricultural systems ...
Household Income Strategies and Natural Disasters: Dynamic Livelihoods in Rural Nicaragua
Berg, van den M.M.
2010-01-01
This paper assesses the impact of hurricane Mitch on livelihood strategies of rural households in Nicaragua. Through destruction or distress sales of productive assets, a hurricane or another natural hazard could induce people with relatively remunerative livelihoods to choose more defensive
Czech Academy of Sciences Publication Activity Database
Krasovská, Maryna V.; Sefcikova, J.; Špačková, Naďa; Šponer, Jiří; Walter, N. G.
2005-01-01
Roč. 22, č. 6 (2005), s. 774 ISSN 0739-1102. [Albany 2005. Conversation /14./. 14.06.2005-18.06.2005, Albany] Institutional research plan: CEZ:AV0Z50040507 Keywords : catalytic strategies * hepatitis delta virus Subject RIV: BO - Biophysics
Programming strategy for efficient modeling of dynamics in a population of heterogeneous cells.
Hald, Bjørn Olav; Garkier Hendriksen, Morten; Sørensen, Preben Graae
2013-05-15
Heterogeneity is a ubiquitous property of biological systems. Even in a genetically identical population of a single cell type, cell-to-cell differences are observed. Although the functional behavior of a given population is generally robust, the consequences of heterogeneity are fairly unpredictable. In heterogeneous populations, synchronization of events becomes a cardinal problem-particularly for phase coherence in oscillating systems. The present article presents a novel strategy for construction of large-scale simulation programs of heterogeneous biological entities. The strategy is designed to be tractable, to handle heterogeneity and to handle computational cost issues simultaneously, primarily by writing a generator of the 'model to be simulated'. We apply the strategy to model glycolytic oscillations among thousands of yeast cells coupled through the extracellular medium. The usefulness is illustrated through (i) benchmarking, showing an almost linear relationship between model size and run time, and (ii) analysis of the resulting simulations, showing that contrary to the experimental situation, synchronous oscillations are surprisingly hard to achieve, underpinning the need for tools to study heterogeneity. Thus, we present an efficient strategy to model the biological heterogeneity, neglected by ordinary mean-field models. This tool is well posed to facilitate the elucidation of the physiologically vital problem of synchronization. The complete python code is available as Supplementary Information. bjornhald@gmail.com or pgs@kiku.dk Supplementary data are available at Bioinformatics online.
Critical dynamics in the evolution of stochastic strategies for the iterated prisoner's dilemma.
Directory of Open Access Journals (Sweden)
Dimitris Iliopoulos
2010-10-01
Full Text Available The observed cooperation on the level of genes, cells, tissues, and individuals has been the object of intense study by evolutionary biologists, mainly because cooperation often flourishes in biological systems in apparent contradiction to the selfish goal of survival inherent in Darwinian evolution. In order to resolve this paradox, evolutionary game theory has focused on the Prisoner's Dilemma (PD, which incorporates the essence of this conflict. Here, we encode strategies for the iterated Prisoner's Dilemma (IPD in terms of conditional probabilities that represent the response of decision pathways given previous plays. We find that if these stochastic strategies are encoded as genes that undergo Darwinian evolution, the environmental conditions that the strategies are adapting to determine the fixed point of the evolutionary trajectory, which could be either cooperation or defection. A transition between cooperative and defective attractors occurs as a function of different parameters such as mutation rate, replacement rate, and memory, all of which affect a player's ability to predict an opponent's behavior. These results imply that in populations of players that can use previous decisions to plan future ones, cooperation depends critically on whether the players can rely on facing the same strategies that they have adapted to. Defection, on the other hand, is the optimal adaptive response in environments that change so quickly that the information gathered from previous plays cannot usefully be integrated for a response.
Macroeconomics, financial crisis and the environment: Strategies for a sustainability transition
Antal, M.; van den Bergh, J.C.J.M.
2013-01-01
We raise fundamental questions about macroeconomics relevant to escaping the financial-economic crisis and shifting to a sustainable economy. First, the feasibility of decoupling environmental pressure from aggregate income is considered. Decoupling as a single environmental strategy is found to be
Directory of Open Access Journals (Sweden)
Chaiwat Wilasang
2016-01-01
Full Text Available Avian influenza virus subtype H5N1 is endemic to Southeast Asia. In Thailand, avian influenza viruses continue to cause large poultry stock losses. The spread of the disease has a serious impact on poultry production especially among rural households with backyard chickens. The movements and activities of chicken traders result in the spread of the disease through traditional trade networks. In this study, we investigate the dynamics of avian influenza in the traditional trade network in Phitsanulok Province, Thailand. We also propose an individual-based model with intervention strategies to control the spread of the disease. We found that the dynamics of the disease mainly depend on the transmission probability and the virus inactivation period. This study also illustrates the appropriate virus disinfection period and the target for intervention strategies on traditional trade network. The results suggest that good hygiene and cleanliness among household traders and trader of trader areas and ensuring that any equipment used is clean can lead to a decrease in transmission and final epidemic size. These results may be useful to epidemiologists, researchers, and relevant authorities in understanding the spread of avian influenza through traditional trade networks.
A critical overview of industrial energy decoupling programs in six developing countries in Asia
International Nuclear Information System (INIS)
Luken, Ralph A.; Piras, Stefano
2011-01-01
In reviewing the journal literature on the decoupling of energy use and industrial output in the Asian region, particularly with respect to developing countries, we found little information about most country programs other than for China and India and only one article that compared the programs of these two countries. For this reason, we used diverse sources to identify the key programmatic features that have contributed, but clearly are not totally responsible for, decoupling achievements of two countries ( China and Thailand) and then, on the basis of these findings, reviewed emerging industrial energy decoupling programs in four other countries (India, Indonesia, Malaysia and Vietnam). We found that the design of the two successful on-going decoupling programs have common features, which are setting an explicit target for decoupling of energy use and industrial output, a government program that offers financial incentives and imposes specific auditing and reporting requirements and involvement of the manufacturing sector in designing and implementing targets as they apply to individual enterprises. We also found that the emerging programs in the other four countries lack some or all of these essential programmatic features. - Highlights: → We reviewed two on-going and four emerging industrial energy decoupling programs. → These six Asian developing countries have very different rates of decoupling. → The two successful on-going programs share three common features. → These are quantitative targets, supportive programs and industry involvement. → The four emerging programs lack some or all of these features.
Directory of Open Access Journals (Sweden)
M. H. El-Saify
2017-01-01
Full Text Available The distillation process is vital in many fields of chemical industries, such as the two-coupled distillation columns that are usually highly nonlinear Multi-Input Multi-Output (MIMO coupled processes. The control of MIMO process is usually implemented via a decentralized approach using a set of Single-Input Single-Output (SISO loop controllers. Decoupling the MIMO process into group of single loops requires proper input-output pairing and development of decoupling compensator unit. This paper proposes a novel intelligent decoupling approach for MIMO processes based on new MIMO brain emotional learning architecture. A MIMO architecture of Brain Emotional Learning Based Intelligent Controller (BELBIC is developed and applied as a decoupler for 4 input/4 output highly nonlinear coupled distillation columns process. Moreover, the performance of the proposed Brain Emotional Learning Based Intelligent Decoupler (BELBID is enhanced using Particle Swarm Optimization (PSO technique. The performance is compared with the PSO optimized steady state decoupling compensation matrix. Mathematical models of the distillation columns and the decouplers are built and tested in simulation environment by applying the same inputs. The results prove remarkable success of the BELBID in minimizing the loops interactions without degrading the output that every input has been paired with.
Energy Technology Data Exchange (ETDEWEB)
Olofsson, K Erik J; Brunsell, Per R; Drake, James R [School of Electrical Engineering, Royal Institute of Technology (KTH), Association EURATOM-VR, Stockholm (Sweden); Witrant, Emmanuel, E-mail: erik.olofsson@ee.kth.s [Control Systems Department, UJF/GIPSA-lab, INPG/UJF Grenoble University (France)
2010-10-15
Recent developments and applications of system identification methods for the reversed-field pinch (RFP) machine EXTRAP T2R have yielded plasma response parameters for decoupled dynamics. These data sets are fundamental for a real-time implementable fast Fourier transform (FFT) decoupled discrete-time fixed-order strongly stabilizing synthesis as described in this work. Robustness is assessed over the data set by bootstrap calculation of the sensitivity transfer function worst-case H{sub {infinity}}-gain distribution. Output tracking and magnetohydrodynamic mode m = 1 tracking are considered in the same framework simply as two distinct weighted traces of a performance channel output-covariance matrix as derived from the closed-loop discrete-time Lyapunov equation. The behaviour of the resulting multivariable controller is investigated with dedicated T2R experiments.
Stability of Mixed-Strategy-Based Iterative Logit Quantal Response Dynamics in Game Theory
Zhuang, Qian; Di, Zengru; Wu, Jinshan
2014-01-01
Using the Logit quantal response form as the response function in each step, the original definition of static quantal response equilibrium (QRE) is extended into an iterative evolution process. QREs remain as the fixed points of the dynamic process. However, depending on whether such fixed points are the long-term solutions of the dynamic process, they can be classified into stable (SQREs) and unstable (USQREs) equilibriums. This extension resembles the extension from static Nash equilibriums (NEs) to evolutionary stable solutions in the framework of evolutionary game theory. The relation between SQREs and other solution concepts of games, including NEs and QREs, is discussed. Using experimental data from other published papers, we perform a preliminary comparison between SQREs, NEs, QREs and the observed behavioral outcomes of those experiments. For certain games, we determine that SQREs have better predictive power than QREs and NEs. PMID:25157502
Simon, Donald L.; Rinehart, Aidan W.; Jones, Scott M.
2017-01-01
Aircraft flying in regions of high ice crystal concentrations are susceptible to the buildup of ice within the compression system of their gas turbine engines. This ice buildup can restrict engine airflow and cause an uncommanded loss of thrust, also known as engine rollback, which poses a potential safety hazard. The aviation community is conducting research to understand this phenomena, and to identify avoidance and mitigation strategies to address the concern. To support this research, a dynamic turbofan engine model has been created to enable the development and evaluation of engine icing detection and control-based mitigation strategies. This model captures the dynamic engine response due to high ice water ingestion and the buildup of ice blockage in the engines low pressure compressor. It includes a fuel control system allowing engine closed-loop control effects during engine icing events to be emulated. The model also includes bleed air valve and horsepower extraction actuators that, when modulated, change overall engine operating performance. This system-level model has been developed and compared against test data acquired from an aircraft turbofan engine undergoing engine icing studies in an altitude test facility and also against outputs from the manufacturers customer deck. This paper will describe the model and show results of its dynamic response under open-loop and closed-loop control operating scenarios in the presence of ice blockage buildup compared against engine test cell data. Planned follow-on use of the model for the development and evaluation of icing detection and control-based mitigation strategies will also be discussed. The intent is to combine the model and control mitigation logic with an engine icing risk calculation tool capable of predicting the risk of engine icing based on current operating conditions. Upon detection of an operating region of risk for engine icing events, the control mitigation logic will seek to change the
Credit Rating via Dynamic Slack-Based Measure And It´s Optimal Investment Strategy
A. Delavarkhalafi; A. Poursherafatan
2015-01-01
In this paper we check the credit rating of firms applied for a loan. In this regard we introduce a model, named Dynamic Slack-Based Measure (DSBM) for measuring credit rating of applicant companies. Selection of financial ratios that represent the financial state of a company -in the best possible way- is one of the most challenging parts of any credit rating analysis. At first, ranking needs to identify the appropriate variables. Therefore we introduce five financial variables to provide a ...
Fritz, Melanie; Hausen, Tobias
2006-01-01
Agrifood supply networks are dynamic structures where firms regularly face the need to search for new market partners. A decision for a transaction with a new partner requires the existence of appropriate control and safeguard mechanisms as well as trust to overcome perceived risk and uncertainties. Electronic transaction environments offer new potentials for the identification of new transaction partners. However, trust and control need to be communicated appropriately in electronic transact...
Many-body strategies for multiqubit gates: Quantum control through Krawtchouk-chain dynamics
Groenland, Koen; Schoutens, Kareljan
2018-04-01
We propose a strategy for engineering multiqubit quantum gates. As a first step, it employs an eigengate to map states in the computational basis to eigenstates of a suitable many-body Hamiltonian. The second step employs resonant driving to enforce a transition between a single pair of eigenstates, leaving all others unchanged. The procedure is completed by mapping back to the computational basis. We demonstrate the strategy for the case of a linear array with an even number N of qubits, with specific X X +Y Y couplings between nearest neighbors. For this so-called Krawtchouk chain, a two-body driving term leads to the iSWAPN gate, which we numerically test for N =4 and 6.
International Nuclear Information System (INIS)
Kloiber, Karin; Spitzer, Romana; Grutsch, Sarina; Kreutz, Christoph; Tollinger, Martin
2011-01-01
Longitudinal exchange experiments facilitate the quantification of the rates of interconversion between the exchanging species, along with their longitudinal relaxation rates, by analyzing the time-dependence of direct correlation and exchange cross peaks. Here we present a simple and robust alternative to this strategy, which is based on the combination of two complementary experiments, one with and one without resolving exchange cross peaks. We show that by combining the two data sets systematic errors that are caused by differential line-broadening of the exchanging species are avoided and reliable quantification of kinetic and relaxation parameters in the presence of additional conformational exchange on the ms–μs time scale is possible. The strategy is applied to a bistable DNA oligomer that displays different line-broadening in the two exchanging species.
Directory of Open Access Journals (Sweden)
Chie eHabagishi
2014-02-01
Full Text Available In daily life, we encounter situations where we must quickly decide which hand to use for a motor action. Here, we investigated whether the hand chosen for a motor action varied over a short timescale (i.e., hours with changes in arm dynamics. Participants performed a reaching task in which they moved a specified hand to reach a target on a virtual reality display. During the task, a resistive viscous force field was abruptly applied to only the dominant hand. To evaluate changes in hand choice caused by this perturbation, participants performed an interleaved choice test in which they could freely choose either hand for reaching. Furthermore, to investigate the effect of temporal changes on arm dynamics and hand choice, we exposed the same participants to another condition in which the force field was introduced gradually. When the abrupt force was applied, use of the perturbed hand significantly decreased and not changed during the training. In contrast, when the incremental force was applied, use of the perturbed hand gradually decreased as force increased. Surprisingly, even though the final amount of force was identical between the two conditions, hand choice was significantly biased toward the unperturbed hand in the gradual condition. These results suggest that time-varying changes in arm dynamics may have a greater influence on hand choice than the amplitude of the resistant force itself.
Microjet Injection Strategies for Mitigating Dynamics in a Lean Premixed Swirl-Stabilized Combustor
LaBry, Zachary
2011-01-04
Combustion dynamics remain a challenge in the development of low-emission, air-breathing combustors for power generation and aircraft propulsion. In this paper, we presenta parametric study on the use of microjet injectors for suppressing or mitigating the combustion dynamics that energize the thermoacoustic instability in a swirl-stabilized, premixed combustor. Microjet injectors consist of small inlet ports intended to inject flow with high momentum at relatively low mass flow rates into the flame-anchoring region. The microjets were configured to inject flow either axially, into the outer recirculation zone, or radially into the inner recirculation zone. Additionally, different injectors were tested with different relative senses of swirl (signs of angular momentum)with respect to the main flow: co-swirling, not swirling, or counter-swirling. We observed that injecting air or premixed fuel/air into the inner recirculation zone via counter-swirling radial microjets, we were able to reduce the overall sound pressure level in the combustor by over 20 dB in the lean end of the operating range. Other injector configurations were not observed to positively influence the combust or stability. Detailed PIV measurements are used to examine possible mechanisms of how the microjets impact the combustion dynamics, and the technology implications of our experiments are discussed.
Microjet Injection Strategies for Mitigating Dynamics in a Lean Premixed Swirl-Stabilized Combustor
LaBry, Zachary; Shanbhogue, Santosh; Ghoniem, Ahmed
2011-01-01
Combustion dynamics remain a challenge in the development of low-emission, air-breathing combustors for power generation and aircraft propulsion. In this paper, we presenta parametric study on the use of microjet injectors for suppressing or mitigating the combustion dynamics that energize the thermoacoustic instability in a swirl-stabilized, premixed combustor. Microjet injectors consist of small inlet ports intended to inject flow with high momentum at relatively low mass flow rates into the flame-anchoring region. The microjets were configured to inject flow either axially, into the outer recirculation zone, or radially into the inner recirculation zone. Additionally, different injectors were tested with different relative senses of swirl (signs of angular momentum)with respect to the main flow: co-swirling, not swirling, or counter-swirling. We observed that injecting air or premixed fuel/air into the inner recirculation zone via counter-swirling radial microjets, we were able to reduce the overall sound pressure level in the combustor by over 20 dB in the lean end of the operating range. Other injector configurations were not observed to positively influence the combust or stability. Detailed PIV measurements are used to examine possible mechanisms of how the microjets impact the combustion dynamics, and the technology implications of our experiments are discussed.
Dynamic optimal strategies in transboundary pollution game under learning by doing
Chang, Shuhua; Qin, Weihua; Wang, Xinyu
2018-01-01
In this paper, we present a transboundary pollution game, in which emission permits trading and pollution abatement costs under learning by doing are considered. In this model, the abatement cost mainly depends on the level of pollution abatement and the experience of using pollution abatement technology. We use optimal control theory to investigate the optimal emission paths and the optimal pollution abatement strategies under cooperative and noncooperative games, respectively. Additionally, the effects of parameters on the results have been examined.
Jung, HoHyun; Chun, Keyoung Jin; Hong, Jaesoo; Lim, Dohyung
2015-01-01
Balance is important in daily activities and essential for maintaining an independent lifestyle in the elderly. Recent studies have shown that balance rehabilitation training can improve the balance ability of the elderly, and diverse balance rehabilitation training equipment has been developed. However, there has been little research into optimized strategies for balance rehabilitation training. To provide an optimized strategy, we analyzed the balance characteristics of participants in response to the rotation of a base plate on multiple axes. Seven male adults with no musculoskeletal or nervous system-related diseases (age: 25.5±1.7 years; height: 173.9±6.4 cm; body mass: 71.3±6.5 kg; body mass index: 23.6±2.4 kg/m2) were selected to investigate the balance rehabilitation training using customized rehabilitation equipment. Rotation of the base plate of the equipment was controlled to induce dynamic rotation of participants in the anterior–posterior, right-diagonal, medial–lateral, and left-diagonal directions. We used a three-dimensional motion capture system employing infrared cameras and the Pedar Flexible Insoles System to characterize the major lower-extremity joint angles, center of body mass, and center of pressure. We found statistically significant differences between the changes in joint angles in the lower extremities in response to dynamic rotation of the participants (P0.05). These results indicate that optimizing rotation control of the base plate of balance rehabilitation training equipment to induce anterior–posterior and medial–lateral dynamic rotation preferentially can lead to effective balance training. Additional tests with varied speeds and ranges of angles of base plate rotation are expected to be useful as well as an analysis of the balance characteristics considering a balance index that reflects the muscle activity and cooperative characteristics. PMID:26508847
International Nuclear Information System (INIS)
Goldstein, P.; Glenn, L.A.
1993-01-01
We compare predictions of the strain hardening model of Glenn (1990), with and without damage, to free field and seismic observations of SALMON, STERLING, and 64 kt (tamped) and 8 kt (decoupled) explosions in an Azgir salt dome in the former Soviet Union (FSU). We find good agreement between the model (without damage) and observations of both SALMON and STERLING. In contrast, the average spectral ratio of the tamped to decoupled Azgir explosions is systematically smaller than predicted by the strain hardening model without damage. Much better agreement is obtained when damage is included in the model of the decoupled Azgir explosion
International Nuclear Information System (INIS)
Goldstein, P.; Glenn, L.A.
1993-05-01
We compare predictions of the strain hardening model of Glenn (1990), with and without damage, to free field and seismic observations of SALMON, STERLING, and 64 kt (tamped) and 8 kt (decoupled) explosions in an Azgir salt dome in the former Soviet Union (FSU). We find good agreement between the model (without damage) and observations of both SALMON and STERLING. In contrast, the average spectral ratio of the tamped to decoupled Azgir explosions is systematically smaller than predicted by the strain hardening model without damage. Much better agreement is obtained when damage is included in the model of the decoupled Azgir explosion
Directory of Open Access Journals (Sweden)
Blair C R Dancy
Full Text Available Membranes define cellular and organelle boundaries, a function that is critical to all living systems. Like other biomolecules, membrane lipids are dynamically maintained, but current methods are extremely limited for monitoring lipid dynamics in living animals. We developed novel strategies in C. elegans combining 13C and 15N stable isotopes with mass spectrometry to directly quantify the replenishment rates of the individual fatty acids and intact phospholipids of the membrane. Using multiple measurements of phospholipid dynamics, we found that the phospholipid pools are replaced rapidly and at rates nearly double the turnover measured for neutral lipid populations. In fact, our analysis shows that the majority of membrane lipids are replaced each day. Furthermore, we found that stearoyl-CoA desaturases (SCDs, critical enzymes in polyunsaturated fatty acid production, play an unexpected role in influencing the overall rates of membrane maintenance as SCD depletion affected the turnover of nearly all membrane lipids. Additionally, the compromised membrane maintenance as defined by LC-MS/MS with SCD RNAi resulted in active phospholipid remodeling that we predict is critical to alleviate the impact of reduced membrane maintenance in these animals. Not only have these combined methodologies identified new facets of the impact of SCDs on the membrane, but they also have great potential to reveal many undiscovered regulators of phospholipid metabolism.
Surface-atmosphere decoupling limits accumulation at Summit, Greenland.
Berkelhammer, Max; Noone, David C; Steen-Larsen, Hans Christian; Bailey, Adriana; Cox, Christopher J; O'Neill, Michael S; Schneider, David; Steffen, Konrad; White, James W C
2016-04-01
Despite rapid melting in the coastal regions of the Greenland Ice Sheet, a significant area (~40%) of the ice sheet rarely experiences surface melting. In these regions, the controls on annual accumulation are poorly constrained owing to surface conditions (for example, surface clouds, blowing snow, and surface inversions), which render moisture flux estimates from myriad approaches (that is, eddy covariance, remote sensing, and direct observations) highly uncertain. Accumulation is partially determined by the temperature dependence of saturation vapor pressure, which influences the maximum humidity of air parcels reaching the ice sheet interior. However, independent proxies for surface temperature and accumulation from ice cores show that the response of accumulation to temperature is variable and not generally consistent with a purely thermodynamic control. Using three years of stable water vapor isotope profiles from a high altitude site on the Greenland Ice Sheet, we show that as the boundary layer becomes increasingly stable, a decoupling between the ice sheet and atmosphere occurs. The limited interaction between the ice sheet surface and free tropospheric air reduces the capacity for surface condensation to achieve the rate set by the humidity of the air parcels reaching interior Greenland. The isolation of the surface also acts to recycle sublimated moisture by recondensing it onto fog particles, which returns the moisture back to the surface through gravitational settling. The observations highlight a unique mechanism by which ice sheet mass is conserved, which has implications for understanding both past and future changes in accumulation rate and the isotopic signal in ice cores from Greenland.
Decoupling Transport from Economic Growth. Towards Transport Sustainability in Europe
International Nuclear Information System (INIS)
Tight, M.R.; Site, P. Delle; Meyer-Ruehle, O.
2004-01-01
This paper reports on a research project that aimed to identify and assess measures which could be used to reduce travel demand while maintaining economic growth and enhancing environmental quality. The research methodology involved a detailed review of past research; contact with over 600 experts from around Europe and elsewhere for ideas on potential measures; detailed questionnaires from over 100 of these experts; and a series of three panel sessions held in different parts of Europe, each of which involved around 16 experts debating the merits of different measures and identifying case study evidence of their effectiveness. The end result was a short list of 13 measures, indicative of broad types, which are considered to be effective, and an indication of their effectiveness if applied across the European Union. Seven illustrative measures are discussed which stand out from the results as having proven potential (though not necessarily at a European scale) to influence transport intensity and/or unit environmental load whilst not having large detrimental effects on GDP. These are the areas where it is felt that European transport policy could most usefully be focussed in terms of decoupling of transport demand and economic growth
Equilibrium thermodynamics and neutrino decoupling in quasi-metric cosmology
Østvang, Dag
2018-05-01
The laws of thermodynamics in the expanding universe are formulated within the quasi-metric framework. The quasi-metric cosmic expansion does not directly influence momenta of material particles, so the expansion directly cools null particles only (e.g., photons). Therefore, said laws differ substantially from their counterparts in standard cosmology. Consequently, all non-null neutrino mass eigenstates are predicted to have the same energy today as they had just after neutrino decoupling in the early universe. This indicates that the predicted relic neutrino background is strongly inconsistent with detection rates measured in solar neutrino detectors (Borexino in particular). Thus quasi-metric cosmology is in violent conflict with experiment unless some exotic property of neutrinos makes the relic neutrino background essentially undetectable (e.g., if all massive mass eigenstates decay into "invisible" particles over cosmic time scales). But in absence of hard evidence in favour of the necessary exotic neutrino physics needed to resolve said conflict, the current status of quasi-metric relativity has been changed to non-viable.
Progressive hypoxia decouples activity and aerobic performance of skate embryos.
Di Santo, Valentina; Tran, Anna H; Svendsen, Jon C
2016-01-01
Although fish population size is strongly affected by survival during embryonic stages, our understanding of physiological responses to environmental stressors is based primarily on studies of post-hatch fishes. Embryonic responses to acute exposure to changes in abiotic conditions, including increase in hypoxia, could be particularly important in species exhibiting long developmental time, as embryos are unable to select a different environment behaviourally. Given that oxygen is key to metabolic processes in fishes and aquatic hypoxia is becoming more severe and frequent worldwide, organisms are expected to reduce their aerobic performance. Here, we examined the metabolic and behavioural responses of embryos of a benthic elasmobranch fish, the little skate (Leucoraja erinacea), to acute progressive hypoxia, by measuring oxygen consumption and movement (tail-beat) rates inside the egg case. Oxygen consumption rates were not significantly affected by ambient oxygen levels until reaching 45% air saturation (critical oxygen saturation, S crit). Below S crit, oxygen consumption rates declined rapidly, revealing an oxygen conformity response. Surprisingly, we observed a decoupling of aerobic performance and activity, as tail-beat rates increased, rather than matching the declining metabolic rates, at air saturation levels of 55% and below. These results suggest a significantly divergent response at the physiological and behavioural levels. While skate embryos depressed their metabolic rates in response to progressive hypoxia, they increased water circulation inside the egg case, presumably to restore normoxic conditions, until activity ceased abruptly around 9.8% air saturation.
Global coupling and decoupling of the APS storage ring
International Nuclear Information System (INIS)
Chae, Yong-Chul; Liu, Jianyang; Teng, L.C.
1995-01-01
This Paper describes a study of controlling the coupling between the horizontal and the vertical betatron oscillations in the APS storage ring. First, we investigate the strengthening of coupling using two families of skew quadrupoles. Using smooth approximation, we obtained the formulae to estimate the coupling ratio defined as the ratio of the vertical and horizontal emittances or, for a single particle, the ratio of the maximum values of the Courant Snyder invariants. Since we knew that the coupling is mostly enhanced by the 21st harmonic content of skew quadrupole distribution, we carried out the harmonic analysis in order to find the optimum arrangement of the skew quadrupoles. The numerical results from tracking a single particle are presented for the various configurations of skew quadrupoles. Second, we describe the global decoupling procedure to minimize the unwanted coupling effects. These are mainly due to the random roll errors of normal quadrupoles. It is shown that even with the rather large rms roll error of 2 mrad we can reduce the Coupling from 70 percent to 10 percent with a skew quadrupole strength which is one order of magnitude lower than the typical normal quadrupole strength
An experimental approach of decoupling Seebeck coefficient and electrical resistivity
Muhammed Sabeer N., A.; Paulson, Anju; Pradyumnan, P. P.
2018-04-01
The Thermoelectrics (TE) has drawn increased attention among renewable energy technologies. The performance of a thermoelectric material is quantified by a dimensionless thermoelectric figure of merit, ZT=S2σT/κ, where S and σ vary inversely each other. Thus, improvement in ZT is not an easy task. So, researchers have been trying different parameter variations during thin film processing to improve TE properties. In this work, tin nitride (Sn3N4) thin films were deposited on glass substrates by reactive RF magnetron sputtering and investigated its thermoelectric response. To decouple the covariance nature of Seebeck coefficient and electrical resistivity for the enhancement of power factor (S2σ), the nitrogen gas pressure during sputtering was reduced. Reduction in nitrogen gas pressure reduced both sputtering pressure and amount of nitrogen available for reaction during sputtering. This experimental approach of combined effect introduced preferred orientation and stoichiometric variations simultaneously in the sputtered Sn3N4 thin films. The scattering mechanism associated with these variations enhanced TE properties by independently drive the Seebeck coefficient and electrical resistivity parameters.
Impersonating the Standard Model Higgs boson: alignment without decoupling
International Nuclear Information System (INIS)
Carena, Marcela; Low, Ian; Shah, Nausheen R.; Wagner, Carlos E.M.
2014-01-01
In models with an extended Higgs sector there exists an alignment limit, in which the lightest CP-even Higgs boson mimics the Standard Model Higgs. The alignment limit is commonly associated with the decoupling limit, where all non-standard scalars are significantly heavier than the Z boson. However, alignment can occur irrespective of the mass scale of the rest of the Higgs sector. In this work we discuss the general conditions that lead to “alignment without decoupling”, therefore allowing for the existence of additional non-standard Higgs bosons at the weak scale. The values of tan β for which this happens are derived in terms of the effective Higgs quartic couplings in general two-Higgs-doublet models as well as in supersymmetric theories, including the MSSM and the NMSSM. Moreover, we study the information encoded in the variations of the SM Higgs-fermion couplings to explore regions in the m A −tan β parameter space
Enhanced coupling and decoupling of underground nuclear explosions
Energy Technology Data Exchange (ETDEWEB)
Terhune, R.W.; Snell, C.M.; Rodean, H.C.
1979-09-04
The seismic coupling efficiency of nuclear explosions was studied in granite by means of computer calculations as a function of scaled explosion source radius. The scaled source radii were varied from 0.1 m/kt/sup 1/3/ (point source) to 20 m/kt/sup 1/3/ (representing a nearly full decoupling cavity). It was found that seismic coupling efficiency is at a maximum when the scaled source radius is approximately 2 m/kt/sup 1/3/. The primary cause of this maximum in seismic wave source strength is the effect of initial source radius on peak particle velocity and pulse duration of the outgoing elastic wave. A secondary cause is that rock vaporization (an energy sink) does not occur for scaled source radii somewhat greater than 1 m/kt/sup 1/3/. Therefore, for scaled source radii greater than 1 m/kt/sup 1/3/, there is additional energy available for seismic wave generations. Available data for some nuclear explosions at the Nevada Test Site do not provide sufficient evidence to either support or negate the enhanced coupling that is indicated by calculations at scaled source radii of 1-2 m/kt/sup 1/3/.
Enhanced coupling and decoupling of underground nuclear explosions
International Nuclear Information System (INIS)
Terhune, R.W.; Snell, C.M.; Rodean, H.C.
1979-01-01
The seismic coupling efficiency of nuclear explosions was studied in granite by means of computer calculations as a function of scaled explosion source radius. The scaled source radii were varied from 0.1 m/kt/sup 1/3/ (point source) to 20 m/kt/sup 1/3/ (representing a nearly full decoupling cavity). It was found that seismic coupling efficiency is at a maximum when the scaled source radius is approximately 2 m/kt/sup 1/3/. The primary cause of this maximum in seismic wave source strength is the effect of initial source radius on peak particle velocity and pulse duration of the outgoing elastic wave. A secondary cause is that rock vaporization (an energy sink) does not occur for scaled source radii somewhat greater than 1 m/kt/sup 1/3/. Therefore, for scaled source radii greater than 1 m/kt/sup 1/3/, there is additional energy available for seismic wave generations. Available data for some nuclear explosions at the Nevada Test Site do not provide sufficient evidence to either support or negate the enhanced coupling that is indicated by calculations at scaled source radii of 1-2 m/kt/sup 1/3/
International Nuclear Information System (INIS)
Wu, Gang; Fan, Ying; Wei, Yi-Ming; Liu, Lan-Cui
2008-01-01
The world's future oil price is affected by many factors. The challenge, therefore, is how to select optimal stockpile acquisition strategies to minimize the cost of maintaining a reserve. This paper provides a new method for analyzing this problem using an uncertain dynamic programming model to analyze stockpile acquisition strategies for strategic petroleum reserve. Using this model, we quantify the impact of uncertain world oil price on optimal stockpile acquisition strategies of China's strategic petroleum reserve for the period 2007-2010 and 2011-2020. Our results show that the future stockpile acquisition is related to oil prices and their probability and, if not considering the occurrence of oil supply shortage, China should at least purchase 25 million barrels when world oil price is at an optimal level. The optimal price of stockpile acquisition of every year has a stronger relationship with the probability of high price; and the optimal expected price and size of stockpile acquisition is different in each year. (author)
International Nuclear Information System (INIS)
Lu, I.J.; Lin, Sue J.; Lewis, Charles
2007-01-01
We adopted the Divisia index approach to explore the impacts of five factors on the total carbon dioxide emissions from highway vehicles in Germany, Japan, South Korea and Taiwan during 1990-2002. CO 2 emission was decomposed into emission coefficient, vehicle fuel intensity, vehicle ownership, population intensity and economic growth. In addition, the decoupling effects among economic growth, transport energy demand and CO 2 emission were analyzed to better understand the fuel performance and CO 2 mitigation strategies for each country. From our results, we suggest that the rapid growths of economy and vehicle ownership were the most important factors for the increased CO 2 emissions , whereas population intensity contributed significantly to emission decrease. Energy conservation performance and CO 2 mitigation in each country are strongly correlated with environmental pressure and economic driving force, except for Germany in 1993 and Taiwan during 1992-1996. To decouple the economic growth and environmental pressure, proponents of sustainable transport policy in Taiwan should focus on improving the operation and energy use of its highway transportation system by implementing an intelligent transportation system (ITS) with demand management, constructing an integrated feeder system, and encouraging the use of green transport modes
EUDAT strategies for handling dynamic data in the solid Earth Sciences
Michelini, Alberto; Evans, Peter; Kemps-Snijder, Mark; Heikkinen, Jani; Buck, Justin; Misutka, Jozef; Drude, Sebastian; Fares, Massimo; Cacciari, Claudio; Fiameni, Giuseppe
2014-05-01
Some dynamic data is generated by sensors which produce data streams that may be temporarily incomplete (owing to latencies or temporary interruptions of the transmission lines between the field sensors and the data acquisition centres) and that may consequently fill up over time (automatically or after manual intervention). Dynamic data can also be generated by massive crowd sourcing where, for example, experimental collections of data can be filled up at random moments. The nature of dynamic data makes it difficult to handle for various reasons: a) establishing valid policies that guide early replication for data preservation and access optimization is not trivial, b) identifying versions of such data - thus making it possible to check their integrity - and referencing the versions is also a challenging task, and c) performance issues are extremely important since all these activities must be performed fast enough to keep up with the incoming data stream. There is no doubt that both applications areas (namely data from sensors and crowdsourcing) are growing in their relevance for science, and that appropriate infrastructure support (by initiatives such as EUDAT) is vital to handle these challenges. In addition, data must be citeable to encourage transparent, reproducible science, and to provide clear metrics for assessing the impact of research, which also drives funding choices. Data stream in real time often undergo changes/revisions while they are still growing, as new data arrives, and they are revised as missing data is recovered, or as new calibration values are applied. We call these "dynamic" data sets, DDS. A common form of DDS is time series data in which measurements are obtained on a regular schedule, with a well-defined sample rate. Examples include the hourly temperature in Barcelona, and the displacement (a 3-D vector quantity) of a seismograph from its rest position, which may record at a rate of 100 or more samples per second. These form streams
de Oliveira Silva, R.; Barioni, L. G.; Hall, J. A. J.; Folegatti Matsuura, M.; Zanett Albertini, T.; Fernandes, F. A.; Moran, D.
2016-05-01
Recent debate about agricultural greenhouse gas emissions mitigation highlights trade-offs inherent in the way we produce and consume food, with increasing scrutiny on emissions-intensive livestock products. Although most research has focused on mitigation through improved productivity, systemic interactions resulting from reduced beef production at the regional level are still unexplored. A detailed optimization model of beef production encompassing pasture degradation and recovery processes, animal and deforestation emissions, soil organic carbon (SOC) dynamics and upstream life-cycle inventory was developed and parameterized for the Brazilian Cerrado. Economic return was maximized considering two alternative scenarios: decoupled livestock-deforestation (DLD), assuming baseline deforestation rates controlled by effective policy; and coupled livestock-deforestation (CLD), where shifting beef demand alters deforestation rates. In DLD, reduced consumption actually leads to less productive beef systems, associated with higher emissions intensities and total emissions, whereas increased production leads to more efficient systems with boosted SOC stocks, reducing both per kilogram and total emissions. Under CLD, increased production leads to 60% higher emissions than in DLD. The results indicate the extent to which deforestation control contributes to sustainable intensification in Cerrado beef systems, and how alternative life-cycle analytical approaches result in significantly different emission estimates.
A Study on Magnetic Decoupling of Compound-Structure Permanent-Magnet Motor for HEVs Application
Directory of Open Access Journals (Sweden)
Qiwei Xu
2016-10-01
Full Text Available The compound-structure permanent-magnet (CSPM motor is used for an electrical continuously-variable transmission (E-CVT in a hybrid electric vehicle (HEV. It can make the internal combustion engine (ICE independent of the road loads and run in the high efficiency area to improve the fuel economy and reduce the emissions. This paper studies the magnetic coupling of a new type of CSPM motor used in HEVs. Firstly, through the analysis of the parameter matching with CSPM in the HEV, we receive the same dynamic properties’ design parameters between the CSPM motor and the THS (Toyota Hybrid System of the Toyota Prius. Next, we establish the equivalent magnetic circuit model of the overall and the secondary model considering the tangential and radial flux distribution in the outer rotor of the CSPM motor. Based on these two models, we explore the internal magnetic coupling rule of the CSPM motor. Finally, finite element method analysis in 2D-ansoft is used to analyze the magnetic field distribution of the CSPM motor in different operation modes. By the result of the finite element method analysis, the internal magnetic decoupling scheme is put forward, laying the theoretical foundation for the further application of the CSPM motor in HEVs.
Schneider, E; Ganschow, L
2000-01-01
In this paper the authors discuss how the concept of dynamic (cognitive) assessment and instruction might relate to the assessment and instruction of at-risk foreign/second language learners. They describe its relevance to a diagnostic/prescriptive approach to instruction for teaching a foreign language to students with identified dyslexia and other at-risk students. They explain how to assess learners' knowledge of the native/foreign/second language through questions and guided discovery. Examples in German and English illustrate its application to foreign/second language instruction.
Decoupling local mechanics from large-scale structure in modular metamaterials
Yang, Nan; Silverberg, Jesse L.
2017-04-01
A defining feature of mechanical metamaterials is that their properties are determined by the organization of internal structure instead of the raw fabrication materials. This shift of attention to engineering internal degrees of freedom has coaxed relatively simple materials into exhibiting a wide range of remarkable mechanical properties. For practical applications to be realized, however, this nascent understanding of metamaterial design must be translated into a capacity for engineering large-scale structures with prescribed mechanical functionality. Thus, the challenge is to systematically map desired functionality of large-scale structures backward into a design scheme while using finite parameter domains. Such “inverse design” is often complicated by the deep coupling between large-scale structure and local mechanical function, which limits the available design space. Here, we introduce a design strategy for constructing 1D, 2D, and 3D mechanical metamaterials inspired by modular origami and kirigami. Our approach is to assemble a number of modules into a voxelized large-scale structure, where the module’s design has a greater number of mechanical design parameters than the number of constraints imposed by bulk assembly. This inequality allows each voxel in the bulk structure to be uniquely assigned mechanical properties independent from its ability to connect and deform with its neighbors. In studying specific examples of large-scale metamaterial structures we show that a decoupling of global structure from local mechanical function allows for a variety of mechanically and topologically complex designs.
Enhancing power density of biophotovoltaics by decoupling storage and power delivery
Saar, Kadi L.; Bombelli, Paolo; Lea-Smith, David J.; Call, Toby; Aro, Eva-Mari; Müller, Thomas; Howe, Christopher J.; Knowles, Tuomas P. J.
2018-01-01
Biophotovoltaic devices (BPVs), which use photosynthetic organisms as active materials to harvest light, have a range of attractive features relative to synthetic and non-biological photovoltaics, including their environmentally friendly nature and ability to self-repair. However, efficiencies of BPVs are currently lower than those of synthetic analogues. Here, we demonstrate BPVs delivering anodic power densities of over 0.5 W m-2, a value five times that for previously described BPVs. We achieved this through the use of cyanobacterial mutants with increased electron export characteristics together with a microscale flow-based design that allowed independent optimization of the charging and power delivery processes, as well as membrane-free operation by exploiting laminar flow to separate the catholyte and anolyte streams. These results suggest that miniaturization of active elements and flow control for decoupled operation and independent optimization of the core processes involved in BPV design are effective strategies for enhancing power output and thus the potential of BPVs as viable systems for sustainable energy generation.
Albert, Mathieu; Paradis, Elise; Kuper, Ayelet
2015-02-01
This paper explores social scientists' and humanities (SSH) scholars' integration within the academic medical research environment. Three questions guided our investigation: Do SSH scholars adapt to the medical research environment? How do they navigate their career within a culture that may be inconsistent with their own? What strategies do they use to gain legitimacy? The study builds on three concepts: decoupling, doxa, and epistemic habitus. Twenty-nine semi-structured interviews were conducted with SSH scholars working in 11 faculties of medicine across Canada. Participants were selected through purposeful and snowball sampling. The data were analyzed by thematic content analysis. For most of our participants, moving into medicine has been a challenging experience, as their research practices and views of academic excellence collided with those of medicine. In order to achieve some level of legitimacy more than half of our participants altered their research practices. This resulted in a dissonance between their internalized appreciation of academic excellence and their new, altered, research practices. Only six participants experienced no form of challenge or dissonance after moving into medicine, while three decided to break with their social science and humanities past and make the medical research community their new home. We conclude that the work environment for SSH scholars in faculties of medicine does not deliver on the promise of inclusiveness made by calls for interdisciplinarity in Canadian health research. Copyright © 2014 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Ng, Tania Y.-T. [Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (China); Rainbow, Philip S. [Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Amiard-Triquet, Claude; Amiard, Jean-Claude [Universite de Nantes, Faculte de Pharmacie, MMS EA2160, Service d' ecotoxicologie, F-44000 Nantes (France); Wang Wenxiong [Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (China)], E-mail: wwang@ust.hk
2008-08-11
This study investigated the kinetics of Cd bioaccumulation, detoxification, subcellular distribution, and efflux in the nereid polychaete Perinereis aibuhitensis after Cd pre-exposure. Cd pre-exposure increased the Cd body burden in the worms, but did not affect the overall Cd uptake and efflux rates and metallothionein-like protein (MTLP) concentrations. During short-term exposure to dissolved Cd, Cd in the cytosolic fraction increased after Cd pre-exposure, and this fraction also increased during the Cd efflux period, indicating that the insoluble fraction of Cd was presumably lost at a faster rate than the loss of cytosolic Cd. Even though the MTLP concentration remained comparable after Cd pre-exposure, both the MTLP synthesis rate and the degradation rate increased, thus leading to a high MTLP turnover in the Cd-exposed worms. However, Cd uptake and efflux into different protein size fractions did not follow the patterns of MTLP synthesis and degradation, strongly suggesting that Cd kinetics is decoupled from the MTLP kinetics in the worms. Our study adds to an increasing body of evidence on the complicated relationship between metal biokinetics and MTLP kinetics in different groups of marine invertebrates which have strong contrasts in their metal handling strategies.
International Nuclear Information System (INIS)
Ng, Tania Y.-T.; Rainbow, Philip S.; Amiard-Triquet, Claude; Amiard, Jean-Claude; Wang Wenxiong
2008-01-01
This study investigated the kinetics of Cd bioaccumulation, detoxification, subcellular distribution, and efflux in the nereid polychaete Perinereis aibuhitensis after Cd pre-exposure. Cd pre-exposure increased the Cd body burden in the worms, but did not affect the overall Cd uptake and efflux rates and metallothionein-like protein (MTLP) concentrations. During short-term exposure to dissolved Cd, Cd in the cytosolic fraction increased after Cd pre-exposure, and this fraction also increased during the Cd efflux period, indicating that the insoluble fraction of Cd was presumably lost at a faster rate than the loss of cytosolic Cd. Even though the MTLP concentration remained comparable after Cd pre-exposure, both the MTLP synthesis rate and the degradation rate increased, thus leading to a high MTLP turnover in the Cd-exposed worms. However, Cd uptake and efflux into different protein size fractions did not follow the patterns of MTLP synthesis and degradation, strongly suggesting that Cd kinetics is decoupled from the MTLP kinetics in the worms. Our study adds to an increasing body of evidence on the complicated relationship between metal biokinetics and MTLP kinetics in different groups of marine invertebrates which have strong contrasts in their metal handling strategies
Decoupling pipeline influences in soil resistivity measurements with finite element techniques
Deo, R. N.; Azoor, R. M.; Zhang, C.; Kodikara, J. K.
2018-03-01
Periodic inspection of pipeline conditions is an important asset management strategy conducted by water and sewer utilities for efficient and economical operations of their assets in field. The Level 1 pipeline condition assessment involving resistivity profiling along the pipeline right-of-way is a common technique for delineating pipe sections that might be installed in highly corrosive soil environment. However, the technique can suffer from significant perturbations arising from the buried pipe itself, resulting in errors in native soil characterisation. To address this problem, a finite element model was developed to investigate the degree to which pipes of different a) diameters, b) burial depths, and c) surface conditions (bare or coated) can influence in-situ soil resistivity measurements using Wenner methods. It was found that the greatest errors can arise when conducting measurements over a bare pipe with the array aligned parallel to the pipe. Depending upon the pipe surface conditions, in-situ resistivity measurements can either be underestimated or overestimated from true soil resistivities. Following results based on simulations and decoupling equations, a guiding framework for removing pipe influences in soil resistivity measurements were developed that can be easily used to perform corrections on measurements. The equations require simple a-prior information on the pipe diameter, burial depth, surface condition, and the array length and orientation used. Findings from this study have immediate application and is envisaged to be useful for critical civil infrastructure monitoring and assessment.
Directory of Open Access Journals (Sweden)
María José Alonso
2008-04-01
Full Text Available This article focuses on an experience of in-service training carried out by a group of educators in literacy. The novelty of the undertaking lies in the methodological proposal analysed: using “chatting gatherings” as a methodological strategy, which supports critical reflection and the construction of knowledge, both in in-service training of professionals and in basic adult education. This experience reveals the nature of learning achieved through dialogical educational processes. Further, it allows us to observe the impact that they may have on the improvement of the professionals’ educational practices.
The Global Nuclear Futures Model: A Dynamic Simulation Tool for Energy Strategies
International Nuclear Information System (INIS)
Bixler, N.E.
2002-01-01
The Global Nuclear Futures Model (GNFM) is a dynamic simulation tool that provides an integrated framework to model key aspects of nuclear energy, nuclear materials storage and disposition, global nuclear materials management, and nuclear proliferation risk. It links nuclear energy and other energy shares dynamically to greenhouse gas emissions and twelve other measures of environmental impact. It presents historical data from 1990 to 2000 and extrapolates energy demand through the year 2050. More specifically, it contains separate modules for energy, the nuclear fuel cycle front end, the nuclear fuel cycle back end, defense nuclear materials, environmental impacts, and measures of the potential for nuclear proliferation. It is globally integrated but also breaks out five regions of the world so that environmental impacts and nuclear proliferation concerns can be evaluated on a regional basis. The five regions are the United States of America (USA), The Peoples Republic of China (China), the former Soviet Union (FSU), the OECD nations excluding the USA, and the rest of the world (ROW). (author)
Effect of arm swing strategy on local dynamic stability of human gait.
Punt, Michiel; Bruijn, Sjoerd M; Wittink, Harriet; van Dieën, Jaap H
2015-02-01
Falling causes long term disability and can even lead to death. Most falls occur during gait. Therefore improving gait stability might be beneficial for people at risk of falling. Recently arm swing has been shown to influence gait stability. However at present it remains unknown which mode of arm swing creates the most stable gait. To examine how different modes of arm swing affect gait stability. Ten healthy young male subjects volunteered for this study. All subjects walked with four different arm swing instructions at seven different gait speeds. The Xsens motion capture suit was used to capture gait kinematics. Basic gait parameters, variability and stability measures were calculated. We found an increased stability in the medio-lateral direction with excessive arm swing in comparison to normal arm swing at all gait speeds. Moreover, excessive arm swing increased stability in the anterior-posterior and vertical direction at low gait speeds. Ipsilateral and inphase arm swing did not differ compared to a normal arm swing. Excessive arm swing is a promising gait manipulation to improve local dynamic stability. For excessive arm swing in the ML direction there appears to be converging evidence. The effect of excessive arm swing on more clinically relevant groups like the more fall prone elderly or stroke survivors is worth further investigating. Excessive arm swing significantly increases local dynamic stability of human gait. Copyright © 2014 Elsevier B.V. All rights reserved.
Stockpile strategy for China's emergency oil reserve: A dynamic programming approach
International Nuclear Information System (INIS)
Bai, Y.; Dahl, C.A.; Zhou, D.Q.; Zhou, P.
2014-01-01
China is currently accelerating construction of its strategic petroleum reserves. How should China fill the SPR in a cost-effective manner in the short-run? How might this affect world oil prices? Using a dynamic programming model to answer these questions, the objective of this paper is to minimize the stockpiling costs, including consumer surplus as well as crude acquisition and holding costs. The crude oil acquisition price in the model is determined by global equilibrium between supply and demand. Demand, in turn, depends on world market conditions including China's stockpile filling rate. Our empirical study under different market conditions shows that China's optimal stockpile acquisition rate varies from 9 to 19 million barrels per month, and the optimal stockpiling drives up the world oil price by 3–7%. The endogenous price increase accounts for 52% of total stockpiling costs in the base case. When the market is tighter or the demand function is more inelastic, the stockpiling affects the market more significantly and pushes prices even higher. Alternatively, in a disruption, drawdown from the stockpile can effectively dampen soaring prices, though the shortage is likely to leave the price higher than before the disruption. - Highlights: • China's SPR policies are examined by dynamic programming. • The optimal stockpile acquisition rate varies from 9 to 19 million barrels per month. • The optimal stockpiling drives up world oil price by 3–7%
Energy Technology Data Exchange (ETDEWEB)
Woo, T. H. [Yonsei University, Wonju (Korea, Republic of)
2016-10-15
This reactor has the specification as the power is 330 MWt pressurized water reactor (PWR) with integral steam generators and advanced safety features. In the plant design, it is planned for electricity generation of 100 MWe and thermal applications of seawater desalination where the life span is a 60-year operation design and three-year refueling cycle. Regarding of the licensing, the standard design was approved from the Korean regulator in mid-2012 and the Korea Atomic Energy Research Institute (KAERI) has a plan to build a demonstration plant to operate from 2017. According to the previous study of the marketing strategy of the Canadian small reactor, Safe LOW-POwer Kritical Experiment (SLOWPOKE) reactor had been investigated in 1988. Therefore, it is interesting to compare SMART and SLOWPOKE. In this work, it is to find out the strategy of the successful marketing of SMART and suggest continuous marketing prospects. There are specifications and parameters of SMART in Tables 1 and 2. The public acceptance (PA) had been studies as safety-public interpretation, SLOWPOKE safety-experience and process, and economics in the previous paper of the SLOWPOKE, which was about the marketing strategy for the commercial nuclear reactor. The highly cognitive networking based dynamical modeling was discussed where the system is treated by a complex and non-linear way. The linear networking of the interested issue was changed by the SD algorithm where the feedback and multiple connections are added to the original networking theory. The non-linear method has shown the complexity of the marketing strategy, especially for the NPP which is the very expensive and safety focused facility.
International Nuclear Information System (INIS)
Woo, T. H.
2016-01-01
This reactor has the specification as the power is 330 MWt pressurized water reactor (PWR) with integral steam generators and advanced safety features. In the plant design, it is planned for electricity generation of 100 MWe and thermal applications of seawater desalination where the life span is a 60-year operation design and three-year refueling cycle. Regarding of the licensing, the standard design was approved from the Korean regulator in mid-2012 and the Korea Atomic Energy Research Institute (KAERI) has a plan to build a demonstration plant to operate from 2017. According to the previous study of the marketing strategy of the Canadian small reactor, Safe LOW-POwer Kritical Experiment (SLOWPOKE) reactor had been investigated in 1988. Therefore, it is interesting to compare SMART and SLOWPOKE. In this work, it is to find out the strategy of the successful marketing of SMART and suggest continuous marketing prospects. There are specifications and parameters of SMART in Tables 1 and 2. The public acceptance (PA) had been studies as safety-public interpretation, SLOWPOKE safety-experience and process, and economics in the previous paper of the SLOWPOKE, which was about the marketing strategy for the commercial nuclear reactor. The highly cognitive networking based dynamical modeling was discussed where the system is treated by a complex and non-linear way. The linear networking of the interested issue was changed by the SD algorithm where the feedback and multiple connections are added to the original networking theory. The non-linear method has shown the complexity of the marketing strategy, especially for the NPP which is the very expensive and safety focused facility
International Nuclear Information System (INIS)
Jana, Debaldev; Agrawal, Rashmi; Upadhyay, Ranjit Kumar; Samanta, G.P.
2016-01-01
Highlights: • Age-selective harvesting of prey and predator are considered by multi-delayed prey-predator system. • System experiences stable coexistence to oscillatory mode and vice versa via Hopf-bifurcation depending upon the parametric restrictions. • MSY, bionomic equilibrium and optimal harvesting policy are also depending upon the age-selection of prey and predator. • All the analytic results are delay dependent. • Numerical examples support the analytical findings. - Abstract: Life history of ecological resource management and empirical studies are increasingly documenting the impact of selective harvesting process on the evolutionary stable strategy of both aquatic and terrestrial ecosystems. In the present study, the interaction between population and their independent and combined selective harvesting are framed by a multi-delayed prey-predator system. Depending upon the age selection strategy, system experiences stable coexistence to oscillatory mode and vice versa via Hopf-bifurcation. Economic evolution of the system which is mainly featured by maximum sustainable yield (MSY), bionomic equilibrium and optimal harvesting vary largely with the commensurate age selections of both population because equilibrium population abundance becomes age-selection dependent. Our study indicates that balance between harvesting delays and harvesting intensities should be maintained for better ecosystem management. Numerical examples support the analytical findings.
Neutronic studies on decoupled hydrogen moderator for a short-pulse spallation source
International Nuclear Information System (INIS)
Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Kai, Tetsuya; Ikeda, Yujiro
2005-01-01
Neutronic studies of decoupled hydrogen moderators were performed by calculations taking into account para hydrogen content, decoupling energy, moderator dimensions/shapes and reflector material. Low-energy parts of calculated spectral intensities with different para hydrogen contents were analyzed by a modified Maxwell function to characterize neutron spectra. The result shows that a 100% para hydrogen moderator gives the highest pulse peak intensity together with the narrowest pulse width and the shortest decay times. Pulse broadening with a reflector was explained by time distributions of source neutrons entering into the moderator through a decoupler. Material dependence of time distribution was studied. A decoupling energy higher than 1 eV does not bring about a large improvement in pulse widths and decay times, even at a large penalty in the peak intensity. The optimal moderator thickness was also discussed for a rectangular parallelepipe-shaped and a canteen-shaped moderator
Qi, Di
Turbulent dynamical systems are ubiquitous in science and engineering. Uncertainty quantification (UQ) in turbulent dynamical systems is a grand challenge where the goal is to obtain statistical estimates for key physical quantities. In the development of a proper UQ scheme for systems characterized by both a high-dimensional phase space and a large number of instabilities, significant model errors compared with the true natural signal are always unavoidable due to both the imperfect understanding of the underlying physical processes and the limited computational resources available. One central issue in contemporary research is the development of a systematic methodology for reduced order models that can recover the crucial features both with model fidelity in statistical equilibrium and with model sensitivity in response to perturbations. In the first part, we discuss a general mathematical framework to construct statistically accurate reduced-order models that have skill in capturing the statistical variability in the principal directions of a general class of complex systems with quadratic nonlinearity. A systematic hierarchy of simple statistical closure schemes, which are built through new global statistical energy conservation principles combined with statistical equilibrium fidelity, are designed and tested for UQ of these problems. Second, the capacity of imperfect low-order stochastic approximations to model extreme events in a passive scalar field advected by turbulent flows is investigated. The effects in complicated flow systems are considered including strong nonlinear and non-Gaussian interactions, and much simpler and cheaper imperfect models with model error are constructed to capture the crucial statistical features in the stationary tracer field. Several mathematical ideas are introduced to improve the prediction skill of the imperfect reduced-order models. Most importantly, empirical information theory and statistical linear response theory are
Energy Technology Data Exchange (ETDEWEB)
Pointer, William David [ORNL
2017-08-01
The objective of this effort is to establish a strategy and process for generation of suitable computational mesh for computational fluid dynamics simulations of departure from nucleate boiling in a 5 by 5 fuel rod assembly held in place by PWR mixing vane spacer grids. This mesh generation process will support ongoing efforts to develop, demonstrate and validate advanced multi-phase computational fluid dynamics methods that enable more robust identification of dryout conditions and DNB occurrence.Building upon prior efforts and experience, multiple computational meshes were developed using the native mesh generation capabilities of the commercial CFD code STAR-CCM+. These meshes were used to simulate two test cases from the Westinghouse 5 by 5 rod bundle facility. The sensitivity of predicted quantities of interest to the mesh resolution was then established using two evaluation methods, the Grid Convergence Index method and the Least Squares method. This evaluation suggests that the Least Squares method can reliably establish the uncertainty associated with local parameters such as vector velocity components at a point in the domain or surface averaged quantities such as outlet velocity magnitude. However, neither method is suitable for characterization of uncertainty in global extrema such as peak fuel surface temperature, primarily because such parameters are not necessarily associated with a fixed point in space. This shortcoming is significant because the current generation algorithm for identification of DNB event conditions relies on identification of such global extrema. Ongoing efforts to identify DNB based on local surface conditions will address this challenge
Burns, Jack O.; Nhan, Bang; Bradley, Richard F.; Tauscher, Keith A.; Rapetti, David; Switzer, Eric
2018-06-01
The redshifted 21-cm monopole is expected to be a powerful probe of the epoch of the first stars and galaxies (10 polarimetry that separates the polarized foreground from the unpolarized 21-cm signal. Initial results from a ground-based prototype called the Cosmic Twilight Polarimeter will be described which tentatively reveal the presence of the expected polarization signature from the foreground. Dynamic polarimetry, when combined with sophisticated pattern recognition techniques based on training sets, machine learning, and statistical information criteria offer promise for precise extraction of the 21-cm spectrum. We describe a new SmallSat mission concept, the Dark Ages Polarimetry Pathfinder (DAPPer), that will utilize these novel approaches for extending the recent detection of a 78 MHz signal down to lower frequencies where we can uniquely probe evidence for the first stars and dark matter.
Efficient Dynamic Adaptation Strategies for Object Tracking Tree in Wireless Sensor Network
Directory of Open Access Journals (Sweden)
CHEN, M.
2012-12-01
Full Text Available Most object tracking trees are established using the predefined mobility profile. However, when the real object's movement behaviors and query rates are different from the predefined mobility profile and query rates, the update cost and query cost of object tracking tree may increase. To upgrade the object tracking tree, the sink needs to send very large messages to collect the real movement information from the network, introducing a very large message overhead, which is referred to as adaptation cost. The Sub Root Message-Tree Adaptive procedure was proposed to dynamically collect the real movement information under the sub-tree and reconstruct the sub-tree to provide good performance based on the collected information. The simulation results indicates that the Sub Root Message-Tree Adaptive procedure is sufficient to achieve good total cost and lower adaptation cost.
Soil and plant nitrogen dynamics of a tomato crop under different fertilization strategies
DEFF Research Database (Denmark)
Doltra, Jordi; Muñoz, P; Antón, A
2010-01-01
(TM) kg N ha-1. The N contents of plants sampled on three occasions during the growing period and those of marketable fruits were also analyzed. Total marketable yield was determined at the end of the harvest period. The EU-Rotate_N model was used to predict the effects of the applied treatments......A field experiment was conducted in 2007 to investigate the effects of the N fertilizer source on the soil and plant N dynamics of a tomato crop grown in a sandy loam soil. The fertilization treatments were: mineral N-fertilization applied by fertigation (TM); organic N-fertilization (TO....... The model was calibrated using data from a previous experiment. No differences between treatments were observed with respect to yield or N content in marketable fruits. The amount of N left in the field at the end of the cropping period was significantly lower in TO than in TC and TM. Simulated plant growth...
Static and dynamic load-balancing strategies for parallel reservoir simulation
International Nuclear Information System (INIS)
Anguille, L.; Killough, J.E.; Li, T.M.C.; Toepfer, J.L.
1995-01-01
Accurate simulation of the complex phenomena that occur in flow in porous media can tax even the most powerful serial computers. Emergence of new parallel computer architectures as a future efficient tool in reservoir simulation may overcome this difficulty. Unfortunately, major problems remain to be solved before using parallel computers commercially: production serial programs must be rewritten to be efficient in parallel environments and load balancing methods must be explored to evenly distribute the workload on each processor during the simulation. This study implements both a static load-balancing algorithm and a receiver-initiated dynamic load-sharing algorithm to achieve high parallel efficiencies on both the IBM SP2 and Intel IPSC/860 parallel computers. Significant speedup improvement was recorded for both methods. Further optimization of these algorithms yielded a technique with efficiencies as high as 90% and 70% on 8 and 32 nodes, respectively. The increased performance was the result of the minimization of message-passing overhead
Solar Thermal Technologies Dynamics and Strategies for Market Creation in Sindh
Directory of Open Access Journals (Sweden)
Asif Ali Shah
2016-04-01
Full Text Available In order to sketch Sindh's RE (Renewable Energy based scenario, it is vital to trace the dynamics of simplest RETs (Renewable Energy Technologies such as STTs (Solar Thermal Technologies. STTs are simple to operate, easy to maintain and requires low cost of fabrication. Due to these advantages, STTs possess scope for mass market creation in Sindh as can provide alternate energy solutions to meet daily fuel requirements of heating and cooking etc. The paper identifies that the low awareness creates a negative perception about the price and efficiency of these technologies in masses, which can be removed once the awareness increases. This paper consists of survey findings, which traces the trends for STTs utilization in Sindh by testing various hypotheses to identify the suitable tactics required for their market creation. Finally the key policy recommendations are provided at the end.
System dynamics model developement for R and D budget allocation strategy
International Nuclear Information System (INIS)
Kwack, S. M.; Kim, D. H.; Lee, Y. S.; Jung, M. T.
2003-01-01
A computer simulation model was developed for R and D budget allocation problems that usually contain very complex and non-linear social issues. The System Dynamics approach was employed, which is proper to complex and non-linear social problem modeling. An issue of budget allocation to each step in five research areas was analyzed for an application example. The base scenario, that assumes to allocate a large portion of budget to demonstration step, was found to have a weakness in long-term sense. To overcome this weakness, some other better alternatives were recommended through the analysis. In addition, this paper suggests the ways to utilize the updated model in the future
Directory of Open Access Journals (Sweden)
Abolfazl Kazemdehdashti
2013-01-01
Full Text Available In this paper, dynamic voltage restorer (DVR compensation methods are compared to each other for the load side connected shunt converter topology of z-source inverter based DVR to choose the best method. Four different topologies are recognized for DVR that two of them have energy storage devices, and two topologies have no energy storage that take ener\\-gy from the grid during the period of compensation. Here the load side connected shunt converter topology that takes necessary energy from the grid is used. Pre-sag compensation, in-phase compensation, energy-optimized methods are the three DVR compensation methods that studied and compared. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived and the characteristics of algorithms are compared with each other. The simulation results done by SIMULINK/ MATLAB shows compensating by this topology based on the compensation methods.
Ponsford, B J; Barlow, D
1999-01-01
This research reviews the factors affecting the pricing or rate schedules of home health care agencies. A large number of factors affect costs and thus rate structures. The major factors include reimbursement structures with accompanying discount structures, administrative burdens, and risks. Channel issues include bargaining power, competition, and size. Staffing issues affect pricing and product through the provider level, productivity, and quality outcomes. Physician and patient issues include quality concerns and choices. These factors are discussed in light of overall marketing strategy and the interaction of pricing with other marketing controllables such as product, place/distribution, and promotion. Economic and accounting principles are also reviewed with consideration to understanding direct and indirect costs in order to enable negotiators to effectively price health care services.
The Dynamic Evolution of Firms’ Pollution Control Strategy under Graded Reward-Penalty Mechanism
Directory of Open Access Journals (Sweden)
Li Ming Chen
2016-01-01
Full Text Available The externality of pollution problem makes firms lack enough incentive to reduce pollution emission. Therefore, it is necessary to design a reasonable environmental regulation mechanism so as to effectively urge firms to control pollution. In order to inspire firms to control pollution, we divide firms into different grades according to their pollution level and construct an evolutionary game model to analyze the interaction between government’s regulation and firms’ pollution control under graded reward-penalty mechanism. Then, we discuss stability of firms’ pollution control strategy and derive the condition of inspiring firms to control pollution. Our findings indicate that firms tend to control pollution after long-term repeated games if government’s excitation level and monitoring frequency meet some conditions. Otherwise, firms tend to discharge pollution that exceeds the stipulated standards. As a result, in order to effectively control pollution, a government should adjust its excitation level and monitoring frequency reasonably.
International Nuclear Information System (INIS)
Kai, Tetsuya; Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Sakata, Hideaki; Ikeda, Yujiro
2001-01-01
We studied decoupled poisoned and un-poisoned composite moderators consisting of 20 mm thick hydrogen and 30 mm thick light water. The neutron pulses from un-poisoned one were much broader with longer decay times than a simple decoupled hydrogen moderator in 50 mm thickness. It was also found that the poisoned composite moderator provides higher pulse peak intensities relative to the hydrogen moderator (poisoned at 20 mm) below several tens meV with no penalty of pulse width. (author)
Decoupling of Fluctuating Power in Single-Phase Systems Through a Symmetrical Half-Bridge Circuit
DEFF Research Database (Denmark)
Tang, Yi; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
approach may inevitably lead to low power density and limited system lifetime. An alternative approach is to use active power decoupling so that the ripple power can be diverted into other energy storage devices to gain an improved system performance. Nevertheless, all existing active methods have...... power decoupling method, and both the input current and output voltage of the converter can be well regulated even when very small dc-link capacitors are employed....
Extreme drought decouples silicon and carbon geochemical linkages in lakes.
Li, Tianyang; Li, Siyue; Bush, Richard T; Liang, Chuan
2018-09-01
Silicon and carbon geochemical linkages were usually regulated by chemical weathering and organism activity, but had not been investigated under the drought condition, and the magnitude and extent of drought effects remain poorly understood. We collected a comprehensive data set from a total of 13 sampling sites covering the main water body of the largest freshwater lake system in Australia, the Lower Lakes. Changes to water quality during drought (April 2008-September 2010) and post-drought (October 2010-October 2013) were compared to reveal the effects of drought on dissolved silica (DSi) and bicarbonate (HCO 3 - ) and other environmental factors, including sodium (Na + ), pH, electrical conductivity (EC), chlorophyll a (Chl-a), total dissolved solids (TDS), dissolved inorganic nitrogen (DIN), total nitrogen (TN), total phosphorus (TP) and water levels. Among the key observations, concentrations of DSi and DIN were markedly lower in drought than in post-drought period while pH, EC and concentrations of HCO 3 - , Na + , Chl-a, TDS, TN, TP and the ratio TN:TP had inverse trends. Stoichiometric ratios of DSi:HCO 3 - , DSi:Na + and HCO 3 - :Na + were significantly lower in the drought period. DSi exhibited significantly negative relationships with HCO 3 - , and DSi:Na + was strongly correlated with HCO 3 - :Na + in both drought and post-drought periods. The backward stepwise regression analysis that could avoid multicollinearity suggested that DSi:HCO 3 - ratio in drought period had significant relationships with fewer variables when compared to the post-drought, and was better predictable using nutrient variables during post-drought. Our results highlight the drought effects on variations of water constituents and point to the decoupling of silicon and carbon geochemical linkages in the Lower Lakes under drought conditions. Copyright © 2018 Elsevier B.V. All rights reserved.
Myological variability in a decoupled skeletal system: batoid cranial anatomy.
Kolmann, Matthew A; Huber, Daniel R; Dean, Mason N; Grubbs, R Dean
2014-08-01
Chondrichthyans (sharks, batoids, and chimaeras) have simple feeding mechanisms owing to their relatively few cranial skeletal elements. However, the indirect association of the jaws to the cranium (euhyostylic jaw suspension) has resulted in myriad cranial muscle rearrangements of both the hyoid and mandibular elements. We examined the cranial musculature of an abbreviated phylogenetic representation of batoid fishes, including skates, guitarfishes and with a particular focus on stingrays. We identified homologous muscle groups across these taxa and describe changes in gross morphology across developmental and functional muscle groups, with the goal of exploring how decoupling of the jaws from the skull has effected muscular arrangement. In particular, we focus on the cranial anatomy of durophagous and nondurophagous batoids, as the former display marked differences in morphology compared to the latter. Durophagous stingrays are characterized by hypertrophied jaw adductors, reliance on pennate versus fusiform muscle fiber architecture, tendinous rather than aponeurotic muscle insertions, and an overall reduction in mandibular kinesis. Nondurophagous stingrays have muscles that rely on aponeurotic insertions onto the skeletal structure, and display musculoskeletal specialization for jaw protrusion and independent lower jaw kinesis, relative to durophagous stingrays. We find that among extant chondrichthyans, considerable variation exists in the hyoid and mandibular muscles, slightly less so in hypaxial muscles, whereas branchial muscles are overwhelmingly conserved. As chondrichthyans occupy a position sister to all other living gnathostomes, our understanding of the structure and function of early vertebrate feeding systems rests heavily on understanding chondrichthyan cranial anatomy. Our findings highlight the incredible variation in muscular complexity across chondrichthyans in general and batoids in particular. © 2014 Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Wei Zhang
2014-01-01
Full Text Available The underwater recovery of autonomous underwater vehicles (AUV is a process of 6-DOF motion control, which is related to characteristics with strong nonlinearity and coupling. In the recovery mission, the vehicle requires high level control accuracy. Considering an AUV called BSAV, this paper established a kinetic model to describe the motion of AUV in the horizontal plane, which consisted of nonlinear equations. On the basis of this model, the main coupling variables were analyzed during recovery. Aiming at the strong coupling problem between the heading control and sway motion, we designed a decoupling compensator based on the fuzzy theory and the decoupling theory. We analyzed to the rules of fuzzy compensation, the input and output membership functions of fuzzy compensator, through compose operation and clear operation of fuzzy reasoning, and obtained decoupling compensation quantity. Simulation results show that the fuzzy decoupling controller effectively reduces the overshoot of the system, and improves the control precision. Through the water tank experiments and analysis of experimental data, the effectiveness and feasibility of AUV recovery movement coordinated control based on fuzzy decoupling method are validated successful, and show that the fuzzy decoupling control method has a high practical value in the recovery mission.
Directory of Open Access Journals (Sweden)
Xiao-Wei Ma
2016-09-01
Full Text Available This paper analyzes Chinese household CO2 emissions in 1994–2012 based on the Logarithmic Mean Divisia Index (LMDI structure decomposition model, and discusses the relationship between household CO2 emissions and economic growth based on a decoupling indicator. The results show that in 1994–2012, household CO2 emissions grew in general and displayed an accelerated growth trend during the early 21st century. Economic growth leading to an increase in energy consumption is the main driving factor of CO2 emission growth (an increase of 1.078 Gt CO2 with cumulative contribution rate of 55.92%, while the decline in energy intensity is the main cause of CO2 emission growth inhibition (0.723 Gt CO2 emission reduction with cumulative contribution rate of 38.27%. Meanwhile, household CO2 emissions are in a weak state of decoupling in general. The change in CO2 emissions caused by population and economic growth shows a weak decoupling and expansive decoupling state, respectively. The CO2 emission change caused by energy intensity is in a state of strong decoupling, and the change caused by energy consumption structure fluctuates between a weak and a strong decoupling state.