Absorption spectrum of a two-level system subjected to a periodic pulse sequence
Fotso, H. F.; Dobrovitski, V. V.
2017-06-01
We investigate how the quantum control of a two-level system (TLS) coupled to photons can modify and tune the TLS's photon absorption spectrum. Tuning and controlling the emission and the absorption are of great interest, e.g., for the development of efficient interfaces between stationary and flying qubits in modern architectures for quantum computation and quantum communication. We consider periodic pulse control, where the TLS is subjected to a periodic sequence of the near-resonant Rabi driving pulses, each pulse implementing a 180∘ rotation. For small interpulse delays, the absorption spectrum features a pronounced peak of stimulated emission at the pulse frequency, similar satellite peaks with smaller spectral weights, and the net absorption peaks on the sides. As long as the detuning between the carrier frequency of the driving and the TLS transition frequency remains moderate, this spectral shape shows little change. Therefore, the pulse control allows shifting the absorption peak to a desired position and locks the overall absorption spectrum to the carrier frequency of the driving pulses. A detailed description of the spectrum and its evolution as a function time, the interpulse spacing, and the detuning is presented.
Model discrimination for dephasing two-level systems
Energy Technology Data Exchange (ETDEWEB)
Gong, Er-ling [Department of Automatic Control, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China); College of Science (Physics), Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom); Zhou, Weiwei [Department of Automatic Control, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China); Schirmer, Sophie, E-mail: sgs29@swan.ac.uk [College of Science (Physics), Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom)
2015-02-06
The problem of model discriminability and parameter identifiability for dephasing two-level systems subject to Hamiltonian control is studied. Analytic solutions of the Bloch equations are used to derive explicit expressions for observables as functions of time for different models. This information is used to give criteria for model discrimination and parameter estimation based on simple experimental paradigms. - Highlights: • Analytic expressions for observables of driven, dephasing two-level systems. • Distinguishability of dephasing models via Rabi-oscillation experiments. • General identifiability of model parameters and cases of failure. • Application to empirically determine of effect of driving on dephasing basis. • Importance for optimal design of coherent controls for qubits subject to dephasing.
Two-level systems driven by large-amplitude fields
Nori, F.; Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.
2009-03-01
We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition, (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems. S. Ashhab, J.R. Johansson, A.M. Zagoskin, F. Nori, Two-level systems driven by large-amplitude fields, Phys. Rev. A 75, 063414 (2007). S. Ashhab et al, unpublished.
The Two-level Management System of University and School
Institute of Scientific and Technical Information of China (English)
Yang Xu
2013-01-01
With the development of our country's higher e-ducation, the school also presents the great-leap-forward devel-opment trend. The previous denotative development has changed into the way of connotative development. The two-level management system of university and school is the most common management mode in many colleges. This paper intro-duces the advantage of this mode in the objective view, analyzes the problems existing in the practice operation, put forward countermeasures to improve the two-level management and proposes a method to build the two-level management system.
Field correlations and effective two level atom-cavity systems
Rebic, S; Tan, S M
2004-01-01
We analyse the properties of the second order correlation functions of the electromagnetic field in atom-cavity systems that approximate two-level systems. It is shown that a recently-developed polariton formalism can be used to account for all the properties of the correlations, if the analysis is extended to include two manifolds - corresponding to the ground state and the states excited by a single photon - rather than just two levels.
Modulated two-level system: exact work statistics.
Verley, Gatien; Van den Broeck, Christian; Esposito, Massimiliano
2013-09-01
We consider an open two-level system driven by a piecewise constant periodic field and described by a rate equation with Fermi, Bose, and Arrhenius rates, respectively. We derive an analytical expression for the generating function and large deviation function of the work performed by the field and show that a work fluctuation theorem holds.
Berry phase in a generalized nonlinear two-level system
Institute of Scientific and Technical Information of China (English)
Liu Ji-Bing; Li Jia-Hua; Song Pei-Jun; Li Wei-Bin
2008-01-01
In this paper,we investigate the behaviour of the geometric phase of a more generalized nonlinear system composed of an effective two-level system interacting with a single-mode quantized cavity field.Both the field nonlinearity and the atom-field coupling nonlinearity are considered.We find that the geometric phase depends on whether the index k is an odd number or an even number in the resonant case.In addition,we also find that the geometric phase may be easily observed when the field nonlinearity is not considered.The fractional statistical phenomenon appears in this system if the strong nonlinear atom-field coupling is considered.We have also investigated the geometric phase of an effective two-level system interacting with a two-mode quantized cavity field.
Possible Minkowskian Language in Two-level Systems
Kim, Y S
2008-01-01
One hundred years ago, in 1908, Hermann Minkowski completed his proof that Maxwell's equations are covariant under Lorentz transformations. During this process, he introduced a four-dimensional space called the Minkowskian space. In 1949, P. A. M. Dirac showed the Minkowskian space can be handled with the light-cone coordinate system with squeeze transformations. While the squeeze is one of the fundamental mathematical operations in optical sciences, it could serve useful purposes in two-level systems. Some possibilities are considered in this report. It is shown possible to cross the light-cone boundary in optical and two-level systems while it is not possible in Einstein's theory of relativity.
Ultra-short strong excitation of two-level systems
Jha, Pankaj K.; Eleuch, Hichem; Grazioso, Fabio
2014-11-01
We present a model describing the use of ultra-short strong pulses to control the population of the excited level of a two-level quantum system. In particular, we study an off-resonance excitation with a few cycles pulse which presents a smooth phase jump i.e. a change of the pulse's phase which is not step-like, but happens over a finite time interval. A numerical solution is given for the time-dependent probability amplitude of the excited level. The control of the excited level's population is obtained acting on the shape of the phase transient, and other parameters of the excitation pulse.
Ultra-short strong excitation of two-level systems
2013-01-01
We present a model describing the use of ultra-short strong pulses to control the population of the excited level of a two-level quantum system. In particular, we study an off-resonance excitation with a few cycles pulse which presents a smooth phase jump i.e. a change of the pulse's phase which is not step-like, but happens over a finite time interval. A numerical solution is given for the time-dependent probability amplitude of the excited level. The control of the excited level's populatio...
Noise from Two-Level Systems in Superconducting Resonators
Neill, C.; Barends, R.; Chen, Y.; Chiaro, B.; Jeffrey, E.; Kelly, J.; Mariantoni, M.; Megrant, A.; Mutus, J.; Ohya, S.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T.; Cleland, A. N.; Martinis, J. M.
2013-03-01
Two-level systems (TLSs) present in amorphous dielectrics and surface interfaces are a significant source of decoherence in superconducting qubits. Linear microwave resonators offer a valuable instrument for characterizing the strongly power-dependent response of these TLSs. Using quarter-wavelength coplanar waveguide resonators, we monitored the microwave response of the resonator at a single near-resonant frequency versus time at varying microwave drive powers. We observe a time dependent variation of the resonator's internal dissipation and resonance frequency. The amplitude of these variations saturates with power in a manner similar to loss from TLSs. These results provide a means for quantifying the number and distribution of TLSs.
Comparison of time optimal control for two level quantum systems
Institute of Scientific and Technical Information of China (English)
Shuang Cong; Jie Wen; Xubo Zou
2014-01-01
The time optimal problem for a two level quantum sys-tem is studied. We compare two different control strategies of bang-bang control and the geometric control, respectively, es-pecial y in the case of minimizing the time of steering the state from North Pole to South Pole on the Bloch sphere with bounded control. The time performances are compared for different param-eters by the individual numerical simulation experiments, and the experimental results are analyzed. The results show that the ge-ometric control spends less time than the bang-bang control does.
Variational Study on a Dissipative Two-Level System
Institute of Scientific and Technical Information of China (English)
ZHU Wei-Wing; REN Qing-Bao; CHEN Qing-Hu
2008-01-01
A new variational approach is proposed to study the ground-state of a two-level system coupled to a dispersionless phonon bath. By the extended coherent state, where the more phonon correlations are easily incorporated, we can obtain very accurate ground state energy and the tunnelling reduction factor in all regime of tunnelling matrix element δo and coupling parameter s. The relative difference between the present ones and those by exact numerical diagonalization is less then 0.001%. In addition, some simple analytical results are given in the limits of δo/s → 0 and ∞.
Two-level tunneling systems in amorphous alumina
Lebedeva, Irina V.; Paz, Alejandro P.; Tokatly, Ilya V.; Rubio, Angel
2014-03-01
The decades of research on thermal properties of amorphous solids at temperatures below 1 K suggest that their anomalous behaviour can be related to quantum mechanical tunneling of atoms between two nearly equivalent states that can be described as a two-level system (TLS). This theory is also supported by recent studies on microwave spectroscopy of superconducting qubits. However, the microscopic nature of the TLS remains unknown. To identify structural motifs for TLSs in amorphous alumina we have performed extensive classical molecular dynamics simulations. Several bistable motifs with only one or two atoms jumping by considerable distance ~ 0.5 Å were found at T=25 K. Accounting for the surrounding environment relaxation was shown to be important up to distances ~ 7 Å. The energy asymmetry and barrier for the detected motifs lied in the ranges 0.5 - 2 meV and 4 - 15 meV, respectively, while their density was about 1 motif per 10 000 atoms. Tuning of motif asymmetry by strain was demonstrated with the coupling coefficient below 1 eV. The tunnel splitting for the symmetrized motifs was estimated on the order of 0.1 meV. The discovered motifs are in good agreement with the available experimental data. The financial support from the Marie Curie Fellowship PIIF-GA-2012-326435 (RespSpatDisp) is gratefully acknowledged.
Two-Level Incremental Checkpoint Recovery Scheme for Reducing System Total Overheads
Li, Huixian; Pang, Liaojun; Wang, Zhangquan
2014-01-01
Long-running applications are often subject to failures. Once failures occur, it will lead to unacceptable system overheads. The checkpoint technology is used to reduce the losses in the event of a failure. For the two-level checkpoint recovery scheme used in the long-running tasks, it is unavoidable for the system to periodically transfer huge memory context to a remote stable storage. Therefore, the overheads of setting checkpoints and the re-computing time become a critical issue which directly impacts the system total overheads. Motivated by these concerns, this paper presents a new model by introducing i-checkpoints into the existing two-level checkpoint recovery scheme to deal with the more probable failures with the smaller cost and the faster speed. The proposed scheme is independent of the specific failure distribution type and can be applied to different failure distribution types. We respectively make analyses between the two-level incremental and two-level checkpoint recovery schemes with the Weibull distribution and exponential distribution, both of which fit with the actual failure distribution best. The comparison results show that the total overheads of setting checkpoints, the total re-computing time and the system total overheads in the two-level incremental checkpoint recovery scheme are all significantly smaller than those in the two-level checkpoint recovery scheme. At last, limitations of our study are discussed, and at the same time, open questions and possible future work are given. PMID:25111048
Franson Interference Generated by a Two-Level System
Peiris, M.; Konthasinghe, K.; Muller, A.
2017-01-01
We report a Franson interferometry experiment based on correlated photon pairs generated via frequency-filtered scattered light from a near-resonantly driven two-level semiconductor quantum dot. In contrast to spontaneous parametric down-conversion and four-wave mixing, this approach can produce single pairs of correlated photons. We have measured a Franson visibility as high as 66%, which goes beyond the classical limit of 50% and approaches the limit of violation of Bell's inequalities (70.7%).
Quantum modeling of two-level photovoltaic systems
Aram, Tahereh Nemati; Asgari, Asghar; Ernzerhof, Matthias; Quémerais, Pascal; Mayou, Didier
2017-06-01
We present a quantum formalism that provides a quantitative picture of the fundamental processes of charge separation that follow an absorption event. We apply the formalism to two-level photovoltaic cells and our purpose is to pedagogically explain the main aspects of the model. The formalism is developed in the energy domain and provides detailed knowledge about existence or absence of localized states and their effects on electronic structure and photovoltaic yield.
A Two-Level Spreading-despreading CDMA System and Its Performance Evaluation
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
A new two-level spreading-despreading scheme is presented in this paper. By adopting the two-level scheme, the Generalized Orthogonal (GO) zone of GO codes can be utilized. In this paper, the forward link of a multi-cell CDMA system employing the two-level scheme is presented and analyzed. The BER performance obtained by Gaussian Approximation is compared with that of the conventional single-level spreading-despreading system. The results reveal that the two*$-level CDMA system introduced in this paper exhibits larger performance gain when time delay can be restricted within a given zone.
Time-Minimal Control of Dissipative Two-level Quantum Systems: the Generic Case
Bonnard, B; Sugny, D
2008-01-01
The objective of this article is to complete preliminary results concerning the time-minimal control of dissipative two-level quantum systems whose dynamics is governed by Lindblad equations. The extremal system is described by a 3D-Hamiltonian depending upon three parameters. We combine geometric techniques with numerical simulations to deduce the optimal solutions.
Design and Implementation of Two-Level Metadata Server in Small-Scale Cluster File System
Institute of Scientific and Technical Information of China (English)
LIU Yuling; YU Hongfen; SONG Weiwei
2006-01-01
The reliability and high performance of metadata service is crucial to the store architecture. A novel design of a two-level metadata server file system (TTMFS) is presented, which behaves high reliability and performance. The merits both centralized management and distributed management are considered simultaneously in our design. In this file system, the advanced-metadata server is responsible for manage directory metadata and the whole namespace. The double-metadata server is responsible for maintaining file metadata. And this paper uses the Markov return model to analyze the reliability of the two-level metadata server. The experiment data indicates that the design can provide high throughput.
The Two-Level System of Higher Education: Western Traditions and Russian Reality
Druzhilov, S. A.
2011-01-01
The law on the two-level system of higher education has now gone into effect in Russia: the bachelor's degree will correspond to the first level of higher education, while the master's degree will correspond to the second level. These levels entail separate state educational standards and separate final certification. In the process of adopting…
Exact Solution of the Two-Level System and the Einstein Solid in the Microcanonical Formalism
Bertoldi, Dalia S.; Bringa, Eduardo M.; Miranda, E. N.
2011-01-01
The two-level system and the Einstein model of a crystalline solid are taught in every course of statistical mechanics and they are solved in the microcanonical formalism because the number of accessible microstates can be easily evaluated. However, their solutions are usually presented using the Stirling approximation to deal with factorials. In…
Broadband EM radiation amplification by means of a monochromatically driven two-level system
Soldatov, Andrey V.
2017-02-01
It is shown that a two-level quantum system possessing dipole moment operator with permanent non-equal diagonal matrix elements and driven by external semiclassical monochromatic high-frequency electromagnetic (EM) (laser) field can amplify EM radiation waves of much lower frequency.
Time-minimal control of dissipative two-level quantum systems: The Integrable case
Bonnard, B
2008-01-01
The objective of this article is to apply recent developments in geometric optimal control to analyze the time minimum control problem of dissipative two-level quantum systems whose dynamics is governed by the Lindblad equation. We focus our analysis on the case where the extremal Hamiltonian is integrable.
Transmission Dynamics of a Driven Two-Level System Dissipated by Leads
Institute of Scientific and Technical Information of China (English)
ZHANG Ping; FAN Wen-Bin; ZHAO Xian-Geng
2001-01-01
We study the transmission dynamics of a driven two-level system dissipated by the two leads. Using the nonequilibrium Green function, we derive an analytical transmission formula for an electron incident from the left lead,through the double quantum dots, to the right lead. The Landauer-type conductance and current are also given.A discussion of the internal tunnelling dynamics reveals crucial effects of the localization and delocalization on the transport of the system.
Zeno and Anti Zeno effect for a two level system in a squeezed bath
Mundarain, D F
2005-01-01
We discuss the appearance of Zeno (QZE) or anti-Zeno (QAE) effect in an exponentially decaying system. We consider the quantum dynamics of a continuously monitored two level system interacting with a squeezed bath. We find that the behavior of the system depends critically on the way in which the squeezed bath is prepared. For specific choices of the squeezing phase the system shows Zeno or anti-Zeno effect in conditions for which it would decay exponentially if no measurements were done. This result allows for a clear interpretation in terms of the equivalent spin system interacting with a fictitious magnetic field.
Energy Technology Data Exchange (ETDEWEB)
Tan, Xinsheng [National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093 (China); Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States); Yu, Haifeng, E-mail: hfyu@nju.edu.cn; Yu, Yang, E-mail: yuyang@nju.edu.cn [National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Han, Siyuan [Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States)
2015-09-07
We demonstrate a fast method to detect microscopic two-level systems in a superconducting phase qubit. By monitoring the population leak after sweeping the qubit bias flux, we are able to measure the two-level systems that are coupled with the qubit. Compared with the traditional method that detects two-level systems by energy spectroscopy, our method is faster and more sensitive. This method supplies a useful tool to investigate two-level systems in solid-state qubits.
Photon-statistics excitation spectroscopy of a single two-level system
Strauß, Max; Placke, Marlon; Kreinberg, Sören; Schneider, Christian; Kamp, Martin; Höfling, Sven; Wolters, Janik; Reitzenstein, Stephan
2016-06-01
We investigate the influence of the photon statistics on the excitation dynamics of a single two-level system. A single semiconductor quantum dot represents the two-level system and is resonantly excited either with coherent laser light, or excited with chaotic light, with photon statistics corresponding to that of thermal radiation. Experimentally, we observe a reduced absorption cross section under chaotic excitation in the steady state. In the transient regime, the Rabi oscillations observable under coherent excitation disappear under chaotic excitation. Likewise, in the emission spectrum, the well-known Mollow triplet, which we observe under coherent drive, disappears under chaotic excitation. Our observations are fully consistent with theoretical predictions based on the semiclassical Bloch equation approach.
Photon-Statistics Excitation Spectroscopy of a Single Two Level System
Strauß, M; Kreinberg, S; Schneider, C; Kamp, M; Höfling, S; Wolters, J; Reitzenstein, S
2016-01-01
We investigate the influence of the photon statistics on the excitation dynamics of a single two level system. A single semiconductor quantum dot represents the two level system and is resonantly excited either with coherent laser light, or excited with chaotic light, with photon statistics corresponding to that of thermal radiation. Experimentally, we observe a reduced absorption cross-section under chaotic excitation in the steady-state. In the transient regime, the Rabi oscillations observable under coherent excitation disappear under chaotic excitation. Likewise, in the emission spectrum the well-known Mollow triplet, which we observe under coherent drive, disappears under chaotic excitation. Our observations are fully consistent with theoretical predictions based on the semi-classical Bloch equation approach.
Weak-Coupling Theory for Low-Frequency Periodically Driven Two-Level Systems
Institute of Scientific and Technical Information of China (English)
CHEN Ai-Xi; HUANG Ke-Lin; WANG Zhi-Ping
2008-01-01
We generalize the Wu-Yang strong-coupling theory to solve analytically periodically driven two-level systems in the weak-coupling and low-frequency regimes for single- and multi-period periodic driving of continuous-wave-type and pulse-type including ultrashort pulses of a few cycles. We also derive a general formula of the AC Stark shift suitable for such diverse situations.
Total Quantum Zeno effect and Intelligent States for a two level system in a squeezed bath
Mundarain, D; Stephany, J
2006-01-01
In this work we show that by frequent measurements of adequately chosen observables, a complete suppression of the decay in an exponentially decaying two level system interacting with a squeezed bath is obtained. The observables for which the effect is observed depend on the the squeezing parameters of the bath. The initial states which display Total Zeno Effect are intelligent states of two conjugate observables associated to the electromagnetic fluctuations of the bath.
Automatic Detection of Cervical Cancer Cells by a Two-Level Cascade Classification System
Directory of Open Access Journals (Sweden)
Jie Su
2016-01-01
Full Text Available We proposed a method for automatic detection of cervical cancer cells in images captured from thin liquid based cytology slides. We selected 20,000 cells in images derived from 120 different thin liquid based cytology slides, which include 5000 epithelial cells (normal 2500, abnormal 2500, lymphoid cells, neutrophils, and junk cells. We first proposed 28 features, including 20 morphologic features and 8 texture features, based on the characteristics of each cell type. We then used a two-level cascade integration system of two classifiers to classify the cervical cells into normal and abnormal epithelial cells. The results showed that the recognition rates for abnormal cervical epithelial cells were 92.7% and 93.2%, respectively, when C4.5 classifier or LR (LR: logical regression classifier was used individually; while the recognition rate was significantly higher (95.642% when our two-level cascade integrated classifier system was used. The false negative rate and false positive rate (both 1.44% of the proposed automatic two-level cascade classification system are also much lower than those of traditional Pap smear review.
Quantum dynamics of a microwave driven superconducting phase qubit coupled to a two-level system
Sun, Guozhu; Wen, Xueda; Mao, Bo; Zhou, Zhongyuan; Yu, Yang; Wu, Peiheng; Han, Siyuan
2010-10-01
We present an analytical and comprehensive description of the quantum dynamics of a microwave resonantly driven superconducting phase qubit coupled to a microscopic two-level system (TLS), covering a wide range of the external microwave field strength. Our model predicts several interesting phenomena in such an ac driven four-level bipartite system including anomalous Rabi oscillations, high-contrast beatings of Rabi oscillations, and extraordinary two-photon transitions. Our experimental results in a coupled qubit-TLS system agree quantitatively very well with the predictions of the theoretical model.
The Master Equation for Two-Level Accelerated Systems at Finite Temperature
Tomazelli, J. L.; Cunha, R. O.
2016-10-01
In this work, we study the behaviour of two weakly coupled quantum systems, described by a separable density operator; one of them is a single oscillator, representing a microscopic system, while the other is a set of oscillators which perform the role of a reservoir in thermal equilibrium. From the Liouville-Von Neumann equation for the reduced density operator, we devise the master equation that governs the evolution of the microscopic system, incorporating the effects of temperature via Thermofield Dynamics formalism by suitably redefining the vacuum of the macroscopic system. As applications, we initially investigate the behaviour of a Fermi oscillator in the presence of a heat bath consisting of a set of Fermi oscillators and that of an atomic two-level system interacting with a scalar radiation field, considered as a reservoir, by constructing the corresponding master equation which governs the time evolution of both sub-systems at finite temperature. Finally, we calculate the energy variation rates for the atom and the field, as well as the atomic population levels, both in the inertial case and at constant proper acceleration, considering the two-level system as a prototype of an Unruh detector, for admissible couplings of the radiation field.
Experimental investigation of slow light propagation in degenerate two-level system
Institute of Scientific and Technical Information of China (English)
Wang Li-Rong; Zhao Yan-Ting; Ma Jie; Zhao Jian-Ming; Xiao Lian-Tuan; Jia Suo-Tang
2006-01-01
Slowing a light pulse in a degenerate two-level system is observed with a double-frequency sweeping technique. The effects of coupling beam intensity, cell temperature and frequency detunings of the coupling and probe beams in resonance, on the slowing of light propagation in such a system are investigated. It is found that group velocities depend strongly on polarization combinations. A group velocity υg=6760m/s of light pulses in caesium vapour is obtained under the optimal parameters.
Analysis of Two-Level Support Systems with Time-Dependent Overflow - A Banking Application
DEFF Research Database (Denmark)
Barth, Wolfgang; Manitz, Michael; Stolletz, Raik
2010-01-01
is available. The analysis of such a system with time-dependent overflow is reduced to the analysis of a continuous-time Markov chain with state-dependent overflow probabilities. To approximate the system with time-dependent overflow, some waiting-based performance measures are modified. Numerical results......In this paper, we analyze the performance of call centers of financial service providers with two levels of support and a time-dependent overflow mechanism. Waiting calls from the front-office queue flow over to the back office if a waiting-time limit is reached and at least one back-office agent...
Load-Balance Policy in Two Level-Cluster File System
Institute of Scientific and Technical Information of China (English)
LIU Yuling; SONG Weiwei; MA Xiaoxue
2006-01-01
In this paper, we explored a load-balancing algorithm in a cluster file system contains two levels of metadata-server,primary-level server quickly distributestasks to second-level servers depending on the closest load-balancing information. At the same time, we explored a method which accurately reflect I/O traffic and storage of storage-node: computing the heat-value of file, according to which we realized a more logical storage allocation. According to the experiment result, we conclude that this new algorithm shortens the executing time of tasks and improves the system performance compared with other load algorithm.
A two-level formal specification of a defense communications system
Energy Technology Data Exchange (ETDEWEB)
Chisholm, G.H. [Argonne National Lab., IL (United States). Decision and Information Sciences Div.; Kemmerer, R.A. [Univ. of California, Santa Barbara, CA (United States). Reliable Software Group
1994-04-01
Computer systems are being used in critical situations with sensitive data, which makes it very important to ensure that these systems perform as desired. The defense communications system contains particularly sensitive data. A two-level ASLAN formal specification of a defense communications system is presented. The ASLAN model is designed to enhance the understanding of critical requirements and demands of the defense communications system. For the top-level (high-level) specifications, the structural details of the actual network are actual network are abstracted to allow more time for examining the interactions between the sites and the network. At this level, DataGrams move through the network, although the actual routing decisions are not specified. More details are added in the second-level specification. At this level, structure is added to the network.
Ultra-short, off-resonant, strong excitation of two-level systems
Jha, Pankaj K; Grazioso, Fabio
2013-01-01
We present a model describing the use of ultra-short strong pulses to populate the excited level of a two-level quantum system. In particular, we study an off-resonance excitation with a few cycles pulse which presents a smooth phase jump i.e. a change of the pulse's phase which is not step-like, but happens over a finite time interval. A numerical solution is given for the time-dependent probability amplitude of the excited level. The enhancement of the excited level's population is optimized with respect to the shape of the phase transient, and to other parameters of the excitation pulse.
Enhancing student learning of two-level quantum systems with interactive simulations
Kohnle, Antje; Campbell, Anna; Korolkova, Natalia; Paetkau, Mark J
2015-01-01
The QuVis Quantum Mechanics Visualization project aims to address challenges of quantum mechanics instruction through the development of interactive simulations for the learning and teaching of quantum mechanics. In this article, we describe evaluation of simulations focusing on two-level systems developed as part of the Institute of Physics Quantum Physics resources. Simulations are research-based and have been iteratively refined using student feedback in individual observation sessions and in-class trials. We give evidence that these simulations are helping students learn quantum mechanics concepts at both the introductory and advanced undergraduate level, and that students perceive simulations to be beneficial to their learning.
Miao, Qiang; Zheng, Yujun
2016-06-29
In this paper, the nature of the multi-order resonance and coherent destruction of tunneling (CDT) for two-level system driven cross avoided crossing is investigated by employing the emitted photons 〈N〉 and the Mandel's Q parameter based on the photon counting statistics. An asymmetric feature of CDT is shown in the spectrum of Mandel's Q parameter. Also, the CDT can be employed to suppress the spontaneous decay and prolong waiting time noticeably. The photon emission pattern is of monotonicity in strong relaxation, and homogeneity in pure dephasing regime, respectively.
Miao, Qiang; Zheng, Yujun
2016-06-01
In this paper, the nature of the multi-order resonance and coherent destruction of tunneling (CDT) for two-level system driven cross avoided crossing is investigated by employing the emitted photons and the Mandel’s Q parameter based on the photon counting statistics. An asymmetric feature of CDT is shown in the spectrum of Mandel’s Q parameter. Also, the CDT can be employed to suppress the spontaneous decay and prolong waiting time noticeably. The photon emission pattern is of monotonicity in strong relaxation, and homogeneity in pure dephasing regime, respectively.
Interaction of Lamb modes with two-level systems in amorphous nanoscopic membranes.
Energy Technology Data Exchange (ETDEWEB)
Kuhn, T.; Anghel, D. V.; Galperin, Y. M.; Manninen, M.; Materials Science Division; Univ. Jyvaskyla; National Inst. for Physics and Nuclear Engineering; Bogolivbov Lab. Theoretical Physics; Univ. Oslo; Russian Academy of Sciences
2007-01-01
Using a generalized model of interaction between a two-level system (TLS) and an arbitrary deformation of the material, we calculate the interaction of Lamb modes with TLSs in amorphous nanoscopic membranes. We compare the mean free paths of the Lamb modes of different symmetries and calculate the heat conductivity {kappa}. In the limit of an infinitely wide membrane, the heat conductivity is divergent. Nevertheless, the finite size of the membrane imposes a lower cutoff for the phonon frequencies, which leads to the temperature dependence {kappa}{alpha}T(a+b ln T). This temperature dependence is a hallmark of the TLS-limited heat conductance at low temperature.
Optimal state transfer of a single dissipative two-level system
Jirari, Hamza; Wu, Ning
2016-04-01
Optimal state transfer of a single two-level system (TLS) coupled to an Ohmic boson bath via off-diagonal TLS-bath coupling is studied by using optimal control theory. In the weak system-bath coupling regime where the time-dependent Bloch-Redfield formalism is applicable, we obtain the Bloch equation to probe the evolution of the dissipative TLS in the presence of a time-dependent external control field. By using the automatic differentiation technique to compute the gradient for the cost functional, we calculate the optimal transfer integral profile that can achieve an ideal transfer within a dimer system in the Fenna-Matthews-Olson (FMO) model. The robustness of the control profile against temperature variation is also analyzed.
Interaction between two SU(1 , 1) quantum systems and a two-level atom
Abdalla, M. Sebawe; Khalil, E. M.; Obada, A. S.-F.
2016-07-01
We consider a two-level atom interacting with two coupled quantum systems that can be represented in terms of su(1 , 1) Lie algebra. The wave function that is obtained using the evolution operator for the atom is initially in a superposition state and the coupled su(1 , 1) systems in a pair coherent Barut-Girardello coherent state. We then discuss atomic inversion, where more periods of revivals are observed and compared with a single su(1 , 1) quantum system. For entanglement and squeezing phenomena, the atomic angles coherence and phase as well as the detuning are effective parameters. The second-order correlation function displays Bunching and anti-Bunching behavior.
On Two-Level State-Dependent Routing Polling Systems with Mixed Service
Directory of Open Access Journals (Sweden)
Guan Zheng
2015-01-01
Full Text Available Based on priority differentiation and efficiency of the system, we consider an N+1 queues’ single-server two-level polling system which consists of one key queue and N normal queues. The novel contribution of the present paper is that we consider that the server just polls active queues with customers waiting in the queue. Furthermore, key queue is served with exhaustive service and normal queues are served with 1-limited service in a parallel scheduling. For this model, we derive an expression for the probability generating function of the joint queue length distribution at polling epochs. Based on these results, we derive the explicit closed-form expressions for the mean waiting time. Numerical examples demonstrate that theoretical and simulation results are identical and the new system is efficient both at key queue and normal queues.
Assessment of two-level heat pump installations’ power efficiency for heat supply systems
Directory of Open Access Journals (Sweden)
Аlla Е. Denysova
2015-06-01
Full Text Available The problem of energy saving becomes one of the most important in power engineering. It is caused by exhaustion of world reserves in hydrocarbon fuel, such as gas, oil and coal representing sources of traditional heat supply. Conventional sources has essential shortcomings: low power, ecological and economic efficiencies, that can be eliminated by using alternative methods of power supply, like the considered one: low-temperature natural heat of ground waters of on the basis of heat pump installations application. The heat supply system considered provides an effective use of two-level heat pump installation operating as heat source the Odessa city ground waters during the lowest ambient temperature period. Proposed is a calculation method of heat pump installations on the basis of geothermal heat supply. Calculated are the values of electric energy consumption N by the compressors’ drive, and the heat supply system transformation coefficient µ for a source of geothermal heat from ground waters of Odessa city allowing to estimate efficiency of two-level heat pump installations.
Amplification without inversion, fast light and optical bistability in a duplicated two-level system
Energy Technology Data Exchange (ETDEWEB)
Ebrahimi Zohravi, Lida; Vafafard, Azar; Mahmoudi, Mohammad, E-mail: mahmoudi@znu.ac.ir
2014-07-01
The optical properties of a weak probe field in a duplicated two-level system are investigated in multi-photon resonance (MPR) condition and beyond it. It is shown that by changing the relative phase of applied fields, the absorption switches to the amplification without inversion in MPR condition. By applying the Floquet decomposition to the equations of motion beyond MPR condition, it is shown that the phase-dependent behavior is valid only in MPR condition. Moreover, it is demonstrated that the group velocity of light pulse can be controlled by the intensity of the applied fields and the gain-assisted superluminal light propagation (fast light) is obtained in this system. In addition, the optical bistability (OB) behavior of the system is studied beyond MPR condition. We apply an indirect incoherent pumping field to the system and it is found that the group velocity and OB behavior of the system can be controlled by the incoherent pumping rate. - Highlights: • We studied the optical properties of DTL system under MPR condition and beyond it. • By changing the relative phase, the absorption switches to the amplification without inversion in MPR condition. • The gain-assisted superluminal light propagation (fast light) is obtained in this system. • The optical bistability (OB) behavior of the system is studied beyond MPR condition. • The incoherent pumping rate has a major role in controlling the group velocity and OB behavior of the system.
Solvent effects on the optical properties of two-level systems with permanent dipole moments
Mastrodomenico, A.; Izquierdo, M. A.; Paz, J. L.; Colmenares, P.
2013-11-01
The inclusion of the permanent dipole moments and the solvent on the optical conventional Bloch equations (OCBE) allowed us to obtain analytical expressions for the optical properties of a two-level molecular system. We employed the methodology developed by Colmenares et al.1, in which they model the collisional effect of the solvent through a stochastical function, ξ(t) = ω0 + σ(t), so the OCBE become a set of coupled integro-differential stochastical equations that we solved, up to third order in the incident field, employing the perturbation theory. Once obtained the analytical expressions for the density matrix elements, macroscopic polarization and effective susceptibility of the system, we studied the optical properties derived in the frequency space, inside and outside the rotating wave approximation.
Equivalence of the measures of non-Markovianty for open two-level systems
Zeng, Hao-Sheng; Zheng, Yan-Ping; Wang, Guo-You
2011-01-01
In order to depict the deviation of quantum time evolution in open systems from Markovian processes, different measures have been presented. We demonstrate that the measure proposed by Breuer, Laine and Piilo [Phys. Rev. Lett. 103, 210401 (2009)] and the two measures proposed by Rivas, Huelga and Plenio [Phys. Rev. Lett. 105, 050403 (2010)] have exactly the same non-Markovian time-evolution intervals and thus are really equivalent each other when they apply to open two-level systems coupled to environments via Jaynes-Cummings or dephasing models. This equivalence implies that the three measures in different ways capture the intrinsical characters of non-Markovianty of quantum evolutional processes. We also show that the maximization in the definition of the first measure can be actually removed for the considered models without influencing the sensibility of the measure to detect non-Markovianty.
Equivalence of the measures of non-Markovianity for open two-level systems
Energy Technology Data Exchange (ETDEWEB)
Zeng Haosheng; Tang Ning; Zheng Yanping; Wang Guoyou [Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Department of Physics, Hunan Normal University, Changsha 410081 (China)
2011-09-15
Different measures have been presented to depict the deviation of quantum time evolution in open systems from Markovian processes. We demonstrate that the measure proposed by Breuer, Laine, and Piilo [Phys. Rev. Lett. 103, 210401 (2009)] and the two measures proposed by Rivas, Huelga, and Plenio [Phys. Rev. Lett. 105, 050403 (2010)] have exactly the same non-Markovian time-evolution intervals and thus are really equivalent to each other when they are applied to open two-level systems coupled to environments via the Jaynes-Cummings or dephasing models. This equivalence implies that the three measures, in different ways, capture the intrinsic character of the non-Markovianity of quantum evolutional processes. We also show that the maximization in the definition of the first measure can be actually removed for the considered models without influencing the sensibility of the measure to detect non-Markovianity.
Quantum mechanical treatment of traveling light in an absorptive medium of two-level systems
Inoue, K.
2016-12-01
Quantum mechanical treatment of a light wave that propagates through an absorptive medium is presented. Unlike a phenomenological beam-splitter model conventionally employed to describe a traveling light in a lossy medium, the time evolution of the field operator is derived using the Heisenberg equation with the Hamiltonian for a physical system, where the light wave interacts with an ensemble of two-level systems in a medium. Using the obtained time-evolved field operators, the mean values and variances of the light amplitude and the photon number are evaluated. The results are in agreement with those obtained in the beam-splitter model, giving a logical theoretical basis for the phenomenological beam-splitter model.
Two Level Versus Matrix Converters Performance in Wind Energy Conversion Systems Employing DFIG
Reddy, Gongati Pandu Ranga; Kumar, M. Vijaya
2017-05-01
Wind power capacity has received enormous growth during past decades. With substantial development of wind power, it is expected to provide a fifth of world's electricity by the end of 2030. In wind energy conversion system, the power electronic converters play an important role. This paper presents the two level and matrix converters performance in wind energy conversion system employing Doubly Fed Induction Generator (DFIG). The DFIG is a wound rotor induction generator. Because of the advantages of the DFIG over other generators it is being used for most of the wind applications. This paper also discusses control of converters using the space vector pulse width modulation technique. The MATLAB/SIMULINK ® software is used to study the performance of the converters.
Three-body entanglement induced by spontaneous emission in a three two-level atoms system
Institute of Scientific and Technical Information of China (English)
Liao Xiang-Ping; Fang Mao-Fa; Zheng Xiao-Juan; Cai Jian-Wu
2006-01-01
We study three-body entanglement induced by spontaneous emission in a three two-level atoms system by using the entanglement tensor approach. The results show that the amount of entanglement is strongly dependent on the initial state of the system and the species of atoms. The three-body entanglement is the result of the coherent superposition of the two-body entanglements. The larger the two-body entanglement is, the stronger the three-body entanglement is. On the other hand, if there exists a great difference in three two-body entanglement measures, the three-body entanglement is very weak. We also find that the maximum of the two-body entanglement obtained with nonidentical atoms is greater than that obtained with identical atoms via adjusting the difference in atomic frequency.
Two-level system noise reduction for Microwave Kinetic Inductance Detectors
Noroozian, Omid; Zmuidzinas, Jonas; LeDuc, Henry G; Mazin, Benjamin A
2009-01-01
Noise performance is one of the most crucial aspects of any detector. Superconducting Microwave Kinetic Inductance Detectors (MKIDs) have an "excess" frequency noise that shows up as a small time dependent jitter of the resonance frequency characterized by the frequency noise power spectrum measured in units of Hz^2/Hz. Recent studies have shown that this noise almost certainly originates from a surface layer of two-level system (TLS) defects on the metallization or substrate. Fluctuation of these TLSs introduces noise in the resonator due to coupling of the TLS electric dipole moments to the resonator's electric field. Motivated by a semi-empirical quantitative theory of this noise mechanism, we have designed and tested new resonator geometries in which the high-field "capacitive" portion of the CPW resonator is replaced by an interdigitated capacitor (IDC) structure with 10 - 20 micron electrode spacing, as compared to the 2 micron spacing used for our more conventional CPW resonators. Measurements show tha...
Nonvolatile optical memory via recoil-induced resonance in a pure two-level system
de Almeida, A. J. F.; Maynard, M.-A.; Banerjee, C.; Felinto, D.; Goldfarb, F.; Tabosa, J. W. R.
2016-12-01
We report on the storage of light via the phenomenon of recoil-induced resonance in a pure two-level system of cold cesium atoms. We use a strong coupling beam and a weak probe beam to couple different external momentum states of the cesium atom via two-photon Raman interaction which leads to the storage of the optical information of the probe beam. We have also measured the probe transmission spectrum, as well as the light storage spectrum which reveals very narrow subnatural resonance features showing absorption and gain. We have demonstrated that this memory presents the unique property of being insensitive to the reading process, which does not destroy the stored information leading to a memory lifetime limited only by the atomic thermal motion.
A Two-Level Task Scheduler on Multiple DSP System for OpenCL
Directory of Open Access Journals (Sweden)
Li Tian
2014-04-01
Full Text Available This paper addresses the problem that multiple DSP system does not support OpenCL programming. With the compiler, runtime, and the kernel scheduler proposed, an OpenCL application becomes portable not only between multiple CPU and GPU, but also between embedded multiple DSP systems. Firstly, the LLVM compiler was imported for source-to-source translation in which the translated source was supported by CCS. Secondly, two-level schedulers were proposed to support efficient OpenCL kernel execution. The DSP/BIOS is used to schedule system level tasks such as interrupts and drivers; however, the synchronization mechanism resulted in heavy overhead during task switching. So we designed an efficient second level scheduler especially for OpenCL kernel work-item scheduling. The context switch process utilizes the 8 functional units and cross path links which was superior to DSP/BIOS in the aspect of task switching. Finally, dynamic loading and software managed CACHE were redesigned for OpenCL running on multiple DSP system. We evaluated the performance using some common OpenCL kernels from NVIDIA, AMD, NAS, and Parboil benchmarks. Experimental results show that the DSP OpenCL can efficiently exploit the computing resource of multiple cores.
A laboratory comparison of portable cooling systems for workers exposed to two levels of heat stress
Terrian, D. M.; Nunneley, S. A.
1983-07-01
Two commercially available liquid cooling systems (LCSs) were tested on subjects wearing the current USAF groundcrew chemical defense ensemble and working in the heat. Each cooling system consisted of an ice-water heat sink, a pump, and a vest or vest-and-cap through which cool water circulated. Subjects walked on a treadmill to produce a time-weighted metabolic rate of about 480 W. Environmental conditions were: hot = 45/31C and warm = 32/22C. Under the hot conditions neither LCS produced and difference from the uncooled control, and all subjects were forced to stop within 40-50 min because of high temperatures, excessive heat rates, or exhaustion. Under the warm condition the LCS did allow T sub re to equilibrate; one system which could be recharged with ice enabled subjects to continue work to the 160-min limit of the protocol. Discussion covers logistics problems and reliability of the two systems. The conclusion is the LCSs are a viable concept for USAF operations, but that better heat sinks must be found and field tested before acceptance.
Equivalence of the measures of non-Markovianity for open two-level systems
Zeng, Hao-Sheng; Tang, Ning; Zheng, Yan-Ping; Wang, Guo-You
2011-09-01
Different measures have been presented to depict the deviation of quantum time evolution in open systems from Markovian processes. We demonstrate that the measure proposed by Breuer, Laine, and Piilo [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.103.210401 103, 210401 (2009)] and the two measures proposed by Rivas, Huelga, and Plenio [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.050403 105, 050403 (2010)] have exactly the same non-Markovian time-evolution intervals and thus are really equivalent to each other when they are applied to open two-level systems coupled to environments via the Jaynes-Cummings or dephasing models. This equivalence implies that the three measures, in different ways, capture the intrinsic character of the non-Markovianity of quantum evolutional processes. We also show that the maximization in the definition of the first measure can be actually removed for the considered models without influencing the sensibility of the measure to detect non-Markovianity.
Low frequency critical current noise and two level system defects in Josephson junctions
Nugroho, Christopher Daniel
The critical current in a Josephson junction is known to exhibit a 1/falpha low frequency noise. Implemented as a superconducting qubit, this low frequency noise can lead to decoherence. While the 1/f noise has been known to arise from an ensemble of two level systems connected to the tunnel barrier, the precise microscopic nature of these TLSs remain a mystery. In this thesis we will present measurements of the 1/f alpha low frequency noise in the critical current and tunneling resistance of Al-AlOx-Al Josephson junctions. Measurements in a wide range of resistively shunted and unshunted junctions confirm the equality of critical current and tunneling resistance noise. That is the critical current fluctuation corresponds to fluctuations of the tunneling resistance. In not too small Al-AlOx-Al junctions we have found that the fractional power spectral density scales linearly with temperature. We confirmed that the 1/falpha power spectrum is the result of a large number of two level systems modulating the tunneling resistance. At small junction areas and low temperatures, the number of thermally active TLSs is insufficient to integrate out a featureless 1/ f spectral shape. By analyzing the spectral variance in small junction areas, we have been able to deduce the TLS defect density, n ≈ 2.53 per micrometer squared per Kelvin spread in the TLS energy per factor e in the TLS lifetimes. This density is consistent with the density of tunneling TLSs found in glassy insulators, as well as the density deduced from coherent TLSs interacting at qubit frequencies. The deduced TLS density combined with the magnitude of the 1/f power spectral density in large area junctions, gives an average TLS effective area, A ˜ 0.3 nanometer squared. In ultra small tunnel junctions, we have studied the time-domain dynamics of isolated TLSs. We have found a TLS whose dynamics is described by the quantum tunneling between the two localized wells, and a one-phonon absorption
Yan, Yiying; Lü, Zhiguo; Zheng, Hang
2016-08-01
We present a theoretical formalism for resonance fluorescence radiating from a two-level system (TLS) driven by any periodic driving and coupled to multiple reservoirs. The formalism is derived analytically based on the combination of Floquet theory and Born-Markov master equation. The formalism allows us to calculate the spectrum when the Floquet states and quasienergies are analytically or numerically solved for simple or complicated driving fields. We can systematically explore the spectral features by implementing the present formalism. To exemplify this theory, we apply the unified formalism to comprehensively study a generic model that a harmonically driven TLS is simultaneously coupled to a radiative reservoir and a dephasing reservoir. We demonstrate that the significant features of the fluorescence spectra, the driving-induced asymmetry and the dephasing-induced asymmetry, can be attributed to the violation of detailed balance condition, and explained in terms of the driving-related transition quantities between Floquet-states and their steady populations. In addition, we find the distinguished features of the fluorescence spectra under the biharmonic and multiharmonic driving fields in contrast with that of the harmonic driving case. In the case of the biharmonic driving, we find that the spectra are significantly different from the result of the RWA under the multiple resonance conditions. By the three concrete applications, we illustrate that the present formalism provides a routine tool for comprehensively exploring the fluorescence spectrum of periodically strongly driven TLSs.
Energy Technology Data Exchange (ETDEWEB)
Yan, Yiying, E-mail: yiyingyan@sjtu.edu.cn; Lü, Zhiguo, E-mail: zglv@sjtu.edu.cn; Zheng, Hang, E-mail: hzheng@sjtu.edu.cn
2016-08-15
We present a theoretical formalism for resonance fluorescence radiating from a two-level system (TLS) driven by any periodic driving and coupled to multiple reservoirs. The formalism is derived analytically based on the combination of Floquet theory and Born–Markov master equation. The formalism allows us to calculate the spectrum when the Floquet states and quasienergies are analytically or numerically solved for simple or complicated driving fields. We can systematically explore the spectral features by implementing the present formalism. To exemplify this theory, we apply the unified formalism to comprehensively study a generic model that a harmonically driven TLS is simultaneously coupled to a radiative reservoir and a dephasing reservoir. We demonstrate that the significant features of the fluorescence spectra, the driving-induced asymmetry and the dephasing-induced asymmetry, can be attributed to the violation of detailed balance condition, and explained in terms of the driving-related transition quantities between Floquet-states and their steady populations. In addition, we find the distinguished features of the fluorescence spectra under the biharmonic and multiharmonic driving fields in contrast with that of the harmonic driving case. In the case of the biharmonic driving, we find that the spectra are significantly different from the result of the RWA under the multiple resonance conditions. By the three concrete applications, we illustrate that the present formalism provides a routine tool for comprehensively exploring the fluorescence spectrum of periodically strongly driven TLSs.
Non-Markovian dynamics of quantum coherence of two-level system driven by classical field
Huang, Zhiming; Situ, Haozhen
2017-09-01
In this paper, we study the quantum coherence dynamics of two-level atom system embedded in non-Markovian reservoir in the presence of classical driving field. We analyze the influence of memory effects, classical driving, and detuning on the quantum coherence. It is found that the quantum coherence has different behaviors in resonant case and non-resonant case. In the resonant case, in stark contrast with previous results, the strength of classical driving plays a negative effect on quantum coherence, while detuning parameter has the opposite effect. However, in non-resonant case through a long time, classical driving and detuning parameter have a different influence on quantum coherence compared with resonant case. Due to the memory effect of environment, in comparison with Markovian regime, quantum coherence presents vibrational variations in non-Markovian regime. In the resonant case, all quantum coherence converges to a fixed maximum value; in the non-resonant case, quantum coherence evolves to different stable values. For zero-coherence initial states, quantum coherence can be generated with evolution time. Our discussions and results should be helpful in manipulating and preserving the quantum coherence in dissipative environment with classical driving field.
Decoherence of a quantum two-level system by spectral diffusion
Matityahu, Shlomi; Shnirman, Alexander; Schön, Gerd; Schechter, Moshe
2016-04-01
We study the dephasing of an individual high-frequency tunneling two-level system (TLS) due to its interaction with an ensemble of low-frequency thermal TLSs which are described by the standard tunneling model (STM). We show that the dephasing by the bath of TLSs explains both the dependence of the Ramsey dephasing rate on an externally applied strain as well as its order of magnitude, as observed in a recent experiment [J. Lisenfeld et al., Sci. Rep. 6, 23786 (2016)], 10.1038/srep23786. However, the theory based on the STM predicts the Hahn-echo protocol to be much more efficient, yielding too low echo dephasing rates, as compared to the experiment. Also the strain dependence of the echo dephasing rate predicted by the STM does not agree with the measured quadratic dependence, which would fit to a high-frequency white noise environment. We suggest that few fast TLSs which are coupled much more strongly to the strain fields than the usual TLSs of the STM give rise to such a white noise. This explains the magnitude and strong fluctuations of the echo dephasing rate observed in the experiment.
Nonadiabatic transitions for a decaying two-level system: geometrical and dynamical contributions
Energy Technology Data Exchange (ETDEWEB)
Schilling, R [Institute of Physics, Johannes Gutenberg-Universitaet Mainz, Staudinger Weg 7, D-55099 Mainz (Germany); Vogelsberger, Mark [Institute of Physics, Johannes Gutenberg-Universitaet Mainz, Staudinger Weg 7, D-55099 Mainz (Germany); Garanin, D A [Physics Department, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States)
2006-11-03
We study the Landau-Zener problem for a decaying two-level system described by a non-Hermitian Hamiltonian, depending analytically on time. Use of a super-adiabatic basis allows us to calculate the survival probability P in the slow-sweep limit, without specifying the Hamiltonian explicitly. It is found that P consists of a 'dynamical' and a 'geometrical' factor. The former is determined by the complex adiabatic eigenvalues E{sub {+-}}(t), only, whereas the latter solely requires the knowledge of {alpha}{sub {+-}}(t), the ratio of the components of each of the adiabatic eigenstates. Both factors can be split into a universal one, depending only on the complex level crossing points, and a nonuniversal one, involving the full time dependence of E{sub {+-}}(t) and {alpha}{sub {+-}}(t). This general result is applied to the Akulin-Schleich model where the initial upper level is damped with damping constant {gamma}. For analytic power-law sweeps we find that Stueckelberg oscillations of P exist for {gamma} smaller than a critical value {gamma}{sub c} and disappear for {gamma} > {gamma}{sub c}. A physical interpretation of this behaviour will be presented by use of a damped harmonic oscillator.
Institute of Scientific and Technical Information of China (English)
Zeng Ke; Fang Mao-Fa
2005-01-01
The entanglement properties of the system of two two-level atoms interacting with a single-mode vacuum field are explored. The quantum entanglement between two two-level atoms and a single-mode vacuum field is investigated by using the quantum reduced entropy; the quantum entanglement between two two-level atoms, and that between a single two-level atom and a single-mode vacuum field are studied in terms of the quantum relative entropy. The influences of the atomic dipole-dipole interaction on the quantum entanglement of the system are also discussed. Our results show that three entangled states of two atoms-field, atom-atom, and atom-field can be prepared via two two-level atoms interacting with a single-mode vacuum field.
Two levels decision system for efficient planning and implementation of bioenergy production
Energy Technology Data Exchange (ETDEWEB)
Ayoub, Nasser [Chemical Resources Laboratory, Process Systems Engineering Division, Tokyo Institute of Technology, R1-19, 4259 Nagatsuta, Midori-ku Yokohama 226-8503 (Japan)]. E-mail: nasser@pse.res.titech.ac.jp; Martins, Ricardo [Chemical Resources Laboratory, Process Systems Engineering Division, Tokyo Institute of Technology, R1-19, 4259 Nagatsuta, Midori-ku Yokohama 226-8503 (Japan); Wang, Kefeng [Chemical Resources Laboratory, Process Systems Engineering Division, Tokyo Institute of Technology, R1-19, 4259 Nagatsuta, Midori-ku Yokohama 226-8503 (Japan); Seki, Hiroya [Chemical Resources Laboratory, Process Systems Engineering Division, Tokyo Institute of Technology, R1-19, 4259 Nagatsuta, Midori-ku Yokohama 226-8503 (Japan); Naka, Yuji [Chemical Resources Laboratory, Process Systems Engineering Division, Tokyo Institute of Technology, R1-19, 4259 Nagatsuta, Midori-ku Yokohama 226-8503 (Japan)
2007-03-15
When planning bioenergy production from biomass, planners should take into account each and every stakeholder along the biomass supply chains, e.g. biomass resources suppliers, transportation, conversion and electricity suppliers. Also, the planners have to consider social concerns, environmental and economical impacts related with establishing the biomass systems and the specific difficulties of each country. To overcome these problems in a sustainable manner, a robust decision support system is required. For that purpose, a two levels general Bioenergy Decision System (gBEDS) for bioenergy production planning and implementation was developed. The core part of the gBEDS is the information base, which includes the basic bioenergy information and the detailed decision information. Basic bioenergy information include, for instance, the geographical information system (GIS) database, the biomass materials' database, the biomass logistic database and the biomass conversion database. The detailed decision information considers the parameters' values database with their default values and the variables database, values obtained by simulation and optimization. It also includes a scenario database, which is used for demonstration to new users and also for case based reasoning by planners and executers. Based on the information base, the following modules are included to support decision making: the simulation module with graph interface based on the unit process (UP) definition and the genetic algorithms (GAs) methods for optimal decisions and the Matlab module for applying data mining methods (fuzzy C-means clustering and decision trees) to the biomass collection points, to define the location of storage and bioenergy conversion plants based on the simulation and optimization model developed of the whole life cycle of bioenergy generation. Furthermore, Matlab is used to set up a calculation model with crucial biomass planning parameters (e.g. costs, CO{sub 2
Semiclassical electrodynamics of alien atoms in interacting media II. Two-level systems
Elçi, Ahmet
1985-03-01
The previously developed self-consistent mean field theory of atoms entering an interacting medium is specialized to two-level alien atoms. It is shown that the medium may invert or split the original two levels, and that there is an intimate connection between the dressed atom spectrum and the statistical nature of the ensemble of alien atoms in the self-consistent mean field approximation. The optical susceptibility of alien atoms while inside the medium is calculated, and the lineshape and position of the optical resonance are shown to depend on the intensity of the optical field applied. There may be more than one phase possible for the atomic ensemble as a result of optical excitation.
A study of two-level system defects in dielectric films using superconducting resonators
Khalil, Moe Shwan
In this dissertation I describe measurements of dielectric loss at microwave frequencies due to two level systems (TLS) using superconducting resonators. Most measurements were performed in a dilution refrigerator at temperatures between 30 and 200 mK and all resonators discussed were fabricated with thin-film superconducting aluminum. I derive the transmission through a non-ideal (mismatched) resonant circuit and find that in general the resonance line-shape is asymmetric. I describe an analysis method for extracting the internal quality factor (Q i), the diameter correction method (DCM), and compare it to a commonly used phenomenological method, the phi rotation method (phiRM). I analytically find that the phiRM deterministically overestimates Qi when the asymmetry of the resonance line-shape is high. Four coplanar resonator geometries were studied, with frequencies spanning 5-7 GHz. They were all superconducting aluminum fabricated on sapphire and silicon substrates. These include a quasi-lumped element resonator, a coplanar strip transmission line resonator, and two hybrid designs that contain both a coplanar strip and a quasi-lumped element. Measured Qi's were as high as 2 x 105 for single photon excitations and there was no systematic variation in loss between quasi-lumped and coplanar strip resonance modes. I also measured the microwave loss tangent of several atomic layer deposition (ALD) grown dielectrics and obtained secondary ion mass spectrometry (SIMS) measurements of the same films. I found that hydrogen defect concentrations were correlated with low temperature microwave loss. In amorphous films that showed excess hydrogen defects on the surface, two independent TLS distributions were required to fit the loss tangent, one for the surface and one for the bulk. In crystalline dielectrics where hydrogen contamination was uniform throughout the bulk, a single bulk TLS distribution was sufficient. Finally, I measured the TLS loss in 250 nm thick HD
Quantum optical properties of a single Inx Ga1-x As-GaAs quantum dot two-level system
Stufler, S.; Ester, P.; Zrenner, A.; Bichler, M.
2005-09-01
We report on a two-level system, defined by the ground-state exciton of a single InGaAs/GaAs quantum dot. Saturation spectroscopy combined with ultrahigh spectral resolution gives us a complete description of the system in the steady-state limit. Rabi oscillations and quantum interference experiments, on the other hand, provide a detailed insight into the coherent high excitation regime. All fundamental properties of the two-level system show an excellent quantitative agreement in both domains, even though obtained under entirely different experimental conditions. We thus are able to demonstrate control over an almost ideal two-level system, suitable for possible applications in quantum information processing.
Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields
Puthumpally-joseph, Raiju; Charron, Eric
2016-01-01
We introduce an accurate non-Hermitian Schr\\"odinger-type approximation of Bloch optical equations for two-level systems. This approximation provides a complete description of the excitation, relaxation and decoherence dynamics in both weak and strong laser fields. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically-adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters.
DEFF Research Database (Denmark)
Malossi, Nicola; Bason, Mark George; Viteau, Matthieu
2013-01-01
We present experimental results on the preparation of a desired quantum state in a two-level system with the maximum possible fidelity using driving protocols ranging from generalizations of the linear Landau-Zener protocol to transitionless driving protocols that ensure perfect following of the ...
The dynamical Cooperative Lamb Shift in a system of two-level atoms in a slab-geometry
Energy Technology Data Exchange (ETDEWEB)
Friedberg, Richard [Department of Physics, Columbia University, New York, NY 10027 (United States); Manassah, Jamal T., E-mail: jmanassah@gmail.co [HMS Consultants, Inc., PO Box 592, New York, NY 10028 (United States)
2009-09-14
Using the eigenmode analysis, we compute the Cooperative Lamb Shift (CLS) as a function of time from the vector photon model for a system of two-level atoms in a slab-geometry for forward and backward emission in two initial states of weak excitation and complete inversion.
DEFF Research Database (Denmark)
Malossi, Nicola; Bason, Mark George; Viteau, Matthieu
2013-01-01
We present experimental results on the preparation of a desired quantum state in a two-level system with the maximum possible fidelity using driving protocols ranging from generalizations of the linear Landau-Zener protocol to transitionless driving protocols that ensure perfect following...
The Tera Two-Level Operating System. Revision 1.2.
2007-11-02
The Tera computer hardware provides for four privilege levels. These privilege levels are used to protect various parts of the system from each other...are for normal use by the operating system (OS). This document describes some of the motivation for using two privilege levels in the OS and discusses the way such an OS is built using the Tera tools.
Magnetic-field-induced mixed-level Kondo effect in two-level systems
Energy Technology Data Exchange (ETDEWEB)
Wong, Arturo; Ngo, Anh T.; Ulloa, Sergio E.
2016-10-17
We consider a two-orbital impurity system with intra-and interlevel Coulomb repulsion that is coupled to a single conduction channel. This situation can generically occur in multilevel quantum dots or in systems of coupled quantum dots. For finite energy spacing between spin-degenerate orbitals, an in-plane magnetic field drives the system from a local-singlet ground state to a "mixed-level" Kondo regime, where the Zeeman-split levels are degenerate for opposite-spin states. We use the numerical renormalization group approach to fully characterize this mixed-level Kondo state and discuss its properties in terms of the applied Zeeman field, temperature, and system parameters. Under suitable conditions, the total spectral function is shown to develop a Fermi-level resonance, so that the linear conductance of the system peaks at a finite Zeeman field while it decreases as a function of temperature. These features, as well as the local moment and entropy contribution of the impurity system, are commensurate with Kondo physics, which can be studied in suitably tuned quantum dot systems.
Controlled Dicke Subradiance from a Large Cloud of Two-Level Systems
Bienaime, Tom; Kaiser, Robin
2012-01-01
Dicke superradiance has been observed in many systems and is based on constructive interferences between many scattered waves. The counterpart of this enhanced dynamics, subradiance, is a destructive interference effect leading to the partial trapping of light in the system. In contrast to the robust superradiance, subradiant states are fragile and spurious decoherence phenomena hitherto obstructed the observation of such metastable states. We show that a dilute cloud of cold atoms is an ideal system to look for subradiance in free space and study various mechanisms to control this subradiance.
Directory of Open Access Journals (Sweden)
Hesham A. Baraka
2015-03-01
The objective of this paper was to introduce a new technique that can support decision makers in the call centers industry to evaluate, and analyze the performance of call centers. The technique presented is derived from the research done on measuring the success or failure of information systems. Two models are mainly adopted namely: the Delone and Mclean model first introduced in 1992 and the Design Reality Gap model introduced by Heeks in 2002. Two indices are defined to calculate the performance of the call center; the success index and the Gap Index. An evaluation tool has been developed to allow call centers managers to evaluate the performance of their call centers in a systematic analytical approach; the tool was applied on 4 call centers from different areas, simple applications such as food ordering, marketing, and sales, technical support systems, to more real time services such as the example of emergency control systems. Results showed the importance of using information systems models to evaluate complex systems as call centers. The models used allow identifying the dimensions for the call centers that are facing challenges, together with an identification of the individual indicators in these dimensions that are causing the poor performance of the call center.
DEFF Research Database (Denmark)
SUN, BO; Dragicevic, Tomislav; Vasquez, Juan Carlos
2015-01-01
This paper applies a hierarchical control for a fast charging station (FCS) composed of paralleled PWM rectifier and dedicated paralleled multiple flywheel energy storage systems (FESSs), in order to mitigate peak power shock on grid caused by sudden connection of electrical vehicle (EV) chargers....... Distributed DC-bus signaling (DBS) and method resistive virtual impedance are employed in the power coordination of grid and flywheel converters, and a centralized secondary controller generates DC voltage correction term to adjust the local voltage set point. The control system is able to realize the power...... control strategy....
Simulation-based Performance Analysis and Tuning for a Two-level Directly Connected System
Energy Technology Data Exchange (ETDEWEB)
Totoni, E; Bhatele, A; Bohm, E J; Jain, N; Mendes, C L; Mokos, R M; Zheng, G; Kale, L V
2011-09-19
Hardware and software co-design is becoming increasingly important due to complexities in supercomputing architectures. Simulating applications before there is access to the real hardware can assist machine architects in making better design decisions that can optimize application performance. At the same time, the application and runtime can be optimized and tuned beforehand. BigSim is a simulation-based performance prediction framework designed for these purposes. It can be used to perform packet-level network simulations of parallel applications using existing parallel machines. In this paper, we demonstrate the utility of BigSim in analyzing and optimizing parallel application performance for future systems based on the PERCS network. We present simulation studies using benchmarks and real applications expected to run on future supercomputers. Future petascale systems will have more than 100,000 cores, and we present simulations at that scale.
Optical driving of macroscopic mechanical motion by a single two-level system
Auffèves, A.; Richard, M.
2014-08-01
A quantum emitter coupled to a nanomechanical oscillator is a hybrid system where a macroscopic degree of freedom is coupled to a purely quantum system. Recent progress in nanotechnology has led to the realization of such devices by embedding single artificial atoms, such as quantum dots or superconducting qubits, into vibrating wires or membranes, opening up new perspectives for quantum information technologies and for the exploration of the quantum-classical boundary. In this paper, we show that the quantum emitter can be turned into a strikingly efficient light-controlled source of mechanical power by exploiting constructive interferences of classical phonon fields in the mechanical oscillator. We show that this mechanism can be exploited to carry out low-background nondestructive single-shot measurement of an optically active quantum bit state.
Nemati Aram, Tahereh; Anghel-Vasilescu, Petrutza; Asgari, Asghar; Ernzerhof, Matthias; Mayou, Didier
2016-09-28
We present a novel simple model to describe molecular photocells where the energy conversion process takes place by a single molecular donor-acceptor complex attached to electrodes. By applying quantum scattering theory, an open quantum system method, the coherent molecular photocell is described by a wave function. We analyze photon absorption, energy conversion, and quantum yield of a molecular photocell by considering the effects of electron-hole interaction and non-radiative recombination. We model the exciton creation, dissociation, and subsequent effects on quantum yield in the energy domain. We find that depending on the photocell structure, the electron-hole interaction can normally decrease or abnormally increase the cell efficiency. The proposed model helps to understand the mechanisms of molecular photocells, and it can be used to optimize their yield.
Certified Randomness from a Two-Level System in a Relativistic Quantum Field
Thinh, Le Phuc; Martin-Martinez, Eduardo
2016-01-01
Randomness is an indispensable resource in modern science and information technology. Fortunately, an experimentally simple procedure exists to generate randomness with well-characterized devices: measuring a quantum system in a basis complementary to its preparation. Towards realizing this goal one may consider using atoms or superconducting qubits, promising candidates for quantum information processing. However, their unavoidable interaction with the electromagnetic field affects their dynamics. At large time scales, this can result in decoherence. Smaller time scales in principle avoid this problem, but may not be well analysed under the usual rotating wave and single-mode approximation (RWA and SMA) which break the relativistic nature of quantum field theory. Here, we use a fully relativistic analysis to quantify the information that an adversary with access to the field could get on the result of an atomic measurement. Surprisingly, we find that the adversary's guessing probability is not minimized for ...
Certified randomness from a two-level system in a relativistic quantum field
Thinh, Le Phuc; Bancal, Jean-Daniel; Martín-Martínez, Eduardo
2016-08-01
Randomness is an indispensable resource in modern science and information technology. Fortunately, an experimentally simple procedure exists to generate randomness with well-characterized devices: measuring a quantum system in a basis complementary to its preparation. Towards realizing this goal one may consider using atoms or superconducting qubits, promising candidates for quantum information processing. However, their unavoidable interaction with the electromagnetic field affects their dynamics. At large time scales, this can result in decoherence. Smaller time scales in principle avoid this problem, but may not be well analyzed under the usual rotating wave and single mode approximation (RWA and SMA) which break the relativistic nature of quantum field theory. Here, we use a fully relativistic analysis to quantify the information that an adversary with access to the field could get on the result of an atomic measurement. Surprisingly, we find that the adversary's guessing probability is not minimized for atoms initially prepared in the ground state (an intuition derived from the RWA and SMA model).
Squeezing Effect of a Nanomechanical Resonator Coupled to a Two-Level System:an Equilibrium Approach
Institute of Scientific and Technical Information of China (English)
LI Jing; CHEN Zhi-De
2009-01-01
The squeezing effect of a nanomechanical resonator coupled to a two-level system is studied by variational calculations based on both the displaced-squeezed-state (DSS) and the displaced-oscillator-state (DOS).The stable region of the DSS ground state at both T = 0 and T≠0 and the corresponding squeezing factor are alculated.It is found that when the resonator frequency lies in (kBT,△),where △ is the tunnelling splitting of the two-level-system in the presence of dissipation,tunnelling splitting of a DSS ground state decreases with the temperature,while tunnelling splitting of a DOS ground state increases with the temperature in low temperature region.This opposite temperature dependence can help to distinguish between the DSS and DOS ground state in the experiment.
Institute of Scientific and Technical Information of China (English)
赵延霆; 赵建明; 肖连团; 尹王保; 贾锁堂
2004-01-01
The electromagnetically induced absorption and electromagnetically induced transparency spectra of degenerate two-level systems with a strong coupling laser were observed. The frequency detuning and intensity effect of the coupling laser were demonstrated simultaneously. A dispersion-like spectrum can be obtained when the coupling laser is situated at blue-side detuning. The absorption inversion was realized when the coupling laser intensity is small. The coherent resonance has a linewidth much narrower than the natural linewidth of the optical transitions.
Two-Level Dipolar System in a Heat Bath: High-Pump Power Effects in the Nonlinear Optical Responses
Paz, J. L.; León-Torres, J. R.; Lascano, Luis; Alvarado, Ysaias J.; Costa-Vera, Cesar
2017-06-01
Using the four-wave mixing spectroscopy, we analyze the nonlinear optical properties in a strongly driven two-level system, using a perturbative treatment where, the pump field is considered at all orders, second order in the probe, and first order for the signal field, when the stochastic effects of the solvent are considered. Significant variations in the nonlinear optical properties due mainly to changes in the probe intensity, chemical concentrations, and transversal relaxation times are observed.
Institute of Scientific and Technical Information of China (English)
Cai-Zhi SUN; Wei ZOU; Xue-Yu LIN
2004-01-01
In the management of unconfined aquifer systems, if the thickness of the aquifer is very small and the drawdown is relatively big, errors may arise when the superposition principle is adopted.directly. In allusion to this limitation, a new management model for the management of unconfined aquifer systems called two-level response matrix method is put forward. This method is applied in groundwater resources management in Shenyang city. The managing results show that this methodcan, in some degree, increase the efficiency of management and decrease the risk of management.
Entropy as a measure of the noise extent in a two-level quantum feedback controlled system
Institute of Scientific and Technical Information of China (English)
Wang Tao-Bo; Fang Mao-Fa; Hu Yao-Hua
2007-01-01
By introducing the von Neumann entropy as a measure of the extent of noise, this paper discusses the entropy evolution in a two-level quantum feedback controlled system. The results show that the feedback control can induce the reduction of the degree of noise, and different control schemes exhibit different noise controlling ability, the extent of the reduction also related with the position of the target state on the Bloch sphere. It is shown that the evolution of entropy can provide a real time noise observation and a systematic guideline to make reasonable choice of control strategy.
Cheng, Guang-Ling; Cong, Lu; Chen, Ai-Xi
2016-04-01
A scheme for two-dimensional (2D) electromagnetically induced grating via spatial gain and phase modulation is presented in a two-level atomic system. Based on the interactions of two orthogonal standing-wave fields, the atom could diffract the weak probe beam into high-order directions and a 2D diffraction grating is generated. It is shown that the diffraction efficiency of the grating can be efficiently manipulated by controlling the Rabi frequencies of control fields, the detunings of the control and probe fields, and interaction length. Different from 2D cross-grating via electromagnetically induced transparency in a four-level atomic system, the present scheme results from the spatial modulation of gain and phase in a simple two-level system, which could lead to 2D gain-phase grating with larger diffraction intensities in the diffraction directions. The studies we present may have potential applications in developing photon devices for optical-switching, optical imaging and quantum information processing.
Design of a Two-level Adaptive Multi-Agent System for Malaria Vectors driven by an ontology
Directory of Open Access Journals (Sweden)
Etang Josiane
2007-07-01
Full Text Available Abstract Background The understanding of heterogeneities in disease transmission dynamics as far as malaria vectors are concerned is a big challenge. Many studies while tackling this problem don't find exact models to explain the malaria vectors propagation. Methods To solve the problem we define an Adaptive Multi-Agent System (AMAS which has the property to be elastic and is a two-level system as well. This AMAS is a dynamic system where the two levels are linked by an Ontology which allows it to function as a reduced system and as an extended system. In a primary level, the AMAS comprises organization agents and in a secondary level, it is constituted of analysis agents. Its entry point, a User Interface Agent, can reproduce itself because it is given a minimum of background knowledge and it learns appropriate "behavior" from the user in the presence of ambiguous queries and from other agents of the AMAS in other situations. Results Some of the outputs of our system present a series of tables, diagrams showing some factors like Entomological parameters of malaria transmission, Percentages of malaria transmission per malaria vectors, Entomological inoculation rate. Many others parameters can be produced by the system depending on the inputted data. Conclusion Our approach is an intelligent one which differs from statistical approaches that are sometimes used in the field. This intelligent approach aligns itself with the distributed artificial intelligence. In terms of fight against malaria disease our system offers opportunities of reducing efforts of human resources who are not obliged to cover the entire territory while conducting surveys. Secondly the AMAS can determine the presence or the absence of malaria vectors even when specific data have not been collected in the geographical area. In the difference of a statistical technique, in our case the projection of the results in the field can sometimes appeared to be more general.
Dynamics of a Landau-Zener transitions in a two-level system driven by a dissipative environment
Ateuafack, M. E.; Diffo, J. T.; Fai, L. C.
2016-02-01
The paper investigates the effects of a two-level quantum system coupled to transversal and longitudinal dissipative environment. The time-dependent phase accumulation, LZ transition probability and entropy in the presence of fast-ohmic, sub-ohmic and super-ohmic quantum noise are derived. Analytical results are obtained in terms of temperature, dissipation strength, LZ parameter and bath cutoff frequency. The bath is observed to modify the standard occupation difference by a decaying random phase factor and also produces dephasing during the transfer of population. The dephasing characteristics or the initial non-zero decoherence rate are observed to increase in time with the bath temperature and depend on the system-bath coupling strength and cutoff frequency. These parameters are found to strongly affect the memory and thus tailor the coherence process of the system.
Dynamics of a Landau–Zener transitions in a two-level system driven by a dissipative environment
Energy Technology Data Exchange (ETDEWEB)
Ateuafack, M.E., E-mail: esouamath@yahoo.fr [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon); Diffo, J.T., E-mail: diffojaures@yahoo.com [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon); Department of Physics, Higher Teachers' Training College, The University of Maroua, PO Box 55 Maroua (Cameroon); Fai, L.C., E-mail: corneliusfai@yahoo.fr [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon)
2016-02-15
The paper investigates the effects of a two-level quantum system coupled to transversal and longitudinal dissipative environment. The time-dependent phase accumulation, LZ transition probability and entropy in the presence of fast-ohmic, sub-ohmic and super-ohmic quantum noise are derived. Analytical results are obtained in terms of temperature, dissipation strength, LZ parameter and bath cutoff frequency. The bath is observed to modify the standard occupation difference by a decaying random phase factor and also produces dephasing during the transfer of population. The dephasing characteristics or the initial non-zero decoherence rate are observed to increase in time with the bath temperature and depend on the system-bath coupling strength and cutoff frequency. These parameters are found to strongly affect the memory and thus tailor the coherence process of the system.
Suh, J.; Weinstein, A. J.; Schwab, K. C.
2013-07-01
We show that the two-level systems (TLS) in lithographic superconducting circuits act as a power-dependent dielectric leading to non-linear responses in a parametrically coupled electromechanical system. Driven TLS shift the microwave resonance frequency and modulate the mechanical resonance through the optical spring effect. By pumping with two tones in a back-action evading measurement, these effects produce a mechanical parametric instability which limits single quadrature imprecision to 1.4 xzp. The microwave resonator noise is also consistent to a TLS-noise model. These observations suggest design strategies for minimizing TLS effects to improve ground-state cooling and quantum non-demolition measurements of motion.
Grace, M; Kosut, R L; Lidar, D A; Rabitz, H; Walmsley, I A; Brif, Constantin; Grace, Matthew; Kosut, Robert L.; Lidar, Daniel A.; Rabitz, Herschel; Walmsley, Ian A.
2007-01-01
Methods of optimal control are applied to a model system of interacting two-level particles (e.g., spin-half atomic nuclei or electrons or two-level atoms) to produce high-fidelity quantum gates while simultaneously negating the detrimental effect of decoherence. One set of particles functions as the quantum information processor, whose evolution is controlled by a time-dependent external field. The other particles are not directly controlled and serve as an effective environment, coupling to which is the source of decoherence. The control objective is to generate target one- and two-qubit unitary gates in the presence of strong environmentally-induced decoherence and under physically motivated restrictions on the control field. The quantum-gate fidelity, expressed in terms of a novel state-independent distance measure, is maximized with respect to the control field using combined genetic and gradient algorithms. The resulting high-fidelity gates demonstrate the feasibility of precisely guiding the quantum ev...
Prigogine, Ilya
2002-01-01
Hamiltonian systems can be classified according Poincaré into integrable and non-integrable systems. On the other hand, our previous work introduced a formulation of dynamics based on the evolution of correlations. It is shown that for integrable systems this method is equivalent to the diagonalisation problem of the Hamiltonian for integrable systems but our method can be easily extended to non-integrable systems through analytic continuation. This leads to a description of unstable dressed excited states, as well as to excitations for interacting fields. The mechanism of the formation of dressed objects will be analysed in terms of two different time scales. The analogy with these dissipative structures will be emphasized. We may distinguish two levels in the formulation of laws of nature. The first is in terms of Hamiltonian dynamics, the second, necessary for classes of non-integrable systems, The first is in terms of Hamiltonian dynamics, the second, necessary for classes of non-integrable systems, aris...
Zeng, H. S.; Tang, N.; Zheng, Y. P.; Xu, T. T.
2012-10-01
By use of the recently presented two measures, the indivisibility and the backflow of information, we study the non-Markovianity of the dynamics for a two-level system interacting with a zero-temperature structured environment without using rotating wave approximation (RWA). In the limit of weak coupling between the system and its reservoir, and by expanding the time-convolutionless (TCL) generator to the forth order with respect to the coupling strength, the time-local non-Markovian master equation for the reduced state of the system is derived. Under the secular approximation, the exact analytic solution is obtained and the sufficient and necessary conditions for the indivisibility and the backflow of information for the system dynamics are presented. In the more general case, we investigate numerically the properties of the two measures for the case of Lorentzian reservoir. Our results show the importance of the counter-rotating terms to the short-time-scale non-Markovian behavior of the system dynamics, further expose the relation between the two measures and their rationality as non-Markovian measures. Finally, the complete positivity of the dynamics of the considered system is discussed.
Random-Defect Laser: Manipulating Lossy Two-Level Systems to Produce a Circuit with Coherent Gain
Rosen, Yaniv J.; Khalil, Moe S.; Burin, Alexander L.; Osborn, Kevin D.
2016-04-01
We demonstrate a laser using material defects known for deleterious microwave absorption in quantum computing. These defects are two-level atomic tunneling systems (TSs), which are manipulated using a uniform swept dc electric field and two ac pump fields. The swept field changes the TS energies. TSs first pass through degeneracy with pump photons, which invert (excite) them with a high probability using rapid adiabatic passage. Population inversion is accomplished in spite of a broad distribution of TS parameters. Afterwards the TSs are brought to degeneracy with the resonator where they emit photons. The emission is found to be dependent on individual cavity-TS interactions, and the narrowing linewidth at increasing photon occupancy indicates stimulated emission. Characterization with a microwave probe shows a transition from ordinary defect loss to negligible microwave absorption, and ultimately to coherent amplification. Thus, instead of absorbing microwave energy, the TSs can be tuned to reduce loss and even amplify signals.
Energy Technology Data Exchange (ETDEWEB)
Skacel, S. T. [Physikalisches Institut, Karlsruher Institut für Technologie, Wolfgang-Gaede-Straße 1, D-76131 Karlsruhe (Germany); Institut für Mikro- und Nanoelektronische Systeme, Karlsruher Institut für Technologie, Hertzstraße 16, D-76187 Karlsruhe (Germany); Kaiser, Ch.; Wuensch, S.; Siegel, M. [Institut für Mikro- und Nanoelektronische Systeme, Karlsruher Institut für Technologie, Hertzstraße 16, D-76187 Karlsruhe (Germany); Rotzinger, H.; Lukashenko, A.; Jerger, M.; Weiss, G. [Physikalisches Institut, Karlsruher Institut für Technologie, Wolfgang-Gaede-Straße 1, D-76131 Karlsruhe (Germany); Ustinov, A. V. [Physikalisches Institut, Karlsruher Institut für Technologie, Wolfgang-Gaede-Straße 1, D-76131 Karlsruhe (Germany); Russian Quantum Center, 100 Novaya St., Skolkovo, Moscow Region 143025 (Russian Federation)
2015-01-12
We have investigated dielectric losses in amorphous silicon oxide (a-SiO) thin films under operating conditions of superconducting qubits (mK temperatures and low microwave powers). For this purpose, we have developed a broadband measurement setup employing multiplexed lumped element resonators using a broadband power combiner and a low-noise amplifier. The measured temperature and power dependences of the dielectric losses are in good agreement with those predicted for atomic two-level tunneling systems (TLS). By measuring the losses at different frequencies, we found that the TLS density of states is energy dependent. This had not been seen previously in loss measurements. These results contribute to a better understanding of decoherence effects in superconducting qubits and suggest a possibility to minimize TLS-related decoherence by reducing the qubit operation frequency.
Deng, Chunqing; Shen, Feiruo; Ashhab, Sahel; Lupascu, Adrian
2016-09-01
We consider the dynamics of a two-level system (qubit) driven by strong and short resonant pulses in the framework of Floquet theory. First we derive analytical expressions for the quasienergies and Floquet states of the driven system. If the pulse amplitude varies very slowly, the system adiabatically follows the instantaneous Floquet states, which acquire dynamical phases that depend on the evolution of the quasienergies over time. The difference between the phases acquired by the two Floquet states corresponds to a qubit state rotation, generalizing the notion of Rabi oscillations to the case of large driving amplitudes. If the pulse amplitude changes very fast, the evolution is nonadiabatic, with transitions taking place between the Floquet states. We quantify and analyze the nonadiabatic transitions during the pulse by employing adiabatic perturbation theory and exact numerical simulations. We find that, for certain combinations of pulse rise and fall times and maximum driving amplitude, a destructive interference effect leads to a remarkably strong suppression of transitions between the Floquet states. This effect provides the basis of a quantum control protocol, which we name Floquet interference efficient suppression of transitions in the adiabatic basis (FIESTA), that can be used to design ultrafast high-fidelity single-qubit quantum gates.
Abbout, Adel
2016-08-05
Using the tools of random matrix theory we develop a statistical analysis of the transport properties of thermoelectric low-dimensional systems made of two electron reservoirs set at different temperatures and chemical potentials, and connected through a low-density-of-states two-level quantum dot that acts as a conducting chaotic cavity. Our exact treatment of the chaotic behavior in such devices lies on the scattering matrix formalism and yields analytical expressions for the joint probability distribution functions of the Seebeck coefficient and the transmission profile, as well as the marginal distributions, at arbitrary Fermi energy. The scattering matrices belong to circular ensembles which we sample to numerically compute the transmission function, the Seebeck coefficient, and their relationship. The exact transport coefficients probability distributions are found to be highly non-Gaussian for small numbers of conduction modes, and the analytical and numerical results are in excellent agreement. The system performance is also studied, and we find that the optimum performance is obtained for half-transparent quantum dots; further, this optimum may be enhanced for systems with few conduction modes.
Abbout, Adel; Ouerdane, Henni; Goupil, Christophe
2016-09-01
Using the tools of random matrix theory we develop a statistical analysis of the transport properties of thermoelectric low-dimensional systems made of two electron reservoirs set at different temperatures and chemical potentials, and connected through a low-density-of-states two-level quantum dot that acts as a conducting chaotic cavity. Our exact treatment of the chaotic behavior in such devices lies on the scattering matrix formalism and yields analytical expressions for the joint probability distribution functions of the Seebeck coefficient and the transmission profile, as well as the marginal distributions, at arbitrary Fermi energy. The scattering matrices belong to circular ensembles which we sample to numerically compute the transmission function, the Seebeck coefficient, and their relationship. The exact transport coefficients probability distributions are found to be highly non-Gaussian for small numbers of conduction modes, and the analytical and numerical results are in excellent agreement. The system performance is also studied, and we find that the optimum performance is obtained for half-transparent quantum dots; further, this optimum may be enhanced for systems with few conduction modes.
Energy Technology Data Exchange (ETDEWEB)
Gramich, Vera; Ankerhold, Joachim [Institut fuer Theoretische Physik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany); Solinas, Paolo; Moettoenen, Mikko [Department of Applied Physics/COMP, Aalto University, P.O. Box 14100, FI-00076 Aalto (Finland); Low Temperature Laboratory, Aalto University, P.O. Box 13500, FI-00076 Aalto (Finland); Pekola, Jukka [Low Temperature Laboratory, Aalto University, P.O. Box 13500, FI-00076 Aalto (Finland)
2012-07-01
Realistic quantum systems are never completely isolated. Even a single atom in zero-temperature vacuum is influenced by the zero-point fluctuations of the electromagnetic field which in turn induces a shift of its transition frequencies known as the Lamb shift. Cavity quantum electrodynamics (QED) provides a particularly convenient setup to observe this shift since the restricted geometries of the cavities allow the atoms to interact only with the fluctuations of single harmonic fields. In contrast to single-frequency environments, typical reservoirs for mesoscopic solid-state devices are characterized by broadband spectral distributions in thermal equilibrium. Within weak-coupling master equations even explicit expressions for the reservoir-induced frequency shifts can be derived, while associated experimental observations are still missing. To fill this gap, we discuss and analyze a theoretical proposal to retrieve the Lamb shift for a superconducting two-level system embedded in an Ohmic environment. Moreover, we present a possible way to measure the Lamb shift in a circuit containing a Cooper pair sluice.
Energy Technology Data Exchange (ETDEWEB)
Sarabi, B.; Ramanayaka, A. N. [Laboratory for Physical Sciences, College Park, Maryland 20740 (United States); Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Burin, A. L. [Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Wellstood, F. C. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States); Osborn, K. D. [Laboratory for Physical Sciences, College Park, Maryland 20740 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States)
2015-04-27
Random tunneling two-level systems (TLSs) in dielectrics have been of interest recently because they adversely affect the performance of superconducting qubits. The coupling of TLSs to qubits has allowed individual TLS characterization, which has previously been limited to TLSs within (thin) Josephson tunneling barriers made from aluminum oxide. Here, we report on the measurement of an individual TLS within the capacitor of a lumped-element LC microwave resonator, which forms a cavity quantum electrodynamics (CQED) system and allows for individual TLS characterization in a different structure and material than demonstrated with qubits. Due to the reduced volume of the dielectric (80 μm{sup 3}), even with a moderate dielectric thickness (250 nm), we achieve the strong coupling regime as evidenced by the vacuum Rabi splitting observed in the cavity spectrum. A TLS with a coherence time of 3.2 μs was observed in a film of silicon nitride as analyzed with a Jaynes-Cummings spectral model, which is larger than seen from superconducting qubits. As the drive power is increased, we observe an unusual but explicable set of continuous and discrete crossovers from the vacuum Rabi split transitions to the Glauber (coherent) state.
Sarabi, B.; Ramanayaka, A. N.; Burin, A. L.; Wellstood, F. C.; Osborn, K. D.
2015-04-01
Random tunneling two-level systems (TLSs) in dielectrics have been of interest recently because they adversely affect the performance of superconducting qubits. The coupling of TLSs to qubits has allowed individual TLS characterization, which has previously been limited to TLSs within (thin) Josephson tunneling barriers made from aluminum oxide. Here, we report on the measurement of an individual TLS within the capacitor of a lumped-element LC microwave resonator, which forms a cavity quantum electrodynamics (CQED) system and allows for individual TLS characterization in a different structure and material than demonstrated with qubits. Due to the reduced volume of the dielectric (80 μm3), even with a moderate dielectric thickness (250 nm), we achieve the strong coupling regime as evidenced by the vacuum Rabi splitting observed in the cavity spectrum. A TLS with a coherence time of 3.2 μs was observed in a film of silicon nitride as analyzed with a Jaynes-Cummings spectral model, which is larger than seen from superconducting qubits. As the drive power is increased, we observe an unusual but explicable set of continuous and discrete crossovers from the vacuum Rabi split transitions to the Glauber (coherent) state.
Sohail, Amjad; Zhang, Yang; Zhang, Jun; Yu, Chang-Shui
2016-06-28
We analytically study the optomechanically induced transparency (OMIT) in the N-cavity system with the Nth cavity driven by pump, probing laser fields and the 1st cavity coupled to mechanical oscillator. We also consider that one atom could be trapped in the ith cavity. Instead of only illustrating the OMIT in such a system, we are interested in how the number of OMIT windows is influenced by the cavities and the atom and what roles the atom could play in different cavities. In the resolved sideband regime, we find that, the number of cavities precisely determines the maximal number of OMIT windows. It is interesting that, when the two-level atom is trapped in the even-labeled cavity, the central absorptive peak (odd N) or dip (even N) is split and forms an extra OMIT window, but if the atom is trapped in the odd-labeled cavity, the central absorptive peak (odd N) or dip (even N) is only broadened and thus changes the width of the OMIT windows rather than induces an extra window.
Coupling of conduction electrons to two-level systems formed by hydrogen: a scattering approach.
Nagy, I; Zawadowski, A
2009-04-29
An effective Hamiltonian for a two-level system (TLS) which could model the interaction between a tunneling proton and the conduction electrons of a metal is investigated in a comparative way. In the conventional first-order Born approximation with plane waves, and for small-distance displacement of the tunneling particle, a simple correlation between the atomic motion and angular momentum change of the scattering electron is deduced. For such a displacement, and within a distorted wave Born approximation for initial and final states, the change in the scattering amplitude is expressed via bounded trigonometric functions of the corresponding difference of scattering phase shifts. The numerical value of this amplitude change is analyzed in the framework of a self-consistent screening description for an impurity embedding in a paramagnetic electron gas. The coupling thus obtained of the tunneling proton to a homogeneous electron gas is too weak to be in the range required for realization of the two-channel Kondo effect.
Mangel, László; Kövér, Erika; Szilágyi, István; Varga, Zsuzsanna; Bércesi, Eva; Nagy, Zsuzsanna; Holcz, Tibor; Karádi, Oszkár; Farkas, Róbert; Csák, Szilvia; Csere, Tibor; Kásler, Miklós
2012-12-16
By now therapy decision taken by a multi-disciplinary oncology team in cancer care has become a routine method in worldwide. However, multi-disciplinary oncology team has to face more and more difficulties in keeping abreast with the fast development in oncology science, increasing expectations, and financial considerations. Naturally the not properly controlled decision mechanisms, the permanent lack of time and shortage of professionals are also hindering factors. Perhaps it would be a way out if the staff meetings and discussions of physicians in the oncology departments were transformed and provided with administrative, legal and decision credentials corresponding to those of multi-disciplinary oncology team. The new form of the oncotherapy oncoteam might be able to decide the optimal and particular treatment after previous consultation with the patient. The oncotherapy oncoteam is also suitable to carry out training and tasks of a cancer centre and by diminishing the psychological burden of the doctors it contributes to an improved patient care. This study presents the two-level multi-disciplinary and oncotherapy oncology team system at the University of Pécs including the detailed analysis of the considerations above.
Comparison of PI and PR current controllers applied on two-level VSC-HVDC transmission system
DEFF Research Database (Denmark)
Manoloiu, A.; Pereria, H.A.; Teodorescu, Remus;
2015-01-01
This paper analyzes differences between αβ and dq reference frames regarding the control of two-level VSC-HVDC current loop and dc-link voltage outer loop. In the first part, voltage feedforward effect is considered with PI and PR controllers. In the second part, the feedforward effect is removed...
Institute of Scientific and Technical Information of China (English)
LI Zuo-wei; YANG Yi-xian; YUAN Dong-feng; HU Zheng-ming
2004-01-01
In this paper, we propose a novel Unequal Error Protection (UEP) scheme with two levels for image transmission using Multilevel Codes (MLC). By providing the best protection for the most important data, the final recovered image quality is remarkably improved both in visual effect and in Peak Signal to Noise power Ratio (PSNR) performance.
Yazdannik, Ahmad R; Haghighat, Somayeh; Saghaei, Mahmoud; Eghbali, Maryam
2013-03-01
Endotracheal suctioning (ETS) is one of the most common supportive measures in intensive care units (ICU). ETS may be associated with complications including hypoxia and tachycardia. Closed system suctioning (CSS) decreases the rate of cardiorespiratory complication mainly due to continuation of ventilatory support and oxygenation during procedure. CSS has questionable efficacy, therefore higher values of negative pressure has been recommended to enhance the efficacy of CSS. This study was designed to evaluate the effects on gas exchange of 200 mmHg suctioning pressure compared with 100 mmHg in CSS. Fifty mechanically ventilated (MV) ICU patients were selected for the study. Two consecutive ten seconds CSS using suction pressures of 100 and 200 mmHg, in random order applied in each subject with the two hours wash out period. Effects of two levels of suction pressure on gas exchange were measured by recording the SPo2 values at 4 times. Repeated measure analysis of variance didn't show any significant difference between two levels of pressure (P = 0.315), but within each groups (100 and 200 mmHg) SPO2 changes was significant (P = 0.000). There was a mild but significant and transient increase in heart rate following both suction pressures, but no significant difference between two groups. The results show that CSS with suction pressure 200 mmHg has no detrimental effect on cardiorespiratory function of MV ICU patients. Since the safety of 200 mmHg suctioning pressure was approved, using 200 mmHg suction pressures is recommended for ETS of MV patients.
Yazdannik, Ahmad R.; Haghighat, Somayeh; Saghaei, Mahmoud; Eghbali, Maryam
2013-01-01
Background: Endotracheal suctioning (ETS) is one of the most common supportive measures in intensive care units (ICU). ETS may be associated with complications including hypoxia and tachycardia. Closed system suctioning (CSS) decreases the rate of cardiorespiratory complication mainly due to continuation of ventilatory support and oxygenation during procedure. CSS has questionable efficacy, therefore higher values of negative pressure has been recommended to enhance the efficacy of CSS. This study was designed to evaluate the effects on gas exchange of 200 mmHg suctioning pressure compared with 100 mmHg in CSS. Materials and Methods: Fifty mechanically ventilated (MV) ICU patients were selected for the study. Two consecutive ten seconds CSS using suction pressures of 100 and 200 mmHg, in random order applied in each subject with the two hours wash out period. Effects of two levels of suction pressure on gas exchange were measured by recording the SPo2 values at 4 times. Results: Repeated measure analysis of variance didn't show any significant difference between two levels of pressure (P = 0.315), but within each groups (100 and 200 mmHg) SPO2 changes was significant (P = 0.000). There was a mild but significant and transient increase in heart rate following both suction pressures, but no significant difference between two groups. Conclusion: The results show that CSS with suction pressure 200 mmHg has no detrimental effect on cardiorespiratory function of MV ICU patients. Since the safety of 200 mmHg suctioning pressure was approved, using 200 mmHg suction pressures is recommended for ETS of MV patients. PMID:23983740
Shorikov, A. F.
2016-12-01
In this article we consider a discrete-time dynamical system consisting of a set a controllable objects (region and forming it municipalities). The dynamics each of these is described by the corresponding linear or nonlinear discrete-time recurrent vector relations and its control system consist from two levels: basic level (control level I) that is dominating level and auxiliary level (control level II) that is subordinate level. Both levels have different criterions of functioning and united by information and control connections which defined in advance. In this article we study the problem of optimization of guaranteed result for program control by the final state of regional social and economic system in the presence of risks vectors. For this problem we propose a mathematical model in the form of two-level hierarchical minimax program control problem of the final states of this system with incomplete information and the general scheme for its solving.
Entanglement in a system of two two-level atoms interacting with a single-mode field
Institute of Scientific and Technical Information of China (English)
Jin Li-Juan; Fang Mao-Fa
2006-01-01
We investigate the entanglement in a system of two coupling atoms interacting with a single-mode field by means of quantum information entropy theory. The quantum entanglement between the two atoms and the coherent field is discussed by using the quantum reduced entropy, and the entanglement between the two coupling atoms is also investigated by using the quantum relative entropy. In addition, the influences of the atomic dipole-dipole interaction intensity and the average photon number of the coherent field on the degree of the entanglement is examined. The results show that the evolution of the degree of entanglement between the two atoms and the field is just opposite to that of the degree of entanglement between the two atoms. And the properties of the quantum entanglement in the system rely on the atomic dipole-dipole interaction and the average photon number of the coherent field.
Directory of Open Access Journals (Sweden)
Gisela C V Ramadas
Full Text Available This paper addresses the challenging task of computing multiple roots of a system of nonlinear equations. A repulsion algorithm that invokes the Nelder-Mead (N-M local search method and uses a penalty-type merit function based on the error function, known as 'erf', is presented. In the N-M algorithm context, different strategies are proposed to enhance the quality of the solutions and improve the overall efficiency. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm.
Ramadas, Gisela C V; Rocha, Ana Maria A C; Fernandes, Edite M G P
2015-01-01
This paper addresses the challenging task of computing multiple roots of a system of nonlinear equations. A repulsion algorithm that invokes the Nelder-Mead (N-M) local search method and uses a penalty-type merit function based on the error function, known as 'erf', is presented. In the N-M algorithm context, different strategies are proposed to enhance the quality of the solutions and improve the overall efficiency. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm.
Pedersen, Rune
2017-01-01
This is a project proposal derived from an urge to re-define the governance of ICT in healthcare towards regional and national standardization of the patient pathways. The focus is on a two-levelled approach for governing EPR systems where the clinicians' model structured variables and patient pathways. The overall goal is a patient centric EPR portfolio. This paper define and enlighten the need for establishing the socio- technical architect role necessary to obtain the capabilities of a modern structured EPR system. Clinicians are not capable to moderate between the technical and the clinical.
Shorikov, A. F.
2016-12-01
This article discusses the discrete-time dynamical system consisting from two controlled objects and described by a linear recurrent vector equations in the presence of uncertain perturbations. This dynamical system has two levels of a control: dominant level (the first level or the level I) and subordinate level (the second level or the level II) and both have different linear terminal criterions of functioning and united a priori by determined information and control connections. It is assumed that the sets constraining all a priori undefined parameters are known and they are a finite sets or convex, closed and bounded polyhedrons in the corresponding finite-dimensional vector spaces. For the dynamical system in question, we propose a mathematical formalization in the form of solving two-level hierarchical minimax program control problem with incomplete information. In this article for solving of the investigated problem is proposed the algorithm that has a form of a recurrent procedure of solving a linear programming and a finite optimization problems. The results obtained in this article can be used for computer simulation of an actual dynamical processes and for designing controlling and navigation systems.
Institute of Scientific and Technical Information of China (English)
S.Abdel-Khalek; M.M.A.Ahmed; A-S F.Obada
2011-01-01
We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic field,initially prepared in a coherent state.Field entropy squeezing as an indicator of the entanglement in a mixed state system is suggested.The temporal evolution of the negativity,Wehrl entropy,Wehrl phase distribution and field entropy squeezing are investigated.The results highlight the important roles played by both the Stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy,Wehrl phase distribution and field entropy squeezing.%We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic Reid, initially prepared in a coherent state. Field entropy squeezing as an indicator of the entanglement in a mixed state system is suggested. The temporal evolution of the negativity, Wehrl entropy, Wehrl phase distribution and field entropy squeezing are investigated. The results highlight the important roles played by both the Stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy, Wehrl phase distribution and field entropy squeezing.
Kale, Y. B.; Tiwari, V. B.; Mishra, S. R.; Singh, S.; Rawat, H. S.
2016-12-01
We report electromagnetically induced absorption (EIA) and transparency (EIT) resonances of sub-natural linewidth in degenerate two level systems (DTLSs) of metastable 84Kr (84Kr*) and 83Kr (83Kr*) atoms. Using the spectrally narrow EIA signals obtained corresponding to the closed hyperfine transition 4p55s[3/2]2(F=13/2) to 4p55p[5/2]3(F‧ = 15 / 2) in 83Kr* atom, we have measured the Landé g-factor (gF) for the lower hyperfine level involved in this transition by application of small values of magnetic field of few Gauss.
Howard, I A
2003-01-01
There is ongoing interest in the kinetic energy functional T sub s [rho] in density functional theory. The present study lies in this area and concerns the Pauli potential V sub P [rho]. A differential equation is obtained here for V sub P (x) in one dimension for a general two-level system. Also, as a specific example, such a functional of rho(x), the ground-state Fermion density, is given for the case of N Fermions which are harmonically confined. (letter to the editor)
Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae
2016-05-01
We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.
Grinberg, Horacio
2008-12-18
The interaction of a two-level cyclic XY n-spin model with a two-mode cavity field involving two-photon transitions is investigated through a generalized Jaynes-Cummings model in the rotating-wave approximation. The two-photon interacting Hamiltonian becomes from the replacement of each single-mode field in the one-photon interacting Hamiltonian with the second-harmonic generation. It was assumed that initially the correlated field modes are in disentangled coherent states having the same photon distribution and that the spin system is in an excited state. At any time t > 0, the spin system and the field are in an entangled state, in this case, via a unitary time evolution operator. Thus, the spontaneous decay of a spin level was treated by considering the interaction of the two-level spin system with the modes of the universe in the vacuum state. The different cases of interest, characterized in terms of a detuning parameter for each mode, which emerge from nonvanishing commutation relations, were analytically implemented and numerically discussed for various values of the initial mean photon number and spin-photon coupling constants. Photon distribution, time evolution of the spin population inversion, as well as the statistical properties of the field leading to the possible production of nonclassical states, such as antibunched light, violations of the Cauchy-Schwartz inequality, and second- and fourth-order squeezing, are examined. The case of zero detuning of both modes was treated in terms of a linearization of the expansion of the time evolution operator, while in other three cases, the computations were conducted via second- and third-order Dyson perturbation expansion of the time evolution operator matrix elements for the excited and ground states of the spin system, respectively.
Biborski, Andrzej; Kądzielawa, Andrzej P.; Spałek, Józef
2015-12-01
An efficient computational scheme devised for investigations of ground state properties of the electronically correlated systems is presented. As an example, (H2)n chain is considered with the long-range electron-electron interactions taken into account. The implemented procedure covers: (i) single-particle Wannier wave-function basis construction in the correlated state, (ii) microscopic parameters calculation, and (iii) ground state energy optimization. The optimization loop is based on highly effective process-pool solution - specific root-workers approach. The hierarchical, two-level parallelism was applied: both shared (by use of Open Multi-Processing) and distributed (by use of Message Passing Interface) memory models were utilized. We discuss in detail the feature that such approach results in a substantial increase of the calculation speed reaching factor of 300 for the fully parallelized solution. The scheme elaborated in detail reflects the situation in which the most demanding task is the single-particle basis optimization.
Rusydi, Febdian; Shukri, Ganes; Saputro, Adithya G.; Agusta, Mohammad K.; Dipojono, Hermawan K.; Suprijadi, Suprijadi
2017-04-01
We study the Q/B-band dipole strength of zinc tetrabenzoporphyrin (ZnTBP) using density functional theory (DFT) in various solvents. The solvents are modeled using the polarized continuum model (PCM). The dipole strength calculations are approached by a two-level system, where the Q-band is described by the HOMO → LUMO electronic transition and the B-band by the HOMO-1 → LUMO electronic transition. We compare the results with the experimental data of the Q/B-band intensity ratio. We also perform time-dependent DFT coupled with PCM to calculate the Q/B-band oscillator strength ratio of ZnTBP. The results of both methods show a general trend with respect to the experimental Q/B-band intensity ratio in solvents, except for the calculation in the water solvent. Even so, the approximation is a good starting point for studying the UV-vis spectrum based on DFT study alone.
Dutta, Rajesh
2016-01-01
We study excitation transfer dynamics in a lattice of two level systems characterized by dynamic disorder. The diagonal and off-diagonal energy disorders arise from the coupling of system and bath. We consider both the same and the independent bath limits. In case of independent bath all diagonal and off-diagonal bath coupling elements fluctuate independently of each other and the dynamics is complicated. We obtain the time dependent population distribution by solving quantum stochastic Liouville equation (QSLE) derived by Kubo. The main result of our study is both the population transfer dynamics and the mean square displacement of the exciton behave the similar way in the same and independent bath cases in the Markovian limit. However, these two baths can give rise to markedly different behavior in the non-Markovian limit where coherent transport becomes important. There are also several additional new results as follows. (i) Exciton migration remains coherent all the time for an average, non-zero off-diago...
Paradis, D; Mény, C; Gromov, V
2011-01-01
In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the Disordered Charge Distribution (DCD) combined with the presence of Two-Level Systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to confront this new model to astronomical observations of different Galactic environments in the FIR/submm, in order to derive a set of canonical model parameters to be used as a Galactic reference to be compared to in future Galactic and extragalactic studies. We confront the TLS model with existing astronomical data. We consider the average emission spectrum at high latitudes in our Galaxy as measured with FIRAS and WMAP, as well as the emission from Galactic compact sources observed with Archeops, for which an inverse relationship between the dust temperature and the emissivity spectral index has been evidenced. We show that, unlike models previously proposed which often invo...
Paradis, D.; Bernard, J.-P.; Mény, C.; Gromov, V.
2011-10-01
Aims: In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the disordered charge distribution (DCD) combined with the presence of two-level systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to compare this new model to astronomical observations of different Galactic environments in the far-infrared/submillimeter, in order to derive a set of canonical model parameters to be used as a Galactic reference to be compared to in future Galactic and extragalactic studies. Methods: We compare the TLS model with existing astronomical data. We consider the average emission spectrum at high latitudes in our Galaxy as measured with FIRAS and WMAP, as well as the emission from Galactic compact sources observed with the Archeops balloon experiment, for which an inverse relationship between the dust temperature and the emissivity spectral index has been shown. Results: We show that, unlike models previously proposed that often invoke two dust components at different temperatures, the TLS model successfully reproduces both the shape of the Galactic spectral energy distribution and its evolution with temperature as observed in the Archeops data. The best TLS model parameters indicate a charge coherence length of ≃13 nm and other model parameters in broad agreement with expectations from laboratory studies of dust analogs. We conclude that the millimeter excess emission, which is often attributed to the presence of very cold dust in the diffuse ISM, is very likely caused solely by TLS emission in disordered amorphous dust grains. We discuss the implications of the new model, in terms of mass determinations from millimeter continuum observations and the expected variations in the emissivity spectral index with wavelength and dust temperature. The implications for analyzing the Herschel and Planck satellite data are discussed. Table 5
Reduction of Subjective and Objective System Complexity
Watson, Michael D.
2015-01-01
Occam's razor is often used in science to define the minimum criteria to establish a physical or philosophical idea or relationship. Albert Einstein is attributed the saying "everything should be made as simple as possible, but not simpler". These heuristic ideas are based on a belief that there is a minimum state or set of states for a given system or phenomena. In looking at system complexity, these heuristics point us to an idea that complexity can be reduced to a minimum. How then, do we approach a reduction in complexity? Complexity has been described as a subjective concept and an objective measure of a system. Subjective complexity is based on human cognitive comprehension of the functions and inter relationships of a system. Subjective complexity is defined by the ability to fully comprehend the system. Simplifying complexity, in a subjective sense, is thus gaining a deeper understanding of the system. As Apple's Jonathon Ive has stated," It's not just minimalism or the absence of clutter. It involves digging through the depth of complexity. To be truly simple, you have to go really deep". Simplicity is not the absence of complexity but a deeper understanding of complexity. Subjective complexity, based on this human comprehension, cannot then be discerned from the sociological concept of ignorance. The inability to comprehend a system can be either a lack of knowledge, an inability to understand the intricacies of a system, or both. Reduction in this sense is based purely on a cognitive ability to understand the system and no system then may be truly complex. From this view, education and experience seem to be the keys to reduction or eliminating complexity. Objective complexity, is the measure of the systems functions and interrelationships which exist independent of human comprehension. Jonathon Ive's statement does not say that complexity is removed, only that the complexity is understood. From this standpoint, reduction of complexity can be approached
Extended Cognitive System and Epistemic Subject
Directory of Open Access Journals (Sweden)
Trybulec Barbara
2015-03-01
Full Text Available The concept of an extended cognitive system is central to contemporary studies of cognition. In the paper I analyze the place of the epistemic subject within the extended cognitive system. Is it extended as well? In answering this question I focus on the differences between the first and the second wave of arguments for the extended mind thesis. I argue that the position of Cognitive Integration represented by Richard Menary is much more intuitive and fruitful in analyses of cognition and knowledge than the early argument formulated by Andy Clark and David Chalmers. Cognitive Integration is compatible with virtue epistemology of John Greco’s agent reliabilism. The epistemic subject is constituted by its cognitive character composed of an integrated set of cognitive abilities and processes. Some of these processes are extended, they are a manipulation of external informational structures and, as such, they constitute epistemic practices. Epistemic practices are normative; to conduct them correctly the epistemic subject needs to obey epistemic norms embedded in the cultural context. The epistemic subject is not extended because of the casual coupling with external informational artifacts which extend his mind from inside the head and into the world. Rather, cognitive practices constitute the subject’s mind, they transform his cognitive abilities, and this is what makes the mind and epistemic subject “extended”.
The Subject Analysis of Payment Systems Characteristics
Directory of Open Access Journals (Sweden)
Korobeynikova Olga Mikhaylovna
2015-09-01
Full Text Available The article deals with the analysis of payment systems aimed at identifying the categorical terminological apparatus, proving their specific features and revealing the impact of payment systems on the state of money turnover. On the basis of the subject analysis, the author formulates the definitions of a payment system (characterized by increasing speed of effecting payments, by the reduction of costs, by high degree of payments convenience for subjects of transactions, by security of payments, by acceptable level of risks and by social efficiency, a national payment system, and a local payment system (characterized by the growth of economic and social efficiency of systems participants, by the process of money turnover optimization on the basis of saving transaction costs and increasing speed of money flows within the local payment systems. According to the economic levels, the payment systems are divided to macrosystems (national payment systems, mezosystems (payment systems localized on the operational and territorial basis, microsystems (payments by individual economic subjects. The establishment of qualitative features of payment systems, which is a basis of the author’s terminological interpretation, gave a possibility to reveal the cause-effect relations of payment systems influence on the state of money turnover in the involved subjects, and on the economy as a whole. The result of the present research consists in revealing the payment systems influence on the state of money turnover which is significant: at the state and regional level – in the optimization of budget and inter-budgetary relations, in acceleration of the money turnover, in deceleration of the money supply and inflation rate, in reduced need in money emission; at the level of economic entities – in accelerating the money turnover and accounts receivable, in the reduction of debit and credit loans, in the growth of profit (turnover; at the household level – in
Hu, F M; Sun, C P; Zhou, L; Shi, Tao; Zhou, Lan
2006-01-01
This is the first one of a series of our papers theoretically studying the coherent control of photon transmission along the coupled resonator optical waveguide (CROW) by doping artificial atoms for various hybrid structures. We will provide the several approaches correspondingly based on Green function, the mean field method and spin wave theory et al. In the present paper we adopt the two-time Green function approach to study the coherent transmission photon in a CROW with homogeneous couplings, each cavity of which is doped by a two-level artificial atom. We calculate the two-time correlation function for photon in the weak-coupling case. Its poles predict the exact dispersion relation, which results in the group velocity coherently controlled by the collective excitation of the doping atoms. We emphasize the role of the population inversion of doping atoms induced by some polarization mechanism.
Bachelard, Nicolas; Sebbah, Patrick; Vanneste, Christian
2014-01-01
We use time-domain numerical simulations of a two-dimensional (2D) scattering system to study the interaction of a collection of emitters resonantly coupled to an Anderson-localized mode. For a small electric field intensity, we observe the strong coupling between the emitters and the mode, which is characterized by linear Rabi oscillations. Remarkably, a larger intensity induces non-linear interaction between the emitters and the mode, referred to as the dynamical Stark effect, resulting in non-linear Rabi oscillations. The transition between both regimes is observed and an analytical model is proposed which accurately describes our numerical observations.
Institute of Scientific and Technical Information of China (English)
2008-01-01
The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory,and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number,the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is,the weaker the entanglement between the quan-tum field and the atom will be,and when the field is strong enough,the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle,namely,the quantum field and the two-level atom are always in the entangled state,and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is,the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.
Institute of Scientific and Technical Information of China (English)
LIU WangYun; YANG ZhiYong; AN YuYing
2008-01-01
The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory, and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number, the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is, the weaker the entanglement between the quan-tum field and the atom will be, and when the field is strong enough, the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle, namely, the quantum field and the two-level atom are always in the entangled state, and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is, the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.
Two-level cervical disc replacement: perspectives and patient selection
Directory of Open Access Journals (Sweden)
Narain AS
2017-02-01
Full Text Available Ankur S Narain, Fady Y Hijji, Daniel D Bohl, Kelly H Yom, Krishna T Kudaravalli, Kern Singh Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA Introduction: Cervical disc replacement (CDR is an emerging treatment option for cervical degenerative disease. Postulated benefits of cervical disc replacement compared to anterior cervical discectomy and fusion include preserved motion at the operative segments and decreased motion at adjacent levels. Multiple studies have been performed investigating the outcomes of CDR in single-level pathology. The investigation of the use of CDR in two-level pathology is an emerging topic within the literature.Purpose: To critically evaluate the literature regarding two-level CDR in order to determine its utility compared to two-level cervical arthrodesis. Patient selection factors including indications and contraindications will also be explored.Methods: The PubMed database was searched for all articles published on the subject of two-level CDR up until October 2016. Studies were classified by publication year, study design, sample size, follow-up interval, and conflict of interest. Outcomes were recorded from each study, and included data on patient-reported outcomes, radiographic measurements, range of motion, peri- and postoperative complications, heterotopic ossification, adjacent segment disease, reoperation rate, and total intervention cost. Results: Fourteen studies were included in this review. All studies demonstrated at least noninferiority of two-level CDR compared to both two-level arthrodesis and single-level CDR. Patient selection in two-level CDR is driven by the inclusion and exclusion criteria presented in prospective, randomized controlled trials. The most common indication is subaxial degenerative disc disease over two contiguous levels presenting with radiculopathy or myelopathy. Furthermore, costs analyses trended toward at least noninferiority of two-level
Institute of Scientific and Technical Information of China (English)
叶朱枫
2015-01-01
The two-level management system emerging with the expansion of higher vocational colleges is not only the objective need of the development of colleges, but also one of the charac-teristics of higher vocational colleges. In order to improve the quality of teaching and management, higher vocational colleges generally implement two-level management system, and the teaching secretary plays an important role in the management system. The expansion of higher vocational colleges will in-evitably lead to the increase of teaching management, which makes the teaching secretary work more complex and challeng-ing. This paper mainly analyzes the new positioning of teaching secretary work under two-level management system as well as how to carry out the work and serve the functions of the secretary better in collaboration with various departments, to ensure the stability of the teaching order and the healthy development of colleges.%随高职院校规模的扩大而出现的二级管理体制不仅是院校发展的客观需要，也是高职院校的办学特色之一。高职院校为提高教学和管理质量，一般都是实行二级管理体制，而且教学秘书在管理体制中起着重要的协调作用。高职院校规模的扩展必然导致教学管理工作的增加，这使得教学秘书的日常工作变得复杂且颇具挑战性。本文主要分析了二级管理体制下教学秘书工作的新定位以及如何更好地开展工作，更好地发挥秘书的职能，配合各部门更好地开展工作，保证教学秩序的稳定性并促进学校的健康发展。
Kocourek, Pavel
2013-01-01
The contribution is devoted to the automatic indexing of grey literature by subject headings of the Polythematic Structured Subject Heading System in the National repository of grey literature. The paper describes the initial situation, previous experience, analysis, stages of implementation and demonstration of indexing.
The User-Subjective Approach to Personal Information Management Systems.
Bergman, Ofer; Beyth-Marom, Ruth; Nachmias, Rafi
2003-01-01
Explains personal information management (PIM) systems and suggests a user-subjective approach to PIM system design. Advocates that PIM systems relate to the subjective value-added attributes that the user gives the stored data so that the user can find information again, recall it when needed, and use it effectively in the next interaction.…
Institute of Scientific and Technical Information of China (English)
金静芬; 范清秋; 赵锐祎
2015-01-01
Objective: To explore the applicability and feasibility of two-level triage system in our tertiary hospital outpatient visit management. Methods: The authors established two-level triage system based on the JCI outpatient safety management goal and homogeneity service, they defined the job description of clinic nurses, established outpatient safety management system, improved clinic environment, using outpatient triage software to support the two-level triage management. Results: The average waiting time decreased from 56.33 min to 40.95 min (P<0.001), the overall satisfaction for outpatient increased from 91.38% to 94.63% (P<0.001) after three-year practice. No one suffered sudden accident death in clinic. The rate of one clinic for one patient was 96.8%. Conclusion: The two-level triage system under JCI standard was safe and efifcient for improving clinic service and outpatient satisfaction. It is an important means to increase outpatient service quality.%目的：构建门诊二级分诊护理管理模式，探索二级分诊管理模式在大型三级甲等医院门诊患者就诊管理中的适用性和可行性。方法：结合JCI门诊患者安全管理目标以及同质化服务要求，完善门诊护士岗位职责，建立并实施二级分诊工作模式，制定门诊患者安全管理制度，优化就诊环境，完善并应用门诊分诊管理软件支持二级分诊护理管理。结果：经过近三年实践，患者就诊等候时间从平均56.33min缩短至40.95min（P<0.001），门诊患者的总体满意度从91.38%提高到94.63%（P<0.001），门诊未发现因突发意外事件死亡，门诊一人一诊间执行率达到96.8%。结论：JCI标准下门诊二级分诊护理管理模式安全可行，提高了就诊效率和患者满意度，是提高门诊综合服务质量的重要手段。
Design of a Two Levels Optical Receiver System for UV Scattering Communication%紫外光散射通信中一种二级光学接收系统设计
Institute of Scientific and Technical Information of China (English)
赵太飞; 柯熙政; 梁薇; 何华
2011-01-01
介绍了大气紫外光通信的特点和光学天线的性能指标,仿真分析了传统的复合抛物面聚光器(CPC)和半球透镜在非视距紫外信道中的聚光性能,设计了一种二级接收的光学聚光系统,并使用ZEMAX软件进行光线追迹,对其光学增益及视场进行分析.结果表明,这种二级光学系统有较高的增益及较大的视场,适合作为非视距紫外光通信中的光学天线.%This paper describes the characteristics of atmospheric ultraviolet (UV) communications and the performance of optical antenna. The concentration performance of the conventional compound parabolic concentrator ( CPC) and ther hemispherical lens in the non-light-of-sight ( NLOS) UV channel have been simulated and analyzed.A kind of two-level receiving optical light-gathering system has been designed, the ZEMAX software was used for the light-tracing and its optic gain as well as the field-of-view have heen analyzed. The simulation results show that this two levels optical systems have a higher gain and a larger field-of-view which is suitable for the optical antenna of the NLOS UV communication.
Two-Level Semantics and Abstract Interpretation
DEFF Research Database (Denmark)
Nielson, Flemming
1989-01-01
Two-level semantics is a variant of Scott/Strachey denotational semantics in which the concept of binding time is treated explicitly. This is done by formally distinguishing between those computations that take place at run-time and those that take place at compile-time. Abstract interpretation...... unique flavour is the insistence on formal proofs of correctness and the methods used to establish these. This paper develops a theory of abstract interpretation for two-level denotational definitions. There are three ingredients in this. First a framework for proving the correctness of analyses...
Expectations of two-level telegraph noise
Fern, J
2006-01-01
We find expectation values of functions of time integrated two-level telegraph noise. Expectation values of this noise are evaluated under simple control pulses. Both the Gaussian limit and $1/f$ noise are considered. We apply the results to a specific superconducting quantum computing example, which illustrates the use of this technique for calculating error probabilities.
Study on the Delay Performance of Station Dependent Two-level Polling Systems%依托站点状态的两级轮询控制系统时延特性分析
Institute of Scientific and Technical Information of China (English)
官铮; 杨志军; 何敏; 钱文华
2016-01-01
Based on priority differentiation and the system eﬃciency, this paper proposes a station dependent two-level polling system. The mixed service two-level polling system is extended by using queue state-dependent routing, in which only active stations with information packets could be visited by server. The scheme meets the requirement not only for conflict free but also for priority differentiation and eﬃciency, and provides a lower latency. An embedded Markov chain framework is set up to drive the closed-form expression for the mean waiting time. Numerical examples demonstrate that theoretical and simulation results are identical and the new system has a better eﬃciency at both key station and normal station.%基于区分业务优先级和提高系统时延性能的网络需求，提出了依托站点状态的两级轮询控制系统。系统在混合服务两级轮询模型的基础上，根据站点缓冲区状态采用并行调度方式仅对有数据分组的活动站点提供服务。该模型既能满足区分站点优先级的需求又能避免空闲查询，从而提高系统利用率、降低等待时延。采用嵌入式马尔科夫链和概率母函数的方法对该系统建立数学模型，对系统平均等待时延特性进行了精确解析。通过理论计算与仿真实验结果的对比验证了理论分析的正确性，与已有两级轮询系统相比，具有更好的时延性能。
Research and simulation of two-level grid-connected photovoltaic inverter system%两级式光伏并网发电系统的研究与仿真
Institute of Scientific and Technical Information of China (English)
安彬; 公茂法; 苏彦平; 王志文; 李岚冰
2014-01-01
在两级式光伏发电系统中，采用基于前级 Boost 变换器的 MPPT 方法，可以使光伏电池达到最优状态，即最大限度的将太阳能转化为电能。后级网侧逆变器采用无差拍控制，使电网功率因数为1。通过两级式并网发电系统的仿真，可以实现最大功率点的跟踪，而且使并网电流与电网电压达到同频同相。因此，光伏模块的效率能够得到提高，逆变控制器的电流呈现高质量的正弦交流波形。通过 Matlab/Simulink 软件进行仿真，前后级都能实现相对独立的功能。仿真结果表明：此方案更有利于系统的模块化设计和集成。%The photovoltaic cell can achieve the optimal state ,and the solar energy is converted into electrical energy suffi -ciently in the two-level PV power system by using the method of MPPT which is based on the front stage Boost converter . The back stage network side inverter adopts the method of deadbeat control and the grid power factor turns to be 1 .The maximum power point tracking is realized ,and the grid current has the same frequency and phase with the grid voltage through simulation .Therefore ,efficiency of the solar module is improved and the sine AC wave of the inverter control circuit is high-quality .Each converter can achieve relatively independent function in the two -level PV power system by the method of Matlab/Simulink software simulation .The simulation shows that it is very conducive to the modular design and integration of the system .
Two-Level Semantics and Abstract Interpretation
DEFF Research Database (Denmark)
Nielson, Flemming
1989-01-01
Two-level semantics is a variant of Scott/Strachey denotational semantics in which the concept of binding time is treated explicitly. This is done by formally distinguishing between those computations that take place at run-time and those that take place at compile-time. Abstract interpretation...... is concerned with the (preferably automatic) analysis of programs. The main purpose of these analyses is to find information that may assist in the efficient implementation of the programs. Abstract interpretation is thus related to data flow analysis, partial evaluation and other program analysis methods. Its...... unique flavour is the insistence on formal proofs of correctness and the methods used to establish these. This paper develops a theory of abstract interpretation for two-level denotational definitions. There are three ingredients in this. First a framework for proving the correctness of analyses...
Institute of Scientific and Technical Information of China (English)
肖安南; 张城玮; 戴先玉
2013-01-01
Through establishing standardized the maintenance management system of security system , se-curity risk classification management and neural network risk early warning are implemented , in two level of province and region setting risk analysis , online inspection and field monitoring officers .Effectively tracking the rectification results , to achieve closed-loop management , the level of substation security risk prevention and control is improved .%通过建立规范化的安防系统运维管理体系，实行安防风险分类管理、神经网络风险预警，在省地两级均设置风险分析、在线稽查和现场监控专责人员。有效跟踪隐患整改结果，实现问题的闭环管理，提高变电站安防风险防控水平。
Two-level convolution formula for nuclear structure function
Ma, Boqiang
1990-05-01
A two-level convolution formula for the nuclear structure function is derived in considering the nucleus as a composite system of baryon-mesons which are also composite systems of quark-gluons again. The results show that the European Muon Colaboration effect can not be explained by the nuclear effects as nucleon Fermi motion and nuclear binding contributions.
System and method for acquisition management of subject position information
Energy Technology Data Exchange (ETDEWEB)
Carrender, Curt (Morgan Hill, CA)
2007-01-23
A system and method for acquisition management of subject position information that utilizes radio frequency identification (RF ID) to store position information in position tags. Tag programmers receive position information from external positioning systems, such as the Global Positioning System (GPS), from manual inputs, such as keypads, or other tag programmers. The tag programmers program each position tag with the received position information. Both the tag programmers and the position tags can be portable or fixed. Implementations include portable tag programmers and fixed position tags for subject position guidance, and portable tag programmers for collection sample labeling. Other implementations include fixed tag programmers and portable position tags for subject route recordation. Position tags can contain other associated information such as destination address of an affixed subject for subject routing.
System and method for acquisition management of subject position information
Energy Technology Data Exchange (ETDEWEB)
Carrender, Curt
2005-12-13
A system and method for acquisition management of subject position information that utilizes radio frequency identification (RF ID) to store position information in position tags. Tag programmers receive position information from external positioning systems, such as the Global Positioning System (GPS), from manual inputs, such as keypads, or other tag programmers. The tag programmers program each position tag with the received position information. Both the tag programmers and the position tags can be portable or fixed. Implementations include portable tag programmers and fixed position tags for subject position guidance, and portable tag programmers for collection sample labeling. Other implementations include fixed tag programmers and portable position tags for subject route recordation. Position tags can contain other associated information such as destination address of an affixed subject for subject routing.
Institute of Scientific and Technical Information of China (English)
栗惠芳; 柏晴; 丁胜; 吴卫丰
2011-01-01
With the popularization of higher education and the accelerated process of internationalization, it＇ s a general practice for most colleges to apply the two level management system of college and school. The paper is to analyze and explore the effective ways of employing the internal control management at the level of schools from the perspectives of system construction, operational mechanism and leadership construction based on literature review and practice analysis. Furthermore, the paper points out that it＇ s imperative for schools to make adaptive adjustments in the above mentioned three aspects, thus facilitating the healthy and rapid development of schools by achieving effectiveness in the fields of teaching, researches, talents cultivation and discipline construction.%随着高等教育大众化和国际化进程的加快，我国大部分高校普遍实行校院两级管理。文章以制度建设、运行机制和领导班子建设三个主要方面为切入点，通过文献梳理和实践分析，对二级学院实施内控管理的有效路径进行分析和探讨。并进一步指出，二级学院迫切需要在上述三个主要方面做出适应性调整，才能在教学、科研、人才队伍和学科建设等方面取得较大成效，促进学院健康、快速发展。
Maintenance Models for Systems subject to Measurable Deterioration
R.P. Nicolai (Robin)
2008-01-01
textabstractComplex engineering systems such as bridges, roads, flood defence structures, and power pylons play an important role in our society. Unfortunately such systems are subject to deterioration, meaning that in course of time their condition falls from higher to lower, and possibly even to u
Subjective evaluation of a 3D videoconferencing system
Rizek, Hadi; Brunnström, Kjell; Wang, Kun; Andrén, Börje; Johanson, Mathias
2014-03-01
A shortcoming of traditional videoconferencing systems is that they present the user with a flat, two-dimensional image of the remote participants. Recent advances in autostereoscopic display technology now make it possible to develop video conferencing systems supporting true binocular depth perception. In this paper, we present a subjective evaluation of a prototype multiview autostereoscopic video conferencing system and suggest a number of possible improvements based on the results. Whereas methods for subjective evaluation of traditional 2D videoconferencing systems are well established, the introduction of 3D requires an extension of the test procedures to assess the quality of depth perception. For this purpose, two depth-based test tasks have been designed and experiments have been conducted with test subjects comparing the 3D system to a conventional 2D video conferencing system. The outcome of the experiments show that the perception of depth is significantly improved in the 3D system, but the overall quality of experience is higher in the 2D system.
Usability evaluation of a vibrotactile feedback system in stroke subjects
Held, Jeremia P.; Klaassen, Bart; van Beijnum, Bernhard J.F.; Luft, Andreas R.; Veltink, Petrus H.
2017-01-01
Background: To increase the functional capabilities of stroke subjects during activities of daily living, patients receive rehabilitative training to recover adequate motor control. With the goal to motivate self-training by use of the arm in daily life tasks, a sensor system (Arm Usage Coach, AUC)
Optical resonance and two-level atoms
Allen, L
1987-01-01
""Coherent and lucid…a valuable summary of a subject to which [the authors] have made significant contributions by their own research."" - Contemporary PhysicsOffering an admirably clear account of the basic principles behind all quantum optical resonance phenomena, and hailed as a valuable contribution to the literature of nonlinear optics, this distinguished work provides graduate students and research physicists probing fields such as laser physics, quantum optics, nonlinear optics, quantum electronics, and resonance optics an ideal introduction to the study of the interaction of electroma
Levitated nanoparticle as a classical two-level atom [Invited
Frimmer, Martin; Gieseler, Jan; Ihn, Thomas; Novotny, Lukas
2017-06-01
The center-of-mass motion of a single optically levitated nanoparticle resembles three uncoupled harmonic oscillators. We show how a suitable modulation of the optical trapping potential can give rise to a coupling between two of these oscillators, such that their dynamics are governed by a classical equation of motion that resembles the Schr\\"odinger equation for a two-level system. Based on experimental data, we illustrate the dynamics of this parametrically coupled system both in the frequency and in the time domain. We discuss the limitations and differences of the mechanical analogue in comparison to a true quantum mechanical system.
Establishing performance requirements of computer based systems subject to uncertainty
Energy Technology Data Exchange (ETDEWEB)
Robinson, D.
1997-02-01
An organized systems design approach is dictated by the increasing complexity of computer based systems. Computer based systems are unique in many respects but share many of the same problems that have plagued design engineers for decades. The design of complex systems is difficult at best, but as a design becomes intensively dependent on the computer processing of external and internal information, the design process quickly borders chaos. This situation is exacerbated with the requirement that these systems operate with a minimal quantity of information, generally corrupted by noise, regarding the current state of the system. Establishing performance requirements for such systems is particularly difficult. This paper briefly sketches a general systems design approach with emphasis on the design of computer based decision processing systems subject to parameter and environmental variation. The approach will be demonstrated with application to an on-board diagnostic (OBD) system for automotive emissions systems now mandated by the state of California and the Federal Clean Air Act. The emphasis is on an approach for establishing probabilistically based performance requirements for computer based systems.
Piping system subjected to seismic hard rock high frequencies
Energy Technology Data Exchange (ETDEWEB)
Rydell, Cecilia, E-mail: cecilia.rydell@byv.kth.se [KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Vattenfall AB, SE-169 92 Stockholm (Sweden); Malm, Richard; Ansell, Anders [KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden)
2014-10-15
Highlights: • A study of the influence of support gaps in the analysis of a piping system. • Piping system located within a nuclear power plant reactor containment building. • Piping system subjected to a seismic hard rock high-frequency load. • Comparison of low- and high-frequency seismic loads. • The influence on the stress response of piping and acceleration response of valves. - Abstract: This paper addresses the influence of support gaps in the analyses of a piping system when subjected to a seismic hard rock high-frequency load. The system is located within the reactor containment building of a nuclear power plant and is assessed to be susceptible to high-frequency loads. The stress response of the pipe and the acceleration response of the valves are evaluated for different support gap sizes. It is shown that the inclusion of the support gaps in the analyses reduces the stress response for almost all pipe elements. On the other hand, the acceleration response of the valves is not necessarily reduced by the consideration of the gaps.
Reliability of structural systems subjected to extreme forcing events
Joo, Han-Kyul; Sapsis, Themistoklis P
2016-01-01
We characterize the complex, heavy-tailed probability distribution functions (pdf) describing the response and its local extrema for structural systems subjected to random forcing that includes extreme events. Our approach is based on the recent probabilistic decomposition-synthesis technique in, where we decouple rare events regimes from the background fluctuations. The result of the analysis has the form of a semi-analytical approximation formula for the pdf of the response (displacement, velocity, and acceleration) and the pdf of the local extrema. For special limiting cases (lightly damped or heavily damped systems) our analysis provides fully analytical approximations. We also demonstrate how the method can be applied to high dimensional structural systems through a two-degrees-of-freedom structural system undergoing rare events due to intermittent forcing. The derived formulas can be evaluated with very small computational cost and are shown to accurately capture the complicated heavy-tailed and asymmet...
Optimizing ETL by a Two-level Data Staging Method
DEFF Research Database (Denmark)
Iftikhar, Nadeem
2016-01-01
In data warehousing, the data from source systems are populated into a central data warehouse (DW) through extraction, transformation and loading (ETL). The standard ETL approach usually uses sequential jobs to process the data with dependencies, such as dimension and fact data. It is a non......-/late-arriving data, and fast-/slowly-changing data. The introduced additional staging area decouples loading process from data extraction and transformation, which improves ETL flexibility and minimizes intervention to the data warehouse. This paper evaluates the proposed method empirically, which shows......-trivial task to process the so-called early-/late-arriving data, which arrive out of order. This paper proposes a two-level data staging area method to optimize ETL. The proposed method is an all-in-one solution that supports processing different types of data from operational systems, including early...
Integrating Character Education Model With Spiral System In Chemistry Subject
Hartutik; Rusdarti; Sumaryanto; Supartono
2017-04-01
Integrating character education is the responsibility of all subject teachers including chemistry teacher. The integration of character education is just administrative requirements so that the character changes are not measurable. The research objective 1) describing the actual conditions giving character education, 2) mapping the character integration of chemistry syllabus with a spiral system, and 3) producing syllabus and guide system integrating character education in chemistry lessons. Of the eighteen value character, each character is mapped to the material chemistry value concepts of class X and repeated the system in class XI and class XII. Spiral system integration means integrating the character values of chemistry subjects in steps from class X to XII repeatedly at different depth levels. Besides developing the syllabus, also made the integration of characters in a learning guide. This research was designed with research and development [3] with the scope of 20 chemistry teachers in Semarang. The focus of the activities is the existence of the current character study, mapping the character values in the syllabus, and assessment of the integration guides of character education. The validity test of Syllabus and Lesson Plans by experts in FGD. The data were taken with questionnaire and interviews, then processed by descriptive analysis. The result shows 1) The factual condition, in general, the teachers designed learning one-time face-to-face with the integration of more than four characters so that behaviour changes and depth of character is poorly controlled, 2) Mapping each character values focused in the syllabus. Meaning, on one or two basic competence in four or five times, face to face, enough integrated with the value of one character. In this way, there are more noticeable changes in students behaviour. Guidance is needed to facilitate the integration of character education for teachers integrating systems. Product syllabus and guidelines
Stochastic Resonance in a Bistable System Subject to Dichotomous Noise
Institute of Scientific and Technical Information of China (English)
ZHOU Yu-Rong; PAN Hui-Mei; GUO Feng; PANG Xiao-Feng
2008-01-01
The stochastic resonance phenomenon in a bistable system subject to Markov dichotomous noise (DN) is investigated. Based on the adiabatic elimination and the two-state theories, the explicit expressions for the signal-to-noise ratio (SNR) and the spectral power amplification (SPA) have been obtained. It is shown that two peaks can occur on the curve of SNR versus the intensity of the DN. Moreover, the SNR is a non-monotonic function of the correlation time of the DN. The SPA varies non-monotonously with the strength of the DN. The dependence of the SNR on the frequency and the amplitude of the external periodic signal are discussed. The effect of the external frequency and the correlation time of the DN on the SPA are analyzed.
Modeling of Two Level Grid Connected PV System and Designing the Key Links%两级式光伏并网系统建模及关键环节的设计
Institute of Scientific and Technical Information of China (English)
孙亮; 袁文强; 吴长鹏
2016-01-01
Set up two-stage photovoltaic grid-connected system model,the control strategy and the key technol-ogy of photovoltaic grid-connected has been studied. Firstly, the front stage adopt DC / DC boost, and with MPPT ( Maximum Power Point Tracking) system to improve the efficiency of the PV system. The traditional MPPT algorithm has been improved,adopted a voltage disturbance observation algorithm which combining with genetic algorithm,even the weather changes greatly,the algorithm is able to accurately track and control the maximum power point. The next stage links adopt single-phase bridge inverter inverts,using the phase-locked loop ( PLL) to achieve the grid current and grid voltage have same phase,because of the grid voltage will in-terfere the grid current,the feedforward compensation of grid voltage has been put forward. Finally,the model using MATLAB simulink simulation software to verify,the method is feasible has been proved.%搭建了两级式光伏并网系统模型，研究其控制策略，分析光伏并网的关键技术环节。前级首先采用DC/DC升压环节，并配合MPPT(最大功率点跟踪)装置来提升光伏系统的工作效率。对传统的MPPT算法进行了改进，采用了与遗传算法相结合的电压干扰观测法，即使外界环境剧烈变化，该算法都能对最大功率点进行准确跟踪控制。后级逆变环节采用单相桥式逆变，利用PLL(锁相环)实现并网电流和电网电压同相位，针对电网电压会对并网电流造成干扰，提出了电网电压前馈补偿控制。最后利用MATLAB软件中simulink模块对模型进行仿真验证，证明了方法的可行性。
Squeezing in the interaction of radiation with two-level atoms
Bandyopadhyay, Abir; Rai, Jagdish
1995-01-01
We propose a simple experimental procedure to produce squeezing and other non-classical properties like photon antibunching of radiation, and amplification without population inversion. The method also decreases the uncertainties of the angular-momentum quadratures representing the two-level atomic system in the interaction of the two-level atoms with quantized radiation.
Two-Level Fingerprinting Codes: Non-Trivial Constructions
Rochanakul, Penying
2011-01-01
We extend the concept of two-level fingerprinting codes, introduced by Anthapadmanabhan and Barg (2009) in context of traceability (TA) codes, to other types of fingerprinting codes, namely identifiable parent property (IPP) codes, secure-frameproof (SFP) codes, and frameproof (FP) codes. We define and propose the first explicit non-trivial construction for two-level IPP, SFP and FP codes.
Grid trust based on pre-measure and two-level reputation
Institute of Scientific and Technical Information of China (English)
ZHANG Lin; WANG Ru-chuan; WANG Hai-yan
2007-01-01
Security has been the focus of grid systems recently. As a kind of tool, grid security infrastructure (GSI) provides the authentication and authorization services and so on. These mechanisms mostly belong to the objective factors, which have not met the needs of security. As the subjective factor, trust model plays an important role in security field. A new two-level reputation trust architecture for grid is given to reduce the costs of system management largely, in which trust relationships amongst virtual organizations (VOs) are built on domain trust managers (DTMs) rather than resource nodes (RNs). Taking inter-domain trust propagation for example, trust model is improved by integrating global reputation and the subjective trust concept of each recommender into synthesizing final trust value. Moreover, before the grid starts to interact with the trustworthy entities, the pre-measure scheme is presented to filter distrustful entities further, which is based on accuracy and honesty. Experimental results indicate that the model can prevent from the malicious attacks better.
Structured Learning of Two-Level Dynamic Rankings
Raman, Karthik; Shivaswamy, Pannaga
2011-01-01
For ambiguous queries, conventional retrieval systems are bound by two conflicting goals. On the one hand, they should diversify and strive to present results for as many query intents as possible. On the other hand, they should provide depth for each intent by displaying more than a single result. Since both diversity and depth cannot be achieved simultaneously in the conventional static retrieval model, we propose a new dynamic ranking approach. Dynamic ranking models allow users to adapt the ranking through interaction, thus overcoming the constraints of presenting a one-size-fits-all static ranking. In particular, we propose a new two-level dynamic ranking model for presenting search results to the user. In this model, a user's interactions with the first-level ranking are used to infer this user's intent, so that second-level rankings can be inserted to provide more results relevant for this intent. Unlike for previous dynamic ranking models, we provide an algorithm to efficiently compute dynamic ranking...
Simuluating quantum many-body systems subject to measurements
DEFF Research Database (Denmark)
Gammelmark, Søren
is found. The technique is exemplified by numerical simulations of the antiferromagnetic Heisenberg spin-chain model subject to various instances of the measurement model. In particular, we focus on local measurements with small support and nonlocal measurements, which induce long-range correlations....
Simulating quantum many-body systems subject to measurements
DEFF Research Database (Denmark)
Gammelmark, Søren
is found. The technique is exemplified by numerical simulations of the antiferromagnetic Heisenberg spin-chain model subject to various instances of the measurement model. In particular, we focus on local measurements with small support and nonlocal measurements, which induce long-range correlations....
Teaching innovation system applied in business management subjects.
Directory of Open Access Journals (Sweden)
Rafael Rosillo
2017-06-01
Blunder offers a fun mobile training. We can know which student learns faster, learns more or learns better a particular topic. If a student plays the subject that the teacher has explained in class the level of learning affects to the final evaluation positively.
Electroretinography in healthy subjects in relation to systemic glucocorticoid intake
DEFF Research Database (Denmark)
Kappelgaard, Per; Hansen, Katrine B; Vilsbøll, Tina
2012-01-01
This study examined electroretinographic function in healthy subjects before and after prednisolone intake. To separate the effect of prednisolone on the retina from the potentially confounding hyperglycemia-inducing effect of prednisolone, electroretinography was made while fasting and at a pre...... to clamped hyperglycemia, neither before, nor after prednisolone (P > 0.05). The stability of ffERG performance in the face of shifting glycemia levels, which differs from what has been found in diabetes, was not influenced by the mild diabetogenic effect of the intervention on insulin resistance (P = 0...
A Semantics-based Communication System for Dysphasic Subjects
Vaillant, P
1997-01-01
Dysphasic subjects do not have complete linguistic abilities and only produce a weakly structured, topicalized language. They are offered artificial symbolic languages to help them communicate in a way more adapted to their linguistic abilities. After a structural analysis of a corpus of utterances from children with cerebral palsy, we define a semantic lexicon for such a symbolic language. We use it as the basis of a semantic analysis process able to retrieve an interpretation of the utterances. This semantic analyser is currently used in an application designed to convert iconic languages into natural language; it might find other uses in the field of language rehabilitation.
SYSTEM OF TAXATION ANALYTICAL INDICATORS OF ECONOMIC SUBJECTS
Directory of Open Access Journals (Sweden)
Krugljak Z. I.
2015-02-01
Full Text Available The article presents the main types and stages of tax analysis at the micro level. The authors analyze the sources are specified taxation. This article describes the general principles of economic analysis and the characteristics of their applications in order to analyze the tax. It was found that the analysis of the taxation organization should be carried out in three areas: the analysis of tax payments; analysis of arrears of taxes and levies; analysis of the tax load. Much attention is paid to the analysis of the tax load of the economic subject. The author presents the results of research the concept of "tax load". The article provides its scientifically based definition: a set of complementary indicators, both quantitatively and qualitatively characterizing the effect of mandatory payments of tax nature, levied in the budget of the Russian Federation, on the financial position of the economic entity. It was found that the composition of the tax load includes indicators that on the scale of application can be divided into public and private. The authors describe in detail the procedure for finding, sat the time lag for which it is advisable to determine the tax load of the economic entity. The authors delineate the scope of application of the tax load in the financial analysis of the economic subject
Uniformity pattern and related criteria for two-level factorials
Institute of Scientific and Technical Information of China (English)
FANG; Kaitai; QIN; Hong
2005-01-01
In this paper,the study of projection properties of two-level factorials in view of geometry is reported.The concept of uniformity pattern is defined.Based on this new concept,criteria of uniformity resolution and minimum projection uniformity are proposed for comparing two-level factorials.Relationship between minimum projection uniformity and other criteria such as minimum aberration,generalized minimum aberration and orthogonality is made explict.This close relationship raises the hope of improving the connection between uniform design theory and factorial design theory.Our results provide a justification of orthogonality,minimum aberration,and generalized minimum aberration from a natural geometrical interpretation.
Model reduction of nonlinear systems subject to input disturbances
Ndoye, Ibrahima
2017-07-10
The method of convex optimization is used as a tool for model reduction of a class of nonlinear systems in the presence of disturbances. It is shown that under some conditions the nonlinear disturbed system can be approximated by a reduced order nonlinear system with similar disturbance-output properties to the original plant. The proposed model reduction strategy preserves the nonlinearity and the input disturbance nature of the model. It guarantees a sufficiently small error between the outputs of the original and the reduced-order systems, and also maintains the properties of input-to-state stability. The matrices of the reduced order system are given in terms of a set of linear matrix inequalities (LMIs). The paper concludes with a demonstration of the proposed approach on model reduction of a nonlinear electronic circuit with additive disturbances.
Electroretinography in healthy subjects in relation to systemic glucocorticoid intake
DEFF Research Database (Denmark)
Kappelgaard, Per; Hansen, Katrine B; Vilsbøll, Tina;
2012-01-01
-caloric diet and by the reduction of physical activity. Full-field electroretinography (ffERG) demonstrated no significant change (P ....011) and post-prandial glycemia (P = 0.023). We conclude that prednisolone had no detectable effect on the ffERG in healthy lean men in this study. Retinal function may be less sensitive to changes in glycemia in healthy subjects than in people with diabetes, a characteristic that was unchanged by a short...... to clamped hyperglycemia, neither before, nor after prednisolone (P > 0.05). The stability of ffERG performance in the face of shifting glycemia levels, which differs from what has been found in diabetes, was not influenced by the mild diabetogenic effect of the intervention on insulin resistance (P = 0...
A Comprehensive Guide to Factorial Two-Level Experimentation
Mee, Robert
2009-01-01
Statistical design of experiments is useful in virtually every quantitative field. This book focuses on two-level factorial designs that provide efficient plans for exploring the effects of many factors at once. It is suitable for engineers, physical scientists, and those who conduct experiments.
Experiments of Two-level Training in Hungarian Higher Education
Korcsog, Andras; And Others
1977-01-01
An experiment designed to train engineering students to two levels of achievement in three-year and five-year programs within a single institution is reported. Organizational and curricular problems created by such integrated schemes are examined. (Author/LBH)
THE TWO-LEVEL MODEL AT FINITE-TEMPERATURE
Energy Technology Data Exchange (ETDEWEB)
Goodman, A.L.
1980-07-01
The finite-temperature HFB cranking equations are solved for the two-level model. The pair gap, moment of inertia and internal energy are determined as functions of spin and temperature. Thermal excitations and rotations collaborate to destroy the pair correlations. Raising the temperature eliminates the backbending effect and improves the HFB approximation.
Robust Control for Uncertain Linear System Subject to Input Saturation
Directory of Open Access Journals (Sweden)
Qingyun Yang
2014-01-01
Full Text Available A robust control scheme using composite nonlinear feedback (CNF technology is proposed to improve tracking control performance for the uncertain linear system with input saturation and unknown external disturbances. A disturbance observer is presented to estimate the unknown disturbance generated by a linear exogenous system. The designed gain matrix of the disturbance observer is determined by solving linear matrix inequalities (LMIs. Based on the output of the designed disturbance observer, a robust CNF controller including a linear feedback control item and a nonlinear item is developed to follow the desired tracking signals. The linear feedback controller is designed using LMIs and the stability of the closed-loop system is proved via rigorous Lyapunov analysis. Finally, the extensive simulation results are presented to illustrate the effectiveness of the proposed control scheme.
SIMPLE: System Automatic Essay Assessment for Indonesian Language Subject Examination
Directory of Open Access Journals (Sweden)
Anak Agung Ratna
2010-10-01
Full Text Available Evaluation of study of a student is a very important aspect of an educational process. Evaluation is aimed at measuring the level of student understanding of the given lecture materials. Measuring student understanding of the course material, using essay-type exam, is generally used as the evaluation tool. In this essay-type exam, the student has to answer questions using sentences, whereby choices of possible answers are not indicated. The student has to answer the questions with his/her sentences. The answers may vary, since it reflects the student's thoughts of the materials. One of the weaknesses of essay-type exam is the difficulty to grade the answers and it tends to be time consuming. Currently, automatic grading systems that may speed up the grading process, are being developed in many research institutions.The method used to grade, varies zorm one system to another, and one of the popular system is he Latent Semantic Analysis (LSA. LSA is a method of grading essay by extracting words and representing the sentence in the form of mathematical or statistical formulation, from a text with a relatively large number of words. The grade of the essay is determined, by matching the important words to a group of words prepared by the human rater. This paper describes an effort to developed LSA, enhanced with word weighting, word order and the word synonym to improve the accuracy of grading. This system is called SIMPLE. SIMPLE is used to grade answers using bahasa Indonesia. The exam is carried out on-line through the Web. From the experiments conducted, for small classes, the conformity of grade compared to the grade of human rater lies between 69.80 % - 94.64 %, and for medium size classes the conformity lies between 77.18 % - 98.42 % with the human rater. These results are roughly proportional with the result of LSA system, which grade essay given in English.
System Identification using Measurements Subject to Stochastic Time Jitter
2004-01-01
When the sensors readings are perturbed by an unknown stochastic time jitter, classical system identification algorithms based on additive amplitude perturbations will give biased estimates. We here outline the maximum likelihood procedure, for the case of both time and amplitude noise, in the frequency domain, based on the measurement DFT. The method directly applies to output error continuous time models, while a simple sinusoid in noise example is used to illustrate the bias removal of the...
Clustering DTDs: An Interactive Two-Level Approach
Institute of Scientific and Technical Information of China (English)
周傲英; 钱卫宁; 钱海蕾; 张龙; 梁宇奇; 金文
2002-01-01
XML (eXtensible Markup Language) is a standard which is widely appliedin data representation and data exchange. However, as an important concept of XML, DTD(Document Type Definition) is not taken full advantage in current applications. In this paper, anew method for clustering DTDs is presented, and it can be used in XML document clustering.The two-level method clusters the elements in DTDs and clusters DTDs separately. Elementclustering forms the first level and provides element clusters, which are the generalization ofrelevant elements. DTD clustering utilizes the generalized information and forms the secondlevel in the whole clustering process. The two-level method has the following advantages: 1) Ittakes into consideration both the content and the structure within DTDs; 2) The generalizedinformation about elements is more useful than the separated words in the vector model; 3) Thetwo-level method facilitates the searching of outliers. The experiments show that this methodis able to categorize the relevant DTDs effectively.
Two-level method with coarse space size independent convergence
Energy Technology Data Exchange (ETDEWEB)
Vanek, P.; Brezina, M. [Univ. of Colorado, Denver, CO (United States); Tezaur, R.; Krizkova, J. [UWB, Plzen (Czech Republic)
1996-12-31
The basic disadvantage of the standard two-level method is the strong dependence of its convergence rate on the size of the coarse-level problem. In order to obtain the optimal convergence result, one is limited to using a coarse space which is only a few times smaller than the size of the fine-level one. Consequently, the asymptotic cost of the resulting method is the same as in the case of using a coarse-level solver for the original problem. Today`s two-level domain decomposition methods typically offer an improvement by yielding a rate of convergence which depends on the ratio of fine and coarse level only polylogarithmically. However, these methods require the use of local subdomain solvers for which straightforward application of iterative methods is problematic, while the usual application of direct solvers is expensive. We suggest a method diminishing significantly these difficulties.
A two level DEA in project based organizations
Directory of Open Access Journals (Sweden)
Mehrdad Hamidi Hedayat
2012-01-01
Full Text Available This paper presents a systematic approach for evaluating the performance of a project based organization using a two level fuzzy data envelopment analysis (DEA technique in project based organizations. In order to determine the required inputs and outputs, important indicators are selected using both expert judgments and statistical analysis and a two-level DEA model is adapted. In this model, by considering different inputs and outputs through a hierarchical process, a large number of sub indicators are provided and rolled up to a higher level. Since inputs and outputs are combinations of qualitative and quantitative indicators, fuzzy logic is also included through the modeling procedure. In addition, since the exact amount cannot be attributed to the indicators, the proposed model uses interval values for the project life cycle. Finally, some of the projects are evaluated throughout the approach proposed in this paper.
Micro- and macrostresses in two level model of coating growth
N. N. Nazarenko; Knyazeva, Anna Georgievna
2014-01-01
In the work, a two level model of coating growing with the diffusion and chemical compounds formation is proposed. The process of coating formation includes different physico-chemical steps and transformations of the structure. From the experiments it was established that the coating consists of the following substances: 4+ titanium oxide, titanium pyrophosphate, calcium pyrophosphate, calcium titanophosphate. Coating growth rate is determined by the deposition rate and the dispersion of the ...
Two-level leader-follower organization in pigeon flocks
Chen, Zhiyong; Zhang, Hai-Tao; Chen, Xi; Chen, Duxin; Zhou, Tao
2015-10-01
The most attractive trait of collective animal behavior is the emergence of highly ordered structures (Cavagna A., Giardina I. and Ginelli F., Phys. Rev. Lett., 110 (2013) 168107). It has been conjectured that the interaction mechanism in pigeon flock dynamics follows a hierarchical leader-follower influential network (Nagy M., Ákos Z., Biro D. and Vicsek T., Nature, 464 (2010) 890). In this paper, a new observation is reported that shows that pigeon flocks actually adopt a much simpler two-level interactive network composed of one leader and some followers. By statistically analyzing the same experimental dataset, we show that for a certain period of time a sole leader determines the motion of the flock while the remaining birds are all followers directly copying the leader's direction with specific time delays. This simple two-level despotic organization is expected to save both motional energy and communication cost, while retaining agility and robustness of the whole group. From an evolutionary perspective, our results suggest that a two-level organization of group flight may be more efficient than a multilevel topology for small pigeon flocks.
Users' subjective evaluation of electronic vision enhancement systems.
Culham, Louise E; Chabra, Anthony; Rubin, Gary S
2009-03-01
The aims of this study were (1) to elicit the users' responses to four electronic head-mounted devices (Jordy, Flipperport, Maxport and NuVision) and (2) to correlate users' opinion with performance. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used these electronic vision enhancement systems (EVESs) for a variety of visual tasks. A questionnaire designed in-house and a modified VF-14 were used to evaluate the responses. Following initial experience of the devices in the laboratory, every patient took home two of the four devices for 1 week each. Responses were re-evaluated after this period of home loan. No single EVES stood out as the strong preference for all aspects evaluated. In the laboratory-based appraisal, Flipperport typically received the best overall ratings and highest score for image quality and ability to magnify, but after home loan there was no significant difference between devices. Comfort of device, although important, was not predictive of rating once magnification had been taken into account. For actual performance, a threshold effect was seen whereby ratings increased as reading speed improved up to 60 words per minute. Newly diagnosed patients responded most positively to EVESs, but otherwise users' opinion could not be predicted by age, gender, diagnosis or previous CCTV experience. User feedback is essential in our quest to understand the benefits and shortcoming of EVESs. Such information should help guide both prescribing and future development of low vision devices.
The Research on Coordinated Decision-Making Method Tax System Based on Subject Data
Directory of Open Access Journals (Sweden)
Zhaoji Yu
2015-01-01
Full Text Available Academically, the research of subject database of tax system aims to set up an efficient, harmonious virtual data application environment. Subject data, in application and management, has been on demand polymerized and autonomously collaborated and has reached a balance between instantaneity and accuracy. This paper defines the connotation and characteristics enterprise informationization, designs a value system of enterprise informationization which is subject database oriented, and builds a model for the import of the subject database of enterprise informationization. Meantime, this paper describes the structure of the subject database based information import model and forges the model’s theoretical basis of subject data import in tax system. Using the model can make an analysis on the information of data warehouse, storage information, and tax information to provide decision support for the tax administrators.
Two-Level Stabilized Finite Volume Methods for Stationary Navier-Stokes Equations
Directory of Open Access Journals (Sweden)
Anas Rachid
2012-01-01
Full Text Available We propose two algorithms of two-level methods for resolving the nonlinearity in the stabilized finite volume approximation of the Navier-Stokes equations describing the equilibrium flow of a viscous, incompressible fluid. A macroelement condition is introduced for constructing the local stabilized finite volume element formulation. Moreover the two-level methods consist of solving a small nonlinear system on the coarse mesh and then solving a linear system on the fine mesh. The error analysis shows that the two-level stabilized finite volume element method provides an approximate solution with the convergence rate of the same order as the usual stabilized finite volume element solution solving the Navier-Stokes equations on a fine mesh for a related choice of mesh widths.
Open-Loop Control in Quantum Optics: Two-Level Atom in Modulated Optical Field
Saifullah, Sergei
2008-01-01
The methods of mathematical control theory are widely used in the modern physics, but still they are less popular in quantum science. We will discuss the aspects of control theory, which are the most useful in applications to the real problems of quantum optics. We apply this technique to control the behavior of the two-level quantum particles (atoms) in the modulated external optical field in the frame of the so called "semi classical model", where quantum two-level atomic system (all other levels are neglected) interacts with classical electromagnetic field. In this paper we propose a simple model of feedforward (open-loop) control for the quantum particle system, which is a basement for further investigation of two-level quantum particle in the external one-dimensional optical field.
Performance of a Two-Level Call Admission Control Scheme for DS-CDMA Wireless Networks
Directory of Open Access Journals (Sweden)
Abraham O. Fapojuwo
2007-11-01
Full Text Available We propose a two-level call admission control (CAC scheme for direct sequence code division multiple access (DS-CDMA wireless networks supporting multimedia traffic and evaluate its performance. The first-level admission control assigns higher priority to real-time calls (also referred to as class 0 calls in gaining access to the system resources. The second level admits nonreal-time calls (or class 1 calls based on the resources remaining after meeting the resource needs for real-time calls. However, to ensure some minimum level of performance for nonreal-time calls, the scheme reserves some resources for such calls. The proposed two-level CAC scheme utilizes the delay-tolerant characteristic of non-real-time calls by incorporating a queue to temporarily store those that cannot be assigned resources at the time of initial access. We analyze and evaluate the call blocking, outage probability, throughput, and average queuing delay performance of the proposed two-level CAC scheme using Markov chain theory. The analytic results are validated by simulation results. The numerical results show that the proposed two-level CAC scheme provides better performance than the single-level CAC scheme. Based on these results, it is concluded that the proposed two-level CAC scheme serves as a good solution for supporting multimedia applications in DS-CDMA wireless communication systems.
Performance of a Two-Level Call Admission Control Scheme for DS-CDMA Wireless Networks
Directory of Open Access Journals (Sweden)
Fapojuwo Abraham O
2007-01-01
Full Text Available We propose a two-level call admission control (CAC scheme for direct sequence code division multiple access (DS-CDMA wireless networks supporting multimedia traffic and evaluate its performance. The first-level admission control assigns higher priority to real-time calls (also referred to as class 0 calls in gaining access to the system resources. The second level admits nonreal-time calls (or class 1 calls based on the resources remaining after meeting the resource needs for real-time calls. However, to ensure some minimum level of performance for nonreal-time calls, the scheme reserves some resources for such calls. The proposed two-level CAC scheme utilizes the delay-tolerant characteristic of non-real-time calls by incorporating a queue to temporarily store those that cannot be assigned resources at the time of initial access. We analyze and evaluate the call blocking, outage probability, throughput, and average queuing delay performance of the proposed two-level CAC scheme using Markov chain theory. The analytic results are validated by simulation results. The numerical results show that the proposed two-level CAC scheme provides better performance than the single-level CAC scheme. Based on these results, it is concluded that the proposed two-level CAC scheme serves as a good solution for supporting multimedia applications in DS-CDMA wireless communication systems.
Subject,Object and Target Systems of Rural Human Resource Development
Institute of Scientific and Technical Information of China (English)
2012-01-01
From subject,object and target subsystems,we analyze the rural human resource development system.The subject system includes government,education and training organizations,society,and rural human resource itself.Different development subject bears different responsibility.Object system includes farmers engaged in farming,farmer workers,rural unemployed people,rural students,rural left-behind people,and other people in rural areas.Different development object has different features.Development target system includes raising quality of rural human resource,keeping reasonable population size,optimizing structure of rural human resource,and improving vitality of rural human resource,etc.
Hanford Environmental Information System (HEIS). Volume 3, Subject Area reference manual
Energy Technology Data Exchange (ETDEWEB)
Schreck, R.I.
1994-01-14
The Hanford Environmental Information System (HEIS) Subject Area manuals are designed as reference guides, that is, each chapter provides the information needed to make best use of each subject area, its tables, and reporting capabilities. Each subject area is documented in a chapter in one of the subject area manuals. Because these are reference manuals, most of the information is also available in the online help system as well. See Section 5.4.2 of the HEIS User`s Guide (DOE-RL 1994a) for a detailed description of the online help.
Hanford Environmental Information System (HEIS). Volume 3, Subject Area reference manual
Energy Technology Data Exchange (ETDEWEB)
Schreck, R.I.
1994-01-14
The Hanford Environmental Information System (HEIS) Subject Area manuals are designed as reference guides, that is, each chapter provides the information needed to make best use of each subject area, its tables, and reporting capabilities. Each subject area is documented in a chapter in one of the subject area manuals. Because these are reference manuals, most of the information is also available in the online help system as well. See Section 5.4.2 of the HEIS User`s Guide (DOE-RL 1994a) for a detailed description of the online help.
A Two-Level Method for Nonsymmetric Eigenvalue Problems
Institute of Scientific and Technical Information of China (English)
Karel Kolman
2005-01-01
A two-level discretization method for eigenvalue problems is studied. Compared to the standard Galerkin finite element discretization technique performed on a fine grid this method discretizes the eigenvalue problem on a coarse grid and obtains an improved eigenvector (eigenvalue) approximation by solving only a linear problem on the fine grid (or two linear problems for the case of eigenvalue approximation of nonsymmetric problems). The improved solution has the asymptotic accuracy of the Galerkin discretization solution. The link between the method and the iterated Galerkin method is established. Error estimates for the general nonsymmetric case are derived.
Negative spontaneous emission by a moving two-level atom
Lannebère, Sylvain; Silveirinha, Mário G.
2017-01-01
In this paper we investigate how the dynamics of a two-level atom is affected by its interaction with the quantized near field of a plasmonic slab in relative motion. We demonstrate that for small separation distances and a relative velocity greater than a certain threshold, this interaction can lead to a population inversion, such that the probability of the excited state exceeds the probability of the ground state, corresponding to a negative spontaneous emission rate. It is shown that the developed theory is intimately related to a classical problem. The problem of quantum friction is analyzed and the differences with respect to the corresponding classical effect are highlighted.
Institute of Scientific and Technical Information of China (English)
GE Jian(葛坚); HOKAO Kazunori
2004-01-01
In this research, the residential environment index system and evaluation model were established by means of subjective and objective methods. The methodology for establishing the evaluation system for residential environment was first analyzed; then the subjective evaluation data-base was established by questionnaire survey; and at the same time, the objective evaluation data-base was constructed by Geographic Information System (GIS); and then the related equation system between subjective and objective system was developed by multiple regression analysis. This research could benefit evaluation of the residential environment quality for various purposes, and also provide important rudimentary data-base for the development and improvement of residential environment for officials. Furthermore, the index system and evaluation model established in this research could construct a strong relation between subjective evaluation and objective data; and thus could provide a comprehensive, efficient and effective methodology for the evaluation of residential environment.
Two-level hierarchical feature learning for image classification
Institute of Scientific and Technical Information of China (English)
Guang-hui SONG; Xiao-gang JIN; Gen-lang CHEN; Yan NIE
2016-01-01
In some image classifi cation tasks, similarities among different categories are different and the samples are usually misclassifi ed as highly similar categories. To distinguish highly similar categories, more specifi c features are required so that the classifi er can improve the classifi cation performance. In this paper, we propose a novel two-level hierarchical feature learning framework based on the deep convolutional neural network (CNN), which is simple and effective. First, the deep feature extractors of different levels are trained using the transfer learning method that fi ne-tunes the pre-trained deep CNN model toward the new target dataset. Second, the general feature extracted from all the categories and the specifi c feature extracted from highly similar categories are fused into a feature vector. Then the fi nal feature representation is fed into a linear classifi er. Finally, experiments using the Caltech-256, Oxford Flower-102, and Tasmania Coral Point Count (CPC) datasets demonstrate that the expression ability of the deep features resulting from two-level hierarchical feature learning is powerful. Our proposed method effectively increases the classifi cation accuracy in comparison with fl at multiple classifi cation methods.
Eigenmode expansion of the polarization for a spherical sample of two-level atoms
Energy Technology Data Exchange (ETDEWEB)
Friedberg, Richard [Physics Department, Columbia University, New York, NY 10027 (United States); Manassah, Jamal T., E-mail: jmanassah@gmail.co [HMS Consultants, Inc., PO Box 592, New York, NY 10028 (United States)
2009-12-07
We derive pseudo-orthogonality relations for both the magnetic and electric eigenmodes of a system of two-level atoms in a sphere configuration. We verify numerically that an arbitrary vector field can be reconstructed to a great accuracy from these eigenmode expansions. We apply this eigenmode analysis to explore superradiance from a sphere with initially uniform polarization.
Systems, Subjects, Sessions: To What Extent Do These Factors Influence EEG Data?
Melnik, Andrew; Legkov, Petr; Izdebski, Krzysztof; Kärcher, Silke M.; Hairston, W. David; Ferris, Daniel P.; König, Peter
2017-01-01
Lab-based electroencephalography (EEG) techniques have matured over decades of research and can produce high-quality scientific data. It is often assumed that the specific choice of EEG system has limited impact on the data and does not add variance to the results. However, many low cost and mobile EEG systems are now available, and there is some doubt as to the how EEG data vary across these newer systems. We sought to determine how variance across systems compares to variance across subjects or repeated sessions. We tested four EEG systems: two standard research-grade systems, one system designed for mobile use with dry electrodes, and an affordable mobile system with a lower channel count. We recorded four subjects three times with each of the four EEG systems. This setup allowed us to assess the influence of all three factors on the variance of data. Subjects performed a battery of six short standard EEG paradigms based on event-related potentials (ERPs) and steady-state visually evoked potential (SSVEP). Results demonstrated that subjects account for 32% of the variance, systems for 9% of the variance, and repeated sessions for each subject-system combination for 1% of the variance. In most lab-based EEG research, the number of subjects per study typically ranges from 10 to 20, and error of uncertainty in estimates of the mean (like ERP) will improve by the square root of the number of subjects. As a result, the variance due to EEG system (9%) is of the same order of magnitude as variance due to subjects (32%/sqrt(16) = 8%) with a pool of 16 subjects. The two standard research-grade EEG systems had no significantly different means from each other across all paradigms. However, the two other EEG systems demonstrated different mean values from one or both of the two standard research-grade EEG systems in at least half of the paradigms. In addition to providing specific estimates of the variability across EEG systems, subjects, and repeated sessions, we also
Systems, Subjects, Sessions: To What Extent Do These Factors Influence EEG Data?
Melnik, Andrew; Legkov, Petr; Izdebski, Krzysztof; Kärcher, Silke M; Hairston, W David; Ferris, Daniel P; König, Peter
2017-01-01
Lab-based electroencephalography (EEG) techniques have matured over decades of research and can produce high-quality scientific data. It is often assumed that the specific choice of EEG system has limited impact on the data and does not add variance to the results. However, many low cost and mobile EEG systems are now available, and there is some doubt as to the how EEG data vary across these newer systems. We sought to determine how variance across systems compares to variance across subjects or repeated sessions. We tested four EEG systems: two standard research-grade systems, one system designed for mobile use with dry electrodes, and an affordable mobile system with a lower channel count. We recorded four subjects three times with each of the four EEG systems. This setup allowed us to assess the influence of all three factors on the variance of data. Subjects performed a battery of six short standard EEG paradigms based on event-related potentials (ERPs) and steady-state visually evoked potential (SSVEP). Results demonstrated that subjects account for 32% of the variance, systems for 9% of the variance, and repeated sessions for each subject-system combination for 1% of the variance. In most lab-based EEG research, the number of subjects per study typically ranges from 10 to 20, and error of uncertainty in estimates of the mean (like ERP) will improve by the square root of the number of subjects. As a result, the variance due to EEG system (9%) is of the same order of magnitude as variance due to subjects (32%/sqrt(16) = 8%) with a pool of 16 subjects. The two standard research-grade EEG systems had no significantly different means from each other across all paradigms. However, the two other EEG systems demonstrated different mean values from one or both of the two standard research-grade EEG systems in at least half of the paradigms. In addition to providing specific estimates of the variability across EEG systems, subjects, and repeated sessions, we also
Directory of Open Access Journals (Sweden)
Ayse KOCALMIS BILHAN
2013-01-01
Full Text Available A space vector PWM method for a two level inverter is proposed in this paper. A two level inverter using space vector modulation strategy has been modeled and simulated with a passive R-L load. Photovoltaic cells are used as DC source for input of two-level inverter. Simulation results are presented for various operation conditions to verify the system model. In this paper, MATLAB/Simulink package program has been used for modeling and simulation of PV cells and two-level space vector pulse width modulation (SVPWM inverter.
42 CFR 419.21 - Hospital outpatient services subject to the outpatient prospective payment system.
2010-10-01
... 42 Public Health 3 2010-10-01 2010-10-01 false Hospital outpatient services subject to the... FOR HOSPITAL OUTPATIENT DEPARTMENT SERVICES Categories of Hospitals and Services Subject to and Excluded From the Hospital Outpatient Prospective Payment System § 419.21 Hospital outpatient services...
Rabi noise spectroscopy of individual two-level tunneling defects
Matityahu, Shlomi; Lisenfeld, Jürgen; Bilmes, Alexander; Shnirman, Alexander; Weiss, Georg; Ustinov, Alexey V.; Schechter, Moshe
2017-06-01
Understanding the nature of two-level tunneling defects is important for minimizing their disruptive effects in various nanodevices. By exploiting the resonant coupling of these defects to a superconducting qubit, one can probe and coherently manipulate them individually. In this work, we utilize a phase qubit to induce Rabi oscillations of single tunneling defects and measure their dephasing rates as a function of the defect's asymmetry energy, which is tuned by an applied strain. The dephasing rates scale quadratically with the external strain and are inversely proportional to the Rabi frequency. These results are analyzed and explained within a model of interacting defects, in which pure dephasing of coherent high-frequency (gigahertz) defects is caused by interaction with incoherent low-frequency thermally excited defects. Our analysis sets an upper bound for the relaxation rates of thermally excited defects interacting strongly with strain fields.
Collective polaritonic modes in an array of two-level quantum emitters coupled to optical nanofiber
Kornovan, D F; Petrov, M I
2016-01-01
In this paper we develop a microscopic analysis of the light scattering on a periodic two-level atomic array coupled to an optical nanofiber. We extend the scattering matrix approach for two-level system interaction with nanofiber fundamental waveguiding mode HE_{11}, that allows us modeling the scattering spectra. We support these results considering the dispersion of the polaritonic states formed by the superposition of the fundamental mode of light HE_{11} and the atomic chain states. To illustrate our approach we start with considering a simple model of light scattering over atomic array in the free space. We discuss the Bragg diffraction at the atomic array and show that the scattering spectrum is defined by the non-symmetric coupling of two-level system with nanofiber and vacuum modes. The proposed method allows considering two-level systems interaction with full account for dipole-dipole interaction both via near fields and long-range interaction owing to nanofiber mode coupling.
Running interfacial waves in two-layer fluid system subject to longitudinal vibrations
Goldobin, Denis S.; Pimenova, Anastasiya V.; Kovalevskaya, Kseniya V.; Lyubimov, Dmitry V.; Lyubimova, Tatyana P.
2014-01-01
We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasi-stationary states of free interface in fluid dynamical systems subject to vibrations, revealed existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary proble...
The Living Logical System Paradigm (SLV) – Economic Process and Economic Subject
2012-01-01
The Paradigm of the Living Logical System (LLS) puts into debate the logical and ontological bases of the orthodox economic models concerning the knowledge of the economic processes. The restraining of the living logical system concept operates with a series of new concepts concerning the subject. Within the current material we attempt to define the concept of economic process, and to define the concept of economic subject. Aside from this endeavor we also consider to define the following con...
Institute of Scientific and Technical Information of China (English)
李宏朝; 胡文娟; 王百军; 陈举民; 王晓静
2016-01-01
In order to ensure stable exploitation of oil, combined with CaiNan Oilfield ac-tual production, taking into account the external environment of the scene, we designed two level distributed automation systems. The system controller uses the well 16 monolithic INTEL 80C196 microcontroller circuit as the core monitoring and control, access to the wellhead temperature and pressure data acquisition via standard signal transmitter. Based on the principle of circuit design and control software design method,developed primarily mod-ular applications. By applying concluded: power factor follower method can achieve signifi-cant energy- saving effect,the modular controller program easy to modify and transplant,to achieve a cost-effective extraction of automated control systems.%为了确保油田稳定开采，结合彩南油田的实际生产情况，考虑外界现场环境，设计了两级分布式采油自动化系统。该系统中油井控制器采用Intel十六位单片机80C196作为测控核心，通过采集变送器标准信号获得井口温度及压力等数据。基于电路设计原理及控制软件设计方法，开发了主要的模块化应用程序。通过应用得出结论：采用功率因数随动技术节电效果显著，模块化控制器程序易于修改和移植，实现了采油自动化控制系统的低成本高效率。
CONSENSUS FORMATION OF TWO-LEVEL OPINION DYNAMICS
Institute of Scientific and Technical Information of China (English)
Yilun SHANG
2014-01-01
Opinion dynamics have received significant attention in recent years. This pa-per proposes a bounded confidence opinion model for a group of agents with two different confidence levels. Each agent in the population is endowed with a confidence interval around her opinion with radius αd or (1-α)d, where α ∈ (0, 1/2] represents the differentiation of confidence levels. We analytically derived the critical confidence bound dc =1/(4α) for the two-level opinion dynamics on Z. A single opinion cluster is formed with probability 1 above this critical value regardless of the ratio p of agents with high/low confidence. Extensive numerical simulations are performed to illustrate our theoretical results. Noticed is a clear impact of p on the collective behavior: more agents with high confidence lead to harder agreement. It is also experimentally revealed that the sharpness of the threshold dc increases with αbut does not depend on p.
An overview of coordinated control for multi-agent systems subject to input saturation
Directory of Open Access Journals (Sweden)
Xiaoling Wang
2016-03-01
Full Text Available Coordinated control of multi-agent systems has widespread application in engineering such as unmanned aerial vehicles and unmanned ground vehicles. Due to the fact that input saturation can lead a control system to deterioration and instability, a lot of efforts have been devoted to investigating this subject of great importance. The present article offers a survey of recent developments on coordinated control of multi-agents systems subject to input saturation. Some preliminaries about graph theory, stability theory and input saturation are first provided, followed by some important results in the area, which are categorized into semi-global and global coordinated controls. Future research topics are finally discussed.
40 CFR 141.510 - Is my system subject to the new finished water reservoir requirements?
2010-07-01
... finished water reservoir requirements? 141.510 Section 141.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced... my system subject to the new finished water reservoir requirements? All subpart H systems which...
Welfare Systems, Support Networks and Subjective Well-Being among Retired Persons
Requena, Felix
2010-01-01
In this article welfare systems and support networks are empirically analyzed to determine which generate the highest level of subjective well-being among retired persons. Propositions derived from support network theories and national welfare system typologies have been analyzed using causal models that indicate the influence of the various…
Hanford Environmental Information System (HEIS). Volume 5, Surface-based subject areas
Energy Technology Data Exchange (ETDEWEB)
1994-01-14
The purpose of the Biota subject area of the Hanford Environmental Information System (HEIS) is to manage the data collected from samples of plants and animals. This includes both samples taken from the plant or animal or samples related to the plant or animal. Related samples include animal feces and animal habitat. Data stored in the Biota subject area include data about the biota samples taken, analysis results counts from population studies, and species distribution maps.
A DISCRETE TIME TWO-LEVEL MIXED SERVICE PARALLEL POLLING MODEL
Institute of Scientific and Technical Information of China (English)
Guan Zheng; Zhao Dongfeng; Zhao Yifan
2012-01-01
We present a discrete time single-server two-level mixed service polling systems with two queue types,one center queue and N normal queues.Two-level means the center queue will be successive served after each normal queue.In the first level,server visits between the center queue and the normal queue.In the second level,normal queues are polled by a cyclic order.Mixed service means the service discipline are exhaustive for center queue,and parallel i-limited for normal queues.We propose an imbedded Markov chain framework to drive the closed-form expressions for the mean cycle time,mean queue length,and mean waiting time.Numerical examples demonstrate that theoretical and simulation results are identical the new system efficiently differentiates priorities.
Effect of Metaboreflex on Cardiovascular System in Subjects of Metabolic Syndrome.
Dubey, Pramita; Tiwari, Sunita; Bajpai, Manish; Singh, Kalpana; Jha, Praveen
2017-07-01
Metaboreflex is a reflex in which muscle receptors send signals regarding metabolic (metabolites accumulation like lactic acid, potassium, adenosine) conditions of the muscles to nucleus tractus solitarius via afferent III and IV fibres to cause haemodynamic adjustments in order to regulate blood flow on the basis of the status of contracting muscle. Dysregulation in its mechanism in metabolic syndrome is demonstrated. To study the effect of metaboreflex by both isometric and rhythmic handgrip exercise on CVS parameters {Blood Pressure (BP), Cardiac Output (CO) and Systemic Vascular Resistance (SVR)} in subjects of metabolic syndrome. In this study, 27 subjects aged 25 to 45 years were enrolled after ethical clearance and proper consent. They were divided into: a) subjects without metabolic syndrome; and b) subjects with metabolic syndrome. Impedance cardiovasography was done to assess cardiac parameters (systolic and diastolic blood pressure, cardiac output, systemic vascular resistance). Pre-exercise parameters were assessed followed by isometric exercise and post-isometric exercise parameter measurement. Again after rest, rhythmic exercise was followed. Finally post exercise parameters were assessed. Student paired t-test for comparison between pre and post exercise parameters were done. Changes in diastolic BP following exercise were statistically significant in subjects without metabolic syndrome (p-value 0.01 and 0.001 following isometric and rhythmic exercise respectively). In subjects with metabolic syndrome also these changes were significant, but to a lesser extent (p-value 0.1 and 0.01 respectively for isometric and rhythmic exercise). Changes in systolic BP following exercise were statistically significant in subjects without metabolic syndrome (p-value 0.001 and 0.001 following isometric and rhythmic exercise respectively). In subjects with metabolic syndrome also these changes were significant (p-value 0.01 and 0.001 respectively for isometric and
Some studies of the interaction between N-two level atoms and three level atom
Directory of Open Access Journals (Sweden)
D.A.M. Abo-Kahla
2016-07-01
Full Text Available In this paper, we present the analytical solution for the model that describes the interaction between a three level atom and two systems of N-two level atoms. The effect of the quantum numbers on the atomic inversion and the purity, for some special cases of the initial states, are investigated. We observe that the atomic inversion and the purity change remarkably by the change of the quantum numbers.
Directory of Open Access Journals (Sweden)
Dolean Victorita
2014-07-01
Full Text Available Multiphase, compositional porous media flow models lead to the solution of highly heterogeneous systems of Partial Differential Equations (PDE. We focus on overlapping Schwarz type methods on parallel computers and on multiscale methods. We present a coarse space [Nataf F., Xiang H., Dolean V., Spillane N. (2011 SIAM J. Sci. Comput. 33, 4, 1623-1642] that is robust even when there are such heterogeneities. The two-level domain decomposition approach is compared to multiscale methods.
Coupling of effective one-dimensional two-level atoms to squeezed light
Clark, S; Clark, Stephen; Parkins, Scott
2002-01-01
A cavity QED system is analyzed which duplicates the dynamics of a two-level atom in free space interacting exclusively with broadband squeezed light. We consider atoms in a three or four-level Lambda-configuration coupled to a high-finesse optical cavity which is driven by a squeezed light field. Raman transitions are induced between a pair of stable atomic ground states via the squeezed cavity mode and coherent driving fields. An analysis of the reduced master equation for the atomic ground states shows that a three-level atomic system has insufficient parameter flexibility to act as an effective two-level atom interacting exclusively with a squeezed reservoir. However, the inclusion of a fourth atomic level, coupled dispersively to one of the two ground states by an auxiliary laser field, introduces an extra degree of freedom and enables the desired interaction to be realised. As a means of detecting the reduced quadrature decay rate of the effective two-level system, we examine the transmission spectrum o...
Keller, J. Y.; Chabir, K.; Sauter, D.
2016-03-01
State estimation of stochastic discrete-time linear systems subject to unknown inputs or constant biases has been widely studied but no work has been dedicated to the case where a disturbance switches between unknown input and constant bias. We show that such disturbance can affect a networked control system subject to deception attacks and data losses on the control signals transmitted by the controller to the plant. This paper proposes to estimate the switching disturbance from an augmented state version of the intermittent unknown input Kalman filter recently developed by the authors. Sufficient stochastic stability conditions are established when the arrival binary sequence of data losses follows a Bernoulli random process.
Pilkey, W. D.; Wang, B. P.; Yoo, Y.; Clark, B.
1973-01-01
A description and applications of a computer capability for determining the ultimate optimal behavior of a dynamically loaded structural-mechanical system are presented. This capability provides characteristics of the theoretically best, or limiting, design concept according to response criteria dictated by design requirements. Equations of motion of the system in first or second order form include incompletely specified elements whose characteristics are determined in the optimization of one or more performance indices subject to the response criteria in the form of constraints. The system is subject to deterministic transient inputs, and the computer capability is designed to operate with a large linear programming on-the-shelf software package which performs the desired optimization. The report contains user-oriented program documentation in engineering, problem-oriented form. Applications cover a wide variety of dynamics problems including those associated with such diverse configurations as a missile-silo system, impacting freight cars, and an aircraft ride control system.
High-voltage transmission tower-line system subjected to disaster loads
Institute of Scientific and Technical Information of China (English)
LI Hongnan; BAI Haifeng
2006-01-01
The high-voltage power transmission system is an important lifeline structure. It is significant for wide researches on the features and ability of the system subjected to earthquake and environmental loads. The promising prosperity of the system has been demonstrated around the world. The corresponding advances of the system with respect to the mechanism of loading action, analytical methods, experimental research measurements, structural vibration control, fatigue damage, lifetime prediction, and design methods are comprehensively discussed herein. Finally, further research work on dynamic response characteristics of high-voltage transmission towerline system in the near future is predicted.
Dynamic Responses of Long-Span Transmission Tower-Line System Subjected to Broken Wires
Institute of Scientific and Technical Information of China (English)
XIA Zheng-chun; LI Li; FANG Qin-han; LONG Xiao-hong
2008-01-01
A macroscopic finite element modeling approach was proposed to calculate the vibration of a tower-line system subjected to broken wires with software ANSYS/LS-DYNA. In the finite element model, not only the nonlinearity of wires and suspension insulators are considered, but also the support towers are included. The incremental and iterative approaches are combined by applying the unbalanced loads incrementally during each iteration cycle. The approach was illustrated with an example of a Hanjiang-River long-span transmission line system subjected to a shield wire and a conductor failure, respectively. The analysis results showed that the proposed dynamic simulation approach can demonstrate the kinetic process of the tower-line system subjected to wire ruptures: The frequencies of line components were lower and densely distributed, but the frequencies of tower components were higher and sparsely distributed. Anyhow, the dynamic effects of wire ruptures on tower-line system could not be ignored in analysis of tower-line system subjected wire failures.
Spherical subjective refraction with a novel 3D virtual reality based system.
Pujol, Jaume; Ondategui-Parra, Juan Carlos; Badiella, Llorenç; Otero, Carles; Vilaseca, Meritxell; Aldaba, Mikel
To conduct a clinical validation of a virtual reality-based experimental system that is able to assess the spherical subjective refraction simplifying the methodology of ocular refraction. For the agreement assessment, spherical refraction measurements were obtained from 104 eyes of 52 subjects using three different methods: subjectively with the experimental prototype (Subj.E) and the classical subjective refraction (Subj.C); and objectively with the WAM-5500 autorefractor (WAM). To evaluate precision (intra- and inter-observer variability) of each refractive tool independently, 26 eyes were measured in four occasions. With regard to agreement, the mean difference (±SD) for the spherical equivalent (M) between the new experimental subjective method (Subj.E) and the classical subjective refraction (Subj.C) was -0.034D (±0.454D). The corresponding 95% Limits of Agreement (LoA) were (-0.856D, 0.924D). In relation to precision, intra-observer mean difference for the M component was 0.034±0.195D for the Subj.C, 0.015±0.177D for the WAM and 0.072±0.197D for the Subj.E. Inter-observer variability showed worse precision values, although still clinically valid (below 0.25D) in all instruments. The spherical equivalent obtained with the new experimental system was precise and in good agreement with the classical subjective routine. The algorithm implemented in this new system and its optical configuration has been shown to be a first valid step for spherical error correction in a semiautomated way. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.
When Models Interact with their Subjects: The Dynamics of Model Aware Systems
Vural, Dervis Can
2011-01-01
A scientific model need not be a passive and static descriptor of its subject. If the subject is affected by the model, the model must be updated to explain its affected subject. In this study, two models regarding the dynamics of model aware systems are presented. The first explores the behavior of "prediction seeking" (PSP) and "prediction avoiding" (PAP) populations under the influence of a model that describes them. The second explores the publishing behavior of a group of experimentalists coupled to a model by means of confirmation bias. It is found that model aware systems can exhibit convergent random or oscillatory behavior and display universal 1/f noise. A numerical simulation of the physical experimentalists is compared with actual publications of neutron life time and {\\Lambda} mass measurements and is in good quantitative agreement.
Ardıç, Mehmet Alper; Işleyen, Tevfik
2017-04-01
This study discusses a process of material development towards teaching the subject of the graphs of quadratic functions (parabola) by utilizing computer algebra systems. Additionally, the results obtained during and after the process of developing materials are summarized. The last section of the study provides recommendations for teachers and researchers who want to develop computer-assisted instruction materials.
47 CFR 76.905 - Standards for identification of cable systems subject to effective competition.
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Standards for identification of cable systems subject to effective competition. 76.905 Section 76.905 Telecommunication FEDERAL COMMUNICATIONS... cognizable investment if the sum of the interests other than those held by or through “passive investors”...
Davidson, J. N.; Stone, D. A.; Foster, M. P.; Gladwin, D.T.
2016-01-01
This paper presents a technique to estimate the temperature of each power electronic device in a thermally coupled, multiple device system subject to dynamic cooling. Using a demonstrator system, the thermal transfer impedance between pairs of devices is determined in the frequency domain for a quantised range of active cooling levels using a technique based on pseudorandom binary sequences. The technique is illustrated by application to the case temperatures of power devices. For each coolin...
Discrete-Time Sliding Mode Control for Uncertain Networked System Subject to Time Delay
Directory of Open Access Journals (Sweden)
Saulo C. Garcia
2015-01-01
Full Text Available We deal with uncertain systems with networked sliding mode control, subject to time delay. To minimize the degenerative effects of the time delay, a simpler format of state predictor is proposed in the control law. Some ultimate bounded stability analyses and stabilization conditions are provided for the uncertain time delay system with proposed discrete-time sliding mode control strategy. A numerical example is presented to corroborate the analyses.
State-Feedback Control for Fractional-Order Nonlinear Systems Subject to Input Saturation
Directory of Open Access Journals (Sweden)
Junhai Luo
2014-01-01
Full Text Available We give a state-feedback control method for fractional-order nonlinear systems subject to input saturation. First, a sufficient condition is derived for the asymptotical stability of a class of fractional-order nonlinear systems. Then based on Gronwall-Bellman lemma and a sector bounded condition of the saturation function, a linear state-feed back controller is designed. Finally, two simulation examples are presented to show the validity of the proposed method.
Biomechanics of running in weightlessness on a treadmill equipped with a subject loading system
Gosseye, Thierry
2011-01-01
One countermeasure used during long duration spaceflight to maintain bone and muscle mass is a treadmill equipped with a subject loading system (SLS) that simulates gravity. To date, little is known about the biomechanics of running in weightlessness on such a treadmill-SLS system. We have designed an instrumented treadmill/force-plate to compare the biomechanics of running in weightlessness to running on Earth. Gravity was simulated by two pneumatic pistons pulling downwards on a subject’s h...
A Stability Criterion for Time-Delay Tension Leg Platform Systems Subjected to External Force
Institute of Scientific and Technical Information of China (English)
Chen-Yuan CHEN; Chien-wen SHEN; Cheng-Wu CHEN; Kevin Fong-Rey LIU; Ming-Jen CHENG
2009-01-01
Stability analysis plays a central role in nonlinear system theory and engineering application.Over the past few yeats,the stability analysis of fuzzy systems has been proposed and there are many successful applications in practical engineering.Therefore,in this paper firstly proposed is the stability analysis on oceanic structure by fuzzy models.In the present study,Takagi-Sugeno (T-S) fuzzy model is proposed for a time delay tension leg platform (TLP) system subjected to an external wave force.In terms of stability analysis,linear matrix inequality (LMI) conditions are derived via Lyapunov theory to guarantee the stability of the TLP system.
Two-level tuning of fuzzy PID controllers.
Mann, G I; Hu, B G; Gosine, R G
2001-01-01
Fuzzy PID tuning requires two stages of tuning; low level tuning followed by high level tuning. At the higher level, a nonlinear tuning is performed to determine the nonlinear characteristics of the fuzzy output. At the lower level, a linear tuning is performed to determine the linear characteristics of the fuzzy output for achieving overall performance of fuzzy control. First, different fuzzy systems are defined and then simplified for two-point control. Non-linearity tuning diagrams are constructed for fuzzy systems in order to perform high level tuning. The linear tuning parameters are deduced from the conventional PID tuning knowledge. Using the tuning diagrams, high level tuning heuristics are developed. Finally, different applications are demonstrated to show the validity of the proposed tuning method.
Intrinsic decoherence in the interaction of two fields with a two-level atom
Energy Technology Data Exchange (ETDEWEB)
Juarez-Amaro, R. [Universidad Tecnologica de la Mixteca, Mexico (Mexico); INAOE, Puebla (Mexico); Escudero-Jimenez, J.L. [INAOE, Puebla (Mexico); Moya-Cessa, H.
2009-06-15
We study the interaction of a two-level atom and two fields, one of them classical. We obtain an effective Hamiltonian for this system by using a method recently introduced that produces a small rotation to the Hamiltonian that allows to neglect some terms in the rotated Hamiltonian. Then we solve a variation of the Schroedinger equation that models decoherence as the system evolves through intrinsic mechanisms beyond conventional quantum mechanics rather than dissipative interaction with an environment. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
Canyon of current suppression in an interacting two-level quantum dot
DEFF Research Database (Denmark)
Karlström, O; Pedersen, Jonas Nyvold; Samuelsson, P
2011-01-01
Motivated by the recent discovery of a canyon of conductance suppression in a two-level equal-spin quantum dot system [Phys. Rev. Lett. 104, 186804 (2010)], the transport through this system is studied in detail. At low bias and low temperature a strong current suppression is found around...... quantum rate equations. The simulations allow for the prediction of how the suppression is affected by the couplings, the charging energy, the position of the energy levels, the applied bias, and the temperature. We find that, away from electron-hole symmetry, the parity of the couplings is essential...
Optimizing ETL by a Two-level Data Staging Method
DEFF Research Database (Denmark)
Liu, Xiufeng; Iftikhar, Nadeem; Nielsen, Per Sieverts
2016-01-01
In data warehousing, the data from source systems are populated into a central data warehouse (DW) through extraction, transformation and loading (ETL). The standard ETL approach usually uses sequential jobs to process the data with dependencies, such as dimension and fact data. It is a non......-/late-arriving data, and fast-/slowly-changing data. The introduced additional staging area decouples loading process from data extraction and transformation, which improves ETL flexibility and minimizes intervention to the data warehouse. This paper evaluates the proposed method empirically, which shows...
Optimization of measurement distance of 109Cd K XRF system for obese subjects
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
The precision of results obtained from the 109Cd K XRF in vivo measurement system of bone lead for obese subjects with high BMI (body mass index) was poor. The main factor affecting the precision was the distance between tibia and detector. Compared with the standard phantom, a large phantom was used to simulate the obese subject in the measurements at different distances to the detector. The counts of Compton scattering increased highly because of the tissue overlying and surrounding tibia of the obese subject. When the distance between leg and detector was too small, the instrument would produce the distorted X-ray spectra, so that the obtained data were inaccurate. In order to ensure good measurement precision and accuracy, the distance between leg and detector should be maintained at 25 mm during the counting period. Meanwhile, the dead time displayed instantly on the instrument should be controlled to around 30%.
The Implications of Contamination for Educational Experiments with Two Levels of Nesting
Rhoads, Christopher
2016-01-01
Experimental evaluations that involve the educational system usually involve a hierarchical structure (students are nested within classrooms that are nested within schools, etc.). Concerns about contamination, where research subjects receive certain features of an intervention intended for subjects in a different experimental group, have often led…
Institute of Scientific and Technical Information of China (English)
李鹏茂; 萨楚尔夫; 苏少龙
2015-01-01
Applying the method of coherent states orthogonalization expansion , the atomic population and the anti-bunching effect of the light field are studied in the system of interaction between a two -level atom and the SchrÖdinger cat state without rotating wave approximation ( RWA) .The results are compared with those in RWA . The influences of the original strength of the light field and two coherent phase angles on the atomic population and antibunching effect with RWA and without RWA are discussed respectively , and the antibunching effect in the weak coupling condition is also discussed without RWA .The results show that the atomic populations with RWA and without RWA have different properties with the different original strengths of the light field .As the original strength of the light field is smaller , the atomic populations with RWA and without RWA show the same properties , but with the increase of the original strength of the light field the population with RWA will show the collapse phe -nomenon .When the coupling strength is larger , the antibunching effects with RWA and without RWA have bigger difference .Without RWA the light field will appear bunching effect , whereas with RWA it will appear alternately the bunching effect and the antibunching effect with the increase of the original strength of light field .%在非旋波近似下，通过采用相干态正交化展开的方法，研究了薛定谔猫态光场与二能级原子相互作用系统中，原子的布局数和光场的反聚束效应，并与旋波近似下的结果进行了对比。在旋波近似与非旋波近似下，讨论了初始光场强度、相干态间的相位角以及失谐量对原子布局数和光场反聚束效应的影响；在非旋波近似下，讨论了强弱耦合情况下光场的反聚束效应。研究结果表明：旋波近似与非旋波近似下，原子的布局数随着初始光场强度的不同，表现出不同的特性；当初始光场强度较小时，
Ultrasonic distance sensor improvement using a two-level neural network
Parvis, Marco; Carullo, Alessio; Ferraris, Franco
1996-01-01
This paper discusses the performance improvement that a neural network can provide to a contactless distance sensor based on the measurement of the time of flight (TOF) of an ultrasonic (US) pulse. The sensor, which embeds a correction system for the temperature effect, achieves a distance uncertainty (rms) of less than 0.5 mm over 0.5 m by using a two-level neural network to process the US echo and determine the TOF in the presence of environmental acoustic noise. The network embeds a "guard...
Quantum averaging and resonances: two-level atom in a one-mode classical laser field
Directory of Open Access Journals (Sweden)
M. Amniat-Talab
2007-06-01
Full Text Available We use a nonperturbative method based on quantum averaging and an adapted from of resonant transformations to treat the resonances of the Hamiltonian of a two-level atom interacting with a one-mode classical field in Floquet formalism. We illustrate this method by extraction of effective Hamiltonians of the system in two regimes of weak and strong coupling. The results obtained in the strong-coupling regime, are valid in the whole range of the coupling constant for the one-photon zero-field resonance.
Stochastic Optimization of Large Scale Multi-Reservoir Systems subject to environmental flow demands
Fernandes Marques, Guilherme; Tilmant, Amaury
2014-05-01
Among the environmental impacts caused by dams, the alteration of flow regimes is one of the most critical to river ecosystems given its influence in long river reaches and its continuous pattern. While the reoperation of reservoir systems to recover some of the natural flow regime is expected to mitigate the impacts, associated costs and losses will be imposed on different power plants depending on flows, power plant and reservoir characteristics, system's topology and other aspects. In a large scale reservoir system this economic impact is not trivial, and it should be properly evaluated to identify coordinated operating solutions that avoid penalizing a single reservoir. This paper combines an efficient stochastic dual dynamic programming method for reservoir optimization subject to environmental flow targets with specific magnitude and return period, which effects on fish recruitment are already known. This allows the evaluation of the economic and power generation impacts in a large scale hydropower system when subject to environmental flow demands. The present paper contributes with methods and results that are useful in (a) quantifying the foregone hydropower and revenues resulting from meeting a specific environmental flow demand, (b) identifying the distribution and reallocation of the foregone hydropower and revenue across a large scale system, and (c) identifying optimal reservoir operating strategies to meet environmental flow demands in a large scale multi-reservoir system.
Subjective intensity of pain during the treatment of periodontal lesions with the Vector-system.
Braun, Andreas; Krause, Felix; Nolden, Rolf; Frentzen, Matthias
2003-04-01
The aim of this study was to measure subjective intensities of pain during the treatment of periodontal lesions with the Vector-system when compared to pain occurring during the treatment with conventional methods. Twenty patients, each of whom had three teeth with comparable periodontal pocket depths, were treated using three different methods: (i) scaling and root planing with hand instruments, (ii) cleaning with a conventional ultrasonic instrument (Siroson S) and (iii) cleaning with the Vector-system. The subjective intensities of pain during the treatment were measured with an intermodal intensity comparison. A visual analog scale was used for the evaluation after the treatment. The results of the intermodal intensity comparison during treatment showed that the use of the Vector-system caused less pain than the cleaning with hand instruments or the conventional ultrasonic system (P cleaning with hand instruments and cleaning with the conventional ultrasonic system were not significantly different (P > 0.05). These results could be confirmed by the visual analog scale. Using the Vector-system for cleaning periodontal lesions it is possible to reduce pain sensations compared to conventional methods. Using cleaning methods that cause less discomfort and pain, it might be possible to increase the patient's compliance during non-surgical periodontal therapy and recall.
Stability and robustness analysis of a linear time-periodic system subjected to random perturbations
Redkar, Sangram; Liu, J.; Sinha, S. C.
2012-03-01
In this work, new methods of guaranteeing the stability of linear time periodic dynamical systems with stochastic perturbations are presented. In the approaches presented here, the Lyapunov-Floquet (L-F) transformation is applied first so that the linear time-periodic part of the equations becomes time-invariant. For the linear time periodic system with stochastic perturbations, a stability theorem and related corollary have been suggested using the results previously obtained by Infante. This technique is not only applicable to systems with stochastic parameters but also to systems with deterministic variation in parameters. Some illustrative examples are presented to show the practical applications. These methods can be used to investigate the degree of robustness and design controllers for systems with time periodic coefficients subjected to random perturbations.
Predictive maintenance policy for a gradually deteriorating system subject to stress
Energy Technology Data Exchange (ETDEWEB)
Deloux, E. [IRCCyN/Ecole des Mines de Nantes, Nantes (France); Castanier, B. [IRCCyN/Ecole des Mines de Nantes, Nantes (France)], E-mail: bruno.castanier@emn.fr; Berenguer, C. [Universite de Technologie de Troyes/CNRS, Troyes (France)
2009-02-15
This paper deals with a predictive maintenance policy for a continuously deteriorating system subject to stress. We consider a system with two failure mechanisms which are, respectively, due to an excessive deterioration level and a shock. To optimize the maintenance policy of the system, an approach combining statistical process control (SPC) and condition-based maintenance (CBM) is proposed. CBM policy is used to inspect and replace the system according to the observed deterioration level. SPC is used to monitor the stress covariate. In order to assess the performance of the proposed maintenance policy and to minimize the long-run expected maintenance cost per unit of time, a mathematical model for the maintained system cost is derived. Analysis based on numerical results are conducted to highlight the properties of the proposed maintenance policy in respect to the different maintenance parameters.
Lloréns, Roberto; Noé, Enrique; Naranjo, Valery; Borrego, Adrián; Latorre, Jorge; Alcañiz, Mariano
2015-01-01
Motion tracking systems are commonly used in virtual reality-based interventions to detect movements in the real world and transfer them to the virtual environment. There are different tracking solutions based on different physical principles, which mainly define their performance parameters. However, special requirements have to be considered for rehabilitation purposes. This paper studies and compares the accuracy and jitter of three tracking solutions (optical, electromagnetic, and skeleton tracking) in a practical scenario and analyzes the subjective perceptions of 19 healthy subjects, 22 stroke survivors, and 14 physical therapists. The optical tracking system provided the best accuracy (1.074 ± 0.417 cm) while the electromagnetic device provided the most inaccurate results (11.027 ± 2.364 cm). However, this tracking solution provided the best jitter values (0.324 ± 0.093 cm), in contrast to the skeleton tracking, which had the worst results (1.522 ± 0.858 cm). Healthy individuals and professionals preferred the skeleton tracking solution rather than the optical and electromagnetic solution (in that order). Individuals with stroke chose the optical solution over the other options. Our results show that subjective perceptions and preferences are far from being constant among different populations, thus suggesting that these considerations, together with the performance parameters, should be also taken into account when designing a rehabilitation system. PMID:25808765
System of Indicators of the Level of Costs of Financing an Economic Subject
Directory of Open Access Journals (Sweden)
Laktionova Aleksandra A.
2013-11-01
Full Text Available The article offers a system of indicators of the level of costs of financing economic subjects, in the basis of which there is a function of formation of recommendations or identification of directions and priorities in the part of selection of one or another source of financing, its urgency and specific features of attraction of resources, on the basis of information on the level of agent’s costs, information asymmetry costs, financial instability, transaction and market indicators of cost of financial resources. The article pays a special attention to a significant structure forming factor of the ownership structure, which identifies the volume and logic of interconnection of all costs of financing and determining incentives and risks in the system of management of financial activity of an economic subject from the point of view of all participants. It exerts especially big influence upon formation of such implicit costs of financing as agent’s costs and information asymmetry costs. The system of factors of stimulants and de-stimulants of costs of financing includes factors of external environment (macro-economic and market indicators of cost and institutional provision and internal environment (ownership structure, characteristic of investment activity and financing an economic subject, organisation of business and corporate management.
Directory of Open Access Journals (Sweden)
Roberto Lloréns
2015-03-01
Full Text Available Motion tracking systems are commonly used in virtual reality-based interventions to detect movements in the real world and transfer them to the virtual environment. There are different tracking solutions based on different physical principles, which mainly define their performance parameters. However, special requirements have to be considered for rehabilitation purposes. This paper studies and compares the accuracy and jitter of three tracking solutions (optical, electromagnetic, and skeleton tracking in a practical scenario and analyzes the subjective perceptions of 19 healthy subjects, 22 stroke survivors, and 14 physical therapists. The optical tracking system provided the best accuracy (1.074 ± 0.417 cm while the electromagnetic device provided the most inaccurate results (11.027 ± 2.364 cm. However, this tracking solution provided the best jitter values (0.324 ± 0.093 cm, in contrast to the skeleton tracking, which had the worst results (1.522 ± 0.858 cm. Healthy individuals and professionals preferred the skeleton tracking solution rather than the optical and electromagnetic solution (in that order. Individuals with stroke chose the optical solution over the other options. Our results show that subjective perceptions and preferences are far from being constant among different populations, thus suggesting that these considerations, together with the performance parameters, should be also taken into account when designing a rehabilitation system.
A Framework for Control System Design Subject to Average Data-Rate Constraints
DEFF Research Database (Denmark)
Silva, Eduardo; Derpich, Milan; Østergaard, Jan
2011-01-01
This paper studies discrete-time control systems subject to average data-rate limits. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source-coding scheme (with unity signal transfer function) has...... to be deployed in the feedback path. For this situation, and by focusing on a class of source-coding schemes built around entropy coded dithered quantizers, we develop a framework to deal with average data-rate constraints in a tractable manner that combines ideas from both information and control theories...
DEFF Research Database (Denmark)
Choisel, Sylvain
the fidelity with which sound reproduction systems can re-create the desired stereo image, a laser pointing technique was developed to accurately collect subjects' responses in a localization task. This method is subsequently applied in an investigation of the effects of loudspeaker directivity...... on the perceived direction of panned sources. The second part of the thesis addresses the identification of auditory attributes which play a role in the perception of sound reproduced by multichannel systems. Short musical excerpts were presented in mono, stereo and several multichannel formats to evoke various...
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P. L. Paggiaro
1995-01-01
Full Text Available In 21 asthmatic subjects, several functions of isolated peripheral neutrophils (chemokinesis and chemotaxis toward 10% E. coli; superoxide anion generation after PMA; leukotriene B4 (LTB4 release from whole blood and isolated neutrophtls, before and after different stimuli were evaluated during an acute exacerbation of asthma, and after 14 – 54 days of treatment with systemic glucocorticosteroids (GCS. During acute exacerbation, superoxide anion generation was higher in asthmatics than in eleven normal subjects (39.2 ± 14.1 vs. 25.2 ± 7.3 nmol, p 20% after GCS treatment (from 131 ± 18 to 117 ± 21 μm, p = 0.005. Chemokinesis sicantly decreased in all subjects, and the changes significantly correlated with an arbitrary score of the total administered dose of GCS (r = 0.57, p < 0.05. These data suggest that neutrophil activation plays a minor role in asthma, and that treatment with GCS is not able to modify most functions of peripheral neutrophils in asthmatic subjects; chemotaxis seems to be related only to the severity of the asthma and it could reflect the improvement of the disease.
Mathew, Lazar; Purkayastha, S. S.; Jayashankar, A.; Radhakrishnan, U.; Sen Gupta, J.; Nayar, H. S.
1985-06-01
Studies were carried out to ascertain the role of sympatho-parasympathetic responses in the process of adaptation to altitude. The assessment of status of autonomic balance was carried out in a group of 20 young male subjects by recording their resting heart rate, blood pressure, oral temperature, mean skin temperature, extremity temperatures, pupillary diameter, cold pressor response, oxygen consumption, cardioacceleration during orthostasis and urinary excretion of catecholamines; in a thermoneutral laboratory. The same parameters were repeated on day 3 and at weekly intervals for a period of 3 weeks, after exposing them to 3,500 m; and also after return to sea level. At altitude, similar studies were carried out in a group of 10 acclimatized lowlanders, 10 high altitude natives and 6 patients who had recently recovered from high altitude pulmonary oedema. In another phase, similar studies were done in two groups of subjects, one representing 15 subjects who had stayed at altitude (3,500 4,000 m) without any ill effects and the other comprising of 10 subjects who had either suffered from high altitude pulmonary oedema (HAPO) or acute mountain sickness (AMS). The results revealed sympathetic overactivity on acute induction to altitude which showed gradual recovery on prolonged stay, the high altitude natives had preponderance to parasympathetic system. Sympathetic preponderance may not be an essential etiological factor for the causation of maladaptation syndromes.
Borrego, Adrián; Latorre, Jorge; Llorens, Roberto; Alcañiz, Mariano; Noé, Enrique
2016-08-09
Even though virtual reality (VR) is increasingly used in rehabilitation, the implementation of walking navigation in VR still poses a technological challenge for current motion tracking systems. Different metaphors simulate locomotion without involving real gait kinematics, which can affect presence, orientation, spatial memory and cognition, and even performance. All these factors can dissuade their use in rehabilitation. We hypothesize that a marker-based head tracking solution would allow walking in VR with high sense of presence and without causing sickness. The objectives of this study were to determine the accuracy, the jitter, and the lag of the tracking system and its elicited sickness and presence in comparison of a CAVE system. The accuracy and the jitter around the working area at three different heights and the lag of the head tracking system were analyzed. In addition, 47 healthy subjects completed a search task that involved navigation in the walking VR system and in the CAVE system. Navigation was enabled by natural locomotion in the walking VR system and through a specific device in the CAVE system. An HMD was used as display in the walking VR system. After interacting with each system, subjects rated their sickness in a seven-point scale and their presence in the Slater-Usoh-Steed Questionnaire and a modified version of the Presence Questionnaire. Better performance was registered at higher heights, where accuracy was less than 0.6 cm and the jitter was about 6 mm. The lag of the system was 120 ms. Participants reported that both systems caused similar low levels of sickness (about 2.4 over 7). However, ratings showed that the walking VR system elicited higher sense of presence than the CAVE system in both the Slater-Usoh-Steed Questionnaire (17.6 ± 0.3 vs 14.6 ± 0.6 over 21, respectively) and the modified Presence Questionnaire (107.4 ± 2.0 vs 93.5 ± 3.2 over 147, respectively). The marker-based solution provided accurate
Stability and performance analysis of a jump linear control system subject to digital upsets
Institute of Scientific and Technical Information of China (English)
王蕊; 孙辉; 马振洋
2015-01-01
This paper focuses on the methodology analysis for the stability and the corresponding tracking performance of a closed-loop digital jump linear control system with a stochastic switching signal. The method is applied to a flight control system. A distributed recoverable platform is implemented on the flight control system and subject to independent digital upsets. The upset processes are used to stimulate electromagnetic environments. Specifically, the paper presents the scenarios that the upset process is directly injected into the distributed flight control system, which is modeled by independent Markov upset processes and independent and identically distributed (IID) processes. A theoretical performance analysis and simulation modelling are both presented in detail for a more complete independent digital upset injection. The specific examples are proposed to verify the methodology of tracking performance analysis. The general analyses for different configurations are also proposed. Comparisons among different configurations are conducted to demonstrate the availability and the characteristics of the design.
Institute of Scientific and Technical Information of China (English)
Jing Tang Xing
2008-01-01
A fluid-structure interaction system subject to Sommerfeld's condition is defined as a Sommerfeld system which is divided into three categories:Fluid Sommerfeld(FS)System,Solid Sommerfeld(SS)System and Fluid Solid Sommerfeld(FSS)System of which Sommerfeld conditions are imposed on a fluid boundary only,a solid boundary only and both fluid and solid boundaries,respectively.This paper follows the previous initial results claimed by simple examples to further mathematically investigate the natural vibrations of generalized Sommerfeld systems.A new parameter representing the speed of radiation wave for generalized 3-D problems with more complicated boundary conditions is introduced into the Sommerfeld condition which allows investigation of the natural vibrations of a Sommerfeld system involving both free surface and compressible waves.The mathematical demonstrations and selected examples confirm and reveal the natural behaviour of generalized Sommerfeld systems defined above.These generalized conclusions can be used in theoretical or engineering analysis of the vibrations of various Sommerfeld systems in engineering.
Institute of Scientific and Technical Information of China (English)
邹旭波; 许晶波; 高孝纯; 符建
2001-01-01
We adopt a dynamical algebraic approach to study the system of a two-level atom moving in a quantized travelling light field and a gravitational field with a multiphoton interaction. The exact solution of the system is obtained and used to discuss the influence of the gravitational field on the collapses and revivals of atomic population, sub-Poissonian statistics.
Diurnal and seasonal variation of the brain serotonin system in healthy male subjects.
Matheson, Granville J; Schain, Martin; Almeida, Rita; Lundberg, Johan; Cselényi, Zsolt; Borg, Jacqueline; Varrone, Andrea; Farde, Lars; Cervenka, Simon
2015-05-15
The mammalian circadian clock underlies both diurnal and seasonal changes in physiology, and its function is thought to be disturbed in both seasonal and non-seasonal depression. In humans, molecular imaging studies have reported seasonal changes in the serotonin system. Despite the role of the circadian clock in generating seasonal physiological changes, however, diurnal variation of serotonin receptors and transporters has never been directly studied in humans. We used positron emission tomography to examine diurnal and seasonal changes in the serotonin 5-HT1A receptor and serotonin transporter in two large cohorts of healthy male subjects, employing a cross-sectional design. In 56 subjects measured with [(11)C]WAY-100635, we observed diurnal increases in the availability of 5-HT1A receptors in the cortex. In 40 subjects measured with [(11)C]MADAM, a decrease in 5-HTT was observed in the midbrain across the day. We also found seasonal changes in the 5-HT1A receptor in serotonin projection regions, with higher availability on days with a longer duration of daylight. Our observation that serotonin receptor and transporter levels may change across the day in humans is corroborated by experimental research in rodents. These findings have important implications for understanding the relationship between the circadian and serotonin systems in both the healthy brain and in affective disorders, as well as for the design of future molecular imaging studies.
Intrinsic decoherence of entanglement of a single quantized field interacting with a two-level atom
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
How the mean photon number, the probability of excited state and intrinsic decoherence coefficient influence the time evolution of entanglement is unknown, when a single-mode quantized optic field and a two-level atom coupling system is governed by Milburn equation. The Jaynes-Cummings model is considered. A lower bound of concurrence is proposed to calculate the entanglement. Simulation results indicate that the entanglement of system increases following the increasing of intrinsic decoherence coefficient or the decreasing of the mean photon number. Besides that, the entanglement of system decreases, while the probability of exited state increases from 0 to 0.1, and increases, while the probability of exited state increases from 0.1 to 1.
Two-level Robust Measurement Fusion Kalman Filter for Clustering Sensor Networks
Institute of Scientific and Technical Information of China (English)
ZHANG Peng; QI Wen-Juan; DENG Zi-Li
2014-01-01
This paper investigates the distributed fusion Kalman filtering over clustering sensor networks. The sensor network is partitioned as clusters by the nearest neighbor rule and each cluster consists of sensing nodes and cluster-head. Using the minimax robust estimation principle, based on the worst-case conservative system with the conservative upper bounds of noise variances, two-level robust measurement fusion Kalman filter is presented for the clustering sensor network systems with uncertain noise variances. It can significantly reduce the communication load and save energy when the number of sensors is very large. A Lyapunov equation approach for the robustness analysis is presented, by which the robustness of the local and fused Kalman filters is proved. The concept of the robust accuracy is presented, and the robust accuracy relations among the local and fused robust Kalman filters are proved. It is proved that the robust accuracy of the two-level weighted measurement fuser is equal to that of the global centralized robust fuser and is higher than those of each local robust filter and each local weighted measurement fuser. A simulation example shows the correctness and effectiveness of the proposed results.
Subject reduction in a Curry-style polymorphic type system with a vectorial structure
Arrighi, Pablo; Valiron, Benoît
2010-01-01
The algebraic lambda-calculus [Vau09] and the linear-algebraic lambda-calculus [AD08] extend the lambda-calculus with the possibility of making arbitrary linear combinations of lambda-terms. The two foundational works of [ADC09] and [DCP10] describe type systems for this calculus respectively accounting for scalars and sums. Building on these approaches, we devise a typed algebraic lambda-calculus merging the two approaches while keeping a language featuring local confluence and a weak subject reduction. This gives rise to an original and general type theory where types, in the same way as terms, have a vector space-like structure. The main contribution of this paper is a subject reduction result, a problem renowned to be a delicate matter under the presence of union-like type constructs.
Directory of Open Access Journals (Sweden)
Li Tian
2010-01-01
Full Text Available The behavior of power transmission tower-line system subjected to spatially varying base excitations is studied in this paper. The transmission towers are modeled by beam elements while the transmission lines are modeled by cable elements that account for the nonlinear geometry of the cables. The real multistation data from SMART-1 are used to analyze the system response subjected to spatially varying ground motions. The seismic input waves for vertical and horizontal ground motions are also generated based on the Code for Design of Seismic of Electrical Installations. Both the incoherency of seismic waves and wave travel effects are accounted for. The nonlinear time history analytical method is used in the analysis. The effects of boundary conditions, ground motion spatial variations, the incident angle of the seismic wave, coherency loss, and wave travel on the system are investigated. The results show that the uniform ground motion at all supports of system does not provide the most critical case for the response calculations.
Double coupling: modeling subjectivity and asymmetric organization in social-ecological systems
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David Manuel-Navarrete
2015-09-01
Full Text Available Social-ecological organization is a multidimensional phenomenon that combines material and symbolic processes. However, the coupling between social and ecological subsystem is often conceptualized as purely material, thus reducing the symbolic dimension to its behavioral and actionable expressions. In this paper I conceptualize social-ecological systems as doubly coupled. On the one hand, material expressions of socio-cultural processes affect and are affected by ecological dynamics. On the other hand, coupled social-ecological material dynamics are concurrently coupled with subjective dynamics via coding, decoding, personal experience, and human agency. This second coupling operates across two organizationally heterogeneous dimensions: material and symbolic. Although resilience thinking builds on the recognition of organizational asymmetry between living and nonliving systems, it has overlooked the equivalent asymmetry between ecological and socio-cultural subsystems. Three guiding concepts are proposed to formalize double coupling. The first one, social-ecological asymmetry, expands on past seminal work on ecological self-organization to incorporate reflexivity and subjectivity in social-ecological modeling. Organizational asymmetry is based in the distinction between social rules, which are symbolically produced and changed through human agents' reflexivity and purpose, and biophysical rules, which are determined by functional relations between ecological components. The second guiding concept, conscious power, brings to the fore human agents' distinctive capacity to produce our own subjective identity and the consequences of this capacity for social-ecological organization. The third concept, congruence between subjective and objective dynamics, redefines sustainability as contingent on congruent relations between material and symbolic processes. Social-ecological theories and analyses based on these three guiding concepts would support the
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Yen-Hsiu Yang
2012-01-01
Full Text Available We propose a generic spatial domain control scheme for a class of nonlinear rotary systems of variable speeds and subject to spatially periodic disturbances. The nonlinear model of the rotary system in time domain is transformed into one in spatial domain employing a coordinate transformation with respect to angular displacement. Under the circumstances that measurement of the system states is not available, a nonlinear state observer is established for providing the estimated states. A two-degree-of-freedom spatial domain control configuration is then proposed to stabilize the system and improve the tracking performance. The first control module applies adaptive backstepping with projected parametric update and concentrates on robust stabilization of the closed-loop system. The second control module introduces an internal model of the periodic disturbances cascaded with a loop-shaping filter, which not only further reduces the tracking error but also improves parametric adaptation. The overall spatial domain output feedback adaptive control system is robust to model uncertainties and state estimated error and capable of rejecting spatially periodic disturbances under varying system speeds. Stability proof of the overall system is given. A design example with simulation demonstrates the applicability of the proposed design.
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P. P. Oleynik
2015-11-01
Full Text Available The paper deals with domain-driven design applicability of information systems for client queuing subject areas. The following optimality criteria were put forward for the final implementation: the possibility of automation with a single system both for small institution and a whole network of institutions; advanced graphical interface with support for sensor screens; implementation of multi-users account of orders from clients; flexible application architecture with the ability of future enhancement; ability of integration with a variety of peripherals. The necessity of each criterion definition is shown. For implementability estimation, test information system was designed, automating the queuing system. Unified modeling language UML is used. Description of each class functionality is given and the association with other classes as well. Attention is paid to the design of tree (hierarchical structures and selection procedure of base classes based on the analysis of existing common attributes. For the system implementation, its own development environment SharpArchitect RAD Studio is used, offering MDA approach for implementation of systems based on standardized meta object system. A graphical view of order form developed prototype is presented, composition and structure are described, and notation developed by the author is given simplifying the prototyping process. Approaches to differentiation of access rights for different user roles are shown. Conformity of the received implementation to each selected optimality criterion is determined. Recommendations for further system development are given.
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Wen-Jer Chang
2014-01-01
Full Text Available For nonlinear discrete-time stochastic systems, a fuzzy controller design methodology is developed in this paper subject to state variance constraint and passivity constraint. According to fuzzy model based control technique, the nonlinear discrete-time stochastic systems considered in this paper are represented by the discrete-time Takagi-Sugeno fuzzy models with multiplicative noise. Employing Lyapunov stability theory, upper bound covariance control theory, and passivity theory, some sufficient conditions are derived to find parallel distributed compensation based fuzzy controllers. In order to solve these sufficient conditions, an iterative linear matrix inequality algorithm is applied based on the linear matrix inequality technique. Finally, the fuzzy stabilization problem for nonlinear discrete ship steering stochastic systems is investigated in the numerical example to illustrate the feasibility and validity of proposed fuzzy controller design method.
A control system for mechanical ventilation of passive and active subjects.
Tehrani, Fleur T
2013-06-01
Synchronization of spontaneous breathing with breaths supplied by the ventilator is essential for providing optimal ventilation to patients on mechanical ventilation. Some ventilation techniques such as Adaptive Support Ventilation (ASV), Proportional Assist Ventilation (PAV), and Neurally Adjusted Ventilatory Assist (NAVA) are designed to address this problem. In PAV, the pressure support is proportional to the patient's ongoing effort during inspiration. However, there is no guarantee that the patient receives adequate ventilation. The system described in this article is designed to automatically control the support level in PAV to guarantee delivery of patient's required ventilation. This system can also be used to control the PAV support level based on the patient's work of breathing. This technique further incorporates some of the features of ASV to deliver mandatory breaths for passive subjects. The system has been tested by using computer simulations and the controller has been implemented by using a prototype.
Buckling Response of Pipe-in-Pipe Systems Subjected to Bending
Institute of Scientific and Technical Information of China (English)
王哲; 陈志华; 刘红波; 何永禹; 马克俭
2015-01-01
The buckling response of pipe-in-pipe(PIP)systems subjected to bending is investigated in this paper. A set of parameterized models are established to explore the bending characteristics of the PIP systems through eigen-value buckling analysis and nonlinear post-buckling analysis. The results show that the length of PIP systems and the height of centralizers are the most significant factors that influence the buckling moment, ultimate bending mo-ment and buckling mode; the other geometric characteristics, such as initial geometric imperfection and friction between centralizers and outer pipes, evidently influence the post-buckling path and ductility of PIPs; the equivalent bending stiffness is dependent on the length and centralizers. Moreover, the range of equivalent bending stiffness is also discussed.
Numerical Simulations of Pile Supported Protective System Subjected to Ship Impact
Institute of Scientific and Technical Information of China (English)
SUN Zhen; WANG Junjie
2006-01-01
The head-on collision process between ship and concrete pile supported protective system is simulated by software LS-DYNA.The influences of pile non-linearity and soil non-linearity on impact force,ship crush depth and the cap displacement of pile supported protective system are discussed.It's shown that for both severe impact case and non-severe impact case,the non-linearity of pile material influence the impact force history,ship crush depth.The non-linearity of pile material and soil has remarkable influence on the cap displacement especially for severe impact case.These issues should not be ignored in the analysis of pile supported protective system subjected to ship impact.
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Xiaohui Mo
2017-01-01
Full Text Available In this paper, finite-time stabilization problem for a class of nonlinear differential-algebraic systems (NDASs subject to external disturbance is investigated via a composite control manner. A composite finite-time controller (CFTC is proposed with a three-stage design procedure. Firstly, based on the adding a power integrator technique, a finite-time control (FTC law is explicitly designed for the nominal NDAS by only using differential variables. Then, by using homogeneous system theory, a continuous finite-time disturbance observer (CFTDO is constructed to estimate the disturbance generated by an exogenous system. Finally, a composite controller which consists of a feedforward compensation part based on CFTDO and the obtained FTC law is proposed. Rigorous analysis demonstrates that not only the proposed composite controller can stabilize the NDAS in finite time, but also the proposed control scheme exhibits nominal performance recovery property. Simulation examples are provided to illustrate the effectiveness of the proposed control approach.
Spiral Wave Dynamics in a Response System Subjected to a Spiral Wave Forcing
Institute of Scientific and Technical Information of China (English)
LI Guang-Zhao; CHEN Yong-Qi; TANG Guo-Ning; LIU Jun-Xian
2011-01-01
@@ Unidirectional linear error feedback coupling of two excitable medium systems displaying spiral waves is considered.The spiral wave in the response system is thus subjected to a spiral wave forcing.We find that the unidirectional feedback coupling can lead to richer behaviour than the mutual coupling.The spiral wave dynamics in the response system depends on the coupling strength and frequency mismatch.When the coupling strength is small, the feedback coupling induces the drift or meander of the forced spiral wave.When the coupling strength is large enough, the feedback coupling may lead to the transition from spiral wave to anti-target or target-like wave.The generation of anti-target wave in coupled excitable media is observed for the first time.Furthermore, when the coupling strength is strong, the synchronization between two subsystems can be established.%Unidirectional linear error feedback coupling of two excitable medium systems displaying spiral waves is considered. The spiral wave in the response system is thus subjected to a spiral wave forcing. We find that the unidirectional feedback coupling can lead to richer behaviour than the mutual coupling. The spiral wave dynamics in the response system depends on the coupling strength and frequency mismatch. When the coupling strength is small, the feedback coupling induces the drift or meander of the forced spiral wave. When the coupling strength is large enough, the feedback coupling may lead to the transition from spiral wave to anti-target or target-like wave. The generation of anti-target wave in coupled excitable media is observed for the first time. Furthermore,when the coupling strength is strong, the synchronization between two subsystems can be established.
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Mr. Anant A. Kapse ,
2014-06-01
Full Text Available Due to excessive displacements of tall buildings occasioned by lateral loads, lateral load resisting systems are usually provided to curtail the load effect. The resistance may be offered by Frame Action, Shear Walls, or combined Walls and Frames (also known as Dual System. In this study, 3D structural modelling base software STAAD-PRO was used to generate and analyze three-dimensional building models for the assessment of the relative effectiveness of the various lateral load resisting systems. Five models were used, one for moment resisting frame & 04 models each for the lateral load resisting systems. Each model consisted of G +10 storey frame structure having total height of 33.0 m. Each building sample was subjected to three-dimensional analysis for the determination of both the lateral displacements at storey top and interstorey drifts. The results of the work showed that the dual system was the most efficient lateral-load resisting system based on deflection criterion, as they yielded the least values for lateral displacements and inter-storey drifts. The moment frame was the least stiff of the resisting systems, yielding the highest values of both the lateral displacement and the inter-storey drift.
Running interfacial waves in a two-layer fluid system subject to longitudinal vibrations
Goldobin, D. S.; Pimenova, A. V.; Kovalevskaya, K. V.; Lyubimov, D. V.; Lyubimova, T. P.
2015-05-01
We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasistationary states of free interface in fluid dynamical systems subject to vibrations, revealed the existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary problems: neither stability problems nor ones associated with propagating waves. In this work, we rigorously derive the evolution equations for long waves in the system, which turn out to be identical to the plus (or good) Boussinesq equation. With these equations one can find all the time-independent-profile solitary waves (standing solitons are a specific case of these propagating waves), which exist below the linear instability threshold; the standing and slow solitons are always unstable while fast solitons are stable. Depending on initial perturbations, unstable solitons either grow in an explosive manner, which means layer rupture in a finite time, or falls apart into stable solitons. The results are derived within the long-wave approximation as the linear stability analysis for the flat-interface state [D.V. Lyubimov and A.A. Cherepanov, Fluid Dynamics 21, 849 (1986)], 10.1007/BF02628017 reveals the instabilities of thin layers to be long wavelength.
Running interfacial waves in a two-layer fluid system subject to longitudinal vibrations.
Goldobin, D S; Pimenova, A V; Kovalevskaya, K V; Lyubimov, D V; Lyubimova, T P
2015-05-01
We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasistationary states of free interface in fluid dynamical systems subject to vibrations, revealed the existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary problems: neither stability problems nor ones associated with propagating waves. In this work, we rigorously derive the evolution equations for long waves in the system, which turn out to be identical to the plus (or good) Boussinesq equation. With these equations one can find all the time-independent-profile solitary waves (standing solitons are a specific case of these propagating waves), which exist below the linear instability threshold; the standing and slow solitons are always unstable while fast solitons are stable. Depending on initial perturbations, unstable solitons either grow in an explosive manner, which means layer rupture in a finite time, or falls apart into stable solitons. The results are derived within the long-wave approximation as the linear stability analysis for the flat-interface state [D.V. Lyubimov and A.A. Cherepanov, Fluid Dynamics 21, 849 (1986)] reveals the instabilities of thin layers to be long wavelength.
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Jaime Vitola
2017-05-01
Full Text Available Structural health monitoring (SHM is a very important area in a wide spectrum of fields and engineering applications. With an SHM system, it is possible to reduce the number of non-necessary inspection tasks, the associated risk and the maintenance cost in a wide range of structures during their lifetime. One of the problems in the detection and classification of damage are the constant changes in the operational and environmental conditions. Small changes of these conditions can be considered by the SHM system as damage even though the structure is healthy. Several applications for monitoring of structures have been developed and reported in the literature, and some of them include temperature compensation techniques. In real applications, however, digital processing technologies have proven their value by: (i offering a very interesting way to acquire information from the structures under test; (ii applying methodologies to provide a robust analysis; and (iii performing a damage identification with a practical useful accuracy. This work shows the implementation of an SHM system based on the use of piezoelectric (PZT sensors for inspecting a structure subjected to temperature changes. The methodology includes the use of multivariate analysis, sensor data fusion and machine learning approaches. The methodology is tested and evaluated with aluminum and composite structures that are subjected to temperature variations. Results show that damage can be detected and classified in all of the cases in spite of the temperature changes.
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A. Baddou
2006-01-01
Full Text Available This paper solves the problem of controlling linear continuous-time systems subject to control signals constrained in magnitude (maybe asymmetrically. A controller design methodology is proposed, based on using an asymmetric Lyapunov function, that avoids the discontinuities in the control vector components resulting from the application of a piecewise linear control law previously proposed. The proposed method gives improved speed of convergence without discontinuities of the control vector components, respecting always the imposed asymmetric constraints. An example illustrates the approach.
Stochastic resonance in linear systems subject to multiplicative and additive noise.
Berdichevsky, V; Gitterman, M
1999-08-01
Exact expressions have been found for the first two moments and the correlation function for an overdamped linear system subject to an external periodic field as well as to multiplicative and additive noise. Stochastic resonance is absent for Gaussian white noise. However, when the multiplicative noise has the form of an asymmetric dichotomous noise, the signal-to-noise ratio (SNR) becomes a nonmonotonic function of the correlation time and the asymmetry of noise. Moreover, the SNR turns out to be a nonmonotonic function of the frequency of the external field as well as strongly depending on the strength of the cross correlation between multiplicative and additive noise.
Directory of Open Access Journals (Sweden)
Mimma eNardelli
2015-03-01
Full Text Available The objective assessment of psychological traits of healthy subjects and psychiatric patients has been growing interest in clinical and bioengineering research fields during the last decade. Several experimental evidences strongly suggest that a link between Autonomic Nervous System (ANS dynamics and specific dimensions such as anxiety, social phobia, stress and emotional regulation might exist. Nevertheless, an extensive investigation on a wide range of psycho-cognitive scales and ANS non-invasive markers gathered from standard and nonlinear analysis still needs to be addressed. In this study, we analyzed the discerning and correlation capabilities of a comprehensive set of ANS features and psycho-cognitive scales in 29 non-pathological subjects monitored during resting conditions. In particular, the state of the art of standard and nonlinear analysis was performed on Heart Rate Variability, InterBreath Interval series, and Inter-Beat Respiration series, which were considered as monovariate and multivariate measurements. Experimental results show that each ANS feature is linked to specific psychological traits. Moreover, nonlinear analysis outperforms the psychological assessment with respect to standard analysis. Considering that the current clinical practice relies only on subjective scores from interviews and questionnaires, this study provides objective tools for the assessment of psychological dimensions.
EVALUATION OF TWO-LEVEL GLOBAL LOAD BALANCING FRAMEWORK IN CLOUD ENVIRONMENT
Directory of Open Access Journals (Sweden)
Po-Huei Liang
2015-05-01
Full Text Available With technological advancements and constant changes of Internet, cloud computing has been today's trend. With the lower cost and convenience of cloud computing services, users have increasingly put their Web resources and information in the cloud environment. The availability and reliability of the client systems will become increasingly important. Today cloud applications slightest interruption, the impact will be significant for users. It is an important issue that how to ensure reliability and stability of the cloud sites. Load balancing would be one good solution. This paper presents a framework for global server load balancing of the Web sites in a cloud with two-level load balancing model. The proposed framework is intended for adapting an open-source load-balancing system and the framework allows the network service provider to deploy a load balancer in different data centers dynamically while the customers need more load balancers for increasing the availability.
A two-level approach towards semantic colon segmentation: removing extra-colonic findings.
Lu, Le; Wolf, Matthias; Liang, Jianming; Dundar, Murat; Bi, Jinbo; Salganicoff, Marcos
2009-01-01
Computer aided detection (CAD) of colonic polyps in computed tomographic colonography has tremendously impacted colorectal cancer diagnosis using 3D medical imaging. It is a prerequisite for all CAD systems to extract the air-distended colon segments from 3D abdomen computed tomography scans. In this paper, we present a two-level statistical approach of first separating colon segments from small intestine, stomach and other extra-colonic parts by classification on a new geometric feature set; then evaluating the overall performance confidence using distance and geometry statistics over patients. The proposed method is fully automatic and validated using both the classification results in the first level and its numerical impacts on false positive reduction of extra-colonic findings in a CAD system. It shows superior performance than the state-of-art knowledge or anatomy based colon segmentation algorithms.
Two-Level Automatic Adaptation of a Distributed User Profile for Personalized News Content Delivery
Directory of Open Access Journals (Sweden)
Maria Papadogiorgaki
2008-01-01
Full Text Available This paper presents a distributed client-server architecture for the personalized delivery of textual news content to mobile users. The user profile consists of two separate models, that is, the long-term interests are stored in a skeleton profile on the server and the short-term interests in a detailed profile in the handset. The user profile enables a high-level filtering of available news content on the server, followed by matching of detailed user preferences in the handset. The highest rated items are recommended to the user, by employing an efficient ranking process. The paper focuses on a two-level learning process, which is employed on the client side in order to automatically update both user profile models. It involves the use of machine learning algorithms applied to the implicit and explicit user feedback. The system's learning performance has been systematically evaluated based on data collected from regular system users.
Phonon induced optical gain in a current carrying two-level quantum dot
Energy Technology Data Exchange (ETDEWEB)
Eskandari-asl, Amir, E-mail: amir.eskandari.asl@gmail.com [Department of Physics, Shahid Beheshti University, G.C. Evin, Tehran 1983963113 (Iran, Islamic Republic of); School of Nano Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box: 19395-5531, Tehran, Iran (Iran, Islamic Republic of)
2017-05-15
In this work we consider a current carrying two level quantum dot (QD) that is coupled to a single mode phonon bath. Using self-consistent Hartree-Fock approximation, we obtain the I-V curve of QD. By considering the linear response of our system to an incoming classical light, we see that depending on the parametric regime, the system could have weak or strong light absorption or may even show lasing. This lasing occurs at high enough bias voltages and is explained by a population inversion considering side bands, while the total electron population in the higher level is less than the lower one. The frequency at which we have the most significant lasing depends on the level spacing and phonon frequency and not on the electron-phonon coupling strength.
Probability of Failure of Safety-Critical Systems Subject to Partial Tests
Brissaud, Florent; Bérenguer, Christophe
2010-01-01
A set of general formulas is proposed for the probability of failure on demand (PFD) assessment of MooN architecture (i.e. k-out-of-n) systems subject to proof tests. The proof tests can be partial or full. The partial tests (e.g. visual inspections, partial stroke testing) are able to detect only some system failures and leave the others latent, whereas the full tests refer to overhauls which restore the system to an as good as new condition. Partial tests may occur at different time instants (periodic or not), up to the full test. The system performances which are investigated are the system availability according to time, the PFD average in each partial test time interval, and the total PFD average calculated on the full test time interval. Following the given expressions, parameter estimations are proposed to assess the system failure rates and the partial test effectiveness according to feedback data from previous test policies. Subsequently, an optimization of the partial test strategy is presented. In ...
Supervising and Controlling Unmanned Systems: A Multi-Phase Study with Subject Matter Experts.
Porat, Talya; Oron-Gilad, Tal; Rottem-Hovev, Michal; Silbiger, Jacob
2016-01-01
Proliferation in the use of Unmanned Aerial Systems (UASs) in civil and military operations has presented a multitude of human factors challenges; from how to bridge the gap between demand and availability of trained operators, to how to organize and present data in meaningful ways. Utilizing the Design Research Methodology (DRM), a series of closely related studies with subject matter experts (SMEs) demonstrate how the focus of research gradually shifted from "how many systems can a single operator control" to "how to distribute missions among operators and systems in an efficient way". The first set of studies aimed to explore the modal number, i.e., how many systems can a single operator supervise and control. It was found that an experienced operator can supervise up to 15 UASs efficiently using moderate levels of automation, and control (mission and payload management) up to three systems. Once this limit was reached, a single operator's performance was compared to a team controlling the same number of systems. In general, teams led to better performances. Hence, shifting design efforts toward developing tools that support teamwork environments of multiple operators with multiple UASs (MOMU). In MOMU settings, when the tasks are similar or when areas of interest overlap, one operator seems to have an advantage over a team who needs to collaborate and coordinate. However, in all other cases, a team was advantageous over a single operator. Other findings and implications, as well as future directions for research are discussed.
Stability Criterion of Linear Stochastic Systems Subject to Mixed H2/Passivity Performance
Directory of Open Access Journals (Sweden)
Cheung-Chieh Ku
2015-01-01
Full Text Available The H2 control scheme and passivity theory are applied to investigate the stability criterion of continuous-time linear stochastic system subject to mixed performance. Based on the stochastic differential equation, the stochastic behaviors can be described as multiplicative noise terms. For the considered system, the H2 control scheme is applied to deal with the problem on minimizing output energy. And the asymptotical stability of the system can be guaranteed under desired initial conditions. Besides, the passivity theory is employed to constrain the effect of external disturbance on the system. Moreover, the Itô formula and Lyapunov function are used to derive the sufficient conditions which are converted into linear matrix inequality (LMI form for applying convex optimization algorithm. Via solving the sufficient conditions, the state feedback controller can be established such that the asymptotical stability and mixed performance of the system are achieved in the mean square. Finally, the synchronous generator system is used to verify the effectiveness and applicability of the proposed design method.
Patini, R; Coviello, V; Raffaelli, L; Manicone, P F; Dehkhargani, S Z; Verdugo, F; Perfetti, G; D'Addona, A
2012-01-01
The present study was conducted to evaluate human pain perception at different phases of dental surgery using a computer controlled device, the Single Tooth Anesthesia System (STA System), versus the traditional syringe technique. One hundred healthy patients participated in this single-blind split-mouth design study. Individuals provided pain ratings at needle insertion, delivery of anesthetic solution and tooth extraction via a numeric visual rating scale or NVRS. The anterior middle superior alveolar, or AMSA, injection was compared with traditional syringe injections in maxillary quadrants. NVRS scores for AMSA were significantly lower for the STA System when compared to traditional syringe technique at needle insertion, delivery of anesthetic solution (p less than 0.0001) and also during tooth extractions (p=0.0002). A higher percentage of patients (23 percent) required a second injection after the traditional syringe technique. Subjects reported having less clinical pain with AMSA injection at every step of the dental surgery. The STA System combines an anesthetic pathway and controlled flow rate resulting in virtually imperceptible needle insertion and injection, and a rapid onset of profound anesthesia. NVRS scoring system facilitated patient comprehension in assessing pain value and intensity experienced. The two anesthetic delivery techniques were therapeutically equivalent for maxillary injections but AMSA/computer controlled protocol significantly minimizes subjective pain perception at needle insertion, anesthetic delivery and during tooth extraction.
DEFF Research Database (Denmark)
Köyluoglu, H.U.; Nielsen, Søren R.K.; Cakmak, A.S.
1994-01-01
perturbation method using stochastic differential equations. The joint statistical moments entering the perturbation solution are determined by considering an augmented dynamic system with state variables made up of the displacement and velocity vector and their first and second derivatives with respect...... to the random parameters of the problem. Equations for partial derivatives are obtained from the partial differentiation of the equations of motion. The zero time-lag joint statistical moment equations for the augmented state vector are derived from the Itô differential formula. General formulation is given...... for multi-degree-of-freedom (MDOF) systems and the method is illustrated for a single-degree-of-freedom (SDOF) oscillator. The results are compared to those of exact results for a random oscillator subject to white noise excitation with random intensity....
Fast state estimation subject to random data loss in discrete-time nonlinear stochastic systems
Mahdi Alavi, S. M.; Saif, Mehrdad
2013-12-01
This paper focuses on the design of the standard observer in discrete-time nonlinear stochastic systems subject to random data loss. By the assumption that the system response is incrementally bounded, two sufficient conditions are subsequently derived that guarantee exponential mean-square stability and fast convergence of the estimation error for the problem at hand. An efficient algorithm is also presented to obtain the observer gain. Finally, the proposed methodology is employed for monitoring the Continuous Stirred Tank Reactor (CSTR) via a wireless communication network. The effectiveness of the designed observer is extensively assessed by using an experimental tested-bed that has been fabricated for performance evaluation of the over wireless-network estimation techniques under realistic radio channel conditions.
Robust model-reference control for descriptor linear systems subject to parameter uncertainties
Institute of Scientific and Technical Information of China (English)
Guangren DUAN; Biao ZHANG
2007-01-01
Robust model-reference control for descriptor linear systems with structural parameter uncertainties is investigated. A sufficient condition for existing a model-reference zero-error asymptotic tracking controller is given. It is shown that the robust model reference control problem can be decomposed into two subproblems: a robust state feedback stabilization problem for descriptor systems subject to parameter uncertainties and a robust compensation problem. The latter aims to find three coefficient matrices which satisfy four matrix equations and simultaneously minimize the effect of the uncertainties to the tracking error. Based on a complete parametric solution to a class of generalized Sylvester matrix equations, the robust compensation problem is converted into a minimization problem with quadratic cost and linear constraints. A numerical example shows the effect of the proposed approach.
Automated Degradation Diagnosis in Character Recognition System Subject to Camera Vibration
Directory of Open Access Journals (Sweden)
Chunmei Liu
2014-01-01
Full Text Available Degradation diagnosis plays an important role for degraded character processing, which can tell the recognition difficulty of a given degraded character. In this paper, we present a framework for automated degraded character recognition system by statistical syntactic approach using 3D primitive symbol, which is integrated by degradation diagnosis to provide accurate and reliable recognition results. Our contribution is to design the framework to build the character recognition submodels corresponding to degradation subject to camera vibration or out of focus. In each character recognition submodel, statistical syntactic approach using 3D primitive symbol is proposed to improve degraded character recognition performance. In the experiments, we show attractive experimental results, highlighting the system efficiency and recognition performance by statistical syntactic approach using 3D primitive symbol on the degraded character dataset.
Anomalous transports in a time-delayed system subjected to anomalous diffusion
Chen, Ru-Yin; Tong, Lu-Mei; Nie, Lin-Ru; Wang, Chaojie; Pan, Wanli
2017-02-01
We investigate anomalous transports of an inertial Brownian particle in a time-delayed periodic potential subjected to an external time-periodic force, a constant bias force, and the Lévy noise. By means of numerical calculations, effect of the time delay and the Lévy noise on its mean velocity are discussed. The results indicate that: (i) The time delay can induce both multiple current reversals (CRs) and absolute negative mobility (ANM) phenomena in the system; (ii) The CRs and ANM phenomena only take place in the region of superdiffusion, while disappear in the regions of normal diffusion; (iii) The time delay can cause state transition of the system from anomalous →normal →anomalous →normal →anomalous →normal transport in the case of superdiffusion.
Satisfactory fault-tolerant controller design for uncertain systems subject to actuator faults
Institute of Scientific and Technical Information of China (English)
Zhang Dengfeng; Su Hongye; Wang Zhiquan
2008-01-01
Based on satisfactory control strategy, a new method for robust passive fault tolerant controller is proposed for a class of uncertain discrete-time systems subject to actuator faults. The state-feedback gain matrix is calculated by linear matrix inequality (LMI) technique. The designed controller guarantees that the closed-loop system meets the pre-specified consistent constraints on circular pole index and steady-state variance index simultaneously for normal case and possible actuator fault case. The consistency of the performance indices is discussed. Furthermore, with the mentioned indices constraints, a solution is obtained by convex optimal technique for the robust satisfactory fault-tolerant controller with optimal control-cost.
DEFF Research Database (Denmark)
Andreasen, Anne Sofie; Larsen, Nadja; Pedersen-Skovsgaard, Theis
2010-01-01
According to animal studies, intake of probiotic bacteria may improve glucose homeostasis. We hypothesised that probiotic bacteria improve insulin sensitivity by attenuating systemic inflammation. Therefore, the effects of oral supplementation with the probiotic bacterium Lactobacillus acidophilus...... course with either L. acidophilus NCFM or placebo. L. acidophilus was detected in stool samples by denaturating gradient gel electrophoresis and real-time PCR. Separated by the 4-week intervention period, two hyperinsulinaemic-euglycaemic clamps were performed to estimate insulin sensitivity. Furthermore......, the systemic inflammatory response was evaluated by subjecting the participants to Escherichia coli lipopolysaccharide injection (0·3 ng/kg) before and after the treatment course. L. acidophilus NCFM was detected in 75 % of the faecal samples after treatment with the probiotic bacterium. Insulin sensitivity...
Shores, M M; Pascualy, M; Lewis, N L; Flatness, D; Veith, R C
2001-05-01
Increased sympathetic nervous system (SNS) activity has been associated with stress, major depression, aging, and several medical conditions. This study assessed the effect of the selective serotonin reuptake inhibitor (SSRI), sertraline, on sympathetic nervous system (SNS) activity in healthy subjects. Twelve healthy volunteers participated in a double-blind, placebo-controlled, norepinephrine (NE) kinetic study, in which the effects of sertraline on SNS activity were ascertained by determining NE plasma concentrations and NE plasma appearance rates and clearance rates in sertraline or placebo conditions. Subjects received 50 mg of sertraline or placebo for two days and then one week later underwent the same protocol with the other drug. By single compartmental analysis, plasma NE appearance rates were significantly lower in the sertraline compared to the placebo condition (0.26+/-0.10 vs 0.40+/-0.23 microg/m(2)/min; P=0.04). Our study found that the net effect of short-term SSRI treatment is an apparent suppression of SNS activity as indicated by a decreased plasma NE appearance rate in the sertraline condition. If this preliminary finding can be extended to long-term treatment of patients, this could have significant therapeutic relevance for treating depression in elderly patients or those with cardiac disease, in which elevated SNS activity may exacerbate underlying medical conditions.
Detecting method of subjects' 3D positions and experimental advanced camera control system
Kato, Daiichiro; Abe, Kazuo; Ishikawa, Akio; Yamada, Mitsuho; Suzuki, Takahito; Kuwashima, Shigesumi
1997-04-01
Steady progress is being made in the development of an intelligent robot camera capable of automatically shooting pictures with a powerful sense of reality or tracking objects whose shooting requires advanced techniques. Currently, only experienced broadcasting cameramen can provide these pictures.TO develop an intelligent robot camera with these abilities, we need to clearly understand how a broadcasting cameraman assesses his shooting situation and how his camera is moved during shooting. We use a real- time analyzer to study a cameraman's work and his gaze movements at studios and during sports broadcasts. This time, we have developed a detecting method of subjects' 3D positions and an experimental camera control system to help us further understand the movements required for an intelligent robot camera. The features are as follows: (1) Two sensor cameras shoot a moving subject and detect colors, producing its 3D coordinates. (2) Capable of driving a camera based on camera movement data obtained by a real-time analyzer. 'Moving shoot' is the name we have given to the object position detection technology on which this system is based. We used it in a soccer game, producing computer graphics showing how players moved. These results will also be reported.
A VLSI Neural Monitoring System With Ultra-Wideband Telemetry for Awake Behaving Subjects.
Greenwald, E; Mollazadeh, M; Hu, C; Wei Tang; Culurciello, E; Thakor, V
2011-04-01
Long-term monitoring of neuronal activity in awake behaving subjects can provide fundamental information about brain dynamics for neuroscience and neuroengineering applications. Here, we present a miniature, lightweight, and low-power recording system for monitoring neural activity in awake behaving animals. The system integrates two custom designed very-large-scale integrated chips, a neural interface module fabricated in 0.5 μm complementary metal-oxide semiconductor technology and an ultra-wideband transmitter module fabricated in a 0.5 μm silicon-on-sapphire (SOS) technology. The system amplifies, filters, digitizes, and transmits 16 channels of neural data at a rate of 1 Mb/s. The entire system, which includes the VLSI circuits, a digital interface board, a battery, and a custom housing, is small and lightweight (24 g) and, thus, can be chronically mounted on small animals. The system consumes 4.8 mA and records continuously for up to 40 h powered by a 3.7-V, 200-mAh rechargeable lithium-ion battery. Experimental benchtop characterizations as well as in vivo multichannel neural recordings from awake behaving rats are presented here.
Subjective evaluation of an active crosstalk reduction system for mobile autostereoscopic displays
Chappuis, Alexandre; Rerabek, Martin; Hanhart, Philippe; Ebrahimi, Touradj
2014-03-01
The Quality of Experience (QoE) provided by autostereoscopic 3D displays strongly depends on the user position. For an optimal image quality, the observer should be located at one of the relevant positions, called sweet spots, where artifacts reducing the QoE, such as crosstalk, are minimum. In this paper, we propose and evaluate a complete active crosstalk reduction system running on an HTC EVO 3D smartphone. To determine the crosstalk level at each position, a full display characterization was performed. Based on the user position and crosstalk profile, the system first helps the user to find the sweet spot using visual feedback. If the user moves away from the sweet spot, then the active crosstalk compensation is performed and reverse stereo phenomenon is corrected. The user preference between standard 2D and 3D modes, and the proposed system was evaluated through a subjective quality assessment. Results show that in terms of depth perception, the proposed system clearly outperforms the 3D and 2D modes. In terms of image quality, 2D mode was found to be best, but the proposed system outperforms 3D mode.
A Wearable System for Gait Training in Subjects with Parkinson’s Disease
Directory of Open Access Journals (Sweden)
Filippo Casamassima
2014-03-01
Full Text Available In this paper, a system for gait training and rehabilitation for Parkinson’s disease (PD patients in a daily life setting is presented. It is based on a wearable architecture aimed at the provision of real-time auditory feedback. Recent studies have, in fact, shown that PD patients can receive benefit from a motor therapy based on auditory cueing and feedback, as happens in traditional rehabilitation contexts with verbal instructions given by clinical operators. To this extent, a system based on a wireless body sensor network and a smartphone has been developed. The system enables real-time extraction of gait spatio-temporal features and their comparison with a patient’s reference walking parameters captured in the lab under clinical operator supervision. Feedback is returned to the user in form of vocal messages, encouraging the user to keep her/his walking behavior or to correct it. This paper describes the overall concept, the proposed usage scenario and the parameters estimated for the gait analysis. It also presents, in detail, the hardware-software architecture of the system and the evaluation of system reliability by testing it on a few subjects.
Directory of Open Access Journals (Sweden)
Bo Chen
2015-01-01
Full Text Available The vibration control and performance evaluation on a transmission-tower line system by using friction dampers subjected to wind excitations are carried out in this study. The three-dimensional finite element (FE model of a transmission tower is firstly constructed. A two-dimensional lumped mass model of a transmission tower is developed for dynamic analysis. The analytical model of transmission tower-line system is proposed by taking the dynamic interaction between the tower and the transmission lines into consideration. The mechanical model of passive friction damper is presented by involving the effects of damper axial stiffness. The equation of motion of the transmission tower-line system incorporated with the friction dampers disturbed by wind excitations is established. A real transmission tower-line system is taken as an example to examine the feasibility and reliability of the proposed control approach. An extensive parameter study is carried out to find the optimal parameters of friction damper and to assess the effects of slipping force axial stiffness and hysteresis loop on control performance. The work on an example structure indicates that the application of friction dampers with optimal parameters could significantly reduce wind-induced responses of the transmission tower-line system.
Fan, Jinhua; Zhang, Youmin; Zheng, Zhiqiang
2013-11-01
A matrix inequality approach is proposed to reliably stabilize a class of uncertain linear systems subject to actuator faults, saturation, and bounded system disturbances. The system states are assumed immeasurable, and a classical observer is incorporated for observation to enable state-based feedback control. Both the stability and stabilization of the closed-loop system are discussed and the closed-loop domain of attraction is estimated by an ellipsoidal invariant set. The resultant stabilization conditions in the form of matrix inequalities enable simultaneous optimization of both the observer gain and the feedback controller gain, which is realized by converting the non-convex optimization problem to an unconstrained nonlinear programming problem. The effectiveness of proposed design techniques is demonstrated through a linearized model of F-18 HARV around an operating point.
Directory of Open Access Journals (Sweden)
Sha Guo
Full Text Available Post-translational modifications on proteins are important in biological processes but may create neo-epitopes that induce autoimmune responses. In this study, we measured the serum IgG and IgM response to a set of non-modified or acetyl- and methyl-modified peptides corresponding to residues 1-19 of the histone 3 N-terminal tail in systemic lupus erythematosus (SLE patients and healthy subjects. Our results indicated that the SLE patients and healthy subjects produced antibodies (Abs to the peptides, but the two groups had different Ab isotype and epitope preferences. Abs to the non-modified form, H31-19, were of the IgG isotype and produced by SLE patients. They could not recognize the scrambled H31-19, which contained the same amino acid composition but a different sequence as H31-19. In comparison, healthy subjects in general did not produce IgG against H31-19. However, about 70% of the healthy subjects produced IgM Abs against mono-methylated K9 of H31-19 (H31-19K9me. Our further studies revealed that ε-amine mono-methylated lysine could completely inhibit the IgM binding to H31-19K9me, but lysine had no inhibitory effect. In addition, the IgM Abs could bind peptides containing a mono-methylated lysine residue but with totally different sequences. Thus, mono-methylated lysine was the sole epitope for the IgM. Interestingly, SLE patients had much lower levels of this type of IgM. There was no obvious correlation between the IgM levels and disease activity and the decreased IgM was unlikely caused by medical treatments.We also found that the IgM Abs were not polyreactive to dsDNA, ssDNA, lipopolysaccharide (LPS or insulin and they did not exist in umbilical cord serum, implying that they were not natural Abs. The IgM Abs against mono-methylated lysine are present in healthy subjects but are significantly lower in SLE patients, suggesting a distinct origin of production and special physiological functions.
Directory of Open Access Journals (Sweden)
M. Corgini
2010-01-01
Full Text Available For a Bose atom system whose energy operator is diagonal in the so-called number operators and its ground state has an internal two-level structure with negative energies, exact expressions for the limit free canonical energy and pressure are obtained. The existence of non-conventional Bose-Einstein condensation has been also proved.
Chao, Li; Wu, Zhen; Wang, Jianing; Liu, Yi; Chen, Yi
2010-07-01
This article is focused on the two-level control system of ODL, which are divided into bottom layer control of linear motor and upper layer control of Piezoelectric Transducer(PZT).This ODL are designed to compensate geometrical optical path difference, which results from the earth rotation, and other disturbances, with high-accuracy and real time. Based on the PLC of PMAC controller, the linear motor tracks the trajectory of the simulated optical path difference to compensate roughly. PZT then compensates the rest error measured by ZLM almost real time. A detailed fulfillment of this method is shown in the article, and the first result data is produced. The result implies that this method is efficient. This article offers the reference for the ODL development with the practical high accuracy of compensation.
Photon absorption and emission statistics of a two-level atom in a cavity
Energy Technology Data Exchange (ETDEWEB)
Lee, Chang J. [Sun Moon University, Asan (Korea, Republic of)
2012-03-15
The absorption and the emission of photons by an atom involves quantum jumps between states. We investigate the quantum jump statistics for the system of a two-level atom and a single-mode cavity field. We use the Jaynes-Cummings model for this problem, perform Monte Carlo numerical simulations, and give a detailed exact analysis on these simulations. These studies reveal that the waiting-time distribution (WTD) for photon absorptions (emissions) has a unique novel statistic, and that the photon absorption (emission) rate is not uniform, but counter-intuitively depends on the position in the Rabi cycle. The effects of the nonclassical nature of the field on the WTD is discussed.
Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields
Institute of Scientific and Technical Information of China (English)
LIU Xiao-Juan; FANG Mao-Fa
2004-01-01
From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number,squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle,the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.
Temperature dependent quantum correlations in three dipolar coupled two-level atoms
Ahmed, Shaik
2016-01-01
We investigate the thermal entanglement characteristics of three dipole-coupled two-level atoms arranged in two different configurations - in a line with nearest neighbour coupling and in a closed loop with each atom interacting with both its neighbours. It is observed that in loop configuration, any one of the three atoms is indeed entangled with the other two atoms in the system, which are not mutually entangled, and further that this feature is specific to only the loop configuration, which is markedly absent in the line configuration. A detailed study of the quantum correlations demonstrated how these can be tuned by varying the temperature and the dipole dipole coupling strength, in both the configurations.
Quantum logic gates with two-level trapped ions beyond Lamb-Dicke limit
Institute of Scientific and Technical Information of China (English)
Zheng Xiao-Juan; Luo Yi-Min; Cai Jian-Wu
2009-01-01
In the system with two two-level ions confined in a linear trap,this paper presents a simple scheme to realize the quantum phase gate(QPG)and the swap gate beyond the Lamb-Dicke(LD)limit.These two-qubit quantum logic gates only involve the internal states of two trapped ions.The scheme does not use the vibrational mode as the data bus and only requires a single resonant interaction of the ions with the lasers.Neither the LD approximation nor the auxiliary atomic level is needed in the proposed scheme.Thus the scheme is simple and the interaction time is very short,which is important in view of decoherence.The experimental feasibility for achieving this scheme is also discussed.
Directory of Open Access Journals (Sweden)
Liudong Xing
2006-01-01
Full Text Available Imperfect coverage (IPC occurs when a malicious component failure causes extensive damage due to inadequate fault detection, fault location or fault recovery. Common-cause failures (CCF are multiple dependent component failures within a system due to a shared root cause. Both imperfect coverage and common-cause failures can exist in distributed computer systems and can contribute significantly to the overall system unreliability. Moreover they can complicate the reliability analysis. In this study, we propose an efficient approach to the reliability analysis of distributed computer systems (DCS with both IPC and CCF. The proposed methodology is to decouple the effects of IPC and CCF from the combinatorics of the solution. The resulting approach is applicable to the computationally efficient binary decision diagrams (BDD based method for the reliability analysis of DCS. We provide a concrete analysis of an example DCS to illustrate the application and advantages of our approach. Due to the consideration of IPC and CCF, our approach can evaluate a wider class of DCS as compared with existing approaches. Due to the nature of the BDD and the separation of IPC and CCF from the solution combinatorics, our approach has high computational efficiency and is easy to implement, which means that it can be easily applied to the accurate reliability analysis of large-scale DCS subject to IPC and CCF. The DCS without IPC or CCF appear to be special cases of our approach.
Nakatani, Masatoshi; Nobuhiro, Atsushi; Yokoshi, Nobuhiko; Ishihara, Hajime
2013-06-07
We theoretically investigate photoexcitation processes of a two-level molecular system coherently coupled with an antenna system having a significant dissipation. The auxiliary antenna enables the whole system to exhibit anomalous optical effects by controlling the coupling with the molecule. For example, in the weak excitation regime, the quantum interference yields a distinctive energy transparency through the antenna, which drastically reduces the energy dissipation. On the other hand, in the strong excitation regime, a population inversion of the two-level molecule appears due to the nonlinear effect. Both phenomena can be explained by regarding the antenna and molecule as one quantum-mechanically coupled system. Such an approach drives further research to exploit the full potential of the coupled systems.
Evaluation of Subjective and Objective Performance Metrics for Haptically Controlled Robotic Systems
Directory of Open Access Journals (Sweden)
Cong Dung Pham
2014-07-01
Full Text Available This paper studies in detail how different evaluation methods perform when it comes to describing the performance of haptically controlled mobile manipulators. Particularly, we investigate how well subjective metrics perform compared to objective metrics. To find the best metrics to describe the performance of a control scheme is challenging when human operators are involved; how the user perceives the performance of the controller does not necessarily correspond to the directly measurable metrics normally used in controller evaluation. It is therefore important to study whether there is any correspondence between how the user perceives the performance of a controller, and how it performs in terms of directly measurable metrics such as the time used to perform a task, number of errors, accuracy, and so on. To perform these tests we choose a system that consists of a mobile manipulator that is controlled by an operator through a haptic device. This is a good system for studying different performance metrics as the performance can be determined by subjective metrics based on feedback from the users, and also as objective and directly measurable metrics. The system consists of a robotic arm which provides for interaction and manipulation, which is mounted on a mobile base which extends the workspace of the arm. The operator thus needs to perform both interaction and locomotion using a single haptic device. While the position of the on-board camera is determined by the base motion, the principal control objective is the motion of the manipulator arm. This calls for intelligent control allocation between the base and the manipulator arm in order to obtain intuitive control of both the camera and the arm. We implement three different approaches to the control allocation problem, i.e., whether the vehicle or manipulator arm actuation is applied to generate the desired motion. The performance of the different control schemes is evaluated, and our
Influence of dietary fat intake on the endocannabinoid system in lean and obese subjects.
Engeli, Stefan; Lehmann, Anne-Christin; Kaminski, Jana; Haas, Verena; Janke, Jürgen; Zoerner, Alexander A; Luft, Friedrich C; Tsikas, Dimitrios; Jordan, Jens
2014-05-01
Endocannabinoid system (ECS) activation promotes obesity-associated metabolic disease. Increased dietary fat intake increases blood endocannabinoids and alters adipose and skeletal muscle ECS gene expression in human. Two weeks isocaloric low- (LFD) and high-fat diets (HFD) in obese (n = 12) and normal-weight (n = 17) subjects in a randomized cross-over study were compared. Blood endocannabinoids were measured in the fasting condition and after food intake using mass spectrometry. Adipose and skeletal muscle gene expression was determined using real-time RT-PCR. Baseline fasting plasma endocannabinoids were similar with both diets. Anandamide decreased similarly with high- or low-fat test meals in both groups. Baseline arachidonoylglycerol plasma concentrations were similar between groups and diets, and unresponsive to eating. In subcutaneous adipose tissue, DAGL-α mRNA was upregulated and fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) mRNAs were down-regulated in obese subjects, but the diets had no influence. In contrast, the HFD produced pronounced reductions in skeletal muscle CB1-R and MAGL mRNA expression, whereas obesity did not affect muscular gene expression. Weight-neutral changes in dietary fat intake cannot explain excessive endocannabinoid availability in human obesity. Obesity and dietary fat intake affect ECS gene expression in a tissue-specific manner. Copyright © 2014 The Obesity Society.
Xu, Lei; Zhai, Wanming
2017-10-01
This paper devotes to develop a computational model for stochastic analysis and reliability assessment of vehicle-track systems subject to earthquakes and track random irregularities. In this model, the earthquake is expressed as non-stationary random process simulated by spectral representation and random function, and the track random irregularities with ergodic properties on amplitudes, wavelengths and probabilities are characterized by a track irregularity probabilistic model, and then the number theoretical method (NTM) is applied to effectively select representative samples of earthquakes and track random irregularities. Furthermore, a vehicle-track coupled model is presented to obtain the dynamic responses of vehicle-track systems due to the earthquakes and track random irregularities at time-domain, and the probability density evolution method (PDEM) is introduced to describe the evolutionary process of probability from excitation input to response output by assuming the vehicle-track system as a probabilistic conservative system, which lays the foundation on reliability assessment of vehicle-track systems. The effectiveness of the proposed model is validated by comparing to the results of Monte-Carlo method from statistical viewpoint. As an illustrative example, the random vibrations of a high-speed railway vehicle running on the track slabs excited by lateral seismic waves and track random irregularities are analyzed, from which some significant conclusions can be drawn, e.g., track irregularities will additionally promote the dynamic influence of earthquakes especially on maximum values and dispersion degree of responses; the characteristic frequencies or frequency ranges respectively governed by earthquakes and track random irregularities are greatly different, moreover, the lateral seismic waves will dominate or even change the characteristic frequencies of system responses of some lateral dynamic indices at low frequency.
Efficiency analysis on a two-level three-phase quasi-soft-switching inverter
DEFF Research Database (Denmark)
Geng, Pan; Wu, Weimin; Huang, Min;
2013-01-01
for non-conventional inverters with special shoot-through state is introduced and illustrated through the analysis on a special two-level three-phase quasi-soft-switching inverter. Efficiency comparison between the classical two-stage two-level three-phase inverter and the two-level three-phase quasi......-soft-switching inverter is carried out. A 10 kW/380 V prototype is constructed to verify the analysis. The experimental results show that the efficiency of the new inverter is higher than that of the traditional two-stage two- level three-phase inverter....
Trophic groups and modules: two levels of group detection in food webs.
Gauzens, Benoit; Thébault, Elisa; Lacroix, Gérard; Legendre, Stéphane
2015-05-06
Within food webs, species can be partitioned into groups according to various criteria. Two notions have received particular attention: trophic groups (TGs), which have been used for decades in the ecological literature, and more recently, modules. The relationship between these two group concepts remains unknown in empirical food webs. While recent developments in network theory have led to efficient methods for detecting modules in food webs, the determination of TGs (groups of species that are functionally similar) is largely based on subjective expert knowledge. We develop a novel algorithm for TG detection. We apply this method to empirical food webs and show that aggregation into TGs allows for the simplification of food webs while preserving their information content. Furthermore, we reveal a two-level hierarchical structure where modules partition food webs into large bottom-top trophic pathways, whereas TGs further partition these pathways into groups of species with similar trophic connections. This provides new perspectives for the study of dynamical and functional consequences of food-web structure, bridging topological and dynamical analysis. TGs have a clear ecological meaning and are found to provide a trade-off between network complexity and information loss.
Critical wetting transitions in two-dimensional systems subject to long-ranged boundary fields
Drzewiński, A.; Maciołek, A.; Barasiński, A.; Dietrich, S.
2009-04-01
Using the quasiexact density-matrix renormalization-group method and ground-state analysis we study interface delocalization transitions in wide two-dimensional Ising strips subject to long-ranged boundary fields with opposite signs at the two surfaces. Based on this approach, our explicit calculations demonstrate that critical wetting transitions do exist for semi-infinite two-dimensional systems even if the corresponding effective interface potentials decay asymptotically for large ℓ as slow as ℓ-δ with δinterface position from the one-dimensional surface. This supersedes opposite claims by Kroll and Lipowsky [Phys. Rev. B 28, 5273 (1983)] and by Privman and Švrakić [Phys. Rev. B 37, 5974 (1988)] obtained within effective interface models. The corresponding wetting phase diagram is determined, including the cases δ=2 and δ=49 with the latter mimicking short-ranged surface fields. Our analysis highlights the limits of reliability of effective interface models.
Falsone, G.; Settineri, D.
2011-06-01
A procedure for evaluating the response cross-correlation of a linear structural system subjected to the action of stationary random multi-correlated processes is presented in this work. It is based on the definition of the fourth-order differential equation governing the modal response cross-correlation and of the corresponding solution. This is expressed in terms of the corresponding fundamental matrix, whose expression is related to the fundamental matrices of the differential equations governing the modal responses. The properties of this matrix allows to define a particular unconditionally stable numerical integration approach, which is composed of two independent step-by-step procedures, a progressive one and a regressive one. The applications have shown a level of accuracy comparable to that corresponding to the numerical solution of the double convolution integral, but the presented approach is characterised by a reduced computational effort.
Directory of Open Access Journals (Sweden)
A. Ghorbanpour Arani
2016-03-01
Full Text Available In this research, the vibrational behavior of magnetostrictive plate (MsP as a smart component is studied. The plate is subjected to an external follower force and a magnetic field in which the vibration response of MsP has been investigated for both loading combinations. The velocity feedback gain parameter is evaluated to study the effect of magnetic field which is generated by the coil. Sinusoidal shear deformation theory is utilized due to its accuracy of polynomial function with respect to other plate theories. Equations of motion are derived using Hamilton’s principle and solved by differential quadrature method (DQM considering general boundary conditions. The effects of aspect ratio, thickness ratio, follower force and velocity feedback gain are investigated on the frequency response of MsP. Results indicate that magneto-mechanical coupling in MsM helps to control vibrational behaviors of systems such as electro-hydraulic actuator, wireless linear Motors and sensors.
Critical wetting transitions in two-dimensional systems subject to long-ranged boundary fields.
Drzewiński, A; Maciołek, A; Barasiński, A; Dietrich, S
2009-04-01
Using the quasiexact density-matrix renormalization-group method and ground-state analysis we study interface delocalization transitions in wide two-dimensional Ising strips subject to long-ranged boundary fields with opposite signs at the two surfaces. Based on this approach, our explicit calculations demonstrate that critical wetting transitions do exist for semi-infinite two-dimensional systems even if the corresponding effective interface potentials decay asymptotically for large l as slow as l(-delta) with deltainterface position from the one-dimensional surface. This supersedes opposite claims by Kroll and Lipowsky [Phys. Rev. B 28, 5273 (1983)] and by Privman and Svrakić [Phys. Rev. B 37, 5974 (1988)] obtained within effective interface models. The corresponding wetting phase diagram is determined, including the cases delta=2 and delta=49 with the latter mimicking short-ranged surface fields. Our analysis highlights the limits of reliability of effective interface models.
Bounding the Failure Probability Range of Polynomial Systems Subject to P-box Uncertainties
Crespo, Luis G.; Kenny, Sean P.; Giesy, Daniel P.
2012-01-01
This paper proposes a reliability analysis framework for systems subject to multiple design requirements that depend polynomially on the uncertainty. Uncertainty is prescribed by probability boxes, also known as p-boxes, whose distribution functions have free or fixed functional forms. An approach based on the Bernstein expansion of polynomials and optimization is proposed. In particular, we search for the elements of a multi-dimensional p-box that minimize (i.e., the best-case) and maximize (i.e., the worst-case) the probability of inner and outer bounding sets of the failure domain. This technique yields intervals that bound the range of failure probabilities. The offset between this bounding interval and the actual failure probability range can be made arbitrarily tight with additional computational effort.
The study of surgical image quality evaluation system by subjective quality factor method
Zhang, Jian J.; Xuan, Jason R.; Yang, Xirong; Yu, Honggang; Koullick, Edouard
2016-03-01
GreenLightTM procedure is an effective and economical way of treatment of benign prostate hyperplasia (BPH); there are almost a million of patients treated with GreenLightTM worldwide. During the surgical procedure, the surgeon or physician will rely on the monitoring video system to survey and confirm the surgical progress. There are a few obstructions that could greatly affect the image quality of the monitoring video, like laser glare by the tissue and body fluid, air bubbles and debris generated by tissue evaporation, and bleeding, just to name a few. In order to improve the physician's visual experience of a laser surgical procedure, the system performance parameter related to image quality needs to be well defined. However, since image quality is the integrated set of perceptions of the overall degree of excellence of an image, or in other words, image quality is the perceptually weighted combination of significant attributes (contrast, graininess …) of an image when considered in its marketplace or application, there is no standard definition on overall image or video quality especially for the no-reference case (without a standard chart as reference). In this study, Subjective Quality Factor (SQF) and acutance are used for no-reference image quality evaluation. Basic image quality parameters, like sharpness, color accuracy, size of obstruction and transmission of obstruction, are used as subparameter to define the rating scale for image quality evaluation or comparison. Sample image groups were evaluated by human observers according to the rating scale. Surveys of physician groups were also conducted with lab generated sample videos. The study shows that human subjective perception is a trustworthy way of image quality evaluation. More systematic investigation on the relationship between video quality and image quality of each frame will be conducted as a future study.
Molnar, Sven; Mihanović, Mate; Grah, Majda; Kezić, Slobodanka; Filaković, Pavo; Degmecić, Dunja
2010-12-01
Schizophrenia and suicidal behaviour are sever and complex mental disorders, largely determined by factors of inheritance. Both disorders present pathological changes in the catecholamine neurotransmitter system. The study was conducted on three groups; a group of subjects suffering from schizophrenia, a second compounded by individuals who attempted suicide and a third group of phenotypically healthy examinees. The blood samples of schizophrenic patients as of those who attempted suicide were obtained at the Psychiatric Hospital "Sveti Ivan" in Zagreb in the year 2004. Tests were conducted on the statistic relation between a total of 18 SNPs within three candidate-genes of the dopamine and adrenergic system (DRD4, SLC6A3 and ADRA2B) and the manifestation of schzophrenia and suicidal behaviour. Cases were genotyped by use of SNPlex system. Statistically significant differences were determined in the allelic frequency between the mentioned groups. Findings show a significant connection between 4 SNPs (ADRA2B rs749457, SLC6A3 rs464094, DRD4 rs11246226 and rs4331145) and schizophrenia, and 2 SNPs with suicidal attempt (ADRA2B rs1018351 i SLC6A3 rs403636). In addition, this is the first study that highlights the potential role/effect of polymorphisms in ADRA2B on the manifestation of schizophrenia, as on suicidal behaviour.
Nagata, Shinichi; Wang, Yaoqiang; Oshima, Akinobu; Zhang, Linghua; Miyake, Hideyoshi; Sasaki, Hideaki; Ishida, Akio
2008-03-01
Brevibacterium sp. JCM 6894 cells grown in the presence of 1.5-2.5 M NaCl for 24 h at 30 degrees C were subjected to the osmotic downshock. Downshocked cells after ectoine release were grown for further 24 h in the fresh medium with same salinity as before shock. When this cyclic system was applied to the strain JCM 6894, the amount of ectoine in the cells increased with an increase of incubation time, which indicates that the cells manipulated by the present conditions were enough active to survive and synthesize ectoine after several times of osmotic downshock. In the presence of 2 M NaCl, the highest yield of ectoine released was achieved in this cyclic system, more than 2.4 g/L during 7 days of incubation. (1)H and (13)C-NMR analyses of solutes released from the cells by the osmotic downshock showed the presence of only ectoine with high purity. Release of ectoine from the cells was carried out within 5 min and its rates were increased by the dilution in the downshock treatment. For the convenience of operations, non-sterilized medium containing 2 M NaCl was examined for the cell growth in the present system, in which almost same level of ectoine yield, release rates, and cell viability were observed as those of sterilized medium.
Directory of Open Access Journals (Sweden)
Jörg Eberhard
Full Text Available OBJECTIVES: We here investigated whether experimental gingivitis enhances systemic markers of inflammation which are also known as surrogate markers of atherosclerotic plaque development. BACKGROUND: Gingivitis is a low-level oral infection induced by bacterial deposits with a high prevalence within Western populations. A potential link between the more severe oral disease periodontitis and cardiovascular disease has already been shown. METHODS: 37 non-smoking young volunteers with no inflammatory disease or any cardiovascular risk factors participated in this single-subject interventional study with an intra-individual control. Intentionally experimental oral inflammation was induced by the interruption of oral hygiene for 21 days, followed by a 21-days resolving phase after reinitiation of oral hygiene. Primary outcome measures at baseline, day 21 and 42 were concentrations of hsCRP, IL-6, and MCP-1, as well as adhesion capacity and oxLDL uptake of isolated blood monocytes. RESULTS: The partial cessation of oral hygiene procedures was followed by the significant increase of gingival bleeding (34.0%, P<0.0001. This local inflammation was associated with a systemic increase in hsCRP (0.24 mg/L, P = 0.038, IL-6 (12.52 ng/L, P = 0.0002 and MCP-1 (9.10 ng/l, P = 0.124 in peripheral blood samples between baseline and day 21, which decreased at day 42. Monocytes showed an enhanced adherence to endothelial cells and increased foam cell formation after oxLDL uptake (P<0.050 at day 21 of gingivitis. CONCLUSIONS: Bacterial-induced gingival low-level inflammation induced a systemic increase in inflammatory markers. Dental hygiene almost completely reversed this experimental inflammatory process, suggesting that appropriate dental prophylaxis may also limit systemic markers of inflammation in subjects with natural gingivitis. International Clinical Trials Register Platform of the World Health Organization, registry number: DRKS00003366, URL
Melgar, Miguel A; Tobler, William D; Ernst, Robert J; Raley, Thomas J; Anand, Neel; Miller, Larry E; Nasca, Richard J
2014-01-01
Background Loss of lumbar lordosis has been reported after lumbar interbody fusion surgery and may portend poor clinical and radiographic outcome. The objective of this research was to measure changes in segmental and global lumbar lordosis in patients treated with presacral axial L4-S1 interbody fusion and posterior instrumentation and to determine if these changes influenced patient outcomes. Methods We performed a retrospective, multi-center review of prospectively collected data in 58 consecutive patients with disabling lumbar pain and radiculopathy unresponsive to nonsurgical treatment who underwent L4-S1 interbody fusion with the AxiaLIF two-level system (Baxano Surgical, Raleigh NC). Main outcomes included back pain severity, Oswestry Disability Index (ODI), Odom's outcome criteria, and fusion status using flexion and extension radiographs and computed tomography scans. Segmental (L4-S1) and global (L1-S1) lumbar lordosis measurements were made using standing lateral radiographs. All patients were followed for at least 24 months (mean: 29 months, range 24-56 months). Results There was no bowel injury, vascular injury, deep infection, neurologic complication or implant failure. Mean back pain severity improved from 7.8±1.7 at baseline to 3.3±2.6 at 2 years (p lordosis, defined as a change in Cobb angle ≤ 5°, was identified in 84% of patients at L4-S1 and 81% of patients at L1-S1. Patients with loss or gain in segmental or global lordosis experienced similar 2-year outcomes versus those with less than a 5° change. Conclusions/Clinical Relevance Two-level axial interbody fusion supplemented with posterior fixation does not alter segmental or global lordosis in most patients. Patients with postoperative change in lordosis greater than 5° have similarly favorable long-term clinical outcomes and fusion rates compared to patients with less than 5° lordosis change. PMID:25694920
Directory of Open Access Journals (Sweden)
Richard L Jones
1995-01-01
Full Text Available OBJECTIVE: To investigate the short term effects of high frequency chest compression (HFCC on several indices of respiratory system mechanics in normal subjects and patients with cystic fibrosis (CF.
Maximum Likelihood Analysis of a Two-Level Nonlinear Structural Equation Model with Fixed Covariates
Lee, Sik-Yum; Song, Xin-Yuan
2005-01-01
In this article, a maximum likelihood (ML) approach for analyzing a rather general two-level structural equation model is developed for hierarchically structured data that are very common in educational and/or behavioral research. The proposed two-level model can accommodate nonlinear causal relations among latent variables as well as effects…
Analysis of Bullwhip Effect for Two-level Supply Chain with Multi-distributed Centers
Institute of Scientific and Technical Information of China (English)
LirongCui
2004-01-01
The bullwhip effect is studied for two-level supply chain with multi-distributed centers. First the model for two-level supply chain with multi-distributed centers is established under some assumptions, then the mathematical description is given for it. Finally a simple example is showed to illustrate the results obtained in the paper.
Protective system for civil buildings and industrial structures subjected to the seismic risk
Ghica, D.; Grigore, A.; Ionescu, C.
2009-04-01
of this device is based of a network of minimum three seismic sensors (accelerometers), which, through a coincidence circuit, endorses the presence of a seismic shock, excluding the accidental triggers caused by local noises and mechanical shocks from neighboring area. When is activated, the system allows to automatically place in safe position the most dangerous installations located in buildings, such as elevators, heating systems using natural gas or high pressure liquid, water pipes, thermal stations, electrical power line etc. Presently, in Romania, such protective systems installed in the buildings and structures subjected to seismic risk are not available. The only possibility of protection against the potential disastrous effects of earthquakes (wounded, lost of human lives, important material losses, explosions, fires, damages of the water and electricity lines) is to adopt clear solutions for preventing and reducing as much as it is possible the dimensions of material damages and casualties.
Optimal service distribution in WSN service system subject to data security constraints.
Wu, Zhao; Xiong, Naixue; Huang, Yannong; Gu, Qiong
2014-08-04
Services composition technology provides a flexible approach to building Wireless Sensor Network (WSN) Service Applications (WSA) in a service oriented tasking system for WSN. Maintaining the data security of WSA is one of the most important goals in sensor network research. In this paper, we consider a WSN service oriented tasking system in which the WSN Services Broker (WSB), as the resource management center, can map the service request from user into a set of atom-services (AS) and send them to some independent sensor nodes (SN) for parallel execution. The distribution of ASs among these SNs affects the data security as well as the reliability and performance of WSA because these SNs can be of different and independent specifications. By the optimal service partition into the ASs and their distribution among SNs, the WSB can provide the maximum possible service reliability and/or expected performance subject to data security constraints. This paper proposes an algorithm of optimal service partition and distribution based on the universal generating function (UGF) and the genetic algorithm (GA) approach. The experimental analysis is presented to demonstrate the feasibility of the suggested algorithm.
Effects of Time Delay on the Bistable System Subjected to Correlated Noises
Institute of Scientific and Technical Information of China (English)
NIE Lin-Ru; Mei Dong-Cheng
2007-01-01
The time-delayed bistable system subjected to the multiplicative and additive noises is investigated. In the condition of small delay time, the stationary probability distribution function (SPDF) is derived, and under the condition of large delay time, the SPDF is stochastically simulated. The analytical and simulative results indicate that: (i) For the case of λ= 0λ denotes the strength of correlations between the multiplicative and additive noises), the time delay affects weakly the SPDF peak structure, and the symmetrical property of the SPDF two-peak structure does not change with the increasing delay time, (ii) For the case of λ≠0, the two-peak structure changes with the increasing delay time, i.e. one peak goes up and the other go down simultaneously as the delay time increases and along with further increase of the delay time, the lower peak disappears gradually while the higher one goes up, i.e. the structure of the SPDF changes from a bimodal to a unimodal and the system becomes monostable.
Sarabi, B; Ramanayaka, A N; Burin, A L; Wellstood, F C; Osborn, K D
2016-04-22
Material-based two-level systems (TLSs), appearing as defects in low-temperature devices including superconducting qubits and photon detectors, are difficult to characterize. In this study we apply a uniform dc electric field across a film to tune the energies of TLSs within. The film is embedded in a superconducting resonator such that it forms a circuit quantum electrodynamical system. The energy of individual TLSs is observed as a function of the known tuning field. By studying TLSs for which we can determine the tunneling energy, the actual p_{z}, dipole moments projected along the uniform field direction, are individually obtained. A distribution is created with 60 p_{z}. We describe the distribution using a model with two dipole moment magnitudes, and a fit yields the corresponding values p=p_{1}=2.8±0.2 D and p=p_{2}=8.3±0.4 D. For a strong-coupled TLS the vacuum-Rabi splitting can be obtained with p_{z} and tunneling energy. This allows a measurement of the circuit's zero-point electric-field fluctuations, in a method that does not need the electric-field volume.
Quantum dynamics of a driven two-level molecule with variable dephasing
Grandi, Samuele; Major, Kyle D.; Polisseni, Claudio; Boissier, Sebastien; Clark, Alex S.; Hinds, E. A.
2016-12-01
The longitudinal (Γ1) and transverse (Γ2) decay rates of a two-level quantum system have a profound influence on its evolution. Atomic systems with Γ2=1/2 Γ1 have been studied extensively, but with the rise of solid-state quantum devices it is also important to consider the effect of stronger transverse relaxation due to interactions with the solid environment. Here we study the quantum dynamics of a single organic dye molecule driven by a laser. We measure the variation of Γ2 with temperature and determine the activation energy for thermal dephasing of the optical dipole. Then we measure the second-order correlation function g(2 )(τ ) of the light emitted by the molecule for various ratios Γ2/Γ1 and saturation parameters S . We show that the general solution to the optical Bloch equations accurately describes the observed quantum dynamics over a wide range of these parameters, and we discuss the limitations of the various approximate expressions for g(2 )(τ ) that appear in the literature.
Testing a Quantum Heat Pump with a Two-Level Spin
Correa, Luis; Mehboudi, Mohammad
2016-04-01
Once in its non-equilibrium steady state, a nanoscale system coupled to several heat baths may be thought-of as a quantum heat pump. Depending on the direction of its stationary heat flows it may function as e.g. a refrigerator or a heat transformer. These continuous heat devices can be arbitrarily complex multipartite systems, and yet their working principle is always the same: They are made up of several elementary three-level stages operating in parallel. As a result, it is possible to devise external black-box testing strategies to learn about their functionality and performance regardless of any internal details. In particular, one such heat pump can be tested by coupling a two-level spin to one of its contact transitions. The steady state of this external probe contains information about the presence of heat leaks and internal dissipation in the device, and also, about the direction of its steady-state heat currents. Provided that the irreversibility of the heat pump is low, one can further estimate its coefficient of performance. These techniques may find applications in the emerging field of quantum thermal engineering, as they facilitate the diagnosis and design optimization of complex thermodynamic cycles.
Testing a Quantum Heat Pump with a Two-Level Spin
Directory of Open Access Journals (Sweden)
Luis A. Correa
2016-04-01
Full Text Available Once in its non-equilibrium steady state, a nanoscale system coupled to several heat baths may be thought of as a “quantum heat pump”. Depending on the direction of its stationary heat flows, it may function as, e.g., a refrigerator or a heat transformer. These continuous heat devices can be arbitrarily complex multipartite systems, and yet, their working principle is always the same: they are made up of several elementary three-level stages operating in parallel. As a result, it is possible to devise external “black-box” testing strategies to learn about their functionality and performance regardless of any internal details. In particular, one such heat pump can be tested by coupling a two-level spin to one of its “contact transitions”. The steady state of this external probe contains information about the presence of heat leaks and internal dissipation in the device and, also, about the direction of its steady-state heat currents. Provided that the irreversibility of the heat pump is low, one can further estimate its coefficient of performance. These techniques may find applications in the emerging field of quantum thermal engineering, as they facilitate the diagnosis and design optimization of complex thermodynamic cycles.
SPONGY (SPam ONtoloGY): email classification using two-level dynamic ontology.
Youn, Seongwook
2014-01-01
Email is one of common communication methods between people on the Internet. However, the increase of email misuse/abuse has resulted in an increasing volume of spam emails over recent years. An experimental system has been designed and implemented with the hypothesis that this method would outperform existing techniques, and the experimental results showed that indeed the proposed ontology-based approach improves spam filtering accuracy significantly. In this paper, two levels of ontology spam filters were implemented: a first level global ontology filter and a second level user-customized ontology filter. The use of the global ontology filter showed about 91% of spam filtered, which is comparable with other methods. The user-customized ontology filter was created based on the specific user's background as well as the filtering mechanism used in the global ontology filter creation. The main contributions of the paper are (1) to introduce an ontology-based multilevel filtering technique that uses both a global ontology and an individual filter for each user to increase spam filtering accuracy and (2) to create a spam filter in the form of ontology, which is user-customized, scalable, and modularized, so that it can be embedded to many other systems for better performance.
Malik, Owais A; Senanayake, S M N Arosha; Zaheer, Dansih
2015-03-01
An intelligent recovery evaluation system is presented for objective assessment and performance monitoring of anterior cruciate ligament reconstructed (ACL-R) subjects. The system acquires 3-D kinematics of tibiofemoral joint and electromyography (EMG) data from surrounding muscles during various ambulatory and balance testing activities through wireless body-mounted inertial and EMG sensors, respectively. An integrated feature set is generated based on different features extracted from data collected for each activity. The fuzzy clustering and adaptive neuro-fuzzy inference techniques are applied to these integrated feature sets in order to provide different recovery progress assessment indicators (e.g., current stage of recovery, percentage of recovery progress as compared to healthy group, etc.) for ACL-R subjects. The system was trained and tested on data collected from a group of healthy and ACL-R subjects. For recovery stage identification, the average testing accuracy of the system was found above 95% (95-99%) for ambulatory activities and above 80% (80-84%) for balance testing activities. The overall recovery evaluation performed by the proposed system was found consistent with the assessment made by the physiotherapists using standard subjective/objective scores. The validated system can potentially be used as a decision supporting tool by physiatrists, physiotherapists, and clinicians for quantitative rehabilitation analysis of ACL-R subjects in conjunction with the existing recovery monitoring systems.
Directory of Open Access Journals (Sweden)
Stefan eKlöppel
2015-09-01
Full Text Available LTP-like plasticity measured by visual evoked potentials (VEP can be induced in the intact human brain by presenting checkerboard reversals. Also associated with LTP-like plasticity, around two third of participants respond to transcranial magnetic stimulation with a paired-associate stimulation (PAS protocol with a potentiation of their motor evoked potentials. LTP-like processes are also required for verbal and motor learning tasks. We compared effect sizes, responder rates and intercorrelations as well as the potential influence of attention between these four assessments in a group of 37 young and healthy volunteers. We observed a potentiation effect of the N75 and P100 VEP component which positively correlated with plasticity induced by PAS. Subjects with a better subjective alertness were more likely to show PAS and VEP potentiation. No correlation was found between the other assessments. Effect sizes and responder rates of VEP potentiation were higher compared to PAS. Our results indicate a high variability of LTP-like effects and no evidence for a system-specific nature. As a consequence, studies wishing to assess individual levels of LTP-like plasticity should employ a combination of multiple assessments.
Rodriguez Lucatero, C.; Schaum, A.; Alarcon Ramos, L.; Bernal-Jaquez, R.
2014-07-01
In this study, the dynamics of decisions in complex networks subject to external fields are studied within a Markov process framework using nonlinear dynamical systems theory. A mathematical discrete-time model is derived using a set of basic assumptions regarding the convincement mechanisms associated with two competing opinions. The model is analyzed with respect to the multiplicity of critical points and the stability of extinction states. Sufficient conditions for extinction are derived in terms of the convincement probabilities and the maximum eigenvalues of the associated connectivity matrices. The influences of exogenous (e.g., mass media-based) effects on decision behavior are analyzed qualitatively. The current analysis predicts: (i) the presence of fixed-point multiplicity (with a maximum number of four different fixed points), multi-stability, and sensitivity with respect to the process parameters; and (ii) the bounded but significant impact of exogenous perturbations on the decision behavior. These predictions were verified using a set of numerical simulations based on a scale-free network topology.
Systemic hydrocortisone/cortisol induces allergic skin reactions in presensitized subjects.
Lauerma, A I; Reitamo, S; Maibach, H I
1991-02-01
To determine whether systemic hydrocortisone can elicit allergic skin reactions in patients with contact hypersensitivity to hydrocortisone, we studied four patients with contact hypersensitivity to hydrocortisone and hydrocortisone-17-butyrate and two patients with contact hypersensitivity to hydrocortisone-17-butyrate but not to hydrocortisone. Open oral provocation with 100 or 250 mg hydrocortisone in patients with hydrocortisone contact hypersensitivity elicited cutaneous reactions at sites of previous allergic dermatitis caused by hydrocortisone in two patients and at sites of earlier allergic patch test reactions caused by hydrocortisone in the other two patients. Provocations in two patients with contact hypersensitivity to hydrocortisone-17-butyrate but not to hydrocortisone remained negative. To determine whether the adrenal cortical hormone cortisol, which is identical to hydrocortisone, could induce similar skin reactions, one patient with hydrocortisone contact hypersensitivity underwent adrenocorticotropic hormone stimulation tests; as a control, one hydrocortisone-sensitive patient underwent analogous provocations with placebo. After an 8-hour infusion with the adrenocorticotropic hormone analog tetracosactide, a similar skin reaction to that seen with oral hydrocortisone was observed, whereas provocations with placebo remained negative. We conclude that both oral hydrocortisone and intrinsic cortisol are able to induce allergic skin reactions in presensitized subjects.
Silvester, J. P.; Newton, R.; Klingbiel, P. H.
1984-01-01
The NASA Lexical Dictionary (NLD), a system that automatically translates input subject terms to those of NASA, was developed in four phases. Phase One provided Phrase Matching, a context sensitive word-matching process that matches input phrase words with any NASA Thesaurus posting (i.e., index) term or Use reference. Other Use references have been added to enable the matching of synonyms, variant spellings, and some words with the same root. Phase Two provided the capability of translating any individual DTIC term to one or more NASA terms having the same meaning. Phase Three provided NASA terms having equivalent concepts for two or more DTIC terms, i.e., coordinations of DTIC terms. Phase Four was concerned with indexer feedback and maintenance. Although the original NLD construction involved much manual data entry, ways were found to automate nearly all but the intellectual decision-making processes. In addition to finding improved ways to construct a lexical dictionary, applications for the NLD have been found and are being developed.
The response of endocrine system to stress loads during space flight in human subject.
Macho, L; Koska, J; Ksinantova, L; Pacak, K; Hoff, T; Noskov, V B; Grigoriev, A I; Vigas, M; Kvetnansky, R
2003-01-01
The responses of endocrine system to the exposure to stress-work load and hormonal changes during oral glucose tolerance tests were studied in the Slovak astronaut before (three weeks before flight), during (on the 4th and the 6th days of space flight), and after space flight (1-3 days and 15-17 days after space flight) on board of space station MIR. Blood samples during the tests were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transferred to Earth in special container for hormonal analysis. Preflight workload produced an increase of plasma norepinephrine and a moderate elevation of epinephrine levels. Plasma levels of insulin, growth hormone, prolactin and cortisol were not markedly changed immediately or 10 min after the end of work load. The higher increases of plasma growth hormone, prolactin and catecholamine levels were noted after workload during space flight as compared to preflight response. The higher plasma glucose and insulin levels were noted during the oral glucose tolerance test in space flight and also in the post flight period. Plasma epinephrine levels were slightly decreasing during glucose tolerance test; however, plasma norepinephrine levels were not changed. The similar patterns of catecholamine levels during glucose tolerance test were found when compared the preflight, in-flight and post flight values. These data demonstrate the changes of the dynamic responses of endocrine system to stress-work and metabolic loads during space flight in human subject.
The response of endocrine system to stress loads during space flight in human subject
Macho, L.; Koška, J.; Kšinantová, L.; Pacak, K.; Hoff, T.; Noskov, V. B.; Grigoriev, A. I.; Vigaš, M.; Kvetňanský, R.
The responses of endocrine system to the exposure to stress-work load and hormonal changes during oral glucose tolerance tests were studied in the Slovak astronaut before (three weeks before flight), during (on the 4th and the 6th days of space flight), and after space flight (1-3 days and 15-17 days after space flight) on board of space station MIR. Blood samples during the tests were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transforred to Earth in special container for hormonal analysis. Preflight workload produced an increase of plasma norepinephrine and a moderate elevation of epinephrine levels. Plasma levels of insulin, growth hormone, prolactin and cortisol were not markedly changed immediately or 10 min after the end of work load. The higher increases of plasma growth hormone, prolactin and catecholamine levels were noted after workload during space flight as compared to preflight response. The higher plasma glucose and insulin levels were noted during the oral glucose tolerance test in space flight and also in the post flight period. Plasma epinephrine levels were slightly decreasing during glucose tolerance test; however, plasma norepinephrine levels were not changed. The similar patterns of catecholamine levels during glucose tolerance test were found when compared the preflight, in-flight and post flight values. These data demonstrate the changes of the dynamic responses of endocrine system to stress-work and metabolic loads during space flight in human subject.
Institute of Scientific and Technical Information of China (English)
XIAO Dong-hai; TAN Chun-lu; WANG Jun-qiang; ZHONG Yuan-chang
2007-01-01
To fit the complicated geographic conditions of the Three Gorges Reservoir area, a two-level multi-objective monitoring system was developed to monitor the atmosphere of the area. Statistical analysis of environmental monitoring data and the macro control principle were employed to configure the upper layer. The lower layer was designed by the application of the thumb rule to a local terrain and specific point sources of pollution therein. The optimized two-level system comprises an upper layer of 16 monitoring stations distributed at places of diverse geographical, ecological, economical and social characteristics, and a lower layer of 16 sub-machines at each monitoring station of the upper layer. This optimal outcome fits the complicated conditions of the Three Gorges Reservoir area, substantially cuts down the installation cost and the operation cost, and provides accurate monitoring data of atmosphere over the entire area with a high resolution.
Economic-mathematical model of two-level minimax program control of economic security of a region
Directory of Open Access Journals (Sweden)
Andrey Fyodorovich Shorikov
2014-09-01
Full Text Available This article discusses a discrete-time dynamical system consisting of a set of a controllable objects (region and forming it municipalities. The dynamics each of these is described by the corresponding vector linear discrete-time recurrent relations, and its control system consist from two levels: basic (control level I that is dominating and subordinate level (control level II. Both levels have different criterions of functioning and united a priori by determined informational and control connections defined in advance. Considered addresses the problem of optimization of management of economic security of the region in the presence of risks. For the investigated problem is proposed in this work an economic-mathematical model of two-level hierarchical minimax program control of economic security of the region in the presence of risk and the general scheme of the solution.
Evaluation of a smartphone-based assessment system in subjects with chronic ankle instability.
Chiu, Ya-Lan; Tsai, Yi-Ju; Lin, Chueh-Ho; Hou, You-Ruei; Sung, Wen-Hsu
2017-02-01
Ankle sprain is the most common sports-related injury, and approximately 80% of patients studied suffered recurrent sprains. These repeated ankle injuries could cause chronic ankle instability, a decrease in sports performance, and a decrease in postural control ability. At the present time, smartphones have become very popular and powerful devices, and smartphone applications (apps) that have been shown to have good validity have been designed to measure human body motion. However, the app focusing on ankle function assessment and rehabilitation is still not widely used and has very limited functions. The purpose of this study is to evaluate the feasibility of smartphone-based systems in the assessment of postural control ability for patients with chronic ankle instability. Fifteen physically active adults (6 male, 9 female; aged = 23.4 ± 5.28 years; height = 167.13 ± 7.3 cm; weight = 62.06 ± 10.82 kg; BMI = 22.08 ± 2.57 kg/ m(2)) were recruited, and these participants had at least one leg that was evaluated as scoring lower than 27 points according to the Cumberland Ankle Instability Tool (CAIT). The smartphone used in the study was ASUS Zenfone 2, and an app developed using MIT App Inventor was used to record built-in accelerometer data during the assessment process. Subjects were asked to perform single leg stance for 20 s in eyes-open and eyes-closed conditions with each leg. The smartphone was fixed in an upright position on the middle of the shin, using an exercise armband, with the screen facing forward. The average of recorded acceleration data was used to represent the postural control performance, and higher values indicated more instability. Data were analyzed with a paired t-test with SPSS 17.0, and the statistical significance was set as alpha smartphone software can be used to discriminate between the different performances of the healthier leg and injured leg, and also between eyes-open and eyes
Information Entropy. and Squeezing of Quantum Fluctuations in a Two-Level Atom
Institute of Scientific and Technical Information of China (English)
FANG Mao-Fa; ZHOU Peng; S. Swain
2000-01-01
We study the atomic squeezing in the language of the quantum information theory. A rigorous entropy uncertainty relation which suits for characterizing the squeezing of a two-level atoms is obtained, and a general definition of information entropy squeezing in the two-level atoms is given. The information entropy squeezing of two-level atoms interacting with a single-mode quantum field is examined. Our results show that the information entropy is a superior measure of the quantum uncertainty of atomic observable, also is a remarkable good precision measure of atomic squeezing. When the population difference of two-level atom is zero, the definition of atomic squeezing based on the Heisenberg uncertainty relation is trivial, while the definition of information entropy squeezing of the atom based on the entropy uncertainty relation is valid and can provide full information on the atomic squeezing in any cases.
Dispersion management for two-level optically labeled signals in IP-over-WDM networks 4
DEFF Research Database (Denmark)
Chi, Nan; Carlsson, Birger; Holm-Nielsen, Pablo Villanueva;
2002-01-01
The transmission characteristics of a two-level optically labeled signal with ASK/DPSK modulation are investigated under varying dispersion management. A limitation of extinction ratio and the resilience of fiber span, compensation ratio, and power level are obtained...
Can Hare's two-level utilitarianism overcome the problems facing act-utilitarianism?
Roberts, Emma
2012-01-01
In order to provide a positive defence of utilitarianism, R.M Hare presented his own theory of 'two-level' utilitarianism, claiming that it overcame the main objections directed towards traditional act utilitarianism. This essay firstly outlines the main problems associated with utilitarianism and examines whether Hare's theory is indeed able to successfully overcome them. It then goes on to examine the coherence of two-level utilitarianism itself, and thus determine whether it can provide a ...
Jones, Richard L; Richard T Lester; Neil E Brown
1995-01-01
OBJECTIVE: To investigate the short term effects of high frequency chest compression (HFCC) on several indices of respiratory system mechanics in normal subjects and patients with cystic fibrosis (CF).DESIGN: Comparative physiological approach. Subjects were blinded to 10 randomized HFCC settings (5, 10, 15, 20 and 25 Hz) with each applied at the lowest and at the highest background vest pressure.SETTING: Pulmonary function and lung mechanics laboratory, University of Alberta.PARTICIPANTS: Te...
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available This paper presents sufficient conditions of asymptotic stability for discrete-time linear systems subject to actuator saturations with an output feedback law. The derived stability results are given in terms of LMIs. A new proof is presented to obtain previous conditions of asymptotic stability. A numerical example is used to illustrate this technique by using a linear optimization problem subject to LMI constraints.
Proposing a two-level stochastic model for epileptic seizure genesis.
Shayegh, F; Sadri, S; Amirfattahi, R; Ansari-Asl, K
2014-02-01
By assuming the brain as a multi-stable system, different scenarios have been introduced for transition from normal to epileptic state. But, the path through which this transition occurs is under debate. In this paper a stochastic model for seizure genesis is presented that is consistent with all scenarios: a two-level spontaneous seizure generation model is proposed in which, in its first level the behavior of physiological parameters is modeled with a stochastic process. The focus is on some physiological parameters that are essential in simulating different activities of ElectroEncephaloGram (EEG), i.e., excitatory and inhibitory synaptic gains of neuronal populations. There are many depth-EEG models in which excitatory and inhibitory synaptic gains are the adjustable parameters. Using one of these models at the second level, our proposed seizure generator is complete. The suggested stochastic model of first level is a hidden Markov process whose transition matrices are obtained through analyzing the real parameter sequences of a seizure onset area. These real parameter sequences are estimated from real depth-EEG signals via applying a parameter identification algorithm. In this paper both short-term and long-term validations of the proposed model are done. The long-term synthetic depth-EEG signals simulated by this model can be taken as a suitable tool for comparing different seizure prediction algorithms.
Regular and Chaotic Quantum Dynamics of Two-Level Atoms in a Selfconsistent Radiation Field
Konkov, L. E.; Prants, S. V.
1996-01-01
Dynamics of two-level atoms interacting with their own radiation field in a single-mode high-quality resonator is considered. The dynamical system consists of two second-order differential equations, one for the atomic SU(2) dynamical-group parameter and another for the field strength. With the help of the maximal Lyapunov exponent for this set, we numerically investigate transitions from regularity to deterministic quantum chaos in such a simple model. Increasing the collective coupling constant b is identical with 8(pi)N(sub 0)(d(exp 2))/hw, we observed for initially unexcited atoms a usual sharp transition to chaos at b(sub c) approx. equal to 1. If we take the dimensionless individual Rabi frequency a = Omega/2w as a control parameter, then a sequence of order-to-chaos transitions has been observed starting with the critical value a(sub c) approx. equal to 0.25 at the same initial conditions.
Preventing IP Source Address Spoofing: A Two-Level,State Machine-Based Method
Institute of Scientific and Technical Information of China (English)
BI Jun; LIU Bingyang; WU Jianping; SHEN Yan
2009-01-01
A signature-and-verification-based method, automatic peer-to-peer anti-spoofing (APPA), is pro-posed to prevent IP source address spoofing. In this method, signatures are tagged into the packets at the source peer, and verified and removed at the verification peer where packets with incorrect signatures are filtered. A unique state machine, which is used to generate signatures, is associated with each ordered pair of APPA peers. As the state machine automatically transits, the signature changes accordingly. KISS ran-dom number generator is used as the signature generating algorithm, which makes the state machine very small and fast and requires very low management costs. APPA has an intre-AS (autonomous system) level and an inter-AS level. In the intra-AS level, signatures are tagged into each departing packet at the host and verified at the gateway to achieve finer-grained anti-spoofing than ingress filtering. In the inter-AS level, signatures are tagged at the source AS border router and verified at the destination AS border muter to achieve prefix-level anti-spoofing, and the automatic state machine enables the peers to change signatures without negotiation which makes APPA attack-resilient compared with the spoofing prevention method. The results show that the two levels are both incentive for deployment, and they make APPA an integrated anti-spoofing solution.
Institute of Scientific and Technical Information of China (English)
牟蕾; 孙晔; 王克勤; 朱姗; 赵忠川
2013-01-01
多校区教学是大众化教育背景下，随着招生规模扩大而产生的一种新的教学模式。作为一种并不成熟的教学管理模式，其所面临的一系列问题使得高校教学质量与保障体系受到了挑战。因此，国内外诸多机构和学者纷纷对此开展了多方位、多层次的研究。文章在简要概述目前多校区两级教学质量监控和保障体系研究现状的基础上，指出了目前在该领域研究中的一些空白和不足，为今后在确定该领域的研究探索方向提供思路。%In the context of popular education, multiple-campus teaching is a brand-new type of model of teaching with the expansion of enrolment amount. As a kind of immature teaching management mode, multiple-campus teaching faces a serial of obstacles which challenge the effective teaching quality and security system. Therefore, many an institution and scholar at home and abroad conducted all round and multi-level studies on it. Based on the research status of the brief overview of the present multi-campus and two stage teaching quality monitoring and security system, the paper points out some gap and weakness in the present research field and pave the way for future exploration and study.
DEFF Research Database (Denmark)
Vogel, A; Bhattacharya, S; Larsen, J L
2011-01-01
impaired patients only 18.2% had significantly higher PDQ scores than the normal range. PDQ scores were highly correlated to depressive symptoms (r = 0.67, p correlated with subjective cognitive complaints. When these variables and self...
Dissociable neural systems for timing: evidence from subjects with basal ganglia lesions.
Directory of Open Access Journals (Sweden)
H Branch Coslett
Full Text Available BACKGROUND: The neural basis of timing remains poorly understood. Although controversy persists, many lines of evidence, including studies in animals, functional imaging studies in humans and lesion studies in humans and animals suggest that the basal ganglia are important for temporal processing [1]. METHODOLOGY/PRINCIPAL FINDINGS: We report data from a wide range of timing tasks from two subjects with disabling neurologic deficits caused by bilateral lesions of the basal ganglia. Both subjects perform well on tasks assessing time estimation, reproduction and production tasks. Additionally, one subject performed normally on psychophysical tasks requiring the comparison of time intervals ranging from milliseconds to seconds; the second subject performed abnormally on the psychophysical task with a 300ms standard but did well with 600ms, 2000ms and 8000ms standards. Both subjects performed poorly on an isochronous rhythm production task on which they are required to maintain rhythmic tapping. CONCLUSIONS/SIGNIFICANCE: As studies of subjects with brain lesions permit strong inferences regarding the necessity of brain structures, these data demonstrate that the basal ganglia are not crucial for many sub- or supra-second timing operations in humans but are needed for the timing procedures that underlie the production of movements. This dissociation suggests that distinct and dissociable processes may be employed to measure time intervals. Inconsistencies in findings regarding the neural basis of timing may reflect the availability of multiple temporal processing routines that are flexibly implemented in response to task demands.
Kochar, Bharati; Martin, Christopher F; Kappelman, Michael D; Spiegel, Brennan M; Chen, Wenli; Sandler, Robert S; Long, Millie D
2017-08-29
Patient reported outcomes (PROs) are important treatment endpoints in inflammatory bowel diseases (IBD). We evaluated the gastrointestinal (GI) PRO Measurement Information System (PROMIS) in IBD subjects. Crohn's and Colitis Foundation of America's Partners is an Internet-based cohort of IBD subjects. Participants complete surveys, including demographics, disease characteristics, PROMIS domains, disease activity (short Crohn's disease activity index or simple clinical colitis activity index) and quality of life (QoL) indices. In a nested cross-sectional study, we used univariate and bivariate analyses to assess associations between 8 GI-PROMIS domains (reflux, swallowing, diarrhea, nausea, belly pain, gas, incontinence, and constipation) and QoL and disease activity indices. The study included 2,378 Crohn's Disease (CD) and 1,455 ulcerative colitis (UC) respondents with a median age of 41 years. Median disease duration was 11 years for CD subjects and 8 years for UC subjects; 57% of CD subjects and 42% of UC subjects were in remission. Among symptomatic CD subjects, those with active CD reported significantly worse symptoms on all 8 domains than those in remission. The same was observed for UC subjects with the exception of disrupted swallowing. IBD subjects with worse QoL reported significantly worse symptoms on all 8 domains compared to those with better QoL. In IBD subjects experiencing GI symptoms, GI-PROMIS domains were strongly associated with disease activity and QoL indices. GI-PROMIS holds potential as PRO measures in IBD and correlates with other validated indices in this population.Am J Gastroenterol advance online publication, 29 August 2017; doi:10.1038/ajg.2017.240.
Linel, Patrice; Wu, Shuang; Deng, Nan; Wu, Hulin
2014-10-01
Recent studies demonstrate that human blood transcriptional signatures may be used to support diagnosis and clinical decisions for acute respiratory viral infections such as influenza. In this article, we propose to use a newly developed systems biology approach for time course gene expression data to identify significant dynamically response genes and dynamic gene network responses to viral infection. We illustrate the methodological pipeline by reanalyzing the time course gene expression data from a study with healthy human subjects challenged by live influenza virus. We observed clear differences in the number of significant dynamic response genes (DRGs) between the symptomatic and asymptomatic subjects and also identified DRG signatures for symptomatic subjects with influenza infection. The 505 common DRGs shared by the symptomatic subjects have high consistency with the signature genes for predicting viral infection identified in previous works. The temporal response patterns and network response features were carefully analyzed and investigated.
Directory of Open Access Journals (Sweden)
M. R. Abdullah
2017-02-01
Full Text Available This study aims to identify the essential performance indicators in two level of soccer expertise. A total of 84 elite’s soccer players and 100 novice players from eight soccer academies in Malaysia were enrolled and subjected to standard anthropometric, fitness, skills related performance testing and responded to the questionnaire in mastery and performance. Principal component analysis (PCA was employed to determine the most indispensable variables pertinent to the requirement of the game in relation to the level of expertise of the players. The initial PCA shows seven components out of 26 as the most significant for both elite and novice soccer players with a considerable eigenvalue > 1. Moreover, the PCA after varimax rotation highlighted seven principles components (PCs for elite and novice players respectively. Each of the seven components contained varifactors (VF selected based on their higher factor loading and that distinguish the players on their expertise. The first PCs for elite’s players revealed strong loading from sit and reach (0.780, vertical jump (0.635, VO2max (0.637 and age (0.752. The second PCs revealed weight (0.639, biceps (0.859, triceps (0.769, subscapular (0.847, suprailiac (0.886 and middle upper arm circumference (0.776. The third PCs revealed 505 agility (0.618, 5m speed (0.712, 10m speed (0.858 and 20m speed (0.929. The forth PCs revealed task (-0.675 and short pass (0.789 and the last PCs revealed sit up (-0.702. For novice’s players, the first PCs revealed vertical jump (0.624, weight (0.861, height (0.856, sitting height (0.632, middle upper arm circumference (0.673, calf circumference (0.790 and maturity (0.651. The second PCs revealed biceps (0.832, triceps (0.899, subscapular (0.816 and suprailiac (0.869. The third PCs revealed 5m speed (-0.847, 10m speed (-0.877, 20m speed (-0.785 and VO2max (0.658. The forth PCs revealed task (0.694 and ego (0.747 and the last PCs revealed short pass (0.766.
Damos, D. L.
1984-01-01
Human factors practitioners often are concerned with mental workload in multiple-task situations. Investigations of these situations have demonstrated repeatedly that individuals differ in their subjective estimates of workload. These differences may be attributed in part to individual differences in definitions of workload. However, after allowing for differences in the definition of workload, there are still unexplained individual differences in workload ratings. The relation between individual differences in multiple-task performance, subjective estimates of workload, information processing abilities, and the Type A personality trait were examined.
Iwata, Chihiro; Abe, Chikara; Tanaka, Kunihiko; Morita, Hironobu
2011-05-16
Arterial pressure (AP) is known to fluctuate during parabolic-flight-induced gravitational changes in human subjects, increasing during hypergravity and decreasing during microgravity. In this study, we examined whether the vestibular system participates in the AP response to the gravitational changes induced by parabolic flight in human subjects. Eight subjects performed parabolic flights in a supine position as their AP was measured. Their vestibular inputs during the gravitational changes were reversibly masked by artificial electrical stimulation (galvanic vestibular stimulation, GVS). The AP responses during the parabolas were then compared between the GVS-off and GVS-on conditions. AP increased during hypergravity and decreased during microgravity. The AP responses at the onset of hypergravity and microgravity were abolished by GVS. These results indicate that the vestibular system elicits pressor and depressor responses during parabolic-flight-induced hypergravity and microgravity, respectively. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Quantum Otto engine of a two-level atom with single-mode fields.
Wang, Jianhui; Wu, Zhaoqi; He, Jizhou
2012-04-01
We establish a quantum Otto engine (QOE) of a two-level atom, which is confined in a one-dimensional (1D) harmonic trap and is coupled to single-mode radiation fields. Besides two adiabatic processes, the QOE cycle consists of two isochoric processes, along one of which the two-level atom as the working substance interacts with a single-mode radiation field. Based on the semigroup approach, we derive the time for completing any adiabatic process and then present a performance analysis of the heat engine model. Furthermore, we generalize the results to the performance optimization for a QOE of a single two-level atom trapped in a 1D power-law potential. Our result shows that the efficiency at maximum power output is dependent on the trap exponent θ but is independent of the energy spectrum index σ.
Two-Level Solutions to Exponentially Complex Problems in Glass Science
DEFF Research Database (Denmark)
Mauro, John C.; Smedskjær, Morten Mattrup
Glass poses an especially challenging problem for physicists. The key to making progress in theoretical glass science is to extract the key physics governing properties of practical interest. In this spirit, we discuss several two-level solutions to exponentially complex problems in glass science....... Topological constraint theory, originally developed by J.C. Phillips, is based on a two-level description of rigid and floppy modes in a glass network and can be used to derive quantitatively accurate and analytically solvable models for a variety of macroscopic properties. The temperature dependence...... of the floppy mode density is used to derive the new MYEGA model of supercooled liquid viscosity, which offers improved descriptions for the temperature and composition dependence of relaxation time. The relaxation behavior of the glassy state can be further elucidated using a two-level energy landscape...
Quantum Otto engine of a two-level atom with single-mode fields
Wang, Jianhui; Wu, Zhaoqi; He, Jizhou
2012-04-01
We establish a quantum Otto engine (QOE) of a two-level atom, which is confined in a one-dimensional (1D) harmonic trap and is coupled to single-mode radiation fields. Besides two adiabatic processes, the QOE cycle consists of two isochoric processes, along one of which the two-level atom as the working substance interacts with a single-mode radiation field. Based on the semigroup approach, we derive the time for completing any adiabatic process and then present a performance analysis of the heat engine model. Furthermore, we generalize the results to the performance optimization for a QOE of a single two-level atom trapped in a 1D power-law potential. Our result shows that the efficiency at maximum power output is dependent on the trap exponent θ but is independent of the energy spectrum index σ.
Two-level system in spin baths: non-adiabatic dynamics and heat transport.
Segal, Dvira
2014-04-28
We study the non-adiabatic dynamics of a two-state subsystem in a bath of independent spins using the non-interacting blip approximation, and derive an exact analytic expression for the relevant memory kernel. We show that in the thermodynamic limit, when the subsystem-bath coupling is diluted (uniformly) over many (infinite) degrees of freedom, our expression reduces to known results, corresponding to the harmonic bath with an effective, temperature-dependent, spectral density function. We then proceed and study the heat current characteristics in the out-of-equilibrium spin-spin-bath model, with a two-state subsystem bridging two thermal spin-baths of different temperatures. We compare the behavior of this model to the case of a spin connecting boson baths, and demonstrate pronounced qualitative differences between the two models. Specifically, we focus on the development of the thermal diode effect, and show that the spin-spin-bath model cannot support it at weak (subsystem-bath) coupling, while in the intermediate-strong coupling regime its rectifying performance outplays the spin-boson model.
Russian Education and Society, 2013
2013-01-01
Teacher education programs in Russia need to be redesigned to be suitable for the changes that have occurred in Russian society, and also to equip teachers to help students connect with their local cultures and ethnicities.
Fidelity decay in interacting two-level boson systems: Freezing and revivals
Benet, Luis; Hernández-Quiroz, Saúl; Seligman, Thomas H.
2011-05-01
We study the fidelity decay in the k-body embedded ensembles of random matrices for bosons distributed in two single-particle states, considering the reference or unperturbed Hamiltonian as the one-body terms and the diagonal part of the k-body embedded ensemble of random matrices and the perturbation as the residual off-diagonal part of the interaction. We calculate the ensemble-averaged fidelity with respect to an initial random state within linear response theory to second order on the perturbation strength and demonstrate that it displays the freeze of the fidelity. During the freeze, the average fidelity exhibits periodic revivals at integer values of the Heisenberg time tH. By selecting specific k-body terms of the residual interaction, we find that the periodicity of the revivals during the freeze of fidelity is an integer fraction of tH, thus relating the period of the revivals with the range of the interaction k of the perturbing terms. Numerical calculations confirm the analytical results.
Fidelity decay in interacting two-level boson systems: Freezing and revivals
Benet, Luis; Seligman, Thomas H
2011-01-01
We study the fidelity decay in the $k$-body embedded ensembles of random matrices for bosons distributed in two single-particle states, considering the reference or unperturbed Hamiltonian as the one-body terms and the diagonal part of the $k$-body embedded ensemble of random matrices, and the perturbation as the residual off-diagonal part of the interaction. We calculate the ensemble-averaged fidelity with respect to an initial random state within linear response theory to second order on the perturbation strength, and demonstrate that it displays the freeze of the fidelity. During the freeze, the average fidelity exhibits periodic revivals at integer values of the Heisenberg time $t_H$. By selecting specific $k$-body terms of the residual interaction, we find that the periodicity of the revivals during the freeze of fidelity is an integer fraction of $t_H$, thus relating the period of the revivals with the range of the interaction $k$ of the perturbing terms. Numerical calculations confirm the analytical re...
Dynamical properties of a two-level system with arbitrary nonlinearities
Indian Academy of Sciences (India)
Mahmoud Abdel-Aty; Nour A Zidan
2003-09-01
We investigate some aspects of a generalized JC-model which include arbitrary forms of non-linearities of both the ﬁeld and the intensity-dependent atom–ﬁeld coupling. We obtain an exactly analytic solution of the model, by means of which we identify and numerically demonstrate the region of parameters where signiﬁcantly large entanglement can be obtained.
Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence
Institute of Scientific and Technical Information of China (English)
Zhang Jian; Shao Bin; Zou Jian
2009-01-01
In this paper,we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling.We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially.The effects of the field squeezing factor,the two-level atomic transition frequency,the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed.Without intrinsic decoherence,the increase of field squeezing factor can break the entropy squeezing.The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing.The influence of the second field frequency is complicated.With the intrinsic decoherence taken into consideration,the results show that the stronger the intrinsic decoherence is,the more quickly the entropy squeezing will disappear.The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing.
2015-03-23
developed from the spectral finite element method (SFEM) in order to expand its high fidelity performance to study nonlinear wave propagation. Later...severe conditions. 15. SUBJECT TERMS Impact Response, Nonlinear Wave Propagation, Spectral Finite Element Method, Wavelets, Force Identification 16...subtitle with volume number and part number, if applicable. On classified documents, enter the title classification in parentheses. 5a. CONTRACT
A modified two-level three-phase quasi-soft-switching inverter
DEFF Research Database (Denmark)
Liu, Yusheng; Wu, Weimin; Blaabjerg, Frede;
2014-01-01
to reduce the extra conduction power loss and the voltage stress across the DC-link capacitor, a modified two-level three-phase quasi-soft-switching inverter is proposed by using a SiC MOSFET instead of an IGBT. The principle of the modified two-level three-phase quasi-soft-switching inverter is analyzed...... in detail. And the performance is verified through simulations and experiments on a 5 kW/380 V three-phase prototype....
Fundamentals of PV Efficiency Interpreted by a Two-Level Model
Alam, Muhammad A
2012-01-01
Elementary physics of photovoltaic energy conversion in a two-level atomic PV is considered. We explain the conditions for which the Carnot efficiency is reached and how it can be exceeded! The loss mechanisms - thermalization, angle entropy, and below-bandgap transmission - explain the gap between Carnot efficiency and the Shockley-Queisser limit. Wide varieties of techniques developed to reduce these losses (e.g., solar concentrators, solar-thermal, tandem cells, etc.) are reinterpreted by using a two level model. Remarkably, the simple model appears to capture the essence of PV operation and reproduce the key results and important insights that are known to the experts through complex derivations.
A two-level cache for distributed information retrieval in search engines.
Zhang, Weizhe; He, Hui; Ye, Jianwei
2013-01-01
To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users' logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.
A Two-Level Cache for Distributed Information Retrieval in Search Engines
Directory of Open Access Journals (Sweden)
Weizhe Zhang
2013-01-01
Full Text Available To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users’ logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.
Directory of Open Access Journals (Sweden)
Faustina K. Idu
2015-03-01
Full Text Available Aim: To investigate the effect of dehydration on intraocular pressure (IOP. Subjects: The study population comprised 50 subjects (27 men and 23 women with a mean age of 42.84 ± 2.64 years.Method: The subjects dehydrated for 18 hours. IOP was assessed in both eyes using the Perkins handheld applanation tonometer. Baseline measurement of IOP was taken before the subjects dehydrated for 18 hours and repeated after dehydration. Blood samples were taken before and after dehydration for the determination of plasma osmolality and plasma antidiuretic hormone (ADH concentrations.Results: A statistically significant (p < 0.001 reduction in the mean weight of subjects occurred after dehydration. There was a significant reduction in IOP from 16.68 mmHg ± 0.32 mmHg to 13.08 mmHg ± 0.31 mmHg after dehydration (p < 0.001. Mean plasma osmolality showed a statistically significant increase (p < 0.05 from baseline of 290.02 mOsmol/kg ± 1.25 mOsmol/kg to 294.96 mOsmol/kg ± 1.33 mOsmol/kg after dehydration. There was also a significant increase (p < 0.05 in mean plasma ADH concentration from 5.36 pg/mL ± 0.21 pg/mL to 6.40 pg/mL ± 0.20 pg/mL after dehydration. There were no significant differences in both systolic and diastolic blood pressures before and after dehydration.Conclusion: Dehydration decreases IOP in healthy humans; this decrease probably results from an increase in plasma osmolality and plasma ADH concentrations.
Guo, Bao-Zhu; Liu, Jun-Jun; AL-Fhaid, A. S.; Younas, Arshad Mahmood M.; Asiri, Asim
2015-08-01
We consider stabilisation for a linear ordinary differential equation system with input dynamics governed by a heat equation, subject to boundary control matched disturbance. The active disturbance rejection control approach is applied to estimate, in real time, the disturbance with both constant high gain and time-varying high gain. The disturbance is cancelled in the feedback loop. The closed-loop systems with constant high gain and time-varying high gain are shown, respectively, to be practically stable and asymptotically stable.
Institute of Scientific and Technical Information of China (English)
LUO Xiang-Dong; GUO Feng; ZHOU Yu-Rong
2009-01-01
The phenomenon of stochastic resonance (SR) in an asymmetric mono-stable system subject to two external periodic forces and multiplicative and additive noise is investigated.It is shown that the signal-to-noise ratio (SNR) for the fundamental and higher harmonics is a non-monotonic function of the intensities of the multiplicative and additive noise, as well as of the system parameter.Moreover, the SNR for the fundamental harmonic decreases with the increase of the system asymmetry, while the SNR for the higher harmonics behaves non-monotonically as the system asymmetry varies.
Two-level Schwartz methods for nonconforming finite elements and discontinuous coefficients
Sarkis, Marcus
1993-01-01
Two-level domain decomposition methods are developed for a simple nonconforming approximation of second order elliptic problems. A bound is established for the condition number of these iterative methods, which grows only logarithmically with the number of degrees of freedom in each subregion. This bound holds for two and three dimensions and is independent of jumps in the value of the coefficients.
Two-Level Solutions to Exponentially Complex Problems in Glass Science
DEFF Research Database (Denmark)
Mauro, John C.; Smedskjær, Morten Mattrup
Glass poses an especially challenging problem for physicists. The key to making progress in theoretical glass science is to extract the key physics governing properties of practical interest. In this spirit, we discuss several two-level solutions to exponentially complex problems in glass science...
M Sakawa; Kato, K.
2009-01-01
This paper considers stochastic two-level linear programming problems. Using the concept of chance constraints and probability maximization, original problems are transformed into deterministic ones. An interactive fuzzy programming method is presented for deriving a satisfactory solution efficiently with considerations of overall satisfactory balance.
How to Calculate the Exact Angle for Two-level Osteotomy in Ankylosing Spondylitis?
Zheng, Guoquan; Song, Kai; Yao, Ziming; Zhang, Yonggang; Tang, Xiangyu; Wang, Zheng; Zhang, Xuesong; Mao, Keya; Cui, Geng; Wang, Yan
2016-09-01
A prospective case series study. To describe and assess a two-level osteotomy method for the management of severe thoracolumbar kyphosis (TLK) in patients with ankylosing spondylitis (AS). To achieve better postoperative outcomes in these patients, a sophisticated preoperative surgical plan is required. Most deformities are managed using a one-level osteotomy and a two-level osteotomy is seldomly reported. Till date, no study has described a two-level osteotomy for these cases. From January 2011 to December 2012, 10 consecutive patients with ankylosing spondylitis who underwent two-level spinal osteotomy were studied. Pre- and postoperative full-length free-standing radiographs, including the whole spine and pelvis, were available for all patients. Pre- and postoperative radiological parameters, including T5-S1 Cobb angles, TLK, lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, and sagittal vertical axis were measured. Health related quality of life , including Oswestry Disability Index and Scoliosis Research Society-22 surveys were administered before surgery and at 1-year follow up. The preoperative and postoperative T5-S1 Cobb angles was 51.3° and -7.1°, respectively (P osteotomy provides an accurate and reproducible method for ankylosing spondylitis correction. By which, we can obtain satisfactory radiological parameters and clinical outcomes. 4.
On the dependence of the two-level source function on its radiation field.
Steinitz, R.; Shine, R. A.
1973-01-01
The consequences of the universally made assumption that the stimulated emission profile is identical to the absorption profile are quantitatively investigated for a two-level atom with Doppler redistribution. The nonlinear terms arising in the source function are evaluated iteratively. We find that the magnitude of the effects is probably completely negligible for visible and UV solar lines.
Experimental Research into the Two-Level Cylindrical Cyclone with a Different Number of Channels
Directory of Open Access Journals (Sweden)
Egidijus Baliukas
2014-10-01
Full Text Available The multichannel two-level cyclone has been designed for separating solid particles from airflow and built at the Laboratory of Environmental Protection Technologies of Vilnius Gediminas Technical University. The conducted research is aimed at determining air flow distribution at two levels and channels of the multichannel cyclone. The multifunctional meter Testo-400 and the dynamic Pitot tube have been used form easuring air flow rates in the channels. The obtained results show that the equal volume of air gets into two levels installed inside the cyclone, and rates are distributed equally in the channels of these levels. The maximum air flow rate is recorded in the first channel and occurs when half-rings are set in such positions so that 75% of air flow returns to the previous channel. The biggest aerodynamic resistance is 1660 Pa and has been recorded in the cyclone having eight channels under air flow distribution ratio 75/25. The highest air purification efficiency has been observed in the two-level six-channel cyclone under air flow distribution ratio 75/25. The effectiveness of separating granite particles is 92.1% and that of wood particles – 91.1 when the particles are up to 20 μm in diameter.
Psychological Corp., New York, NY.
Under the guidance of an advisory committee from the American Association for Respiratory Therapy (AART), The Psychological Corporation developed three forms of two criterion-referenced proficiency examinations to measure the skills, understandings, and knowledge required in entry level jobs for two levels of respiratory therapy personnel. The…
Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter
DEFF Research Database (Denmark)
Zhou, Dao; Blaabjerg, Frede; Lau, M.
2013-01-01
The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model...
A two-level stochastic collocation method for semilinear elliptic equations with random coefficients
Energy Technology Data Exchange (ETDEWEB)
Chen, Luoping; Zheng, Bin; Lin, Guang; Voulgarakis, Nikolaos
2017-05-01
In this work, we propose a novel two-level discretization for solving semilinear elliptic equations with random coefficients. Motivated by the two-grid method for deterministic partial differential equations (PDEs) introduced by Xu, our two-level stochastic collocation method utilizes a two-grid finite element discretization in the physical space and a two-level collocation method in the random domain. In particular, we solve semilinear equations on a coarse mesh $\\mathcal{T}_H$ with a low level stochastic collocation (corresponding to the polynomial space $\\mathcal{P}_{P}$) and solve linearized equations on a fine mesh $\\mathcal{T}_h$ using high level stochastic collocation (corresponding to the polynomial space $\\mathcal{P}_p$). We prove that the approximated solution obtained from this method achieves the same order of accuracy as that from solving the original semilinear problem directly by stochastic collocation method with $\\mathcal{T}_h$ and $\\mathcal{P}_p$. The two-level method is computationally more efficient, especially for nonlinear problems with high random dimensions. Numerical experiments are also provided to verify the theoretical results.
DEFF Research Database (Denmark)
Bianchi, Federica; Hjortkjær, Jens; Santurette, Sébastien
2017-01-01
in pitch discrimination across all participants, but not within the musicians group alone. Only neural activity in the right auditory cortex scaled with the fine pitch-discrimination thresholds within the musicians. These findings suggest two levels of neuroplasticity in musicians, whereby training...
Constrained Maximum Likelihood Estimation for Two-Level Mean and Covariance Structure Models
Bentler, Peter M.; Liang, Jiajuan; Tang, Man-Lai; Yuan, Ke-Hai
2011-01-01
Maximum likelihood is commonly used for the estimation of model parameters in the analysis of two-level structural equation models. Constraints on model parameters could be encountered in some situations such as equal factor loadings for different factors. Linear constraints are the most common ones and they are relatively easy to handle in…
Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
The present status and subjects on thermal-hydraulic analysis for next-generation light water reactors (LWRs) with passive safety systems were summarized based on survey results and discussion by subcommittee on improvement of reactor thermal-hydraulic analysis codes under nuclear code committee in Japan Atomic Energy Research Institute. This survey was performed to promote the research of improvement of reactor thermal-hydraulic analysis codes in future. In the first part of this report, the status and subjects on system analysis and those on evaluation of passive safety system performance are summarized for various types of reactor proposed before. In the second part, the status and subjects on multidimensional two-phase flow analysis are reviewed, since the multidimensional analysis was recognized as one of most important subjects through the investigation in the first part. Besides, databases for bubbly flow and annular dispersed flow were explored, those are needed to assess and verify each multidimensional analytical method. The contents in this report are the forefront of thermal-hydraulic analysis for LWRs and those include current findings for the development of multidimensional two-phase flow analytical method. Thus, we expect that the contents can offer various useful information against the improvement of reactor thermal-hydraulic analysis codes in future. (author)
Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-01
The present status and subjects on thermal-hydraulic analysis for next-generation light water reactors (LWRs) with passive safety systems were summarized based on survey results and discussion by subcommittee on improvement of reactor thermal-hydraulic analysis codes under nuclear code committee in Japan Atomic Energy Research Institute. This survey was performed to promote the research of improvement of reactor thermal-hydraulic analysis codes in future. In the first part of this report, the status and subjects on system analysis and those on evaluation of passive safety system performance are summarized for various types of reactor proposed before. In the second part, the status and subjects on multidimensional two-phase flow analysis are reviewed, since the multidimensional analysis was recognized as one of most important subjects through the investigation in the first part. Besides, databases for bubbly flow and annular dispersed flow were explored, those are needed to assess and verify each multidimensional analytical method. The contents in this report are the forefront of thermal-hydraulic analysis for LWRs and those include current findings for the development of multidimensional two-phase flow analytical method. Thus, we expect that the contents can offer various useful information against the improvement of reactor thermal-hydraulic analysis codes in future. (author)
DEFF Research Database (Denmark)
Krajcik, Michal; Tomasi, Roberta; Simone, Angela
2013-01-01
mixing ventilation systems was found. The next two tests simulated an office room during summer, ventilated and cooled either by a displacement ventilation system alone or by a displacement ventilation system combined with radiant floor cooling. Displacement ventilation combined with floor cooling had...... lower floor temperature, warmer supply air, and less homogeneous vertical temperature profile, but it did not result in thermal discomfort on feet/lower legs or discomfort due to a vertical air temperature difference higher than for a displacement ventilation system alone, where the floor temperature......Sixteen subjects evaluated the indoor environment in four experiments with different combinations of ventilation systems and radiant heating/cooling systems. In the first two tests, the simulated residential room was equipped either by a mixing ventilation system supplying warm air for space...
Directory of Open Access Journals (Sweden)
C. Marino
2011-10-01
Full Text Available Thermal comfort conditions in the built environment are strictly related not only to the thermal and geometric building features and to air-conditioning systems, but also to the building destination, to its using profile and to the biological-metabolic-psychological characteristics of users. As a consequence, there is a strong claim for new models, both subjective and adaptive to the environment, in aparticular holistic vision of the problem, with regards to the novel tern user-plant-building system. In such a frame, through the paper the characterization of an algorithm aimed at subjective adaptive thermal comfort evaluations, enriching the one proposed by Fanger with an adaptive approach, is carried out using a Multi Agent System (MAS, based on Intelligent Agents, able to follow user’s needs and preferences in different contexts and expectations.
A two-level generative model for cloth representation and shape from shading.
Han, Feng; Zhu, Song-Chun
2007-07-01
In this paper, we present a two-level generative model for representing the images and surface depth maps of drapery and clothes. The upper level consists of a number of folds which will generate the high contrast (ridge) areas with a dictionary of shading primitives (for 2D images) and fold primitives (for 3D depth maps). These primitives are represented in parametric forms and are learned in a supervised learning phase using 3D surfaces of clothes acquired through photometric stereo. The lower level consists of the remaining flat areas which fill between the folds with a smoothness prior (Markov random field). We show that the classical ill-posed problem-shape from shading (SFS) can be much improved by this two-level model for its reduced dimensionality and incorporation of middle-level visual knowledge, i.e., the dictionary of primitives. Given an input image, we first infer the folds and compute a sketch graph using a sketch pursuit algorithm as in the primal sketch [10], [11]. The 3D folds are estimated by parameter fitting using the fold dictionary and they form the "skeleton" of the drapery/cloth surfaces. Then, the lower level is computed by conventional SFS method using the fold areas as boundary conditions. The two levels interact at the final stage by optimizing a joint Bayesian posterior probability on the depth map. We show a number of experiments which demonstrate more robust results in comparison with state-of-the-art work. In a broader scope, our representation can be viewed as a two-level inhomogeneous MRF model which is applicable to general shape-from-X problems. Our study is an attempt to revisit Marr's idea [23] of computing the 2(1/2)D sketch from primal sketch. In a companion paper [2], we study shape from stereo based on a similar two-level generative sketch representation.
Geerse, Daphne J; Coolen, Bert H; Roerdink, Melvyn
2017-03-02
The ability to adapt walking to environmental circumstances is an important aspect of walking, yet difficult to assess. The Interactive Walkway was developed to assess walking adaptability by augmenting a multi-Kinect-v2 10-m walkway with gait-dependent visual context (stepping targets, obstacles) using real-time processed markerless full-body kinematics. In this study we determined Interactive Walkway's usability for walking-adaptability assessments in terms of between-systems agreement and sensitivity to task and subject variations. Under varying task constraints, 21 healthy subjects performed obstacle-avoidance, sudden-stops-and-starts and goal-directed-stepping tasks. Various continuous walking-adaptability outcome measures were concurrently determined with the Interactive Walkway and a gold-standard motion-registration system: available response time, obstacle-avoidance and sudden-stop margins, step length, stepping accuracy and walking speed. The same holds for dichotomous classifications of success and failure for obstacle-avoidance and sudden-stops tasks and performed short-stride versus long-stride obstacle-avoidance strategies. Continuous walking-adaptability outcome measures generally agreed well between systems (high intraclass correlation coefficients for absolute agreement, low biases and narrow limits of agreement) and were highly sensitive to task and subject variations. Success and failure ratings varied with available response times and obstacle types and agreed between systems for 85-96% of the trials while obstacle-avoidance strategies were always classified correctly. We conclude that Interactive Walkway walking-adaptability outcome measures are reliable and sensitive to task and subject variations, even in high-functioning subjects. We therefore deem Interactive Walkway walking-adaptability assessments usable for obtaining an objective and more task-specific examination of one's ability to walk, which may be feasible for both high
Directory of Open Access Journals (Sweden)
N. Farahpour
2004-01-01
Full Text Available The mechanism of the neuromuscular system’s disorders in Adolescent Idiopathic Scoliosis (AIS are not well known. The objectives of this study were to assess the dynamic balance of the AIS patients and the influence of exercise therapy on patients' dynamic balance. Eleven teenager scoliotic subjects after three months exercise therapy, nine similar patients without therapy and 13 healthy age matched subjects as control group were studied. Using dynamic stability platform, the deviation of COG of subjects in different positions, including up right standing, standing with head flexion and standing with head hyper extension were measured. The tests were repeated in both lose and stable condition of the foot platform. Results showed that the stability of the foot platform resulted in COG's deviation by 1.13 0.08 in all subjects. Dynamic balance of scoliotic patients without treatment was similar to that of the normal subjects. While, exercised patients had less COG deviation than the other groups. The change in head position increased the COG deviation by 2.5 times in control and non-exercised patients and 1.5 times in exercised patients. The dynamic balance in scoliosis was not affected. Exercise improved the dynamic balance in scoliotic subjects. Exercise therapy is recommended to improve the proprioceptives function.
Energy Technology Data Exchange (ETDEWEB)
Guerrero Sanz, J.; Perez Alcaniz, T.; Garcia Garcia, I.
2012-07-01
The implementation of a Plan Cybersecurity ensures that systems and communications networks that perform functions related to both physical security such emergency action and their support systems, and interfaces that may affect them, are protected with an effective system against cyber attacks.
Stochastic Predator-Prey System Subject to Lévy Jumps
Directory of Open Access Journals (Sweden)
Xinzhu Meng
2016-01-01
Full Text Available This paper investigates a new nonautonomous impulsive stochastic predator-prey system with the omnivorous predator. First, we show that the system has a unique global positive solution for any given initial positive value. Second, the extinction of the system under some appropriate conditions is explored. In addition, we obtain the sufficient conditions for almost sure permanence in mean and stochastic permanence of the system by using the theory of impulsive stochastic differential equations. Finally, we discuss the biological implications of the main results and show that the large noise can make the system go extinct. Simulations are also carried out to illustrate our theoretical analysis conclusions.
Directory of Open Access Journals (Sweden)
Fangfang Qin
2016-01-01
Full Text Available This paper proposes a two-level additive Schwarz preconditioning algorithm for the weak Galerkin approximation of the second-order elliptic equation. In the algorithm, a P1 conforming finite element space is defined on the coarse mesh, and a stable intergrid transfer operator is proposed to exchange the information between the spaces on the coarse mesh and the fine mesh. With the framework of the Schwarz method, it is proved that the condition number of the preconditioned system only depends on the rate of the coarse mesh size and the overlapping size. Some numerical experiments are carried out to verify the theoretical results.
Institute of Scientific and Technical Information of China (English)
李春先; 方卯发
2003-01-01
We study the squeezing for a two-level atom in the Jaynes-Cummings model with intensity-dependent coupling using quantum information entropy, and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing. Our results show that, the squeezed component number depends on the atomic initial distribution angle, while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing. Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.
An EOQ Model with Stock-Dependent Demand under Two Levels of Trade Credit and Time Value of Money
Directory of Open Access Journals (Sweden)
H.A.O. Jia-Qin
2013-05-01
Full Text Available Since the value of money changes with time, it is necessary to take account of the influence of time factor in making the replenishment policy. In this study, to investigate the influence of the time value of money to the inventory strategy, an inventory system for deteriorating items with stock-dependent demand is investigated under two levels of trade credit. The method to efficiently determine the optimal cycle time is presented. Numerical examples are provided to demonstrate the model and the method.
Baleghi-Zadeh, Sousan; Ayub, Ahmad Fauzi Mohd; Mahmud, Rosnaini; Daud, Shaffe Mohd
2014-12-01
In recent years, the use of learning management system by universities has been increasingly growing. However, the results of several studies have revealed that students do not fully use the information systems. The present study proposes a model which investigates the influence of three constructs of perceived ease of use, perceived usefulness, and subjective norm on behavior intention to use of learning management system. The sample size was 216 Malaysian undergraduate students. The results of the study revealed that the proposed model accounts for 31.1 % variance of behavior intention to use.
DEFF Research Database (Denmark)
Kehayova, Nushka; Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor
2016-01-01
A novel method for local hospital bed ventilation, called HBIVCU (Hospital Bed with Integrated Ventilation and Cleansing Unit), was studied in a human subject experiment. The goal of this study was to identify human response to the microenvironment generated by a hospital bed with installed HBIVCU...... and to compare with human response to the micro-environment at a hospital bed without local ventilation. 32 participants took part in two experimental conditions - hospital bed with and without installed HBIVCU. Subject’s votes on the bed microenvironment were collected via standardized questionnaires...
Stability analysis of direct contact heat exchangers subject to system perturbations
Jacobs, H. R.
1985-01-01
The work deals with the operational stability of a spray column type heat exchanger subject to disturbances typical of those which can occur for geothermal applications. A computer program was developed to solve the one dimensional transient two phase flow problem and it was applied to the design of a spray column. The operation and design of the East Mesa 500kW/sub e/ direct contactor was assessed. It is shown that the heat transfer is governed by the internal resistance of the dispersed phase. The performance is well represented by diffusion of heat within the drops.
Resistance of Concrete Masonry Walls With Membrane Catcher Systems Subjected to Blast Loading
2010-12-01
effectiveness of systems comprised of polymers, composites, geotextiles , and thin steel and aluminum sheets has been researched extensively over the past...secondary debris resulting from blast pressure, and the effectiveness of systems comprising polymers, composites, geotextiles , and thin steel and aluminum...wall structure undergoes large transient displacements. Initially, relatively stiff composite laminates and geotextiles were investigated, including
Organizing for Instruction in Education Systems and School Organizations: "How" the Subject Matters
Spillane, James P.; Hopkins, Megan
2013-01-01
Teaching, the core technology of schooling, is an essential consideration in investigations of education systems and school organizations. Taking teaching seriously as an explanatory variable in research on education systems and organizations necessitates moving beyond treating it as a unitary practice, so as to take account of the school subjects…
A Two-Level Undercut-Profile Substrate for Chemical-Solution-Based Filamentary Coated Conductors
DEFF Research Database (Denmark)
Wulff, Anders Christian; Lundeman, Jesper H.; Hansen, Jørn B.
2016-01-01
. In the present study, the 2LUPS concept is applied to a commercial cube-textured Ni-5at.% W tape, and the surface of the 2LUPS coated with two Gd2Zr2O7 buffer layers using chemical solution deposition is examined. Except for narrow regions near the edge of upper plateaus, the plateaus are found to be covered......A recently developed two-level undercut-profile substrate (2LUPS), containing two levels of plateaus connected by a curved wall with an undercut profile, enables self-forming filaments in a coated conductor during physical line-of-sight deposition of buffer and superconducting layers...... by strongly textured Gd2Zr2O7 buffer layers after dip coating and sintering....
Dynamical decoherence in a cavity with a large number of two-level atoms
Frasca, M
2004-01-01
We consider a large number of two-level atoms interacting with the mode of a cavity in the rotating-wave approximation (Tavis-Cummings model). We apply the Holstein-Primakoff transformation to study the model in the limit of the number of two-level atoms, all in their ground state, becoming very large. The unitary evolution that we obtain in this approximation is applied to a macroscopic superposition state showing that, when the coherent states forming the superposition are enough distant, then the state collapses on a single coherent state describing a classical radiation mode. This appear as a true dynamical effect that could be observed in experiments with cavities.
Two-Level Bregman Method for MRI Reconstruction with Graph Regularized Sparse Coding
Institute of Scientific and Technical Information of China (English)
刘且根; 卢红阳; 张明辉
2016-01-01
In this paper, a two-level Bregman method is presented with graph regularized sparse coding for highly undersampled magnetic resonance image reconstruction. The graph regularized sparse coding is incorporated with the two-level Bregman iterative procedure which enforces the sampled data constraints in the outer level and up-dates dictionary and sparse representation in the inner level. Graph regularized sparse coding and simple dictionary updating applied in the inner minimization make the proposed algorithm converge with a relatively small number of iterations. Experimental results demonstrate that the proposed algorithm can consistently reconstruct both simulated MR images and real MR data efficiently, and outperforms the current state-of-the-art approaches in terms of visual comparisons and quantitative measures.
A novel two-level dielectric barrier discharge reactor for methyl orange degradation.
Tao, Xumei; Wang, Guowei; Huang, Liang; Ye, Qingguo; Xu, Dongyan
2016-12-15
A novel pilot two-level dielectric barrier discharge (DBD) reactor has been proposed and applied for degradation of continuous model wastewater. The two-level DBD reactor was skillfully realized with high space utilization efficiency and large contact area between plasma and wastewater. Various conditions such as applied voltage, initial concentration and initial pH value on methyl orange (MO) model wastewater degradation were investigated. The results showed that the appropriate applied voltage was 13.4 kV; low initial concentration and low initial pH value were conducive for MO degradation. The percentage removal of 4 L MO with concentration of 80 mg/L reached 94.1% after plasma treatment for 80min. Based on ultraviolet spectrum (UV), Infrared spectrum (IR), liquid chromatography-mass spectrometry (LC-MS) analysis of degradation intermediates and products, insights in the degradation pathway of MO were proposed.
Quantum transport in a two-level quantum dot driven by coherent and stochastic fields
Ke, Sha-Sha; Miao, Ling-E.; Guo, Zhen; Guo, Yong; Zhang, Huai-Wu; Lü, Hai-Feng
2016-12-01
We study theoretically the current and shot noise properties flowing through a two-level quantum dot driven by a strong coherent field and a weak stochastic field. The interaction x(t) between the quantum dot and the stochastic field is assumed to be a Gaussian-Markovian random process with zero mean value and correlation function = Dκe - κ | t - t ‧ | , where D and κ are the strength and bandwidth of the stochastic field, respectively. It is found that the stochastic field could enhance the resonant effect between the quantum dot and the coherent field, and generate new resonant points. At the resonant points, the state population difference between two levels is suppressed and the current is considerably enhanced. The zero-frequency shot noise of the current varies dramatically between sub- and super-Poissonian characteristics by tuning the stochastic field appropriately.
Theoretical treatment of the interaction between two-level atoms and periodic waveguides
Zang, Xiaorun
2015-01-01
Light transport in periodic waveguides coupled to a two-level atom is investigated. By using optical Bloch equations and a photonic modal formalism, we derive semi-analytical expressions for the scattering matrix of one atom trapped in a periodic waveguide. The derivation is general, as the expressions hold for any periodic photonic or plasmonic waveguides. It provides a basic building block to study collective effects arising from photon-mediated multi-atom interactions in periodic waveguides.
Spontaneously induced atom-radiation entanglement in an ensemble of two-level atoms
Tesfa, Sintayehu
2007-01-01
Analysis of the spontaneously induced correlation on atom-radiation entanglement in an ensemble of two-level atoms initially prepared in the upper level and placed in a cavity containing a squeezed radiation employing the method of evaluating the coherent-state propagator is presented. It is found that the cavity radiation exhibits squeezing which is directly attributed to the squeezed radiation in the cavity. The intensity of the cavity radiation increases with the squeeze parameter and inte...
Directory of Open Access Journals (Sweden)
Mariana Jesica Lerchundi
2017-01-01
Full Text Available This text wants to compare the main differences between the Faults Code and Coexistence Code of the Province of Córdoba (Argentina taking young people as empirical subjects of reflection, which are the most affected by the regulations. From the content analysis and critical discourse analysis, the differences between the two standards were found. Here are detailed only some of them that allow us to infer changes in the penal system maintaining the violation of rights of young people.
Two-level, two-objective evolutionary algorithms for solving unit commitment problems
Energy Technology Data Exchange (ETDEWEB)
Georgopoulou, Chariklia A.; Giannakoglou, Kyriakos C. [National Technical University of Athens, School of Mechanical Engineering, Laboratory of Thermal Turbomachines, Parallel CFD and Optimization Unit, P.O. Box 64069, Athens 157 10 (Greece)
2009-07-15
A two-level, two-objective optimization scheme based on evolutionary algorithms (EAs) is proposed for solving power generating Unit Commitment (UC) problems by considering stochastic power demand variations. Apart from the total operating cost to cover a known power demand distribution over the scheduling horizon, which is the first objective, the risk of not fulfilling possible demand variations forms the second objective to be minimized. For this kind of problems with a high number of decision variables, conventional EAs become inefficient optimization tools, since they require a high number of evaluations before reaching the optimal solution(s). To considerably reduce the computational burden, a two-level algorithm is proposed. At the low level, a coarsened UC problem is defined and solved using EAs to locate promising solutions at low cost: a strategy for coarsening the UC problem is proposed. Promising solutions migrate upwards to be injected into the high level EA population for further refinement. In addition, at the high level, the scheduling horizon is partitioned in a small number of subperiods of time which are optimized iteratively using EAs, based on objective function(s) penalized to ensure smooth transition from/to the adjacent subperiods. Handling shorter chromosomes due to partitioning increases method's efficiency despite the need for iterating. The proposed two-level method and conventional EAs are compared on representative test problems. (author)
Two-level total disc replacement with Mobi-C(r over 3-years
Directory of Open Access Journals (Sweden)
Reginald Davis
2014-01-01
Full Text Available Objective: To evaluate the safety and effectiveness of two-level total disc replacement (TDR using a Mobi-C(r Cervical Artificial Disc at the 36 month follow-up. Methods: a Prospective, randomized, controlled, multicenter clinical trial of an artificial cervical disc (Mobi-C(r Cervical Artificial Disc was conducted under the Investigational Device Exemptions (IDE and the U.S. Food & Drug Administration (FDA regulations. A total of 339 patients with degenerative disc disease were enrolled to receive either two-level treatment with TDR, or a two-level anterior cervical discectomy and fusion (ACDF as control. The 234 TDR patients and 105 ACDF patients were followed up at regular time points for three years after surgery. Results: At 36 months, both groups demonstrated an improvement in clinical outcome measures and a comparable safety profile. NDI scores, SF-12 PCS scores, patient satisfaction, and overall success indicated greater statistically significant improvement from baseline for the TDR group, in comparison to the ACDF group. The TDR patients experienced lower subsequent surgery rates and a lower rate of adjacent segment degeneration. On average, the TDR patients maintained segmental range of motion through 36 months with no device failure. Conclusion: Results at three-years support TDR as a safe, effective and statistically superior alternative to ACDF for the treatment of degenerative disc disease at two contiguous cervical levels.
Institute of Scientific and Technical Information of China (English)
Ahmad A. Moreb
2007-01-01
Reliability allocation problem is commonly treated using a closed-form expression relating the cost to reliability. A recent approach has introduced the use of discrete integer technique for un-repairable systems. This research addresses the allocation problem for repairable systems. It presents an integer formulation for finding the optimum selection of components based on the integer values of their Mean Time to Failure (MTTF) and Mean Time to Repair (MTTR). The objective is to minimize the total cost under a system reliability constraint, in addition to other physical constraints. Although, a closed-form expression relating the cost to reliability may not be a linear; however, in this research, the objective function will always be linear regardless of the shape of the equivalent continuous closed-form function. An example is solved using the proposed method and compared with the solution of the continuous closed-form version. The formulation for all possible system configurations, components and subsystems are also considered.
Preparation of municipal procurement subjects to work in the contract system
Directory of Open Access Journals (Sweden)
Marina Knyazevа
2014-03-01
Full Text Available The article is devoted to analysis of readiness of municipal servants and employees of budgetary institutions to work in contractual system. The author offers the number of tools, helping to improve the quality of their training.
Improving Ranking Persian Subjects in Search Engine Using Fuzzy Inference System
Directory of Open Access Journals (Sweden)
Elaheh Golzardi
2013-09-01
Full Text Available According to the research, the efficiency of the search engines which done the rankings of Farsi content was much lower than the English search engines. After reviewing the literature, we found that, so far there been no ratings Persian system with fuzzy system and however, due to its proven performance in the field of fuzzy systems, also a search engine designed to accomplish this goal. Therefore, we prefer to advance this goal, so we establish a fuzzy inference system. It is created with the best evidence that can be considered to have been largely bringing the intended page to a user. Proposed method, display the relevant pages to the user in order to allow users to reach to their intended pages with less time and less cost. Also, in order to evaluate this method, Comparisons with other search engines was done.
Buragienė, Sidona; Šarauskis, Egidijus; Romaneckas, Kęstutis; Sasnauskienė, Jurgita; Masilionytė, Laura; Kriaučiūnienė, Zita
2015-05-01
Intensive agricultural production strongly influences the global processes that determine climate change. Thus, tillage can play a very important role in climate change. The intensity of soil carbon dioxide (CO₂) emissions, which contribute to the greenhouse effect, can vary depending on the following factors: the tillage system used, meteorological conditions (which vary in different regions of the world), soil properties, plant residue characteristics and other factors. The main purpose of this research was to analyse and assess the effects of autumn tillage systems with different intensities on CO₂ emissions from soils during different seasons and under the climatic conditions of Central Lithuania. The research was conducted at the Experimental Station of Aleksandras Stulginskis University from 2009 to 2012; and in 2014. The soils at the experimental site were classified as Eutric Endogleyic Planosol (Drainic). The investigations were conducted using five tillage systems with different intensities, typical of the Baltic Region. Deep conventional ploughing was performed at a depth of 230-250 mm, shallow ploughing was conducted at a depth of 120-150 mm, deep loosening was conducted at depths of 250-270 mm, and shallow loosening was conducted at depths of 120-150 mm. The fifth system was a no-tillage system. Overall, autumn tillage resulted in greater CO₂ emissions from the soil over both short- and long-term periods under the climatic conditions of Central Lithuania, regardless of the tillage system applied. The highest soil CO₂ emissions were observed for the conventional deep ploughing tillage system, and the lowest emissions were observed for the no-tillage system. The meteorological conditions greatly influenced the CO₂ emissions from the soil during the spring. Soil CO₂ emissions were enhanced as precipitation and the air and soil temperatures increased. Long-term investigations regarding the dynamics of CO₂ emissions from soils during the maize
Dynamical Consensus Algorithm for Second-Order Multi-Agent Systems Subjected to Communication Delay
Institute of Scientific and Technical Information of China (English)
LIU Cheng-Lin; LIU Fei
2013-01-01
To solve the dynamical consensus problem of second-order multi-agent systems with communication delay,delay-dependent compensations are added into the normal asynchronously-coupled consensus algorithm so as to make the agents achieve a dynamical consensus.Based on frequency-domain analysis,sufficient conditions are gained for second-order multi-agent systems with communication delay under leaderless and leader-following consensus algorithms respectively.Simulation illustrates the correctness of the results.
Effects of small time delay on a bistable system subject to Levy stable noise
Energy Technology Data Exchange (ETDEWEB)
Huang Jiamin; Tao Weiming; Xu Bohou, E-mail: taowm@zju.edu.cn [Department of Mechanics, Zhejiang University, Hangzhou 310027 (China)
2011-09-23
Levy stable noise is often used to describe impulsive noise bursting in communication systems. This paper investigates the effects of small time delay on a bistable system driven by an aperiodic bipolar pulse signal and Levy stable noise. We obtain the dynamical probability density of the system response by solving the approximated time-delayed fractional Fokker-Planck equation (FFPE) via an implicit finite difference method. A new approach to evaluate the system response time is presented. The bit error rate (BER) is employed to measure the performance of the bistable system in detecting binary signals. The theoretical BER is validated by the Monte-Carlo simulation. We find that the existence of time delay can change both the drift term and the diffusion coefficient in time-delayed FFPE. For small noise intensity, the time delay extends the system response time and thus reduces the detection performance. However, effects of this kind will fade away with the increase of noise intensity. (paper)
Energy Technology Data Exchange (ETDEWEB)
Surh, Han-Bum [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ryu, Tae-Young; Park, Jin-Sung [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Ahn, Eun-Woo; Choi, Chul-Sun [Korea Electric Power Corporation Engineering & Construction Company, Inc., 2354 Yonggu-daero, Giheung-gu, Yongin 446-713 (Korea, Republic of); Koo, Ja Choon [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Choi, Jae-Boong [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); Kim, Moon Ki, E-mail: mkkim@me.skku.ac.kr [School of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of); SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746 (Korea, Republic of)
2015-10-15
Highlights: • Piping system in the APR 1400 NPP with a base isolation design is studied. • Seismic response of piping system in base isolated building are investigated. • Stress classification method is examined for piping subjected to seismic loading. • Primary stress of piping is reduced due to base isolation design. • Substantial secondary stress is observed in the main steam piping. - Abstract: In this study, the stress response of the piping system in the advanced power reactor 1400 (APR 1400) with a base isolation design subjected to seismic loading is addressed. The piping system located between the auxiliary building with base isolation and the turbine building with a fixed base is considered since it can be subjected to substantial relative support movement during seismic events. First, the support responses with respect to the base characteristic are investigated to perform seismic analysis for multiple support excitations. Finite element analyses are performed to predict the piping stress response through various analysis methods such as the response spectrum, seismic support movement and time history method. To separately evaluate the inertial effect and support movement effect on the piping stress, the stress is decomposed into a primary and secondary stress using the proposed method. Finally, influences of the base isolation design on the piping system in the APR 1400 are addressed. The primary stress based on the inertial loading is effectively reduced in a base isolation design, whereas a considerable amount of secondary stress is generated in the piping system connecting a base isolated building with a fixed base building. It is also confirmed that both the response spectrum analysis and seismic support movement analysis provide more conservative estimations of the piping stress compared to the time history analysis.
Faintuch, Joel; Horie, Lilian M; Barbeiro, Hermes V; Barbeiro, Denise F; Soriano, Francisco G; Ishida, Robson K; Cecconello, Ivan
2007-03-01
Morbidly obese patients frequently display asymptomatic chronic activation of acute phase response, with potentially adverse metabolic and cardiovascular consequences. Nutritional preparations to improve this phenomenon have rarely been administered. Aiming to investigate the supplementation of flaxseed flour, a source of omega-3 fatty acids, a prospective randomized double-blind cross-over study was designed. Outpatient obese subjects (n=41) were clinically and biochemically screened, and results for 24 randomized subjects are shown. Age was 40.8 +/- 11.6 years (83.3% females) and body mass index (BMI) was 47.1 +/- 7.2 kg/m2. Flaxseed flour (Farinha de Linhaca Dourada LinoLive, Cisbra, Brazil) in the amount of 30 g/day (5 g of alpha-linolenic acid - omega-3) and an equal mass of placebo (manioc flour) were administered for 2 weeks each. Variables included general biochemical investigation, white blood cell count (WBC), C-reactive protein (CRP), serum amyloid A (SAA) and fibronectin. No intolerance was registered. Body weight and general biochemical indices remained stable. Initial CRP and SAA were elevated (13.7 +/- 9.9 and 17.4 +/- 8.0 ). WBC (8100 +/- 2100/mm3) and fibronectin (463.2 +/- 61.3 mg/dL) were acceptable but in the upper normal range. Corresponding findings after supplementation of flaxseed were 10.6 +/- 6.2 mg/L, 14.3 +/- 9.2 mg/L, 7300 +/- 1800/mm3 and 412.8 +/- 38.6 respectively (Pchange during the control period regarding baseline occurred when placebo was randomized to be given first; however, when it followed omega-3 supplementation, CRP and SAA recovered, whereas WBC and fibronection remained depressed during those 2 weeks (7500 +/- 2100/mm3 and 393.2 +/- 75.8 mg/dL, P<0.05). 1) Various inflammatory markers were elevated in the studied population, although not necessarily exceeding the normal range; 2) Significant reduction could be demonstrated; 3) Some persistent effects of flaxseed supplement 2 weeks after discontinuation were observed.
Earth system science. A new subject for study (geo physiology) or a new philosophy?
Energy Technology Data Exchange (ETDEWEB)
Guerzoni, S. [Consiglio Nazionale delle Ricerche, Istituto di Geologia Marina, Bologna (Italy); Harding, S. [Schumacher College, Dartington (United Kingdom); Lenton, T. [Centre for Ecology and Hydrology, Edinburgh Research Station, Bush Estate, Midlothian (United Kingdom); Ricci Lucchi, F. [Bologna Univ., Bologna (Italy). Dipt. Scienze della Terra
2001-07-01
Earth system science is the unifying term for a new approach to studying the planet as a whole. Key to this new science is James Lovelock's Gaia Theory. Lovelock saw that life transforms the atmosphere, oceans and land surface, and that together they form a whole system with remarkable properties of self-regulation and organisation, which he called Gaia. The original Gaia hypothesis became a focal point of debate and inspired a shift in scientific perception towards a more systemic view of the planet. This embraces the coupling between the surface Earth system (Gaia) and the inner Earth system (referred to by some as Vulcan). The influence of Gaia theory has been sufficiently pervasive that most natural scientist now accept that the development of life and its non-living environment are inextricably coupled together. In this work are presented the history of life, the cycling of nutrients and oxygen at different scales. Some chapters are concerned with modelling Gaia from ecological and evolutionary perspectives. At the end of the debate, some philosophical hypothesis about a new analytical and integrative ecology approaches.
Systems Engineering and Safety Issues in Scientific Facilities Subject to Ionizing Radiations
Directory of Open Access Journals (Sweden)
Pierre Bonnal
2013-10-01
Full Text Available The conception and development of large- scale scientific facilities emitting ionizing radiations rely more on project management practices in use in the process industry than on systems engineering practices. This paper aims to highlight possible reasons for this present situation and to propose some ways to enhance systems engineering so that the specific radiation safety requirements are considered and integrated in the approach. To do so, we have reviewed lessons learned from the management of large-scale scientific projects and more specifically that of the Large Hadron Collider project at CERN. It is shown that project management and systems engineering practices are complementary and can beneficially be assembled in an integrated and lean managerial framework that grants the appropriate amount of focus to safety and radiation safety aspects.
Systems Engineering and Safety Issues in Scientific Facilities Subject to Ionizing Radiations
Directory of Open Access Journals (Sweden)
Pierre Bonnal
2013-10-01
Full Text Available The conception and development of large-scale scientific facilities emitting ionizing radiations rely more on project management practices in use in the process industry than on systems engineering practices. This paper aims to highlight possible reasons for this present situation and to propose some ways to enhance systems engineering so that the specific radiation safety requirements are considered and integrated in the approach. To do so, we have reviewed lessons learned from the management of large-scale scientific projects and more specifically that of the Large Hadron Collider project at CERN. It is shown that project management and systems engineering practices are complementary and can beneficially be assembled in an integrated and lean managerial framework that grants the appropriate amount of focus to safety and radiation safety aspects.
Stabilization of ODE-Schrodinger cascaded systems subject to boundary control matched disturbance
Directory of Open Access Journals (Sweden)
Ya-Ping Guo
2015-09-01
Full Text Available In this article, we consider the state feedback stabilization of ODE-Schrodinger cascaded systems with the external disturbance. We use the backstepping transformation to handle the unstable part of the ODE, then design a feedback control which is used to cope with the disturbance and stabilize the Schrodinger part. By active disturbance rejection control (ADRC approach, the disturbance is estimated by a constant high gain estimator, then the feedback control law can be designed. Next, we show that the resulting closed-loop system is practical stable, where the peaking value appears in the initial stage and the stabilized result requires that the derivative of disturbance be uniformly bounded. To avoid the peak phenomenon and to relax the restriction on the disturbance, a time varying high gain estimator is presented and asymptotical stabilization of the corresponding closed-loop system is proved. Finally, the effectiveness of the proposed control is verified by numerical simulations.
Energy Analysis for TMD-Structure Systems Subjected to Impact Loading
Institute of Scientific and Technical Information of China (English)
王树青; 李华军; 嵇春艳; 焦桂英
2002-01-01
This paper investigates the characteristics of reduction of the lateral vibration by use of a Tuned Mass Damper(TMD) for offshore jacket platforms under impact loading. Unlike traditional analysis, the present analysis focnses on theenergy concept of TMD/structure systems. In this study, a time domain is taken. The platform is modeled as a simplifiedsingle-degree-of-freedom (SDOF) system by extraction of the first vibration mode of the structure and the excited force isassumed to be impact loading. The energy dissipation and energy transmission of the structure-TMD system are studied.Finally, an optimized TMD design for the modeled platform is demonstrated based on a new type of cost function - maxi-mum dissipated energy by TMD. Results indicate that TMD control is effective in reducing the standard deviation of thedeck motion but less effective in reducing the maximum response under impact loading.
Doubly Fed Induction Generator Wind Turbine Systems Subject to Recurring Symmetrical Grid Faults
DEFF Research Database (Denmark)
Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan
2016-01-01
grid faults is established. The analysis is based on the DFIG wind turbine system with the typical low-voltage ride-through strategy-with rotor-side crowbar. The stator natural flux produced by the voltage recovery after the first grid fault may be superposed on the stator natural flux produced......New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the doubly Ffed induction generator (DFIG) wind turbine system under recurring symmetrical grid faults is analyzed. The mathematical model of the DFIG under recurring symmetrical...... by the second grid fault, so that the transient rotor and stator current and torque fluctuations under the second grid fault may be influenced by the characteristic of the first grid fault, including the voltage dips level and the grid fault angle, as well as the duration between two faults. The mathematical...
Han, Shi-Yuan; Chen, Yue-Hui; Tang, Gong-You
2017-03-28
In this paper, the problem of sensor fault and delay tolerant control problem for a class of networked control systems under external disturbances is investigated. More precisely, the dynamic characteristics of the external disturbance and sensor fault are described as the output of exogenous systems first. The original sensor fault and delay tolerant control problem is reformulated as an equivalence problem with designed available system output and reformed performance index. The feedforward and feedback sensor fault tolerant controller (FFSFTC) can be obtained by utilizing the solutions of Riccati matrix equation and Stein matrix equation. Based on the designed fault diagnoser, the proposed FFSFTC is further reconstructed to compensate for the sensor fault and delayed measurement effects. Finally, numerical examples are provided to illustrate the effectiveness of our proposed FFSFTC with different cases with various types of sensor faults, measurement delays and external disturbances.
Directory of Open Access Journals (Sweden)
K. A. A. Rahman
2012-12-01
Full Text Available Brain is known to be one of the powerful systems in human body because of its ability to give command and communicate throughout the body. The spinal cord is the pathway for impulses from the brain to the body as well as from the body to the brain. However, the bounty of this pathway could be lost due to spinal cord injury (SCI and that results in a loss of function especially mobility. A combination of Brain Computer Interface (BCI and Functional Electrical Stimulation (FES is among one of the technique to regain the mobility function of human body which will be the focused area of this research. In this study, Electroencephalography (EEG system will be used to capture the brain signal which will then drive the FES. A paraplegic subject will be involved in this study. The subject will be required to move the knee joint with involvement few muscle contraction. Overall, in this paper the combination of BCI-FES methods for development of rehabilitation system will be proposed. From this preliminary study, it can be summarized that the combination between BCI and FES potentially would provide a better rehabilitation system for SCI patient in comparison to the conventional FES system.
Wang, Chenhui
2016-01-01
In this paper, control of uncertain fractional-order financial chaotic system with input saturation and external disturbance is investigated. The unknown part of the input saturation as well as the system’s unknown nonlinear function is approximated by a fuzzy logic system. To handle the fuzzy approximation error and the estimation error of the unknown upper bound of the external disturbance, fractional-order adaptation laws are constructed. Based on fractional Lyapunov stability theorem, an adaptive fuzzy controller is designed, and the asymptotical stability can be guaranteed. Finally, simulation studies are given to indicate the effectiveness of the proposed method. PMID:27783648
Development control systems takeover: subject robotic arm on the example anthropomorhic robot AR-601
Sirazetdinov, R.; Devaev, V.; Zakirzyanova, G.
2016-06-01
It is proposed the formation software architecture of complex motion for robotic systems in the form of sets of behavior - patterns - similar to the motor reflexes of living organisms. To form patterns of behavior of the robot teh authors used a methodology of structural analysis of complex systems IDEF0, then developed types of elementary algorithms (patterns) that make up the dynamics of the anthropomorphic robot jump. The work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University.
Wang, Xu; Saberi, Ali; Grip, H°avard Fjær; Stoorvogel, Antonie Arij
2013-01-01
In this paper, we study the disturbance response of open-loop neutrally stable linear systems with saturating linear feedback controller. It is shown that the closed-loop states remain bounded if the disturbances con- sists of those signals that do not have large sustained frequency components
DEFF Research Database (Denmark)
Jin, Quan; Simone, Angela; Olesen, Bjarne W.
2017-01-01
Given the global trends of rising energy demand and the increasing utilization of low-grade renewable energy, low-temperature heating systems can play key roles in improving building energy efficiency while providing a comfortable indoor environment. To meet the need to retrofit existing buildings...
The value of subjectivity: problems and prospects for 360-degree appraisal systems
Heijden, van der Beatrice I.J.M.; Nijhof, André H.J.
2004-01-01
This article focuses on the problems and prospects of 360-degree feedback methods. The rationale behind these appraisal systems is that different evaluation perspectives add objectivity and incremental validity to the assessment of individual performance. This assumption is challenged in this articl
The value of subjectivity: problems and prospects for 360-degree appraisal systems
van der Heijden, Beatrice; Nijhof, A.H.J.
2004-01-01
This article focuses on the problems and prospects of 360-degree feedback methods. The rationale behind these appraisal systems is that different evaluation perspectives add objectivity and incremental validity to the assessment of individual performance. This assumption is challenged in this articl
The value of subjectivity: problems and prospects for 360-degree appraisal systems
van der Heijden, Beatrice; Nijhof, A.H.J.
2004-01-01
This article focuses on the problems and prospects of 360-degree feedback methods. The rationale behind these appraisal systems is that different evaluation perspectives add objectivity and incremental validity to the assessment of individual performance. This assumption is challenged in this
SOME ASPECTS OF IMMUNE SYSTEM FUNCTIONING IN HEALTHY DONORS SUBJECTED TO XENOGENOUS EXPOSURE
Directory of Open Access Journals (Sweden)
O. O. Obukhova
2006-01-01
Full Text Available Abstract. In present work, we studied some interrelations between tobacco smoking and the processes of immune system stimulation in healthy blood donors. In our opinion, this issue is especially important for the big industrial center, with rather strong antigenic exposure of the organism. The levels of circulating immune complexes (CIC were used as a marker index which reflects specific antigen-antibody interactions during inflammation. According to the results obtained, the majority of persons who have high CIC levels were tobacco smokers (53.76%. Moreover, the percentage of persons with high CIC content, like as the mean values of this index is increased proportionally to the duration of smoking. A mixture of tobacco smoke components seems to exert direct toxic effect upon various compartments of the immune system and causes local irritation of bronchial tree, thus producing local and systemic inflammatory reaction. It is, possibly, an additional factor which determines activation of immune system, with a background of adverse antropogenic exposures typical to industrial centers. The data obtained allow us to affirm a toxic action of tobacco smoke upon the organism of smokers, with development of inflammatory reactions that are displayed as increased CIC levels at preclinical stage.
Decentralized robust frequency control for power systems subject to wind power variability
Liu, Juhua
As the penetration of wind energy generation increases in electric power systems, the frequency performance degrades mainly for two reasons. First, the intermittency of wind power introduces additional generation-load imbalance in the system, causing frequency to deviate from nominal values. Second, modern wind turbine generators are often decoupled from the grid by power electronics, making the wind turbines contribute no inertia to the grid. When more conventional generation is displaced by such wind generation, the total system inertia will decrease and the grid is more susceptible to generation-load imbalance. Therefore, frequency control must be revisited and enhanced in order to accommodate large-scale integration of wind energy. This dissertation mainly concerns the re-design of generator compensators to improve frequency performance of power systems when the penetration of wind power is high. Hinfinity methods can be used to synthesize controllers to achieve stability and robust performance in the presence disturbances. However, standard Hinfinity methods tend to produce complex controllers when the order of the system is high. Furthermore, when standard Hinfinity methods are continued with a naive decentralized control design, the resulting decentralized controllers may compete against each other and lead to instability. Therefore, we develop a passivity-based decentralized control framework for power system frequency control. A storage function is derived from the entropy of individual generators. Tellegen's theorem is invoked to derive the storage function for the entire power network. With this storage function, the power network is shown to be passive with respect to a supply rate, which is the sum of decentralized input-output products. Stability can then be assured when passive controllers are connected in negative feedback interconnection to the system. Proportional-integral-derivative (PID) controllers with positive gains are passive controllers
Directory of Open Access Journals (Sweden)
Xun Yang
2016-01-01
Full Text Available This paper investigates the dynamic response of a train-bridge system subjected to earthquakes, and the running safety indices of the train on the bridge under earthquake are studied. Taking a long span cable-stayed bridge across the Huangpu River as an example, a full three-dimensional finite element model of the train-bridge system was established, in which the soil-bridge and rail-train interactions were considered. Parallel computing based on contact balance was utilized to deal with this large-scale numerical simulation problem. The dynamic nonlinear analysis was performed on a Hummingbird supercomputer using the finite element code LS-DYNA 971. The results show that the acceleration responses of the train subjected to an earthquake are much greater than the ones without earthquake input, and the running safety of a moving train is affected by both the earthquake intensity and the running speed of the train. The running safety of the moving train can be evaluated by the threshold curve between earthquake intensity and train speed. The proposed modeling strategies and the simulated results can give a reference prediction of the dynamic behaviour of the train-bridge subjected to an earthquake.
Chen, Liang-Ming; Lv, Yue-Yong; Li, Chuan-Jiang; Ma, Guang-Fu
2016-12-01
In this paper, we investigate cooperatively surrounding control (CSC) of multi-agent systems modeled by Euler-Lagrange (EL) equations under a directed graph. With the consideration of the uncertain dynamics in an EL system, a backstepping CSC algorithm combined with neural-networks is proposed first such that the agents can move cooperatively to surround the stationary target. Then, a command filtered backstepping CSC algorithm is further proposed to deal with the constraints on control input and the absence of neighbors’ velocity information. Numerical examples of eight satellites surrounding one space target illustrate the effectiveness of the theoretical results. Project supported by the National Basic Research Program of China (Grant No. 2012CB720000) and the National Natural Science Foundation of China (Grant Nos. 61304005 and 61403103).
Stability of Non-Neutral and Neutral Dynamic Switched Systems Subject to Internal Delays
Directory of Open Access Journals (Sweden)
M. De la Sen
2005-01-01
Full Text Available This study deals with the quadratic stability and linear state-feedback and output-feedback stabilization of switched delayed linear dynamic systems with, in general, a finite number of non commensurate constant internal point delays. The results are obtained based on Lyapunov’s stability analysis via appropriate Krasovsky-Lyapunov’s functionals and the related stability study is performed to obtain both delay independent and delay dependent results. It is proved that the stabilizing switching rule is arbitrary if all the switched subsystems are quadratically stable and that it exists a (in general, non-unique stabilizing switching law when the system is polytopic, stable at some interior point of the polytope but with non-necessarily stable parameterizations at the vertices defining the subsystems.
Queue size and delay analysis for a communication system subject to traffic activity mode changes
Zukerman, M.; Rubin, I.
1986-06-01
A discrete single-server queueing/communication system in which the arrival distribution is changing stochastically with time is considered. The distribution of the number of messages to arrive within a time slot depends on a traffic activity process of modes. This process of modes is a two-state Markov chain: mode 0 and mode 1, which represent light and heavy traffic conditions, respectively. The transition probabilities of this Markov chain, or mode duration parameters (MDP's) determine the distribution of the duration of time the process stays in each mode. Expressions for the z-transform, expectation, and variance are obtained for the steady-state queue size and delay. A special consideration is given to the effect of the MDPs on the system performance, and the limiting cases (where the MDPs approach zero) are studied.
Kjellerup, B V; Kjeldsen, K U; Lopes, F; Abildgaard, L; Ingvorsen, K; Frølund, B; Sowers, K R; Nielsen, P H
2009-11-01
Severe biofilm formation and biocorrosion have been observed in heating systems even when the water quality complied with existing standards. The coupling between water chemistry, biofilm formation, species composition, and biocorrosion in a heating system was investigated by adding low concentrations of nutrients and oxygen under continuous and alternating dosing regimes. Molecular analysis of 16S rRNA gene fragments demonstrated that the amendments did not cause changes in the overall bacterial community composition. The combined alternating dosing of nutrients and oxygen caused increased rates of pitting (bio-) corrosion. Detection of bacteria involved in sulfide production and oxidation by retrieval of the functional dsrAB and apsA genes revealed the presence of Gram-positive sulfate- and sulfite-reducers and an unknown sulfur-oxidizer. Therefore, to control biocorrosion, sources of oxygen and nutrients must be limited, since the effect of the alternating operational conditions apparently is more important than the presence of potentially corrosive biofilm bacteria.
Robust stabilization using LMI techniques of neutral time-delay systems subject to input saturation
El Fezazi, Nabil; El Haoussi, Fatima; Houssaine Tissir, El; Alvarez, Teresa; Tadeo, Fernando
2017-01-01
The robust stabilization of uncertain saturated neutral systems with state delay is solved in this paper: based on a free weighting matrix approach, sufficient conditions are obtained via an LMI formulation. From these conditions, state feedback gains that ensure stability for the largest set of admissible initial conditions can be calculated solving optimization problems with LMI constraints. Some applications of this methodology to feedback control are then presented and compared with previous results in the literature.
Borrego, Adrián; Latorre, Jorge; Llorens, Roberto; Alcañiz, Mariano; Noé, Enrique
2016-01-01
Background Even though virtual reality (VR) is increasingly used in rehabilitation, the implementation of walking navigation in VR still poses a technological challenge for current motion tracking systems. Different metaphors simulate locomotion without involving real gait kinematics, which can affect presence, orientation, spatial memory and cognition, and even performance. All these factors can dissuade their use in rehabilitation. We hypothesize that a marker-based head tracking solution w...
Sato, Shinji
2015-01-01
Characteristics of the 2011 Tohoku Tsunami have been revealed by collaborative tsunami surveys extensively performed under the coordination of the Joint Tsunami Survey Group. The complex behaviors of the mega-tsunami were characterized by the unprecedented scale and the low occurrence frequency. The limitation and the performance of tsunami countermeasures were described on the basis of tsunami surveys, laboratory experiments and numerical analyses. These findings contributed to the introduction of two-level tsunami hazards to establish a new strategy for tsunami disaster mitigation, combining structure-based flood protection designed by the Level-1 tsunami and non-structure-based damage reduction planned by the Level-2 tsunami.
Thermal analysis of multi-MW two-level wind power converter
Zhou, Dao; Blaabjerg, Frede; Mogens, Lau; Tonnes, Michael
2012-01-01
In this paper, the multi-MW wind turbine of partial-scale and full-scale two-level power converter with DFIG and direct-drive PMSG are designed and compared in terms of their thermal performance. Simulations of different configurations regarding loss distribution and junction temperature in the power device in the whole range of wind speed are presented and analyzed. It is concluded that in both partial-scale and full-scale power converter the most thermal stressed power device in the generat...
Two-level correlation function of critical random-matrix ensembles
E. Cuevas
2004-01-01
The two-level correlation function $R_{d,\\beta}(s)$ of $d$-dimensional disordered models ($d=1$, 2, and 3) with long-range random-hopping amplitudes is investigated numerically at criticality. We focus on models with orthogonal ($\\beta=1$) or unitary ($\\beta=2$) symmetry in the strong ($b^d \\ll 1$) coupling regime, where the parameter $b^{-d}$ plays the role of the coupling constant of the model. It is found that $R_{d,\\beta}(s)$ is of the form $R_{d,\\beta}(s)=1+\\delta(s)-F_{\\beta}(s^{\\beta}/...
Solving the scattering of N photons on a two-level atom without computation
Roulet, Alexandre; Scarani, Valerio
2016-09-01
We propose a novel approach for solving the scattering of light onto a two-level atom coupled to a one-dimensional waveguide. First we express the physical quantity of interest in terms of Feynman diagrams and treat the atom as a non-saturable linear beamsplitter. By using the atomic response to our advantage, a relevant substitution is then made that captures the nonlinearity of the atom, and the final result is obtained in terms of simple integrals over the initial incoming wavepackets. The procedure is not limited to post-scattering quantities and allows for instance to derive the atomic excitation during the scattering event.
Phase Dependence of Few-Cycle Pulsed Laser Propagation in a Two-Level Atom Medium
Institute of Scientific and Technical Information of China (English)
肖健; 王中阳; 徐至展
2002-01-01
The phase-dependent feature of few-cycle pulsed laser propagation in a resonant two-level atom medium is demonstrated by solving the full Maxwell-Bloch equations. Even in the perturbative region, the propagating carrier field and the corresponding spectra of the few-cycle pulsed laser are sensitive to the initial phase due to self-phase modulation. For the larger pulse area, the fact that the carrier-wave reshaping comes from the carrier wave Rabi flopping is also responsible for this sensitivity, and the phase-dependent feature is more evident.
SPECTRUM OF A FEW-CYCLE LASER PULSE PROPAGATING IN A TWO-LEVEL ATOM MEDIUM
Institute of Scientific and Technical Information of China (English)
肖健; 王中阳; 徐至展
2001-01-01
The spectrum evolution of a few-cycle optical pulse in a resonant two-level atom medium is studied theoretically by using the full Maxwell-Bloch equations. On the propagating pulse, significantly much faster oscillation components separated with the main pulse appear due to strong self-phase modulation and pulse reshaping. In this case, ideal selfinduced transparency cannot occur for a 2r pulse. The spectrum of the 4r pulse shows an evident oscillatory feature because of the continuum interference of the separate pulses. For larger pulse areas, continuum generation from near ultraviolet to infrared occurs.
Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter
DEFF Research Database (Denmark)
Zhou, Dao; Blaabjerg, Frede; Lau, M.;
2013-01-01
The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model....... It is concluded that the injection of the reactive power could have serious impact on the power loss and thermal profile, especially at lower wind speed. Furthermore, the introduction of the reactive power could also shorten the lifetime of the wind power converter significantly....
Dynamics of Two-Level Trapped Ion in a Standing Wave Laser in Noncommutative Space
Institute of Scientific and Technical Information of China (English)
YANG Xiao-Xue; WU Ying
2007-01-01
We study the dynamics of a two-level trapped ion in a standing wave electromagnetic field in two-dimensional (2D) noncommutative spaces in the Lamb-Dicke regime under the rotating wave approximation. We obtain the explicit analytical expressions for the energy spectra, energy eigenstates, unitary time evolution operator, atomic inversion, and phonon number operators. The Rabi oscillations, the collapse, and revivals in the average atomic inversion and the average phonon number are explicitly shown to contain the information of the parameter of the space noncommutativity,which sheds light on proposing new schemes based on the dynamics of trappedion to test the noncommutativity.
Radiation Rate of a Two-Level Atom in a Spacetime with a Reflecting Boundary
Institute of Scientific and Technical Information of China (English)
LU Shi-Zhuan; YU Hong-Wei
2005-01-01
@@ We study a two-level atom in interaction with a real massless scalar quantum field in a spacetime with a reflecting boundary. We calculate the rate of change of the atomic energy for the atom. The presence of the boundary modifies the quantum fluctuations of the scalar field, which in turn modifies the rate of change of the atomic energy.It is found that the modifications induced by the presence of a boundary make the spontaneous radiation rate of an excited atom to oscillate near the boundary and this oscillatory behaviour may offer a possible opportunity for experimental tests for geometrical (boundary) effects in flat spacetime.
Propagation of Few-Cycle Pulse Laser in Two-Level Atom Medium
Institute of Scientific and Technical Information of China (English)
肖健; 王中阳; 徐至展
2001-01-01
By comparing the numerical solutions of Maxwell-Bloch equations beyond and within the slowly-varying envelope approximation and the rotating-wave approximation for the propagation of a few-cycle pulse laser in a resonant two-level atom medium, we found that both the Rabi flopping and the refractive index, and subsequently the carrier and the propagation velocity of the few-cycle pulse, are closely connected with the time-derivative behaviour of the electric field. This is because the Rabi flopping is such that the soliton pulse splits during propagation and that a shorter pulse propagates faster than a broader one.
Fractal Two-Level Finite Element Method For Free Vibration of Cracked Beams
Directory of Open Access Journals (Sweden)
A.Y.T. Leung
1998-01-01
Full Text Available The fractal two-level finite element method is extended to the free vibration behavior of cracked beams for various end boundary conditions. A cracked beam is separated into its singular and regular regions. Within the singular region, infinite number of finite elements are virturally generated by fractal geometry to model the singular behavior of the crack tip. The corresponding numerous degrees of freedom are reduced to a small set of generalized displacements by fractal transformation technique. The solution time and computer storage can be remarkably reduced without sacrifying accuracy. The resonant frequencies and mode shapes computed compared well with the results from a commercial program.
Phase Dependence of Fluorescence Spectrum of a Two-Level Atom in a Trichromatic Field
Institute of Scientific and Technical Information of China (English)
LI Jing-Yan; HU Xiang-Ming; LI Xiao-Xia; SHI Wen-Xing; XU Qing; GUO Hong-Ju
2005-01-01
@@ We examine the phase-dependent effects in resonance fluorescence of a two-level atom driven by a trichromatic modulated field. It is shown that the fluorescence spectrum depends crucially on the sum of relative phases of the sideband components compared to the central component, not simply on the respective phases. The appearance or disappearance of the central peak and the selective elimination of the sideband peaks are achieved simply by varying the sum phase. Once the sum phase is fixed, the spectrum keeps its features unchanged regardless of the respective relative phases.
The dynamic properties of the two-level entangled atom in an optical field
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
The interaction of an optical field and one of the entangled atoms is analyzed in detail in this paper. Furthermore, the dynamic properties of the two-level entangled atom are manifested. The properties of the action are dependent on the initial state of the atom. After detecting the atom out of the field, we can obtain the state of the other atom moving in the field. It is shown that the state of the atom out of the field influences the dynamic properties of the atom in the field.
Spectral density of Cooper pairs in two level quantum dot-superconductors Josephson junction
Dhyani, A.; Rawat, P. S.; Tewari, B. S.
2016-09-01
In the present paper, we report the role of quantum dot energy levels on the electronic spectral density for a two level quantum dot coupled to s-wave superconducting leads. The theoretical arguments in this work are based on the Anderson model so that it necessarily includes dot energies, single particle tunneling and superconducting order parameter for BCS superconductors. The expression for single particle spectral function is obtained by using the Green's function equation of motion technique. On the basis of numerical computation of spectral function of superconducting leads, it has been found that the charge transfer across such junctions can be controlled by the positions and availability of the dot levels.
Haffoudhi, Houda
2005-01-01
URL des Cahiers :http://mse.univ-paris1.fr/MSEFramCahier2005.htm; Cahiers de la Maison des Sciences Economiques 2005.54 - ISSN : 1624-0340; International environmental agreements (IEAs) are increasingly important in a globalized economy. The aim of our paper is study the effect of political pressure groups-lobbies on the size and stability of IEAs. To this purpose we use the framework of two-level games to explain how national political situation influences the decisions of governments at the...
Directory of Open Access Journals (Sweden)
Zohreh Molamohamadi
2014-01-01
Full Text Available In the traditional inventory system, it was implicitly assumed that the buyer pays to the seller as soon as he receives the items. In today’s competitive industry, however, the seller usually offers the buyer a delay period to settle the account of the goods. Not only the seller but also the buyer may apply trade credit as a strategic tool to stimulate his customers’ demands. This paper investigates the effects of the latter policy, two-level trade credit, on a retailer’s optimal ordering decisions within the economic order quantity framework and allowable shortages. Unlike most of the previous studies, the demand function of the customers is considered to increase with time. The objective of the retailer’s inventory model is to maximize the profit. The replenishment decisions optimally are obtained using genetic algorithm. Two special cases of the proposed model are discussed and the impacts of parameters on the decision variables are finally investigated. Numerical examples demonstrate the profitability of the developed two-level supply chain with backorder.
Energy Technology Data Exchange (ETDEWEB)
Yuan, R.-Y., E-mail: yuanry@cnu.edu.cn [Center for Theoretical Physics, Department of Physics, Capital Normal University, Beijing 100048 (China); Zhao, X.; Ji, A.-C. [Center for Theoretical Physics, Department of Physics, Capital Normal University, Beijing 100048 (China); Guo, Y., E-mail: guoy66@tsinghua.edu.cn [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China); Yan, H. [Laboratory of Thin Film Materials, Beijing University of Technology, Beijing 100022 (China)
2015-09-04
Both the charging and orbital quantization energies of InAs quantum dot (QD) typically correspond to the terahertz (THz) region. In this letter, under the asymmetric THz irradiations on two leads, electron transport through a two-level InAs QD is theoretically discussed. We demonstrate that when both the frequencies and amplitudes of THz irradiations on two leads are different with the higher asymmetry, the photon–electron pump effect vanishes, even a negative platform appears on the left of the Coulomb peak and a positive platform occurs on the right of the Coulomb interaction related energy level, respectively. This behavior is favorable for the design of THz optoelectronic device. - Highlights: • Asymmetric terahertz waves are irradiated on two leads in two-level InAs QD system. • Only with different frequencies, a negative current resonance is obtained. • A negative platform appears on the left of the Coulomb peak with higher asymmetry. • For the low terahertz field strength, a positive platform occurs. • We report the behaviors are favorable for the design of THz optoelectronic device.
Kirsten, Giovanna A; Takahashi, Marcos Kenzo; Rached, Rodrigo N; Giannini, Marcelo; Souza, Evelise M
2010-06-01
The aim of this study was to evaluate the microhardness of dentin subjacent to the bonding interface of composite restorations using fluoride-releasing adhesive systems submitted to pH-cycling regimen associated or not to fluoride therapies. Thirty human third molars were prepared with class V cavities with dentin cervical margins. The adhesive systems One-Up Bond F Plus (OU), Prime&Bond NT (NT), Clearfil Protect Bond (CF), Optibond Solo Plus (OP) and also the controls [-] Single Bond 2 (SB) and [+] Ketac Molar (KM) were used previously to composite resin restorations. The restorations were sectioned into four slabs and submitted to different storage media for 15 days: distilled water, pH-cycling, pH-cycling associated to NaF 0.05% and associated to NaF 1.23%. The Knoop microhardness test was performed in dentin at 50, 100, 150 and 300 microm from the adhesive interface. Data was analyzed by three-way ANOVA and Tukey HSD test (p<0.05). KM resulted in significantly higher microhardness when compared to all the adhesive systems at 50 microm, with the exception of OU, that was similar to KM when submitted to pH-cycling alone or associated to 1.23% NaF. Microhardness of dentin was significantly higher with all the tested materials, when pH-cycling was associated to NaF 0.05%, at 50 microm and 100 microm depths. OU resulted in similar dentin hardness at all depths and storage media. The incorporation of NaF 0.05% fluoride therapy to the cariogenic challenge was capable to recover the original microhardness of dentin at 50 and 100 microm with all the tested materials. Copyright 2010 Elsevier Ltd. All rights reserved.
Effect of Asymmetry in a Bistable System Subject to Multiplicative Colored Noise
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
By the method of the stochastic energetics, we investigate the stochastic resonance (SR) phenomenon of an overdamped Brown particle in an asymmetric bistable potential, driven by external periodical signal and multiplicative noise. The expressions have been obtained for the quasi-steady-state probability distribution function. It is found that the input energy (IE) pumped into the system by the external driving shows an SR-like behavior as a function of the noise strength, whereas the IE turns to be a monotonic function of the correlation time of the noise. The effect of potential asymmetry is also studied on SR and IE.
Energy Technology Data Exchange (ETDEWEB)
Chacon, Ricardo, E-mail: rchacon@unex.e [Departamento de Fisica Aplicada, Escuela de IngenierIas Industriales, Universidad de Extremadura, Apartado Postal 382, E-06071 Badajoz (Spain)
2010-06-04
Theory concerning the emergence and control of chaotic escape from a potential well by means of autoresonant excitations is presented in the context of generic, dissipative and multistable systems. General scaling laws relating both the onset and lifetime of transient chaos to the parameters of autoresonant excitations are derived theoretically using vibrational mechanics, Melnikov analysis and energy-based autoresonance theory. Numerical experiments show that these scaling laws are robust against both the presence of noise and driving re-shaping. (fast track communication)
Analysis of ventilation systems subjected to explosive transients: far-field analysis
Energy Technology Data Exchange (ETDEWEB)
Tang, P.K.; Andrae, R.W.; Bolstad, J.W.; Duerre, K.H.; Gregory, W.S.
1981-11-01
Progress in developing a far-field explosion simulation computer code is outlined. The term far-field implies that this computer code is suitable for modeling explosive transients in ventilation systems that are far removed from the explosive event and are rather insensitive to the particular characteristics of the explosive event. This type of analysis is useful when little detailed information is available and the explosive event is described parametrically. The code retains all the features of the TVENT code and allows completely compressible flow with inertia and choking effects. Problems that illustrate the capabilities and limitations of the code are described.
Modelling of Freight Trains Classification Using Queueing System Subject to Breakdowns
Directory of Open Access Journals (Sweden)
Michal Dorda
2013-01-01
Full Text Available The paper presents a mathematical model and a simulation model of the freight trains classification process. We model the process as a queueing system with a server which is represented by a hump at a marshalling yard. We distinguish two types of shunting over the hump; primary shunting represents the classification of inbound freight trains over the hump (it is the primary function of marshalling yards, and secondary shunting is, for example, represented by the classification of trains of wagons entering the yard via industrial sidings. Inbound freight trains are considered to be customers in the system, and all needs of secondary shunting are failures of the hump because performing secondary shunting occupies the hump, and therefore inbound freight trains cannot be sorted. All random variables of the model are considered to be exponentially distributed with the exception of customer service times which are Erlang distributed. The mathematical model was created using method of stages and can be solved numerically employing a suitable software tool. The simulation model was created using coloured Petri nets. Both models are tested in conditions of a marshalling yard.
Energy Technology Data Exchange (ETDEWEB)
Huynh, K.T., E-mail: tuan.huynh@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Barros, A., E-mail: anne.barros@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Castro, I.T., E-mail: inmatorres@unex.e [Departamento de Matematicas, Escuela Politecnica, 10071 Caceres (Spain)
2011-04-15
This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices.
Full-scale testing of pipework systems and flexible risers subject to noise and vibration
Energy Technology Data Exchange (ETDEWEB)
Every, M.J.; Goyder, G.D.; Jee, T.; Swindell, R.
2005-07-01
The occurrence of potentially damaging noise and vibration levels in pipework has required the development of a full-scale testing facility. This facility can expose pipework to high static pressures and flow and can generate the large dynamic pressures that constitute noise. A consortium was formed that assembled the various specialist knowledge needed for the test facility. The outcome of the test work enables production flow through a flexible riser system throughout a range of flow rates and most significantly to be substantially increased. The benefits are an increased profitability of the asset, greater confidence in fatigue life prediction and an improved understanding for use in design. Flexible risers are increasingly being used offshore and most recently for the export of dry gas. This has given rise to the phenomenon of the 'singing riser', which generates sufficiently large noise levels to cause fatigue damage to the riser system. This phenomenon is currently limiting production rates offshore. As gas flows within the riser it passes over internal corrugation, which gives rise to vortex shedding from corrugated edges. The frequency of the vortex shedding is described by the Strouhal relationship so that it depends upon the flow velocity and the riser geometry. It appears from measurements on several offshore risers that this is fairly constant for a range of export pressures and flow rates. The shedding of the vortices is not necessarily correlated along the length of the riser. However, if there is small-bore pipework attached to the riser system which has a similar acoustic frequency to the Strouhal frequency then 'lock-on' can occur which may cause full correlation of vortex shedding. The lock-on mechanism is not totally understood but when the small-bore pipework's acoustic frequency is excited it provides a positive feed back to enhance the vortex shedding within the riser. The consequence is that the shedding within the
SCREENING OF MEDIUM COMPOUNDS USING A TWO-LEVEL FACTORIAL DESIGN FOR SACCHAROMYCES BOULARDII
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GUOWEI SHU
2016-04-01
Full Text Available Even if the probiotic effect of Saccharomyces boulardii is has been reported, this yeast is rarely used in medium composition. Based on single factor experiment, two-level factorial design was employed to evaluate the effect of carbon sources (sucrose, glucose, nitrogen sources (soy peptone, beef extract, yeast extract, calf serum, malt extract and salts (K2HPO4, KH2PO4, MgSO4, Na2HPO4, NaH2PO4, CaCl2, sodium citrate, sodium glutamate on the growth of S. boulardii. At the same time, the optical density (OD in the medium was measured at 560 nm after 36 h of incubation. The result of two-level factorial design experiment showed that calf serum (p = 0.0214 and sodium citrate (p = 0.0045 are the significant growth factors of S. boulardii, sucrose (p = 0.0861 and malt extract (p = 0.0763 are important factors. In addition, sucrose and sodium citrate showed positive effect on the growth of S. boulardii. However, calf serum and malt extract showed negative effect on the growth. And we determined that the optimum medium composition for S. boulardii was as follow: 37.5 g·L-1 sucrose, 6 g·L-1 calf serum, 6 g·L-1 malt extract, 5 g·L-1 sodium citrate.
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Shen-yan Chen
2015-01-01
Full Text Available This paper presents an Improved Genetic Algorithm with Two-Level Approximation (IGATA to minimize truss weight by simultaneously optimizing size, shape, and topology variables. On the basis of a previously presented truss sizing/topology optimization method based on two-level approximation and genetic algorithm (GA, a new method for adding shape variables is presented, in which the nodal positions are corresponding to a set of coordinate lists. A uniform optimization model including size/shape/topology variables is established. First, a first-level approximate problem is constructed to transform the original implicit problem to an explicit problem. To solve this explicit problem which involves size/shape/topology variables, GA is used to optimize individuals which include discrete topology variables and shape variables. When calculating the fitness value of each member in the current generation, a second-level approximation method is used to optimize the continuous size variables. With the introduction of shape variables, the original optimization algorithm was improved in individual coding strategy as well as GA execution techniques. Meanwhile, the update strategy of the first-level approximation problem was also improved. The results of numerical examples show that the proposed method is effective in dealing with the three kinds of design variables simultaneously, and the required computational cost for structural analysis is quite small.
Thermal analysis of multi-MW two-level wind power converter
DEFF Research Database (Denmark)
Zhou, Dao; Blaabjerg, Frede; Mogens, Lau;
2012-01-01
In this paper, the multi-MW wind turbine of partial-scale and full-scale two-level power converter with DFIG and direct-drive PMSG are designed and compared in terms of their thermal performance. Simulations of different configurations regarding loss distribution and junction temperature in the p......In this paper, the multi-MW wind turbine of partial-scale and full-scale two-level power converter with DFIG and direct-drive PMSG are designed and compared in terms of their thermal performance. Simulations of different configurations regarding loss distribution and junction temperature...... in the power device in the whole range of wind speed are presented and analyzed. It is concluded that in both partial-scale and full-scale power converter the most thermal stressed power device in the generator-side converter will have higher mean junction temperature and larger junction temperature...... fluctuation compared to grid-side converter at the rated wind speed. Moreover, the thermal performance of the generator-side converter in the partial-scale power converter becomes crucial around the synchronous operating point and should be considered carefully....
DEFF Research Database (Denmark)
Bennetzen, M F; Wellner, Niels; Ahmed, Shamaila Saghir;
2011-01-01
Endocannabinoids (ECs) have a role in obesity by affecting appetite and through peripheral effects. Obesity is associated with a dysregulation of the endocannabinoid system (ECS).......Endocannabinoids (ECs) have a role in obesity by affecting appetite and through peripheral effects. Obesity is associated with a dysregulation of the endocannabinoid system (ECS)....
Institute of Scientific and Technical Information of China (English)
Pingke LI; Shu-Cherng FANG
2009-01-01
This paper shows that the problem of minimizing a linear fractional function subject to a system of sup-T equations with a continuous Archimedean triangular norm T can be reduced to a 0-1linear fractional optimization problem in polynomial time. Consequently, parametrization techniques,e.g., Dinkelbach's algorithm, can be applied by solving a classical set covering problem in each iteration.Similar reduction can also be performed on the sup-T equation constrained optimization problems with an objective function being monotone in each variable separately. This method could be extended as well to the case in which the triangular norm is non-Archimedean.
Directory of Open Access Journals (Sweden)
Dongdong Zhang
2014-01-01
Full Text Available A novel hybrid FRP-aluminum truss system has been employed in a two-rut modular bridge superstructure composed of twin inverted triangular trusses. The actual flexural behavior of a one-rut truss has been previously investigated under the on-axis loading test; however, the structural performance of the one-rut truss subjected to an off-axis load is still not fully understood. In this paper, a geometrical linear finite element model is introduced and validated by the on-axis loading test; the structural performance of the one-rut truss subjected to off-axis load was numerically obtained; the dissimilarities of the structural performance between the two different loading cases are investigated in detail. The results indicated that (1 the structural behavior of the off-axis load differs from that of the on-axis load, and the off-axis load is the critical loading condition controlling the structural performance of the triangular truss; (2 under the off-axis load, the FRP trussed members and connectors bear certain out-of-plane bending moments and are subjected to a complicated stress state; and (3 the stress state of these members does not match that of the initial design, and optimization for the redesign of these members is needed, especially for the pretightened teeth connectors.
Directory of Open Access Journals (Sweden)
Emiko Sato
2012-06-01
Full Text Available Renin-Angiotensin System (RAS, oxidative stress and inflammation is involved in the pathogenesis of hypertension and salt sensitivity of hypertension. The present study was designed to evaluate the role of RAS, oxidative stress and inflammation to the regulation of blood pressure in young subjects. 111 young students (19.2±0.8 years old who have taken health checkup were randomly selected for the study. Urinary excretions of angiotensinogen (AGT, oxidative stress (TBARS, and inflammatory markers (MCP-1 were analyzed. Urinary excretions of these parameters were estimated by 24-hour urinary creatinine excretion, age, height and body weight. Subjects were divided to two groups based on the blood pressure: below 140/90 mmHg (Normal and over 140/90 mmHg (High. Blood pressure was significantly increased with increased BMI. Urinary AGT, TBARS, and MCP-1 of high blood pressure group were significantly (p<0.05 increased compared to those of normal blood pressure. Urinary AGT has significant positive correlation with urinary TBARS, though it did not have a significant correlation with MCP-1. Estimated 24-h urinary Na excretion was significantly increased with increased urinary MCP-1, and TBARS. These results indicate that increase in blood pressure is accompanied with RAS, oxidative stress, and inflammation in young subjects, which is associated with salt intake.
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Majid Gholipour
2013-08-01
Full Text Available Background: The prevalence of obesity has risen enormously over the past few decad-es. Both food intake (Appetite and energy expenditure can influence body weight. Acylated ghrelin enhances appetite, and its plasma level is suppressed by growth horm-one. The present study, examines the effects of an intermittent exercise with progress-ive intensities on acylated ghrelin, appetite, and growth hormone in inactive male students with two levels of obesity.Methods: Eleven inactive males were allocated into two groups on the basis of their body mass index (BMI. Six subjects in group one, BMI= 31.18±0.92 kg/m2, and five subjects in group two, BMI= 36.94±2.25 kg/m2, ran on the treadmill with progressive intensities of 50, 60, 70 and 80% of VO2max for 10, 10, 5, and 2 min respectively. Blood samples were collected before the exercise (as the resting values, after each workload (during the exercise, and at 30, 60, and 120 min (during recovery.Results: Plasma acylated ghrelin concentrations and hunger ratings in two groups were decreased and remained significantly lower than resting values (P=0.008 and P=0.002 respectively at the end of the trial and there was no significant differences between groups. Growth hormone levels in two groups were increased and remained significant-ly higher than resting values (groups one P=0.012, group two P=0.005 at the end of the trial and there was no significant differences between groups. In addition, there were no significant differences between area under the curves (AUC values over total periods for acylated ghrelin, hunger ratings, and growth hormone in two groups.Conclusion: These findings indicate that individuals with two levels of obesity have the same response to the different intensities of treadmill running and two hours thereafter during recovery period, which can be considered for designing a more effective weighting loss training program.
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Astrid van Huisstede
2013-01-01
Full Text Available Background. Obesity and asthma are associated. There is a relationship between lung function impairment and the metabolic syndrome. Whether this relationship also exists in the morbidly obese patients is still unknown. Hypothesis. Low-grade systemic inflammation associated with the metabolic syndrome causes inflammation in the lungs and, hence, lung function impairment. Methods. This is cross-sectional study of morbidly obese patients undergoing preoperative screening for bariatric surgery. Metabolic syndrome was assessed according to the revised NCEP-ATP III criteria. Results. A total of 452 patients were included. Patients with the metabolic syndrome (n=293 had significantly higher blood monocyte (mean 5.3 versus 4.9, P=0.044 and eosinophil percentages (median 1.0 versus 0.8, P=0.002, while the total leukocyte count did not differ between the groups. The FEV1/FVC ratio was significantly lower in patients with the metabolic syndrome (76.7% versus 78.2%, P=0.032. Blood eosinophils were associated with FEV1/FVC ratio (adj. B −0.113, P=0.018. Conclusion. Although the difference in FEV1/FVC ratio between the groups is relatively small, in this cross-sectional study, and its clinical relevance may be limited, these data indicate that the presence of the metabolic syndrome may influence lung function impairment, through the induction of relative eosinophilia.
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Palaniswamy Radha
2011-06-01
Full Text Available Oxidative stress can arise from an imbalance between the generation and elimination of reactive oxygen species leading to the excess levels, which in turn cause various diseases and cell death. Reactive oxygen species can be eliminated by a number of enzymic and non-enzymic antioxidant defense mechanisms. This was studied in Majorana hortensis using in vitro model simulating the in vivo system. Precision-cut goat liver slices were challenged with a standard oxidant (H2O2 both in the presence and in the absence of the different extracts of the leaves. The enzymic and non-enzymic antioxidants were analyzed in the homogenate of the liver slices after incubation. The oxidant treated liver slices showed a decrease in the levels of antioxidants compared to the untreated control. But in the presence of the leaf extracts, the antioxidant status was reverted back to a significant extent. Thus, the results showed that the leaf extracts of the candidate plant can improve the antioxidant status in the goat liver slices exposed in vitro to oxidative stress.
Ge, Xiaohua; Han, Qing-Long
2016-06-07
This paper addresses the consensus problem for a continuous-time multiagent system (MAS) with Markovian network topologies and external disturbance. Different from some existing results, global jumping modes of the Markovian network topologies are not required to be completely available for consensus protocol design. A network topology mode regulator (NTMR) is first developed to decompose unavailable global modes into several overlapping groups, where overlapping groups refer to the scenario that there exist commonly shared local modes between any two distinct groups. The NTMR schedules which group modes each agent may access at every time step. Then a new group mode-dependent distributed consensus protocol on the basis of relative measurement outputs of neighboring agents is delicately constructed. In this sense, the proposed consensus protocol relies only on group and partial modes and eliminates the need for complete knowledge of global modes. Sufficient conditions on the existence of desired distributed consensus protocols are derived to ensure consensus of the MAS with a prescribed H∞ performance level. Two examples are provided to show the effectiveness of the proposed consensus protocol.
Electromechanical performance of induction motor/drive systems subjected to voltage sags
Tunaboylu, Serdar N.
Induction Motors are workhorses for many industries. They are extensively utilized in industrial variable-frequency drive (VFD) or adjustable-speed drive (ASD) applications as well as constant speed applications. Recent advances in power electronics have made AC motor drives an economically viable solution for ASD applications traditionally dominated by dc motor drives. In this study, electromechanical performance variables of an Induction Motor (IM) have been studied during the balanced voltage sags. For this purpose a laboratory prototype of an industrial mixer has been designed. IM has been coupled to a speed reducer that is worm gear type with a ratio 10 to 1. Then the reducer is vertically coupled to a food process mixer within a metal canister. The mixer represents a high friction load with practically zero inertia. Voltage, current, speed, and power measurements have been collected and compared with the simulation results from Simnon. An open-loop control Volts per Hertz boost strategy has been used in order to compensate the speed loss during the three-phase balanced voltage sags. Both compensated and uncompensated cases have been run and compared with simulation results. Results are verified with a reasonably good agreement that the total system modeling is successful and boost compensation circuit is effective.
Directory of Open Access Journals (Sweden)
Abdelkrim Thameur
2015-01-01
Full Text Available This paper proposes a regulation method of back-to-back connected two-level PWM rectifier-five-level Voltage Source Inverter (VSI in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of two-level PWM rectifier. In the second part, five-level Neutral Point Clamped (NPC voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the excellent performance of the proposed technique.
Energy Technology Data Exchange (ETDEWEB)
Friedberg, Richard [Physics Department, Columbia University, New York, NY 10027 (United States); Manassah, Jamal T., E-mail: jmanassah@gmail.co [HMS Consultants, Inc., P.O. Box 592, New York, NY 10028 (United States)
2010-04-05
We give the analytic expressions for the initial Cooperative Decay Rate and Cooperative Lamb Shift for a spherical cloud of two-level atoms for the cases of uniform and Gaussian number density distributions. We derive these expressions in both scalar and vector models for the cases when the system's initial polarization is uniform and when it is coherently phased.
Directory of Open Access Journals (Sweden)
Qiang Fu
2014-01-01
Full Text Available A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.
2014-01-01
A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed. PMID:24723838
Chung, Kun-Jen
2013-09-01
An inventory problem involves a lot of factors influencing inventory decisions. To understand it, the traditional economic production quantity (EPQ) model plays rather important role for inventory analysis. Although the traditional EPQ models are still widely used in industry, practitioners frequently question validities of assumptions of these models such that their use encounters challenges and difficulties. So, this article tries to present a new inventory model by considering two levels of trade credit, finite replenishment rate and limited storage capacity together to relax the basic assumptions of the traditional EPQ model to improve the environment of the use of it. Keeping in mind cost-minimisation strategy, four easy-to-use theorems are developed to characterise the optimal solution. Finally, the sensitivity analyses are executed to investigate the effects of the various parameters on ordering policies and the annual total relevant costs of the inventory system.
Directory of Open Access Journals (Sweden)
M. De la Sen
2008-01-01
Full Text Available This paper investigates key aspects of realization and partial realization theories for linear time-invariant systems being subject to a set of incommensurate internal and external point delays. The results are obtained based on the use of formal Laurent expansions whose coefficients are polynomial matrices of appropriate orders and which are also appropriately related to truncated and infinite block Hankel matrices. The above-mentioned polynomial matrices arise in a natural way from the transcendent equations associated with the delayed dynamics. The results are linked to the properties of controllability and observability of dynamic systems. Some related overview is given related to robustness concerned with keeping the realization properties under mismatching between a current transfer matrix and a nominal one.
Ma, Yuechao; Yang, Pingjing; Yan, Yifang; Zhang, Qingling
2017-01-10
This paper investigates the problem of robust observer-based passive control for uncertain singular time-delay system subject to actuator saturation. A polytopic approach is used to describe the saturation behavior. First, by constructing Lyapunov-Krasovskii functional, a less conservative sufficient condition is obtained which guarantees that the closed-loop system is regular, impulse free, stable and robust strictly passive. Then, with this condition, the design method of state feedback controller and the observer are given by solving linear matrix inequalities. In addition, a domain of attraction in which the admissible initial states are ensured to converge asymptotically to the origin is solved as a convex optimization problem. Finally, some simulations are provided to demonstrate the effectiveness and superiority of the proposed method.
Ho, N S K; Tong, K Y; Hu, X L; Fung, K L; Wei, X J; Rong, W; Susanto, E A
2011-01-01
An exoskeleton hand robotic training device is specially designed for persons after stroke to provide training on their impaired hand by using an exoskeleton robotic hand which is actively driven by their own muscle signals. It detects the stroke person's intention using his/her surface electromyography (EMG) signals from the hemiplegic side and assists in hand opening or hand closing functional tasks. The robotic system is made up of an embedded controller and a robotic hand module which can be adjusted to fit for different finger length. Eight chronic stroke subjects had been recruited to evaluate the effects of this device. The preliminary results showed significant improvement in hand functions (ARAT) and upper limb functions (FMA) after 20 sessions of robot-assisted hand functions task training. With the use of this light and portable robotic device, stroke patients can now practice more easily for the opening and closing of their hands at their own will, and handle functional daily living tasks at ease. A video is included together with this paper to give a demonstration of the hand robotic system on chronic stroke subjects and it will be presented in the conference.
Spectroscopic properties of a two-level atom interacting with a complex spherical nanoshell
Moroz, A
2004-01-01
Frequency shifts, radiative decay rates, the Ohmic loss contribution to the nonradiative decay rates, fluorescence yields, and photobleaching of a two-level atom radiating anywhere inside or outside a complex spherical nanoshell, i.e. a stratified sphere consisting of alternating silica and gold concentric spherical shells, are studied. The changes in the spectroscopic properties of an atom interacting with complex nanoshells are significantly enhanced, often more than two orders of magnitude, compared to the same atom interacting with a homogeneous dielectric sphere. The changes strongly depend on the nanoshell parameters and the atom position. When an atom approaches a metal shell,the radiative decay rates are strongly enhanced and they increase faster than the Ohmic loss contribution to the nonradiative decay rates. However, the majority of the emitted radiation does not escape to spatial infinity but instead is absorbed. The enhancement of the radiative decay rates in a close proximity of metal boundaries...
DEFF Research Database (Denmark)
Nysteen, Anders; McCutcheon, Dara; Mørk, Jesper
2015-01-01
We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could...... be quantified via a reduction in coincidence clicks in a Hong–Ou–Mandel measurement setup, analogous to a linear beam splitter. Changes to the spectra and phase of the scattered photons, however, would lead to reduced interference with other photons when implemented in a larger optical circuit. We introduce...... suitable fidelity measures which account for these changes and find that high values can still be achieved even when accounting for all properties of the scattered photonic state....
Giant Cooperative Lamb Shift in a density-modulated slab of two-level atoms
Energy Technology Data Exchange (ETDEWEB)
Manassah, Jamal T., E-mail: jmanassah@gmail.co [Department of Electrical Engineering, City College of New York, NY 10031 (United States)
2010-04-19
A 'slab' of two-level atoms prepared in a superradiant Dicke state exhibits interesting enhancement of the Cooperative Decay Rate (CDR) when its density is modulated at the Bragg condition. In this Letter, complete analytical formulas are given, not only for CDR but also for the Cooperative Lamb Shift (CLS), both at and near the Bragg condition, as a function of the depth of modulation, the thickness of the slab, and the detuning from the Bragg condition. A major new result is that for detuning O(1/m) (where m=thickness/wavelength) the CLS takes on 'giant' values, proportional to m. The reason for this giant CLS is explored.
Controlling spontaneous emission of a two-level atom by hyperbolic metamaterials
Liu, Zheng; Jiang, Xunya
2012-01-01
Within the frame of quantum optics we analyze the properties of spontaneous emission of two-level atom in media with indefinite permittivity tensor where the geometry of the dispersion relation is characterized by an ellipsoid or a hyperboloid(hyperbolic medium). The decay rate is explicitly given with the orientation of the dipole transition matrix element taken into account. It indicates that for the ellipsoid case the intensity of the photons coupled into different modes can be tuned by changing the direction of the matrix element and for the hyperboloid case it is found that spontaneous emission in hyperbolic medium can be dramatically enhanced compared to the dielectric background. Moreover, spontaneous emission exhibit the strong directivity and get the maximum in the asymptote direction.
TWO-LEVEL HIERARCHICAL COORDINATION QUEUING METHOD FOR TELECOMMUNICATION NETWORK NODES
Directory of Open Access Journals (Sweden)
M. V. Semenyaka
2014-07-01
Full Text Available The paper presents hierarchical coordination queuing method. Within the proposed method a queuing problem has been reduced to optimization problem solving that was presented as two-level hierarchical structure. The required distribution of flows and bandwidth allocation was calculated at the first level independently for each macro-queue; at the second level solutions obtained on lower level for each queue were coordinated in order to prevent probable network link overload. The method of goal coordination has been determined for multilevel structure managing, which makes it possible to define the order for consideration of queue cooperation restrictions and calculation tasks distribution between levels of hierarchy. Decisions coordination was performed by the method of Lagrange multipliers. The study of method convergence has been carried out by analytical modeling.
Zhao, Tao; Hwang, Feng-Nan; Cai, Xiao-Chuan
2016-07-01
We consider a quintic polynomial eigenvalue problem arising from the finite volume discretization of a quantum dot simulation problem. The problem is solved by the Jacobi-Davidson (JD) algorithm. Our focus is on how to achieve the quadratic convergence of JD in a way that is not only efficient but also scalable when the number of processor cores is large. For this purpose, we develop a projected two-level Schwarz preconditioned JD algorithm that exploits multilevel domain decomposition techniques. The pyramidal quantum dot calculation is carefully studied to illustrate the efficiency of the proposed method. Numerical experiments confirm that the proposed method has a good scalability for problems with hundreds of millions of unknowns on a parallel computer with more than 10,000 processor cores.
Stimuli-Responsive Reversible Two-Level Adhesion from a Structurally Dynamic Shape-Memory Polymer.
Michal, Brian T; Spencer, Emily J; Rowan, Stuart J
2016-05-01
A shape-memory adhesive has been prepared that exhibits two levels of reversible adhesion. The adhesive is a semicrystalline cross-linked polymer that contains dynamic disulfide bonds. Melting of the crystalline regions via heat causes a drop in the modulus of the material facilitating wetting of the substrate as well as enhancing the surface contact area with the substrate, which result in the formation of an adhesive bond. Exposure to higher heat or UV light results in dynamic exchange of the disulfide bonds, which yields a further drop in the modulus/viscosity that improves surface wetting/contact and strengthens the adhesive bond. This improvement in adhesion is shown to apply over different substrates, contact forces, and deformation modes. Furthermore, the adhesive acts as a thermal shape-memory material and can be used to create joints that can reposition themselves upon application of heat.
Effect of Phase Shifted Frequency Modulation on Two Level Atom-Field Interaction
Institute of Scientific and Technical Information of China (English)
K.V. Priyesh; Ramesh Babu Thayyullathil
2012-01-01
We have studied the effect of phase shifted frequency modulation on two level atom with field interaction using Jaynes-Cummings model. Here the frequency of the interacting field is sinusoidally varying with time with a constant phase. Due to the presence of phase in the frequency modulation, the variation of population inversion with time is different from the standard case. There are no exact collapses and revivals in the variation of population inversion but it oscillates sinusoidally with time. In coherent field atom interaction the population inversion behaves as in the case of Fock state atom interaction, when frequency modulation with a non zero phase is applied. The study done with squeezed field has shown the same behavior of the population inversion.