Development and Validation in Air Traffic Control by Means of Real-Time Simulations
Directory of Open Access Journals (Sweden)
Stephan Herr
2009-02-01
Full Text Available The airspace in Central Europe is already one of the busiest airspaces in the world and the forecasts predict further traffic increases. The current air transport system is reaching its capacity limits, not only at airports but also in parts of the en-route area. This is mainly due to the workload constraints of air traffic controllers. In the past, many technical system functionalities were developed with the aim of reducing controller workload and thus enabling the safe handling of the predicted traffic growth. But these new functionalities alone will not provide adequate relief to air traffic controllers. Their working procedures and the airspace structure will have to be adapted accordingly. In order to obtain real operational benefits, these technical innovations must be integrated into an overall concept which – in addition to the above-mentioned factors – also takes account of ergonomic aspects and human-machine interfaces. When developing such an overall concept, additional evaluation and validation measures are indispensable to ensure that the desired operational benefits are achieved. This is why DFS has for many years used fast- and real-time simulations to assess and optimise any changes to be made to the air traffic control system. The working methods of DFS in this context are in keeping with the European Operational Concept Validation Methodology of 2007, in short E-OCVM. This paper outlines the development and validation activities of DFS using the MSP D/L project as an example. The project deals with the introduction of the new role of air traffic controllers as multi-sector planners (MSP and new system functionalities, such as air/ground data link (D/L. The project included the development of an operational concept for using the new functionalities as well as for defining working procedures and the airspace structure. This concept was subsequently evaluated by means of a fast-time simulation and two real-time simulations
Gasohol Quality Control for Real Time Applications by Means of a Multimode Interference Fiber Sensor
Rodríguez Rodríguez, Adolfo J.; Baldovino-Pantaleón, Oscar; Domínguez Cruz, Rene F.; Zamarreño, Carlos R.; Matías, Ignacio R.; May-Arrioja, Daniel A.
2014-01-01
In this work we demonstrate efficient quality control of a variety of gasoline and ethanol (gasohol) blends using a multimode interference (MMI) fiber sensor. The operational principle relies on the fact that the addition of ethanol to the gasohol blend reduces the refractive index (RI) of the gasoline. Since MMI sensors are capable of detecting small RI changes, the ethanol content of the gasohol blend is easily determined by tracking the MMI peak wavelength response. Gasohol blends with ethanol contents ranging from 0% to 50% has been clearly identified using this device, which provides a linear response with a maximum sensitivity of 0.270 nm/% EtOH. The sensor can also distinguish when water incorporated in the blend has exceeded the maximum volume tolerated by the gasohol blend, which is responsible for phase separation of the ethanol and gasoline and could cause serious engine failures. Since the MMI sensor is straightforward to fabricate and does not require any special coating it is a cost effective solution for real time and in-situ monitoring of the quality of gasohol blends. PMID:25256111
Gasohol Quality Control for Real Time Applications by Means of a Multimode Interference Fiber Sensor
Directory of Open Access Journals (Sweden)
Adolfo J. Rodríguez Rodríguez
2014-09-01
Full Text Available In this work we demonstrate efficient quality control of a variety of gasoline and ethanol (gasohol blends using a multimode interference (MMI fiber sensor. The operational principle relies on the fact that the addition of ethanol to the gasohol blend reduces the refractive index (RI of the gasoline. Since MMI sensors are capable of detecting small RI changes, the ethanol content of the gasohol blend is easily determined by tracking the MMI peak wavelength response. Gasohol blends with ethanol contents ranging from 0% to 50% has been clearly identified using this device, which provides a linear response with a maximum sensitivity of 0.270 nm/% EtOH. The sensor can also distinguish when water incorporated in the blend has exceeded the maximum volume tolerated by the gasohol blend, which is responsible for phase separation of the ethanol and gasoline and could cause serious engine failures. Since the MMI sensor is straightforward to fabricate and does not require any special coating it is a cost effective solution for real time and in-situ monitoring of the quality of gasohol blends.
The mean first passage time in an energy-diffusion controlled regime with power-law distributions
International Nuclear Information System (INIS)
Zhou, Yanjun; Du, Jiulin
2013-01-01
Based on the mean first passage time (MFPT) theory, we derive an expression of the MFPT in an energy-diffusion controlled regime with a power-law distribution. We discuss the finite barrier effect (i.e. the thermal energy k B T is not small with respect to the potential barrier E b ) and compare it with Kramers’ infinite barrier result both in a power-law distribution and in a Maxwell–Boltzmann distribution. It is shown that the MFPT with a power-law distribution extends Kramers’ low-damping result to a relatively low barrier. We pay attention to the energy-diffusion controlled regime, which is of great interest in the context of Josephson junctions, and study how the power-law parameter κ affects the current distribution function in experiments with Josephson junctions. (paper)
DEFF Research Database (Denmark)
Lind, Morten
2004-01-01
assumptions. Means-end analysis also lacks a proper definition of the control concept. It is proposed that control is defined as a binary relation that assign functional roles to subsystems. This control concept leads to distinct but entangled process and control hierarchies. It is argued that the problems...
Controlling Access to Suicide Means
Directory of Open Access Journals (Sweden)
Miriam Iosue
2011-12-01
Full Text Available Background: Restricting access to common means of suicide, such as firearms, toxic gas, pesticides and other, has been shown to be effective in reducing rates of death in suicide. In the present review we aimed to summarize the empirical and clinical literature on controlling the access to means of suicide. Methods: This review made use of both MEDLINE, ISI Web of Science and the Cochrane library databases, identifying all English articles with the keywords “suicide means”, “suicide method”, “suicide prediction” or “suicide prevention” and other relevant keywords. Results: A number of factors may influence an individual’s decision regarding method in a suicide act, but there is substantial support that easy access influences the choice of method. In many countries, restrictions of access to common means of suicide has lead to lower overall suicide rates, particularly regarding suicide by firearms in USA, detoxification of domestic and motor vehicle gas in England and other countries, toxic pesticides in rural areas, barriers at jumping sites and hanging, by introducing “safe rooms” in prisons and hospitals. Moreover, decline in prescription of barbiturates and tricyclic antidepressants (TCAs, as well as limitation of drugs pack size for paracetamol and salicylate has reduced suicides by overdose, while increased prescription of SSRIs seems to have lowered suicidal rates. Conclusions: Restriction to means of suicide may be particularly effective in contexts where the method is popular, highly lethal, widely available, and/or not easily substituted by other similar methods. However, since there is some risk of means substitution, restriction of access should be implemented in conjunction with other suicide prevention strategies.
Time independent mean-field theory
International Nuclear Information System (INIS)
Negele, J.W.
1980-02-01
The physical and theoretical motivations for the time-dependent mean-field theory are presented, and the successes and limitations of the time-dependent Hartree-Fock initial-vaue problem are reviewed. New theoretical developments are described in the treatment of two-body correlations and the formulation of a quantum mean-field theory of large-amplitude collective motion and tunneling decay. Finally, the mean-field theory is used to obtain new insights into the phenomenon of pion condensation in finite nuclei. 18 figures
International Nuclear Information System (INIS)
Sato, Haruo; Sasaki, Masayoshi.
1974-01-01
Object: To enable wire rope to be readily removed from guide pulleys for the inspection or replacement of control rods. Structure: A pair of guide pulleys disposed to oppose each other are provided on their periphery with respective notches which are arranged in a staggered fashion. In this way, the rope is made to be removed from the notches for inspection of the control rod or for other purposes. (Kamimura, M.)
Mean Transit Time and Mean Residence Time for Linear Diffusion–Convection–Reaction Transport System
Directory of Open Access Journals (Sweden)
Jacek Waniewski
2007-01-01
Full Text Available Characteristic times for transport processes in biological systems may be evaluated as mean transit times (MTTs (for transit states or mean residence times (MRT (for steady states. It is shown in a general framework of a (linear reaction–diffusion–convection equation that these two times are related. Analytical formulas are also derived to calculate moments of exit time distribution using solutions for a stationary state of the system.
Discrete time and continuous time dynamic mean-variance analysis
Reiss, Ariane
1999-01-01
Contrary to static mean-variance analysis, very few papers have dealt with dynamic mean-variance analysis. Here, the mean-variance efficient self-financing portfolio strategy is derived for n risky assets in discrete and continuous time. In the discrete setting, the resulting portfolio is mean-variance efficient in a dynamic sense. It is shown that the optimal strategy for n risky assets may be dominated if the expected terminal wealth is constrained to exactly attain a certain goal instead o...
Time dependent mean-field games
Gomes, Diogo A.
2014-01-06
We consider time dependent mean-field games (MFG) with a local power-like dependence on the measure and Hamiltonians satisfying both sub and superquadratic growth conditions. We establish existence of smooth solutions under a certain set of conditions depending both on the growth of the Hamiltonian as well as on the dimension. In the subquadratic case this is done by combining a Gagliardo-Nirenberg type of argument with a new class of polynomial estimates for solutions of the Fokker-Planck equation in terms of LrLp- norms of DpH. These techniques do not apply to the superquadratic case. In this setting we recur to a delicate argument that combines the non-linear adjoint method with polynomial estimates for solutions of the Fokker-Planck equation in terms of L1L1-norms of DpH. Concerning the subquadratic case, we substantially improve and extend the results previously obtained. Furthermore, to the best of our knowledge, the superquadratic case has not been addressed in the literature yet. In fact, it is likely that our estimates may also add to the current understanding of Hamilton-Jacobi equations with superquadratic Hamiltonians.
Continuous time finite state mean field games
Gomes, Diogo A.; Mohr, Joana; Souza, Rafael Rigã o
2013-01-01
In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games. © 2013 Springer Science+Business Media New York.
Continuous time finite state mean field games
Gomes, Diogo A.
2013-04-23
In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games. © 2013 Springer Science+Business Media New York.
Continuous Time Finite State Mean Field Games
Energy Technology Data Exchange (ETDEWEB)
Gomes, Diogo A., E-mail: dgomes@math.ist.utl.pt [Instituto Superior Tecnico, Center for Mathematical Analysis, Geometry, and Dynamical Systems, Departamento de Matematica (Portugal); Mohr, Joana, E-mail: joana.mohr@ufrgs.br; Souza, Rafael Rigao, E-mail: rafars@mat.ufrgs.br [UFRGS, Instituto de Matematica (Brazil)
2013-08-01
In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N{yields}{infinity} of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games.
Continuous Time Finite State Mean Field Games
International Nuclear Information System (INIS)
Gomes, Diogo A.; Mohr, Joana; Souza, Rafael Rigão
2013-01-01
In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games
Mean Field Type Control with Congestion
Energy Technology Data Exchange (ETDEWEB)
Achdou, Yves, E-mail: achdou@ljll.univ-paris-diderot.fr; Laurière, Mathieu [Univ. Paris Diderot, Sorbonne Paris Cité, Laboratoire Jacques-Louis Lions, UMR 7598, UPMC, CNRS (France)
2016-06-15
We analyze some systems of partial differential equations arising in the theory of mean field type control with congestion effects. We look for weak solutions. Our main result is the existence and uniqueness of suitably defined weak solutions, which are characterized as the optima of two optimal control problems in duality.
Tunneling time, what is its meaning?
International Nuclear Information System (INIS)
McDonald, C R; Orlando, G; Vampa, G; Brabec, T
2015-01-01
The tunnel time ionization dynamics for bound systems in laser fields are investigated. Numerical analysis for a step function switch-on of the field allows for the tunnel time to be defined as the time it takes the ground state to develop the under-barrier wavefunction components necessary to achieve the static field ionization rate. A relation between the tunnel time and the Keldysh time is established. The definition of the tunnel time is extended to time varying fields and experimental possibilities for measuring the tunnel time are discussed
[The mean timing of periodontic care rendering].
Zorina, O A; Abaev, Z M; Domashev, D I; Boriskina, O A
2012-01-01
The time-studies demonstrated that the periodontologist spend 30.3 +/- 2.6 minutes on the primary ambulatory visit of patient and 16.4 +/- 0.9 minutes on the revisit of patient (non-registering time spending on preventive and curative activities). Time spending on curative preventive activities in each group of patients with periodontal diseases depended on both the severity of inflammatory destructive processes in periodontium and therapy stage.
Directory of Open Access Journals (Sweden)
Chan AWK
2016-09-01
Full Text Available Aileen WK Chan, Doris SF Yu, KC Choi, Diana TF Lee, Janet WH Sit, Helen YL Chan The Nethersole School of Nursing, The Chinese University of Hong Kong, Hong Kong SAR, People’s Republic of China Purpose: Age-related cognitive decline is a growing public health concern worldwide. More than a quarter of adults with cognitive impairment experience sleep disturbance. The objective of this pilot study was to evaluate the preliminary effects of tai chi qigong (TCQ on improving the night-time sleep quality of older adults with cognitive impairment. Participants: Older adults with cognitive impairment who complain of sleep disturbance. Methods: A randomized controlled trial with two groups. Fifty-two subjects were recruited from two district elderly community centers and randomly assigned to either the TCQ group (n=27 or the control group (n=25. The intervention group received TCQ training consisting of two 60-minute sessions each week for 2 months. The control group was advised to maintain their usual activities. Sleep quality was measured by the Chinese Pittsburgh Sleep Quality Index. Quality of life was measured by Short-form 12, cognitive functions measured by mini-mental state examination, and subjective memory deficits measured by the memory inventory for Chinese. Results: Data were collected at baseline, 2 months, and 6 months. Significant results were noted at 6 months in the Chinese Pittsburgh Sleep Quality Index global score (P=0.004, sleep duration (P=0.003, habitual sleep efficiency (P=0.002, and the Short-form 12 mental health component (P<0.001. The TCQ participants reported better sleep quality and a better (quality of life mental health component than the control group. Conclusion: TCQ can be considered a useful nonpharmacological approach for improving sleep quality in older adults with cognitive impairment.Clinical trial registration: CUHK_CCT00448 (https://www2.ccrb.cuhk.edu.hk/registry/public/287. Keywords: cognitive decline, mind
Sadeghieh, Ali; Sazgar, Hadi; Goodarzi, Kamyar; Lucas, Caro
2012-01-01
This paper presents a new intelligent approach for adaptive control of a nonlinear dynamic system. A modified version of the brain emotional learning based intelligent controller (BELBIC), a bio-inspired algorithm based upon a computational model of emotional learning which occurs in the amygdala, is utilized for position controlling a real laboratorial rotary electro-hydraulic servo (EHS) system. EHS systems are known to be nonlinear and non-smooth due to many factors such as leakage, friction, hysteresis, null shift, saturation, dead zone, and especially fluid flow expression through the servo valve. The large value of these factors can easily influence the control performance in the presence of a poor design. In this paper, a mathematical model of the EHS system is derived, and then the parameters of the model are identified using the recursive least squares method. In the next step, a BELBIC is designed based on this dynamic model and utilized to control the real laboratorial EHS system. To prove the effectiveness of the modified BELBIC's online learning ability in reducing the overall tracking error, results have been compared to those obtained from an optimal PID controller, an auto-tuned fuzzy PI controller (ATFPIC), and a neural network predictive controller (NNPC) under similar circumstances. The results demonstrate not only excellent improvement in control action, but also less energy consumption. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.
Neutron mean annihilation time and inverse of the mean annihilation rate in nuclear reactor
International Nuclear Information System (INIS)
Hayashi, Masatoshi
1999-01-01
There is a dogma in nuclear reactor theory that in a critical reactor the mean annihilation time of neutron is equal to the mean generation time. The author insists that this is a dogma from the basic reexamination of the mean annihilation time of neutron. There are two kinds of neutrons, one participating in chain reactions and the other not participating in chain reactions. The mean annihilation time of neutron is the mean time of the time to annihilation of all neutrons generated in the reactor. The 'prompt neutron life' as a dynamic characteristic parameter proper to nuclear reactor can not be understood as the mean time of neutron to annihilation. The author explains the logic quantitatively with two kinds of nuclear reactors, a bare reactor and an infinite reactor, for which two different mean neutron annihilation times can be defined. Thus, (1) the inverse of the annihilation rate can not simply be considered as the mean annihilation time, (2) the mean annihilation time of a critical reactor is not necessarily equal to the mean generation time, and (3) the prompt neutron life used as a dynamic characteristic parameter of a nuclear reactor can not be understood as the mean time of neutron to annihilation. (M.M.)
Measuring device for control rod driving time
International Nuclear Information System (INIS)
Tanaka, Kazuhiko; Hanabusa, Masatoshi.
1993-01-01
The present invention concerns a measuring device for control driving time having a function capable of measuring a selected control rod driving time and measuring an entire control rod driving time simultaneously. A calculation means and a store means for the selected rod control rod driving time, and a calculation means and a store means for the entire control rod driving time are disposed individually. Each of them measures the driving time and stores the data independent of each other based on a selected control rod insert ion signal and an entire control rod insertion signal. Even if insertion of selected and entire control rods overlaps, each of the control rod driving times can be measured reliably to provide an advantageous effect capable of more accurately conducting safety evaluation for the nuclear reactor based on the result of the measurement. (N.H.)
Continuous time modeling of panel data by means of SEM
Oud, J.H.L.; Delsing, M.J.M.H.; Montfort, C.A.G.M.; Oud, J.H.L.; Satorra, A.
2010-01-01
After a brief history of continuous time modeling and its implementation in panel analysis by means of structural equation modeling (SEM), the problems of discrete time modeling are discussed in detail. This is done by means of the popular cross-lagged panel design. Next, the exact discrete model
Simple relations between mean passage times and Kramers' stationary rate
International Nuclear Information System (INIS)
Boilley, David; Jurado, Beatriz; Schmitt, Christelle
2004-01-01
The classical problem of the escape time of a metastable potential well in a thermal environment is generally studied by various quantities like Kramers' stationary escape rate, mean first passage time, nonlinear relaxation time, or mean last passage time. In addition, numerical simulations lead to the definition of other quantities as the long-time limit escape rate and the transient time. In this paper, we propose some simple analytical relations between all these quantities. In particular, we point out the hypothesis used to evaluate these various times in order to clarify their comparison and applicability, and show how average times include the transient time and the long-time limit of the escape rate
Mean Waiting Time and Patients' Satisfaction in GOPD, Federal ...
African Journals Online (AJOL)
Mean Waiting Time and Patients' Satisfaction in GOPD, Federal Medical Centre, Owerri. ... Journal Home > Vol 4, No 2 (2013) > ... dis-satisfaction as noted from this study should be addressed by the staff and management of the hospital.
Discrete and continuous time dynamic mean-variance analysis
Reiss, Ariane
1999-01-01
Contrary to static mean-variance analysis, very few papers have dealt with dynamic mean-variance analysis. Here, the mean-variance efficient self-financing portfolio strategy is derived for n risky assets in discrete and continuous time. In the discrete setting, the resulting portfolio is mean-variance efficient in a dynamic sense. It is shown that the optimal strategy for n risky assets may be dominated if the expected terminal wealth is constrained to exactly attain a certain goal instead o...
Mean exit time and survival probability within the CTRW formalism
Montero, M.; Masoliver, J.
2007-05-01
An intense research on financial market microstructure is presently in progress. Continuous time random walks (CTRWs) are general models capable to capture the small-scale properties that high frequency data series show. The use of CTRW models in the analysis of financial problems is quite recent and their potentials have not been fully developed. Here we present two (closely related) applications of great interest in risk control. In the first place, we will review the problem of modelling the behaviour of the mean exit time (MET) of a process out of a given region of fixed size. The surveyed stochastic processes are the cumulative returns of asset prices. The link between the value of the MET and the timescale of the market fluctuations of a certain degree is crystal clear. In this sense, MET value may help, for instance, in deciding the optimal time horizon for the investment. The MET is, however, one among the statistics of a distribution of bigger interest: the survival probability (SP), the likelihood that after some lapse of time a process remains inside the given region without having crossed its boundaries. The final part of the manuscript is devoted to the study of this quantity. Note that the use of SPs may outperform the standard “Value at Risk" (VaR) method for two reasons: we can consider other market dynamics than the limited Wiener process and, even in this case, a risk level derived from the SP will ensure (within the desired quintile) that the quoted value of the portfolio will not leave the safety zone. We present some preliminary theoretical and applied results concerning this topic.
A mean-variance frontier in discrete and continuous time
Bekker, Paul A.
2004-01-01
The paper presents a mean-variance frontier based on dynamic frictionless investment strategies in continuous time. The result applies to a finite number of risky assets whose price process is given by multivariate geometric Brownian motion with deterministically varying coefficients. The derivation is based on the solution for the frontier in discrete time. Using the same multiperiod framework as Li and Ng (2000), I provide an alternative derivation and an alternative formulation of the solu...
A mean-variance frontier in discrete and continuous time
Bekker, Paul A.
2004-01-01
The paper presents a mean-variance frontier based on dynamic frictionless investment strategies in continuous time. The result applies to a finite number of risky assets whose price process is given by multivariate geometric Brownian motion with deterministically varying coefficients. The derivation
Pixel-by-pixel mean transit time without deconvolution.
Dobbeleir, Andre A; Piepsz, Amy; Ham, Hamphrey R
2008-04-01
Mean transit time (MTT) within a kidney is given by the integral of the renal activity on a well-corrected renogram between time zero and time t divided by the integral of the plasma activity between zero and t, providing that t is close to infinity. However, as the data acquisition of a renogram is finite, the MTT calculated using this approach might result in the underestimation of the true MTT. To evaluate the degree of this underestimation we conducted a simulation study. One thousand renograms were created by convoluting various plasma curves obtained from patients with different renal clearance levels with simulated retentions curves having different shapes and mean transit times. For a 20 min renogram, the calculated MTT started to underestimate the MTT when the MTT was higher than 6 min. The longer the MTT, the greater was the underestimation. Up to a MTT value of 6 min, the error on the MTT estimation is negligible. As normal cortical transit is less than 2 min, this approach is used for patients to calculate pixel-to-pixel cortical mean transit time and to create a MTT parametric image without deconvolution.
Technical means overview of the oversize cargoes customs control
Directory of Open Access Journals (Sweden)
Dukhnitskiy P.S.
2016-11-01
Full Text Available this article focuses on the technical means used by the customs authorities when they control oversize cargoes. Customs inspection efficiency improvement as one of the main forms of customs control during the implementation of sampling is possible by the use of technical means of customs control.
Technical means overview of the oversize cargoes customs control
Dukhnitskiy P.S.
2016-01-01
this article focuses on the technical means used by the customs authorities when they control oversize cargoes. Customs inspection efficiency improvement as one of the main forms of customs control during the implementation of sampling is possible by the use of technical means of customs control.
Shapes and dynamics from the time-dependent mean field
International Nuclear Information System (INIS)
Stevenson, P.D.; Goddard, P.M.; Rios, A.
2015-01-01
Explaining observed properties in terms of underlying shape degrees of freedom is a well-established prism with which to understand atomic nuclei. Self-consistent mean-field models provide one tool to understand nuclear shapes, and their link to other nuclear properties and observables. We present examples of how the time-dependent extension of the mean-field approach can be used in particular to shed light on nuclear shape properties, particularly looking at the giant resonances built on deformed nuclear ground states, and at dynamics in highly-deformed fission isomers. Example calculations are shown of 28 Si in the first case, and 240 Pu in the latter case
Reducing the time requirement of k-means algorithm.
Osamor, Victor Chukwudi; Adebiyi, Ezekiel Femi; Oyelade, Jelilli Olarenwaju; Doumbia, Seydou
2012-01-01
Traditional k-means and most k-means variants are still computationally expensive for large datasets, such as microarray data, which have large datasets with large dimension size d. In k-means clustering, we are given a set of n data points in d-dimensional space R(d) and an integer k. The problem is to determine a set of k points in R(d), called centers, so as to minimize the mean squared distance from each data point to its nearest center. In this work, we develop a novel k-means algorithm, which is simple but more efficient than the traditional k-means and the recent enhanced k-means. Our new algorithm is based on the recently established relationship between principal component analysis and the k-means clustering. We provided the correctness proof for this algorithm. Results obtained from testing the algorithm on three biological data and six non-biological data (three of these data are real, while the other three are simulated) also indicate that our algorithm is empirically faster than other known k-means algorithms. We assessed the quality of our algorithm clusters against the clusters of a known structure using the Hubert-Arabie Adjusted Rand index (ARI(HA)). We found that when k is close to d, the quality is good (ARI(HA)>0.8) and when k is not close to d, the quality of our new k-means algorithm is excellent (ARI(HA)>0.9). In this paper, emphases are on the reduction of the time requirement of the k-means algorithm and its application to microarray data due to the desire to create a tool for clustering and malaria research. However, the new clustering algorithm can be used for other clustering needs as long as an appropriate measure of distance between the centroids and the members is used. This has been demonstrated in this work on six non-biological data.
Determination of beta attenuation coefficients by means of timing method
International Nuclear Information System (INIS)
Ermis, E.E.; Celiktas, C.
2012-01-01
Highlights: ► Beta attenuation coefficients of absorber materials were found in this study. ► For this process, a new method (timing method) was suggested. ► The obtained beta attenuation coefficients were compatible with the results from the traditional one. ► The timing method can be used to determine beta attenuation coefficient. - Abstract: Using a counting system with plastic scintillation detector, beta linear and mass attenuation coefficients were determined for bakelite, Al, Fe and plexiglass absorbers by means of timing method. To show the accuracy and reliability of the obtained results through this method, the coefficients were also found via conventional energy method. Obtained beta attenuation coefficients from both methods were compared with each other and the literature values. Beta attenuation coefficients obtained through timing method were found to be compatible with the values obtained from conventional energy method and the literature.
Reaction paths based on mean first-passage times
International Nuclear Information System (INIS)
Park, Sanghyun; Sener, Melih K.; Lu Deyu; Schulten, Klaus
2003-01-01
Finding representative reaction pathways is important for understanding the mechanism of molecular processes. We propose a new approach for constructing reaction paths based on mean first-passage times. This approach incorporates information about all possible reaction events as well as the effect of temperature. As an application of this method, we study representative pathways of excitation migration in a photosynthetic light-harvesting complex, photosystem I. The paths thus computed provide a complete, yet distilled, representation of the kinetic flow of excitation toward the reaction center, thereby succinctly characterizing the function of the system
The impact of mean time to repair modifications
International Nuclear Information System (INIS)
Nitoi, M.; Apostol, M.; Florescu, G.; Farcasiu, M.
2004-01-01
The assessment of the nuclear power plant safety is one of the safety principles; its application intends to lead to the improvement of safety in all the states that have nuclear power plants. The sensitivity analyses are an integral part of the probabilistic safety evaluation of the Cernavoda nuclear plant safety (CPSE - Cernavoda Probabilistic Safety Evaluation Study). An impact study of the changes in model and assumptions on final result gives a better perspective on study conclusions. The paper presents the impact on plant systems unavailability of the changes in components mean time to repair. (author)
Time-Dependent Mean-Field Games with Logarithmic Nonlinearities
Gomes, Diogo A.; Pimentel, Edgard
2015-01-01
In this paper, we prove the existence of classical solutions for time-dependent mean-field games with a logarithmic nonlinearity and subquadratic Hamiltonians. Because the logarithm is unbounded from below, this nonlinearity poses substantial mathematical challenges that have not been addressed in the literature. Our result is proven by recurring to a delicate argument which combines Lipschitz regularity for the Hamilton-Jacobi equation with estimates for the nonlinearity in suitable Lebesgue spaces. Lipschitz estimates follow from an application of the nonlinear adjoint method. These are then combined with a priori bounds for solutions of the Fokker-Planck equation and a concavity argument for the nonlinearity.
Time-Dependent Mean-Field Games with Logarithmic Nonlinearities
Gomes, Diogo A.
2015-10-06
In this paper, we prove the existence of classical solutions for time-dependent mean-field games with a logarithmic nonlinearity and subquadratic Hamiltonians. Because the logarithm is unbounded from below, this nonlinearity poses substantial mathematical challenges that have not been addressed in the literature. Our result is proven by recurring to a delicate argument which combines Lipschitz regularity for the Hamilton-Jacobi equation with estimates for the nonlinearity in suitable Lebesgue spaces. Lipschitz estimates follow from an application of the nonlinear adjoint method. These are then combined with a priori bounds for solutions of the Fokker-Planck equation and a concavity argument for the nonlinearity.
Medical and scientific writing: Time to go lean and mean
Directory of Open Access Journals (Sweden)
Payal Bhardwaj
2017-01-01
Full Text Available The Lean Six Sigma methodology for process improvements and driving efficiency is old, but lean writing was adopted late by the pharmaceutical world in terms of size of the documents. The documents were lean earlier, and then became voluminous, and now we are about to complete a full circle in this regard, i.e., coming back to the lean documents again using e-formats and hyperlinking. Furthermore, writing has become more and more precise over time. The need for this lean and mean medical and scientific writing arose from voluminous research globally, both industry and academia which are abuzz with skyrocketing regulatory and scientific submission volumes. The quantum of literature is so much that reviewers or information seekers firmly believe that going through even selected and relevant literature has become highly challenging. Considering this, there has been much insistence on downsizing the medical writing documents, which could be tempting enough to be leveraged for scientific publications as well. Here, we present the need for lean and mean medical writing, discuss this concept in relation to the pharmaceutical industry, and how to apply this to key documents. Furthermore, presented is the proposed algorithm for lean and mean clinical study reports and manuscripts. These thoughts are aligned to the recently established concept of data transparency, and can be easily achieved by web links between the protocols and clinical trial results disclosed publicly, and the corresponding manuscripts.
Continuous-Time Mean-Variance Portfolio Selection under the CEV Process
Ma, Hui-qiang
2014-01-01
We consider a continuous-time mean-variance portfolio selection model when stock price follows the constant elasticity of variance (CEV) process. The aim of this paper is to derive an optimal portfolio strategy and the efficient frontier. The mean-variance portfolio selection problem is formulated as a linearly constrained convex program problem. By employing the Lagrange multiplier method and stochastic optimal control theory, we obtain the optimal portfolio strategy and mean-variance effici...
Complexity, Sustainability, Justice, and Meaning: Chronological Versus Dynamical Time
Directory of Open Access Journals (Sweden)
Horacio Velasco
2009-11-01
="font-size: small; font-family: Times New Roman;">
Times New Roman;">When nonlinear dynamics came to be complemented with semiotic modulation through the implement of symbol-mediated language (a complementation subsequently termed semantic closure as first instantiated through the communicating (as opposed to merely dynamically interacting molecular complexes of the cell, what can be termed semiotic hysteresis was born. The paper attempts to show that indefinitely evolving complexity, sustainability, justice, and meaning are indissolubly bound with chronological time in the sense of semiotic hysteresis (as afforded initially by non-cognitive semantic closure and subsequently, at least one hopes, by cognitive semantic closure: This semiotic hysteresis yields the indefinite evolutionary time of the living condition—including culture.
Times New Roman;">
The meaning of transit times in NDT of reinforced concrete
International Nuclear Information System (INIS)
Suarez Antola, R.
2007-10-01
Transit times of longitudinal pulses that travel near reinforcing steel bars are usually smaller than in plain concrete. Chung first, and then Bungey, demonstrated the importance of including bar diameters in the correction factors when pulses propagating parallel and near to the bars can not be avoided. Besides the influence of geometric dispersion and mode conversion on pulse propagation, there is an effect due to a specific pattern of radial variation of longitudinal wave velocities from the surface of the embedded steel bar. Wall effects produce a region (a sheath) of concrete surrounding the steel bar, with smaller longitudinal pulse velocities in comparison with the velocity farther away from the bar. Then the acoustics energy travels trapped in a kind of composite leaky waveguide with a velocity less than the compression (P) wave velocity in steel and in concrete but greater than the extensional wave velocity in steel. A mathematical model of the propagation of a longitudinal wave-packet is constructed, taking into account both attenuation and dispersion effects. An asymptotic analysis of pulse propagation and the introduction of a threshold of detection in the receiving transducer, allows the derivation of an approximate analytical formula for transit times. Then the meaning of transit times in NDT of concrete is discussed. The above mentioned formula is used to study the effects of the reinforcing bar radius, the propagation parameters in plain concrete and in the sheath surrounding the steel bar, the path length between the transmitting and the receiving transducers, and the energy and the spectral composition of the pulse injected by the emitter in the tested body. Chung s empirical correlation between the measured pulse velocity and bar radius is reviewed and a new correlation is proposed
Evaluation of hospital disinfection as a means of controlling endemic ...
African Journals Online (AJOL)
Evaluation of hospital environment disinfection as a means of controlling endemic nosocomial pathogens in a University Teaching Hospital in Nigeria was evaluated. Disinfectant used in the Hospital was collected from the Infection Control unit and prepared in different concentrations. The isolated bacterial species from the ...
Mean Residence Time and Emergency Drinking Water Supply.
Kralik, Martin; Humer, Franko
2013-04-01
Mean Residence Times (MRTs) of the raw water of drinking water supplies is the measurement of the water-isotopes (oxygen-18, hydrogen-2 and tritium (3H)). The traceability and the quality oft he lumped model calculation is based on the quality and the density of input (meteorological) stations in the region with monthly measurements. In addition, noble gas measurements in the groundwater (helium-3, krypton-85) and of industrial tracer gases (chlorofluorocarbon (CFC) and sulphurhexaflorid (SF6)) are important tools to estimate the MRTs of the raw water in the aquifers. To exclude the presence of small amounts of very recent waters, which are in cases of accidents some times heavily polluted, the raw water is tested for natural radionuclides (beryllium-7 or sulphur-35) with very short half-life or artificial fluorescence tracers. In addition, the estimate of the MRTs of groundwater is an essential part of the vulnerability assessment of drinking water supplies due to climate change impacts (frequency of droughts and floods in the recharge area) and offers a valuable tool to specify a sustainable water abstraction. The applicability of this approach was tested in several springs and groundwater monitoring wells used for raw water abstraction for drinking water supply in Austria.
The application of mean control chart in managing industrial processes
Directory of Open Access Journals (Sweden)
Papić-Blagojević Nataša
2013-01-01
Full Text Available Along with the advent of mass production comes the problem of monitoring and maintaining the quality of the product, which stressed the need for the application of selected statistical and mathematical methods in the control process. The main objective of applying the methods of statistical control is continuous quality improvement through permanent monitoring of the process in order to discover the causes of errors. Shewart charts are the most popular method of statistical process control, which performs separation of controlled and uncontrolled variations along with detection of increased variations. This paper presents the example of Shewart mean control chart with application in managing industrial process.
The meaning of "control" for childbearing women in the US.
Namey, Emily E; Lyerly, Anne Drapkin
2010-08-01
Childbearing women, healthcare providers, and commentators on birth broadly identify control as an important issue during childbirth; however, control is rarely defined in literature on the topic. Here we seek to deconstruct the term control as used by childbearing women to better understand the issues and concepts underpinning it. Based on qualitative interviews with 101 parous women in the United States, we analyze meanings of control within the context of birth narratives. We find these meanings correspond to five distinct domains: self-determination, respect, personal security, attachment, and knowledge. We also find ambivalence about this term and concept, in that half our sample recognizes "you cannot control birth". Together, these findings call into question the usefulness of the term for measuring quality or improving maternity care and highlight other concepts which may be more fruitfully explored. (c) 2010 Elsevier Ltd. All rights reserved.
Chemical control of flowering time
DEFF Research Database (Denmark)
Ionescu, Irina Alexandra; Møller, Birger Lindberg; Sánchez Pérez, Raquel
2017-01-01
Flowering at the right time is of great importance; it secures seed production and therefore species survival and crop yield. In addition to the genetic network controlling flowering time, there are a number of much less studied metabolites and exogenously applied chemicals that may influence...... on the genetic aspects of flowering time regulation in annuals, but less so in perennials. An alternative to plant breeding approaches is to engineer flowering time chemically via the external application of flower-inducing compounds. This review discusses a variety of exogenously applied compounds used in fruit...
Applying Mean-Field Approximation to Continuous Time Markov Chains
Kolesnichenko, A.V.; Senni, Valerio; Pourranjabar, Alireza; Remke, A.K.I.; Stoelinga, M.I.A.
2014-01-01
The mean-field analysis technique is used to perform analysis of a system with a large number of components to determine the emergent deterministic behaviour and how this behaviour modifies when its parameters are perturbed. The computer science performance modelling and analysis community has found
Parental Regulation of Teenagers' Time: Processes and Meanings
Sarre, Sophie
2010-01-01
Parental regulation of teenagers' time is pervasive. Parents attempt to constrain, well into adolescence, what their children do with their time, when they do it and how long they do it for. This article draws on interviews with 14- to 16-year-olds in the UK to explore teenagers' experiences of parents' temporal regulation, and whether their…
A Biological Perspective on the Meaning of Time
Rothschild, Lynn J.
2014-01-01
We have become impatient waiting for a web page to load, but the first member of our species evolved about 150,000 years ago - a geological instant as brief and as transitory as a text message. The shortest generation time of a bacterium is a sprint at under ten minutes, whereas a 200-year old whale, turtle or tree is not unknown. Life is a phenomenon that integrates processes ranging from the near instantaneous reactions of photosynthesis to the more stately pace of evolution. Here I will elucidate these processes with radically different time scales that go to creating and maintaining the diversity of life on earth, the clocks that nature uses to time them, and how modern biology is being used to alter the natural time scales.
ST Elevation in AVR: When Time May Not Mean Muscle
2017-10-31
REPORT TYPE 1013112017 Presentation 4. TITLE AND SUBTITLE ST Elevation in AVR: When Thne May Not Mean !Vfu&cle 6. AUTHOR{S) Capt \\Villiam T...ACCF/AHA Guideline for the Management of ST -Elevation Myocardial Infarction A Report of the Arnerican College of C ardiology Foundation/ Ameri can...C7Q n ([) G) ro )::>t w :J r+ c.. < -· ro ti) ti) ro ti) OJ m ti) -ro n Take home points •Don’t ignore ST elevation in aVR •Look closely
Continuous-Time Mean-Variance Portfolio Selection under the CEV Process
Directory of Open Access Journals (Sweden)
Hui-qiang Ma
2014-01-01
Full Text Available We consider a continuous-time mean-variance portfolio selection model when stock price follows the constant elasticity of variance (CEV process. The aim of this paper is to derive an optimal portfolio strategy and the efficient frontier. The mean-variance portfolio selection problem is formulated as a linearly constrained convex program problem. By employing the Lagrange multiplier method and stochastic optimal control theory, we obtain the optimal portfolio strategy and mean-variance efficient frontier analytically. The results show that the mean-variance efficient frontier is still a parabola in the mean-variance plane, and the optimal strategies depend not only on the total wealth but also on the stock price. Moreover, some numerical examples are given to analyze the sensitivity of the efficient frontier with respect to the elasticity parameter and to illustrate the results presented in this paper. The numerical results show that the price of risk decreases as the elasticity coefficient increases.
Lean Mean Times--Budgeting for School Media Technology.
Johnson, Doug
1995-01-01
Discusses budgeting strategies for school media technology programs. Highlights include sources for school funding, school district budget information, control of the budget, how to write an effective budget, working with other community and school groups, local politics, and sidebars that discuss spreadsheets and maintenance budgets. (LRW)
Real-Time Nonlocal Means-Based Despeckling.
Breivik, Lars Hofsoy; Snare, Sten Roar; Steen, Erik Normann; Solberg, Anne H Schistad
2017-06-01
In this paper, we propose a multiscale nonlocal means-based despeckling method for medical ultrasound. The multiscale approach leads to large computational savings and improves despeckling results over single-scale iterative approaches. We present two variants of the method. The first, denoted multiscale nonlocal means (MNLM), yields uniform robust filtering of speckle both in structured and homogeneous regions. The second, denoted unnormalized MNLM (UMNLM), is more conservative in regions of structure assuring minimal disruption of salient image details. Due to the popularity of anisotropic diffusion-based methods in the despeckling literature, we review the connection between anisotropic diffusion and iterative variants of NLM. These iterative variants in turn relate to our multiscale variant. As part of our evaluation, we conduct a simulation study making use of ground truth phantoms generated from clinical B-mode ultrasound images. We evaluate our method against a set of popular methods from the despeckling literature on both fine and coarse speckle noise. In terms of computational efficiency, our method outperforms the other considered methods. Quantitatively on simulations and on a tissue-mimicking phantom, our method is found to be competitive with the state-of-the-art. On clinical B-mode images, our method is found to effectively smooth speckle while preserving low-contrast and highly localized salient image detail.
Mean residence times for tritium in some terrestrial plants
International Nuclear Information System (INIS)
Gogate, S.S.; Krishnamoorthy, T.M.; Soman, S.D.
1975-01-01
Uptake of tritiated water from a single or multiple exposure, its fixation and elimination from 3 terrestrial plants, Raphanus sativus L., Amaranthus viridis L. and Phyllanthus fraternus Webster under experimental field conditions are described. Tissue free water tritium (TFWT) attains peak concentration within 4 hr after a single exposure in R. sativus and then decreases with a single component from both leaves and root, with a biological half-time of 36.4 +- 4.2 and 48.5 +- 7.2 hr respectively. TFWT in leaves of A. viridis reaches its peak value within 0.5 hr of exposure and its decay exhibits 2 component fall, one having a very short half-life of 2.4 +- 0.7 hr and the other a long half-time of 86.1 +- 2.0 hr. The two component decay of tritium in TFWT is well represented in P. fraternus. The long-lived components are nearly 8 times of the short-lived ones, both in leaves and stems respectively. Generally, the long -lived component accounts for 15% of the peak TFWT. Tissue bound tritium (TBT) reaches to 4% of TFWT in Phyllanthus sp. TBT elimination time is many times longer than the experimental periods employed in the present study. (author)
The Geometrical Meaning of Time – Some Cosmological Implications
International Nuclear Information System (INIS)
Yahalom, Asher
2015-01-01
It is stated in many text books that the any metric appearing in general relativity should be locally Lorentzian i.e. of the type g μv = diag(1, -1, -1, -1) this is usually presented as an independent axiom of the theory, which cannot be deduced from other assumptions. The meaning of this assertion is that a specific coordinate (the temporal coordinate) is given a unique significance with respect to the other spatial coordinates. It was shown that the above assertion is a consequence of requirement that the metric of empty space should be linearly stable and need not be assumed. Some cosmological implications of the above result will be suggested
Harteveld, Casper
The second world to be considered concerns Meaning. In contrast to Reality and Play, this world relates to the people, disciplines, and domains that are focused on creating a certain value. For example, if this value is about providing students knowledge about physics, it involves teachers, the learning sciences, and the domains education and physics. This level goes into the aspects and criteria that designers need to take into account from this perspective. The first aspect seems obvious when we talk of “games with a serious purpose.” They have a purpose and this needs to be elaborated on, for example in terms of what “learning objectives” it attempts to achieve. The subsequent aspect is not about what is being pursued but how. To attain a value, designers have to think about a strategy that they employ. In my case this concerned looking at the learning paradigms that have come into existence in the past century and see what they have to tell us about learning. This way, their principles can be translated into a game environment. This translation involves making the strategy concrete. Or, in other words, operationalizing the plan. This is the third aspect. In this level, I will further specifically explain how I derived requirements from each of the learning paradigms, like reflection and exploration, and how they can possibly be related to games. The fourth and final aspect is the context in which the game is going to be used. It matters who uses the game and when, where, and how the game is going to be used. When designers have looked at these aspects, they have developed a “value proposal” and the worth of it may be judged by criteria, like motivation, relevance, and transfer. But before I get to this, I first go into how we human beings are meaning creators and what role assumptions, knowledge, and ambiguity have in this. I will illustrate this with some silly jokes about doctors and Mickey Mouse, and with an illusion.
An Elementary Derivation of Mean Wait Time in Polling Systems
Cady, Field
2012-01-01
Polling systems are a well-established subject in queueing theory. However, their formal treatments generally rely heavily on relatively sophisticated theoretical tools, such as moment generating functions and Laplace transforms, and solutions often require the solution of large systems of equations. We show that, if you are willing to only have the average waiting of a system time rather than higher moments, it can found through an elementary derivation based only on algebra and some well-kn...
Does the dose-solubility ratio affect the mean dissolution time of drugs?
Lánský, P; Weiss, M
1999-09-01
To present a new model for describing drug dissolution. On the basis of the new model to characterize the dissolution profile by the distribution function of the random dissolution time of a drug molecule, which generalizes the classical first order model. Instead of assuming a constant fractional dissolution rate, as in the classical model, it is considered that the fractional dissolution rate is a decreasing function of the dissolved amount controlled by the dose-solubility ratio. The differential equation derived from this assumption is solved and the distribution measures (half-dissolution time, mean dissolution time, relative dispersion of the dissolution time, dissolution time density, and fractional dissolution rate) are calculated. Finally, instead of monotonically decreasing the fractional dissolution rate, a generalization resulting in zero dissolution rate at time origin is introduced. The behavior of the model is divided into two regions defined by q, the ratio of the dose to the solubility level: q 1 (saturation of the solution, saturation time). The singular case q = 1 is also treated and in this situation the mean as well as the relative dispersion of the dissolution time increase to infinity. The model was successfully fitted to data (1). This empirical model is descriptive without detailed physical reasoning behind its derivation. According to the model, the mean dissolution time is affected by the dose-solubility ratio. Although this prediction appears to be in accordance with preliminary application, further validation based on more suitable experimental data is required.
From linear to nonlinear control means: a practical progression.
Gao, Zhiqiang
2002-04-01
With the rapid advance of digital control hardware, it is time to take the simple but effective proportional-integral-derivative (PID) control technology to the next level of performance and robustness. For this purpose, a nonlinear PID and active disturbance rejection framework are introduced in this paper. It complements the existing theory in that (1) it actively and systematically explores the use of nonlinear control mechanisms for better performance, even for linear plants; (2) it represents a control strategy that is rather independent of mathematical models of the plants, thus achieving inherent robustness and reducing design complexity. Stability analysis, as well as software/hardware test results, are presented. It is evident that the proposed framework lends itself well in seeking innovative solutions to practical problems while maintaining the simplicity and the intuitiveness of the existing technology.
Continuous-Time Mean-Variance Portfolio Selection with Random Horizon
International Nuclear Information System (INIS)
Yu, Zhiyong
2013-01-01
This paper examines the continuous-time mean-variance optimal portfolio selection problem with random market parameters and random time horizon. Treating this problem as a linearly constrained stochastic linear-quadratic optimal control problem, I explicitly derive the efficient portfolios and efficient frontier in closed forms based on the solutions of two backward stochastic differential equations. Some related issues such as a minimum variance portfolio and a mutual fund theorem are also addressed. All the results are markedly different from those in the problem with deterministic exit time. A key part of my analysis involves proving the global solvability of a stochastic Riccati equation, which is interesting in its own right
Continuous-Time Mean-Variance Portfolio Selection with Random Horizon
Energy Technology Data Exchange (ETDEWEB)
Yu, Zhiyong, E-mail: yuzhiyong@sdu.edu.cn [Shandong University, School of Mathematics (China)
2013-12-15
This paper examines the continuous-time mean-variance optimal portfolio selection problem with random market parameters and random time horizon. Treating this problem as a linearly constrained stochastic linear-quadratic optimal control problem, I explicitly derive the efficient portfolios and efficient frontier in closed forms based on the solutions of two backward stochastic differential equations. Some related issues such as a minimum variance portfolio and a mutual fund theorem are also addressed. All the results are markedly different from those in the problem with deterministic exit time. A key part of my analysis involves proving the global solvability of a stochastic Riccati equation, which is interesting in its own right.
Mean-Variance Hedging on Uncertain Time Horizon in a Market with a Jump
International Nuclear Information System (INIS)
Kharroubi, Idris; Lim, Thomas; Ngoupeyou, Armand
2013-01-01
In this work, we study the problem of mean-variance hedging with a random horizon T∧τ, where T is a deterministic constant and τ is a jump time of the underlying asset price process. We first formulate this problem as a stochastic control problem and relate it to a system of BSDEs with a jump. We then provide a verification theorem which gives the optimal strategy for the mean-variance hedging using the solution of the previous system of BSDEs. Finally, we prove that this system of BSDEs admits a solution via a decomposition approach coming from filtration enlargement theory
Mean-Variance Hedging on Uncertain Time Horizon in a Market with a Jump
Energy Technology Data Exchange (ETDEWEB)
Kharroubi, Idris, E-mail: kharroubi@ceremade.dauphine.fr [Université Paris Dauphine, CEREMADE, CNRS UMR 7534 (France); Lim, Thomas, E-mail: lim@ensiie.fr [Université d’Evry and ENSIIE, Laboratoire d’Analyse et Probabilités (France); Ngoupeyou, Armand, E-mail: armand.ngoupeyou@univ-paris-diderot.fr [Université Paris 7, Laboratoire de Probabilités et Modèles Aléatoires (France)
2013-12-15
In this work, we study the problem of mean-variance hedging with a random horizon T∧τ, where T is a deterministic constant and τ is a jump time of the underlying asset price process. We first formulate this problem as a stochastic control problem and relate it to a system of BSDEs with a jump. We then provide a verification theorem which gives the optimal strategy for the mean-variance hedging using the solution of the previous system of BSDEs. Finally, we prove that this system of BSDEs admits a solution via a decomposition approach coming from filtration enlargement theory.
Continuous-Time Mean-Variance Portfolio Selection: A Stochastic LQ Framework
International Nuclear Information System (INIS)
Zhou, X.Y.; Li, D.
2000-01-01
This paper is concerned with a continuous-time mean-variance portfolio selection model that is formulated as a bicriteria optimization problem. The objective is to maximize the expected terminal return and minimize the variance of the terminal wealth. By putting weights on the two criteria one obtains a single objective stochastic control problem which is however not in the standard form due to the variance term involved. It is shown that this nonstandard problem can be 'embedded' into a class of auxiliary stochastic linear-quadratic (LQ) problems. The stochastic LQ control model proves to be an appropriate and effective framework to study the mean-variance problem in light of the recent development on general stochastic LQ problems with indefinite control weighting matrices. This gives rise to the efficient frontier in a closed form for the original portfolio selection problem
Characterization and optimized control by means of multi-parameter controllers
Energy Technology Data Exchange (ETDEWEB)
Nielsen, Carsten; Hoeg, S.; Thoegersen, A. (Dan-Ejendomme, Hellerup (Denmark)) (and others)
2009-07-01
Poorly functioning HVAC systems (Heating, Ventilation and Air Conditioning), but also separate heating, ventilation and air conditioning systems are costing the Danish society billions of kroner every year: partly because of increased energy consumption and high operational and maintenance costs, but mainly due to reduced productivity and absence due to illness because of a poor indoor climate. Typically, the operation of buildings and installations takes place today with traditional build-ing automation, which is characterised by 1) being based on static considerations 2) the individual sensor being coupled with one actuator/valve, i.e. the sensor's signal is only used in one place in the system 3) subsystems often being controlled independently of each other 4) the dynamics in building constructions and systems which is very important to the system and comfort regulation is not being considered. This, coupled with the widespread tendency to use large glass areas in the facades without sufficient sun shading, means that it is difficult to optimise comfort and energy consumption. Therefore, the last 10-20 years have seen a steady increase in the complaints of the indoor climate in Danish buildings and, at the same time, new buildings often turn out to be considerably higher energy consuming than expected. The purpose of the present project is to investigate the type of multi parameter sensors which may be generated for buildings and further to carry out a preliminary evaluation on how such multi parameter controllers may be utilized for optimal control of buildings. The aim of the project isn't to develop multi parameter controllers - this requires much more effort than possible in the present project. The aim is to show the potential of using multi parameter sensors when controlling buildings. For this purpose a larger office building has been chosen - an office building with at high energy demand and complaints regarding the indoor climate. In order to
Reading comprehension metacognitive strategies as a means for controlling behavior
Directory of Open Access Journals (Sweden)
Dinorah Aladina Caballero López
2014-07-01
Full Text Available Textual comprehension implies the use of various metacognitive strategies by the students when they have to face a text to be competent readers. That is why the objective of this article is to illustrate the application of metacognitive strategies in order to achieve an efficient textual comprehension, taking into account the self – regulation the student exerts over his own learning process. It is applied as the main method historical-logical studies based on a professional-researching systematic practice; at the same time observation is largely used. The main result is the introduction of metacognitive strategies in reading comprehension, which subsequently favor the self-control of personal behavior. The article is the result of a research project sponsored by the department of Special Education. Key words: reading comprehension, metacognitive strategies, behavior self-control.
A Random Parameter Model for Continuous-Time Mean-Variance Asset-Liability Management
Directory of Open Access Journals (Sweden)
Hui-qiang Ma
2015-01-01
Full Text Available We consider a continuous-time mean-variance asset-liability management problem in a market with random market parameters; that is, interest rate, appreciation rates, and volatility rates are considered to be stochastic processes. By using the theories of stochastic linear-quadratic (LQ optimal control and backward stochastic differential equations (BSDEs, we tackle this problem and derive optimal investment strategies as well as the mean-variance efficient frontier analytically in terms of the solution of BSDEs. We find that the efficient frontier is still a parabola in a market with random parameters. Comparing with the existing results, we also find that the liability does not affect the feasibility of the mean-variance portfolio selection problem. However, in an incomplete market with random parameters, the liability can not be fully hedged.
Pest control of ligniperdous insects by means of ionizing radiation
International Nuclear Information System (INIS)
Baer, M.; Koehler, W.
1983-01-01
Wooden objects of art and monuments are endangered by wood-destroying insects. The treatment of these objects with ionizing radiation is one way to control these pests. For this purpose the portable HWK-3 high-dose irradiation device was developed. In July 1979, a radiation experiment was made under field conditions in Potsdam-Sanssouci in order to gain experience in the operation and effectiveness of the new device. During the following 18 months the results of this experiment were evaluated by means of the SM 231 vibration measuring instrument. It became evident that a total dose of over 3 kGy would kill all of the death-watch beetles (Anobium punctatum de Geer) and doses down to 0.55 kGy would largely diminish the population, with future damages caused by death-watch beetles being highly unlikely. Delayed damages in the larvae caused by low total doses still add to the effectiveness of the pest control. (author)
A Stochastic Maximum Principle for Risk-Sensitive Mean-Field Type Control
Djehiche, Boualem; Tembine, Hamidou; Tempone, Raul
2015-01-01
In this paper we study mean-field type control problems with risk-sensitive performance functionals. We establish a stochastic maximum principle (SMP) for optimal control of stochastic differential equations (SDEs) of mean-field type, in which the drift and the diffusion coefficients as well as the performance functional depend not only on the state and the control but also on the mean of the distribution of the state. Our result extends the risk-sensitive SMP (without mean-field coupling) of Lim and Zhou (2005), derived for feedback (or Markov) type optimal controls, to optimal control problems for non-Markovian dynamics which may be time-inconsistent in the sense that the Bellman optimality principle does not hold. In our approach to the risk-sensitive SMP, the smoothness assumption on the value-function imposed in Lim and Zhou (2005) needs not be satisfied. For a general action space a Peng's type SMP is derived, specifying the necessary conditions for optimality. Two examples are carried out to illustrate the proposed risk-sensitive mean-field type SMP under linear stochastic dynamics with exponential quadratic cost function. Explicit solutions are given for both mean-field free and mean-field models.
A Stochastic Maximum Principle for Risk-Sensitive Mean-Field Type Control
Djehiche, Boualem
2015-02-24
In this paper we study mean-field type control problems with risk-sensitive performance functionals. We establish a stochastic maximum principle (SMP) for optimal control of stochastic differential equations (SDEs) of mean-field type, in which the drift and the diffusion coefficients as well as the performance functional depend not only on the state and the control but also on the mean of the distribution of the state. Our result extends the risk-sensitive SMP (without mean-field coupling) of Lim and Zhou (2005), derived for feedback (or Markov) type optimal controls, to optimal control problems for non-Markovian dynamics which may be time-inconsistent in the sense that the Bellman optimality principle does not hold. In our approach to the risk-sensitive SMP, the smoothness assumption on the value-function imposed in Lim and Zhou (2005) needs not be satisfied. For a general action space a Peng\\'s type SMP is derived, specifying the necessary conditions for optimality. Two examples are carried out to illustrate the proposed risk-sensitive mean-field type SMP under linear stochastic dynamics with exponential quadratic cost function. Explicit solutions are given for both mean-field free and mean-field models.
International Nuclear Information System (INIS)
Lee, D. Y.; Park, J. H.; Hwang, I. K.; Cha, K. H.; Choi, J. K.; Lee, K. Y.; Park, J. K.
2001-01-01
The design life of nuclear power plants (NPPs) under recent construction is about fifty to sixty years. However, the duration that equipments of control systems operate without failures is at most five to ten years. Design for diversity and adequate maintenance strategy are required for NPP protection system in order to use the control equipment which has shorter life time than the design life of NPP. Fault Tree Analysis (FTA) technique, which has been applied to Probabilistics Safety Analysis (PSA), has been introduced to quantitatively evaluate the reliability of NPP I and C systems. The FTA, however, cannot properly consider the effect of maintenance. In this work, we have reviewed quantitative reliability evaluation techniques using the reliability block diagram and failure rates and applied it to the evaluation of mean time between forced outage for reactor protection system
Quantitatively Probing the Means of Controlling Nanoparticle Assembly on Surfaces
Energy Technology Data Exchange (ETDEWEB)
Patete, J.m.; Wong, S.; Peng, X.; Serafin, J.M.
2011-05-17
As a means of developing a simple, cost-effective, and reliable method for probing nanoparticle behavior, we have used atomic force microscopy to gain a quantitative 3D visual representation of the deposition patterns of citrate-capped Au nanoparticles on a substrate as a function of (a) sample preparation, (b) the choice of substrate, (c) the dispersion solvent, and (d) the number of loading steps. Specifically, we have found that all four parameters can be independently controlled and manipulated in order to alter the resulting pattern and quantity of as-deposited nanoparticles. From these data, the sample preparation technique appears to influence deposition patterns most broadly, and the dispersion solvent is the most convenient parameter to use in tuning the quantity of nanoparticles deposited onto the surface under spin-coating conditions. Indeed, we have quantitatively measured the effect of surface coverage for both mica and silicon substrates under preparation techniques associated with (i) evaporation under ambient air, (ii) heat treatment, and (iii) spin-coating preparation conditions. In addition, we have observed a decrease in nanoparticle adhesion to a substrate when the ethylene glycol content of the colloidal dispersion solvent is increased, which had the effect of decreasing interparticle-substrate interactions. Finally, we have shown that substrates prepared by these diverse techniques have potential applicability in surface-enhanced Raman spectroscopy.
Quantitatively Probing the Means of Controlling Nanoparticle Assembly on Surfaces
International Nuclear Information System (INIS)
Patete, J.M.; Wong, S.; Peng, X.; Serafin, J.M.
2011-01-01
As a means of developing a simple, cost-effective, and reliable method for probing nanoparticle behavior, we have used atomic force microscopy to gain a quantitative 3D visual representation of the deposition patterns of citrate-capped Au nanoparticles on a substrate as a function of (a) sample preparation, (b) the choice of substrate, (c) the dispersion solvent, and (d) the number of loading steps. Specifically, we have found that all four parameters can be independently controlled and manipulated in order to alter the resulting pattern and quantity of as-deposited nanoparticles. From these data, the sample preparation technique appears to influence deposition patterns most broadly, and the dispersion solvent is the most convenient parameter to use in tuning the quantity of nanoparticles deposited onto the surface under spin-coating conditions. Indeed, we have quantitatively measured the effect of surface coverage for both mica and silicon substrates under preparation techniques associated with (i) evaporation under ambient air, (ii) heat treatment, and (iii) spin-coating preparation conditions. In addition, we have observed a decrease in nanoparticle adhesion to a substrate when the ethylene glycol content of the colloidal dispersion solvent is increased, which had the effect of decreasing interparticle-substrate interactions. Finally, we have shown that substrates prepared by these diverse techniques have potential applicability in surface-enhanced Raman spectroscopy.
BIOLOGICAL CONTROL OF WEEDS BY MEANS OF PLANT PATHOGENS
Marija Ravlić; Renata Baličević
2014-01-01
Biological control is the use of live beneficial organisms and products of their metabolism in the pests control. Plant pathogens can be used for weed control in three different ways: as classical, conservation and augmentative (inoculative and inundated) biological control. Inundated biological control involves the use of bioherbicides (mycoherbicides) or artificial breeding of pathogens and application in specific stages of crops and weeds. Biological control of weeds can be used where chem...
Optimal control of LQG problem with an explicit trade-off between mean and variance
Qian, Fucai; Xie, Guo; Liu, Ding; Xie, Wenfang
2011-12-01
For discrete-time linear-quadratic Gaussian (LQG) control problems, a utility function on the expectation and the variance of the conventional performance index is considered. The utility function is viewed as an overall objective of the system and can perform the optimal trade-off between the mean and the variance of performance index. The nonlinear utility function is first converted into an auxiliary parameters optimisation problem about the expectation and the variance. Then an optimal closed-loop feedback controller for the nonseparable mean-variance minimisation problem is designed by nonlinear mathematical programming. Finally, simulation results are given to verify the algorithm's effectiveness obtained in this article.
BIOLOGICAL CONTROL OF WEEDS BY MEANS OF PLANT PATHOGENS
Directory of Open Access Journals (Sweden)
Marija Ravlić
2014-06-01
Full Text Available Biological control is the use of live beneficial organisms and products of their metabolism in the pests control. Plant pathogens can be used for weed control in three different ways: as classical, conservation and augmentative (inoculative and inundated biological control. Inundated biological control involves the use of bioherbicides (mycoherbicides or artificial breeding of pathogens and application in specific stages of crops and weeds. Biological control of weeds can be used where chemical herbicides are not allowed, if resistant weed species are present or in the integrated pest management against weeds with reduced herbicides doses and other non-chemical measures, but it has certain limitations and disadvantages.
Green operations of belt conveyors by means of speed control
He, D.; Pang, Y.; Lodewijks, G.
2017-01-01
Belt conveyors can be partially loaded due to the variation of bulk material flow loaded onto the conveyor. Speed control attempts to reduce the belt conveyor energy consumption and to enable the green operations of belt conveyors. Current research of speed control rarely takes the conveyor dynamics
Team Electronic Gameplay Combining Different Means of Control
Pope, Alan T. (Inventor); Palsson, Olafur S. (Inventor)
2014-01-01
Disclosed are methods and apparatuses provided for modifying the effect of an operator controlled input device on an interactive device to encourage the self-regulation of at least one physiological activity by a person different than the operator. The interactive device comprises a display area which depicts images and apparatus for receiving at least one input from the operator controlled input device to thus permit the operator to control and interact with at least some of the depicted images. One effect modification comprises measurement of the physiological activity of a person different from the operator, while modifying the ability of the operator to control and interact with at least some of the depicted images by modifying the input from the operator controlled input device in response to changes in the measured physiological signal.
Constrained deterministic leader-follower mean field control
Möller, L.; Gentile, B.; Parise, F.; Grammatico, S.; Lygeros, J.
2016-01-01
We consider a mean field game among a large population of noncooperative agents divided into two categories: leaders and followers. Each agent is subject to heterogeneous convex constraints and minimizes a quadratic cost function; the cost of each leader is affected by the leaders' aggregate
Tunneling time distribution by means of Nelson's quantum mechanics and wave-particle duality
International Nuclear Information System (INIS)
Hara, Koh'ichiro; Ohba, Ichiro
2003-01-01
We calculate a tunneling time distribution by means of Nelson's quantum mechanics and investigate its statistical properties. The relationship between the average and deviation of tunneling time suggests the existence of 'wave-particle duality' in the tunneling phenomena
Dynamical control of quantum systems in the context of mean ergodic theorems
International Nuclear Information System (INIS)
Bernád, J Z
2017-01-01
Equidistant and non-equidistant single pulse ‘bang–bang’ dynamical controls are investigated in the context of mean ergodic theorems. We show the requirements in which the limit of infinite pulse control for both the equidistant and the non-equidistant dynamical control converges to the same unitary evolution. It is demonstrated that the generator of this evolution can be obtained by projecting the generator of the free evolution onto the commutant of the unitary operator representing the pulse. Inequalities are derived to prove this statement and in the case of non-equidistant approach these inequalities are optimised as a function of the time intervals. (paper)
T.R. Jackson; R. Haggerty; S.V. Apte; A. Coleman; K.J. Drost
2012-01-01
Surface transient storage (STS) has functional significance in stream ecosystems because it increases solute interaction with sediments. After volume, mean residence time is the most important metric of STS, but it is unclear how this can be measured accurately or related to other timescales and field-measureable parameters. We studied mean residence time of lateral...
Gastrointestinal mean transit times in young and middle-aged healthy subjects
DEFF Research Database (Denmark)
Graff, J; Brinch, K; Madsen, Jan Lysgård
2001-01-01
To investigate the effects of age and gender on gastric, small intestinal and colonic mean transit times, a study was conducted in 32 healthy volunteers: eight young women (22-30 years), eight young men (20-28 years), eight middle-aged women (43-51 years) and eight middle-aged men (38-53 years......, small intestinal and colonic mean transit times were calculated. The gastric, small intestinal and colonic mean transit times were significantly longer in women. Ageing was shown to accelerate the gastric and small intestinal transit significantly. In the group of men the colonic mean transit time...... was unaffected by age, but middle-aged women had a significantly slower colonic transit than young women. We therefore conclude that both age and gender have to be considered when reference values for gastric, small intestinal and colonic mean transit times have to be established....
Time-optimal control with finite bandwidth
Hirose, M.; Cappellaro, P.
2018-04-01
Time-optimal control theory provides recipes to achieve quantum operations with high fidelity and speed, as required in quantum technologies such as quantum sensing and computation. While technical advances have achieved the ultrastrong driving regime in many physical systems, these capabilities have yet to be fully exploited for the precise control of quantum systems, as other limitations, such as the generation of higher harmonics or the finite response time of the control apparatus, prevent the implementation of theoretical time-optimal control. Here we present a method to achieve time-optimal control of qubit systems that can take advantage of fast driving beyond the rotating wave approximation. We exploit results from time-optimal control theory to design driving protocols that can be implemented with realistic, finite-bandwidth control fields, and we find a relationship between bandwidth limitations and achievable control fidelity.
Optimization of a radiodiagnostic service by means of quality control
International Nuclear Information System (INIS)
Carrizales, L.; Gamez, L.; Reggio, F.; Gamboa, M.; Quintero, A.; Almeida, J.
2001-01-01
Most of the radio diagnosis institutions (public and private) in Venezuela have a lack quality control applied to radiological equipment, as well as capable staff to implement it. It is intended to implant training programs and corrective policies to optimize their services [es
Effects of computing time delay on real-time control systems
Shin, Kang G.; Cui, Xianzhong
1988-01-01
The reliability of a real-time digital control system depends not only on the reliability of the hardware and software used, but also on the speed in executing control algorithms. The latter is due to the negative effects of computing time delay on control system performance. For a given sampling interval, the effects of computing time delay are classified into the delay problem and the loss problem. Analysis of these two problems is presented as a means of evaluating real-time control systems. As an example, both the self-tuning predicted (STP) control and Proportional-Integral-Derivative (PID) control are applied to the problem of tracking robot trajectories, and their respective effects of computing time delay on control performance are comparatively evaluated. For this example, the STP (PID) controller is shown to outperform the PID (STP) controller in coping with the delay (loss) problem.
Surveillance and control of containment by means of radioactive measurements
International Nuclear Information System (INIS)
Roche, H.; Seveon, J.J.; Rousseau, L.; Delalande, J.
1983-12-01
In this paper, the radioactive measurements participating in the surveillance and control of the reactor containment as well as the possible procedures or operating rules related to, especially the ultimate procedures which could be implemented in case of a beyond of design accident, are presented. However, an overall view of the plant radiation monitoring system installed on the French plants is first given. If necessary, difference between 900 MW and 1300 MW units are emphasized
Control of ring lasers by means of coupled cavities
DEFF Research Database (Denmark)
Buchhave, Preben; Abitan, Haim; Tidemand-Lichtenberg, Peter
2000-01-01
Variable phase coupling to an external ring is used to control a unidirectional ring laser. The observed behavior of the coupled rings is explained theoretically. We have found experimentally that by quickly changing the phase of the feedback from the external ring it is possible to Q......-switch the ring laser. Also, at certain values of the phase of the feedback in the external ring, instabilities in the total system occur and oscillations arise in the ring laser....
Mean-field approximations of fixation time distributions of evolutionary game dynamics on graphs
Ying, Li-Min; Zhou, Jie; Tang, Ming; Guan, Shu-Guang; Zou, Yong
2018-02-01
The mean fixation time is often not accurate for describing the timescales of fixation probabilities of evolutionary games taking place on complex networks. We simulate the game dynamics on top of complex network topologies and approximate the fixation time distributions using a mean-field approach. We assume that there are two absorbing states. Numerically, we show that the mean fixation time is sufficient in characterizing the evolutionary timescales when network structures are close to the well-mixing condition. In contrast, the mean fixation time shows large inaccuracies when networks become sparse. The approximation accuracy is determined by the network structure, and hence by the suitability of the mean-field approach. The numerical results show good agreement with the theoretical predictions.
The Meaning of Time. An Introduction into Philosophical, Biological and Physical Aspects of Time
1991-01-15
mentioned already Plato (428-347BC) as the originator of the essential quasistatic view of time and history. He was preceded by Parmenides (540BC and Zeno...after. * Being and Entities: Being is the most universal concept. It was 31 discovered by Parmenides (- 500 B.C.), who saw that of all the diversity of
Discrete-time nonlinear sliding mode controller
African Journals Online (AJOL)
user
Keywords: Discrete-time delay system, Sliding mode control, nonlinear sliding ... of engineering systems such as chemical process control, delay in the actuator ...... instrumentation from Motilal Nehru National Institute of Technology (MNNIT),.
Mean germination time and germination rate of oat seeds subjected to stationary magnetic field
International Nuclear Information System (INIS)
Martinez Ramirez, Elvira; Florez Garcia, Mercedes; Carbonell, Maria Victoria; Amaya Garcia de la Escosura, Jose Manuel
2007-01-01
The objective of the present study is to determine and quantify the effect produced by stationary magnetic fields on oat seed germination (Avena sativa, L. var. c obena ) . For this purpose, seeds were exposed to a magnetic field 125 mT of 250 mT during different periods of time: 20 minutes (E1, E5), 1 hour (E2, E6), 24 hours (E3, E7), or in a conic form (E4, E8) during the whole germination process. Germination tests were carried out under laboratory conditions with cylindrical magnets to obtain the magnetic field. For magnetic treatment seed on Petri dishes were placed on magnets during time necessary for each treatment. Seeds without exposition to the magnetic field were used as control group. Parameters used for germination speed analysis were: number of germinated seeds (G), mean germination time (MGT) and necessary time for germination of 1, 10, 25, 50 and 75% of N number of speeds used for each treatment (T1, T10, T25, T50, and T75). These parameters were supplied through the software Seed calculator, as well as the corresponding germination curves. In general, from the results obtained it can be said that the time required to obtain different germination percentages was lower for seeds exposed to the magnetic field (treatments E1 and E8). Reduction in time for E1 treatment stands up with 20 a minutes-exposition-time to 125 mT. MGT obtained for seeds with magnetic treatment E1 was significantly lower (11.48%) than the control group. Parameters T1, T10, T25 were also lower for seeds submitted to treatment, obtaining reductions of 46.62 %, 24.02 % and 13.46 % respectively. Reduction in germination parameters indicates that germination speed is higher. Because parameters T1 and T10 are related to the beginning of germination, this study represents a progress in germination and a reduction in the induction phase in most of the magnetic treatments applied. Previous studies done by authors about the influence of stationary magnetic fields have shown increases in
Means, methods and performances of the AREVA's HTR compact controls
International Nuclear Information System (INIS)
Banchet, J.; Guillermier, P.; Tisseur, D.; Vitali, M. P.
2008-01-01
In the AREVA's HTR development program, the reactor plant is composed of a prismatic core containing graphite cylindrical fuel elements, called compacts, where TRISO particles are dispersed. Starting from its past compacting process, the latter being revamped through the use of state of the art equipments, CERCA, 100% AREVA NP's subsidiary, was able to recover the quality of past compacts production. The recovered compacting process is composed of the following manufacturing steps: graphite matrix granulation, mix between the obtained granulates and particles, compacting and calcining at low pressure and temperature. To adapt this past process to new manufacturing equipments, non destructive examination tests were carried out to assess the compact quality, the latter being assessed via in house developed equipments and methods at each step of the design of experiments. As for the manufacturing process, past quality control methods were revamped to measure compact dimensional features (diameter, perpendicularity and cone effect), visual aspect, SiC layer failure fraction (via anodic disintegration and burn leach test) and homogeneity via 2D radiography coupled to ceramography. Although meeting quality requirements, 2D radiography method could not provide a quantified specification for compact homogeneity characterization. This limitation yielded the replacement of this past technique by a method based on X-Ray tomography. Development was conducted on this new technique to enable the definition of a criterion to quantify compact homogeneity, as well as to provide information about the distances in between particles. This study also included a comparison between simulated and real compacts to evaluate the accuracy of the technique as well as the influence of particle packing fraction on compact homogeneity. The developed quality control methods and equipments guided the choices of manufacturing parameters adjustments at the development stage and are now applied for
Optimized load sharing control by means of thermal reliability management
DEFF Research Database (Denmark)
Nesgaard, Carsten; Andersen, Michael Andreas E.
2004-01-01
time and system cost. However, due to non-ideal parts each converter unit deviates from the ideal case, which makes a power system comprised of parallel-connected converters a rather poor performing system. To account for the non-ideal parts some form of load sharing is needed, whereby it is ensured......With new applications for high-current low-output voltage power systems emerging nearly every day the need for new and cost-efficient power system designs is a matter of course. As output voltage levels continue to decrease an approach that seems more and more attractive is the implementation...... that each converter in the configuration delivers its share of the total output power. In other words parallel-operation of multiple converters is employed when specifications require a highly reliable system, designable within a very short time frame and at low costs. However, to make full use...
Mean Square Exponential Stability of Stochastic Switched System with Interval Time-Varying Delays
Directory of Open Access Journals (Sweden)
Manlika Rajchakit
2012-01-01
Full Text Available This paper is concerned with mean square exponential stability of switched stochastic system with interval time-varying delays. The time delay is any continuous function belonging to a given interval, but not necessary to be differentiable. By constructing a suitable augmented Lyapunov-Krasovskii functional combined with Leibniz-Newton’s formula, a switching rule for the mean square exponential stability of switched stochastic system with interval time-varying delays and new delay-dependent sufficient conditions for the mean square exponential stability of the switched stochastic system are first established in terms of LMIs. Numerical example is given to show the effectiveness of the obtained result.
Going Open: Does it Mean Giving Away Control?
Directory of Open Access Journals (Sweden)
Michael Weiss
2013-01-01
Full Text Available Open source software has evolved from being an effort driven by a collective of volunteers to become an integral part of commercial software. Constant demands for new features besides maintaining product quality made companies seek open source as an answer for these demands. These growing demands brought with them control of quality, architecture, contribution management, and community management. This article explores the governance strategies adopted by open source software projects to manage the quality of complements (such as plug-ins that extend a platform's functionality developed by community members outside the core team. The outcomes of the research contribute to our understanding of the strategies followed by different open source platform owners (the open source project initiators to manage external innovation in the case of platform extensions in two areas: i governance models and ii regulatory tools.
Mean Value SI Engine Model for Control Studies
DEFF Research Database (Denmark)
Hendricks, Elbert; Sorenson, Spencer C
1990-01-01
This paper presents a mathematically simple nonlinear three state (three differential equation) dynamic model of an SI engine which has the same steady state accuracy as a typical dynamometer measurement of the engine over its entire speed/load operating range (± 2.0%). The model's accuracy...... for large, fast transients is of the same order in the same operating region. Because the model is mathematically compact, it has few adjustable parameters and is thus simple to fit to a given engine either on the basis of measurements or given the steady state results of a larger cycle simulation package....... The model can easily be run on a Personal Computer (PC) using a ordinary differential equation (ODE) integrating routine or package. This makes the model is useful for control system design and evaluation....
Restrictive Diet Control as a Means of Child Abuse.
Kudek, Matthew R; Luyet, Francois; Herringa, Ryan J; Knox, Barbara L
2018-03-01
We have recently encountered a series of cases where an obese caretaker is juxtaposed to a severely starved, malnourished dependent. The cases described all share a common characteristic: that the primary perpetrator was an obese caretaker who tried to exert absolute control over their victim's daily life in a way that included either a severe restriction or complete denial of food. Because the pathophysiology of both child abuse and obesity are incredibly complex and multifactorial, these cases are presented to encourage further discussion and more rigorous investigation into the validity of a hypothesis that has been derived from this set of cases: that the obesity of a child's caretaker may be an additional risk factor for child maltreatment by starvation.
Testing power system controllers by real-time simulation
DEFF Research Database (Denmark)
Venne, Philippe; Guillaud, Xavier; Sirois, Frédéric
2007-01-01
In this paper, we present a number of state-of-the art methods for testing power system controllers based on the use of a real-time power system simulator. After introducing Hypersim, we list and discuss the different means of connection between the controller under tests and the power system...
Time management training and perceived control of time at work.
Häfner, Alexander; Stock, Armin
2010-01-01
The purpose of the present study was to examine the effects of time management training, which was based on psychological theory and research, on perceived control of time, perceived stress, and performance at work. The authors randomly assigned 71 employees to a training group (n = 35) or a waiting-list control group (n = 36). As hypothesized, time management training led to an increase in perceived control of time and a decrease in perceived stress. Time management training had no impact on different performance indicators. In particular, the authors explored the use and the perceived usefulness of the techniques taught. Participants judged the taught techniques as useful, but there were large differences concerning the actual use of the various techniques.
Pricing as a means of controlling alcohol consumption.
Sharma, Anurag; Sinha, Kompal; Vandenberg, Brian
2017-09-01
Reducing the affordability of alcohol, by increasing its price, is the most effective strategy for controlling alcohol consumption and reducing harm. We review meta-analyses and systematic reviews of alcohol tax/price effects from the past decade, and recent evaluations of tax/price policies in the UK, Canada and Australia. While the magnitudes of price effects vary by sub-group and alcoholic beverage type, it has been consistently shown that price increases lead to reductions in alcohol consumption. There remains, however, a lack of consensus on the most appropriate taxation and pricing policy in many countries because of concerns about effects by different consumption level and income level and disagreement on policy design between parts of the alcoholic beverage industries. Recent developments in the research highlight the importance of obtaining accurate alcohol price data, reducing bias in estimating price responsiveness, and examining the impact on the heaviest drinkers. There is a need for further research focusing on the substitution effects of taxation and pricing policies, estimation of the true tax pass-through rates, and empirical analysis of the supply-side response (from alcohol producers and retailers) to various alcohol pricing strategies. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com
Social Bots: Human-Like by Means of Human Control?
Grimme, Christian; Preuss, Mike; Adam, Lena; Trautmann, Heike
2017-12-01
Social bots are currently regarded an influential but also somewhat mysterious factor in public discourse and opinion making. They are considered to be capable of massively distributing propaganda in social and online media, and their application is even suspected to be partly responsible for recent election results. Astonishingly, the term social bot is not well defined and different scientific disciplines use divergent definitions. This work starts with a balanced definition attempt, before providing an overview of how social bots actually work (taking the example of Twitter) and what their current technical limitations are. Despite recent research progress in Deep Learning and Big Data, there are many activities bots cannot handle well. We then discuss how bot capabilities can be extended and controlled by integrating humans into the process and reason that this is currently the most promising way to realize meaningful interactions with other humans. This finally leads to the conclusion that hybridization is a challenge for current detection mechanisms and has to be handled with more sophisticated approaches to identify political propaganda distributed with social bots.
On the Linear Relation between the Mean and the Standard Deviation of a Response Time Distribution
Wagenmakers, Eric-Jan; Brown, Scott
2007-01-01
Although it is generally accepted that the spread of a response time (RT) distribution increases with the mean, the precise nature of this relation remains relatively unexplored. The authors show that in several descriptive RT distributions, the standard deviation increases linearly with the mean. Results from a wide range of tasks from different…
Characterisation of cerebral blood flow via determining the vascular mean transit time
International Nuclear Information System (INIS)
Lindner, P.; Thelen, M.
1987-01-01
By using a recently developed algorithm it is possible to quantify the dynamic information of a DSA sequence of the brain. The theory of algorithm allows to calculate vascular mean transit from time density curves. The algorithm minimizes the problems of densitometry with regard to 'quantitative DSA'. There is a strong correlation between vascular mean transit times and cerebral blood flow values, and therefore the results for mean transit times also correspond to the results obtained for cerebral blood flow. By computerized postprocessing of DSA-images it is possible to generate functional images of the brain with a spatial resolution that had not been attainable so far. The images represent the distribution pattern of reverse vascular mean transit times. The results from 36 patients with proven stenoses of the cervical vessels are reported. (orig.) [de
Gastrointestinal mean transit times in young and middle-aged healthy subjects
DEFF Research Database (Denmark)
Graff, J; Brinch, K; Madsen, Jan Lysgård
2001-01-01
To investigate the effects of age and gender on gastric, small intestinal and colonic mean transit times, a study was conducted in 32 healthy volunteers: eight young women (22-30 years), eight young men (20-28 years), eight middle-aged women (43-51 years) and eight middle-aged men (38-53 years......). After ingestion of a meal containing 111Indium-labelled water and 99mTechnetium-labelled omelette imaging of the abdomen was performed at intervals of 30 min until all radioactivity was located in the colon and henceforth at intervals of 24 h until all radioactivity had cleared from the colon. Gastric......, small intestinal and colonic mean transit times were calculated. The gastric, small intestinal and colonic mean transit times were significantly longer in women. Ageing was shown to accelerate the gastric and small intestinal transit significantly. In the group of men the colonic mean transit time...
Computer simulation of nuclear reactor control by means of heuristic learning controller
International Nuclear Information System (INIS)
Bubak, M.; Moscinski, J.
1976-01-01
A trial of application of two techniques of Artificial Intelligence: heuristic Programming and Learning Machines Theory for nuclear reactor control is presented. Considering complexity of the mathematical models describing satisfactorily the nuclear reactors, value changes of these models parameters in course of operation, knowledge of some parameters value with too small exactness, there appear diffucluties in the classical approach application for these objects control systems design. The classical approach consists in definition of the permissible control actions set on the base of the set performance index and the object mathematical model. The Artificial Intelligence methods enable construction of the control system, which gets during work an information being a priori inaccessible and uses it for its action change for the control to be the optimum one. Applying these methods we have elaborated the reactor power control system. As the performance index there has been taken the integral of the error square. For the control system there are only accessible: the set power trajectory, the reactor power and the control rod position. The set power trajectory has been divided into time intervals called heuristic intervals. At the beginning of every heuristic interval, on the base of the obtained experience, the control system chooses from the control (heuristic) set the optimum control. The heuristic set it is the set of relations between the control rod rate and the state variables, the set and the obtained power, similar to simplifications applied by nuclear reactors operators. The results obtained for the different control rod rates and different reactor (simulated on the digital computer) show the proper work of the system. (author)
Timing and motor control in drumming
DEFF Research Database (Denmark)
Dahl, Sofia; Grossbach, Michael; Altenmüller, Eckart
the stick movement becomes increasingly difficult, sometimes resulting in irregularities in timing and/or striking force. Timing irregularities can also be a revealing sign of motor control problems, such as focal dystonia (Jabusch, Vauth & Altenmüller, 2004). The "breakdown" in motor control can therefore...
Chiapponi, Chiara; Piras, Fabrizio; Fagioli, Sabrina; Girardi, Paolo; Caltagirone, Carlo; Spalletta, Gianfranco
2014-08-01
Macrostructural-volumetric abnormalities of the hippocampus have been described in schizophrenia. Here, we characterized age-related changes of hippocampal mean diffusivity as an index of microstructural damage by carrying out a neuroimaging study in 85 patients with a DSM-IV-TR diagnosis of schizophrenia and 85 age- and gender-matched healthy controls. We performed analyses of covariance, with diagnosis as fixed factor, mean diffusivity as dependent variable and age as covariate. Patients showed an early increase in mean diffusivity in the right and left hippocampus that increased with age. Thus, microstructural hippocampal changes associated with schizophrenia cannot be confined to a specific time window. Copyright © 2014 Elsevier B.V. All rights reserved.
Means for controlling operation of power sources associated with an axial tomographic system
International Nuclear Information System (INIS)
1976-01-01
An axial tomographic system is described having scanner means normally in an off-condition where all associated power sources are electrically isolated from the units driven thereby. It also includes means for activating the scanner means to establish an on-condition, control means including means to measure one or more system parameters when the scanner means is in an on-condition and to determine if the measured parameters are within predetermined limits, and means for maintaining the on-condition only if the control means is properly operational and all measured system parameters are within the predetermined limits
Minimal Time Problem with Impulsive Controls
Energy Technology Data Exchange (ETDEWEB)
Kunisch, Karl, E-mail: karl.kunisch@uni-graz.at [University of Graz, Institute for Mathematics and Scientific Computing (Austria); Rao, Zhiping, E-mail: zhiping.rao@ricam.oeaw.ac.at [Austrian Academy of Sciences, Radon Institute of Computational and Applied Mathematics (Austria)
2017-02-15
Time optimal control problems for systems with impulsive controls are investigated. Sufficient conditions for the existence of time optimal controls are given. A dynamical programming principle is derived and Lipschitz continuity of an appropriately defined value functional is established. The value functional satisfies a Hamilton–Jacobi–Bellman equation in the viscosity sense. A numerical example for a rider-swing system is presented and it is shown that the reachable set is enlargered by allowing for impulsive controls, when compared to nonimpulsive controls.
Directory of Open Access Journals (Sweden)
Ella V. Nesterik
2013-01-01
Full Text Available This article analyses linguistic means of depersonalization and dematerialization in the descriptions of subjective perception of time by characters, detects functions, fulfilled by them in such contexts. Subjective perception of time is considered as a text category and is studied in terms of text linguistics
Work Time Control and Sleep Disturbances
DEFF Research Database (Denmark)
Salo, Paula; Ala-Mursula, Leena; Rod, Naja Hulvej
2014-01-01
OBJECTIVES: Employee control over work times has been associated with favorable psychosocial and health-related outcomes, but the evidence regarding sleep quality remains inconclusive. We examined cross-sectional and prospective associations between work time control and sleep disturbances...... in a large working population, taking into account total hours worked. METHODS: The data were from a full-panel longitudinal cohort study of Finnish public sector employees who responded to questions on work time control and sleep disturbances in years 2000-2001, 2004-2005, 2008-2009, and 2012. The analysis....... RESULTS: Consistently in both cross-sectional and longitudinal models, less control over work time was associated with greater sleep disturbances in the total population and among those working normal 40-hour weeks. Among participants working more than 40 hours a week, work time that was both very high...
How can streamflow and climate-landscape data be used to estimate baseflow mean response time?
Zhang, Runrun; Chen, Xi; Zhang, Zhicai; Soulsby, Chris; Gao, Man
2018-02-01
Mean response time (MRT) is a metric describing the propagation of catchment hydraulic behavior that reflects both hydro-climatic conditions and catchment characteristics. To provide a comprehensive understanding of catchment response over a longer-time scale for hydraulic processes, the MRT function for baseflow generation was derived using an instantaneous unit hydrograph (IUH) model that describes the subsurface response to effective rainfall inputs. IUH parameters were estimated based on the "match test" between the autocorrelation function (ACFs) derived from the filtered base flow time series and from the IUH parameters, under the GLUE framework. Regionalization of MRT was conducted using estimates and hydroclimate-landscape indices in 22 sub-basins of the Jinghe River Basin (JRB) in the Loess Plateau of northwest China. Results indicate there is strong equifinality in determination of the best parameter sets but the median values of the MRT estimates are relatively stable in the acceptable range of the parameters. MRTs vary markedly over the studied sub-basins, ranging from tens of days to more than a year. Climate, topography and geomorphology were identified as three first-order controls on recharge-baseflow response processes. Human activities involving the cultivation of permanent crops may elongate the baseflow MRT and hence increase the dynamic storage. Cross validation suggests the model can be used to estimate MRTs in ungauged catchments in similar regions of throughout the Loess Plateau. The proposed method provides a systematic approach for MRT estimation and regionalization in terms of hydroclimate and catchment characteristics, which is helpful in the sustainable water resources utilization and ecological protection in the Loess Plateau.
When the mean is not enough: Calculating fixation time distributions in birth-death processes.
Ashcroft, Peter; Traulsen, Arne; Galla, Tobias
2015-10-01
Studies of fixation dynamics in Markov processes predominantly focus on the mean time to absorption. This may be inadequate if the distribution is broad and skewed. We compute the distribution of fixation times in one-step birth-death processes with two absorbing states. These are expressed in terms of the spectrum of the process, and we provide different representations as forward-only processes in eigenspace. These allow efficient sampling of fixation time distributions. As an application we study evolutionary game dynamics, where invading mutants can reach fixation or go extinct. We also highlight the median fixation time as a possible analog of mixing times in systems with small mutation rates and no absorbing states, whereas the mean fixation time has no such interpretation.
Time Optimal Control Laws for Bilinear Systems
Directory of Open Access Journals (Sweden)
Salim Bichiou
2018-01-01
Full Text Available The aim of this paper is to determine the feedforward and state feedback suboptimal time control for a subset of bilinear systems, namely, the control sequence and reaching time. This paper proposes a method that uses Block pulse functions as an orthogonal base. The bilinear system is projected along that base. The mathematical integration is transformed into a product of matrices. An algebraic system of equations is obtained. This system together with specified constraints is treated as an optimization problem. The parameters to determine are the final time, the control sequence, and the states trajectories. The obtained results via the newly proposed method are compared to known analytical solutions.
Describing temporal variability of the mean Estonian precipitation series in climate time scale
Post, P.; Kärner, O.
2009-04-01
Applicability of the random walk type models to represent the temporal variability of various atmospheric temperature series has been successfully demonstrated recently (e.g. Kärner, 2002). Main problem in the temperature modeling is connected to the scale break in the generally self similar air temperature anomaly series (Kärner, 2005). The break separates short-range strong non-stationarity from nearly stationary longer range variability region. This is an indication of the fact that several geophysical time series show a short-range non-stationary behaviour and a stationary behaviour in longer range (Davis et al., 1996). In order to model series like that the choice of time step appears to be crucial. To characterize the long-range variability we can neglect the short-range non-stationary fluctuations, provided that we are able to model properly the long-range tendencies. The structure function (Monin and Yaglom, 1975) was used to determine an approximate segregation line between the short and the long scale in terms of modeling. The longer scale can be called climate one, because such models are applicable in scales over some decades. In order to get rid of the short-range fluctuations in daily series the variability can be examined using sufficiently long time step. In the present paper, we show that the same philosophy is useful to find a model to represent a climate-scale temporal variability of the Estonian daily mean precipitation amount series over 45 years (1961-2005). Temporal variability of the obtained daily time series is examined by means of an autoregressive and integrated moving average (ARIMA) family model of the type (0,1,1). This model is applicable for daily precipitation simulating if to select an appropriate time step that enables us to neglet the short-range non-stationary fluctuations. A considerably longer time step than one day (30 days) is used in the current paper to model the precipitation time series variability. Each ARIMA (0
Waxman, D
2012-06-01
A fundamental result of population genetics states that a new mutation, at an unlinked neutral locus in a randomly mating diploid population, has a mean time of fixation of ∼4N(e) generations, where N(e) is the effective population size. This result is based on an assumption of fixed population size, which does not universally hold in natural populations. Here, we analyze such neutral fixations in populations of changing size within the framework of the diffusion approximation. General expressions are derived for the mean and variance of the fixation time in changing populations. Some explicit results are given for two cases: (i) the effective population size undergoes a sudden change, representing a sudden population expansion or a sudden bottleneck; (ii) the effective population changes linearly for a limited period of time and then remains constant. Additionally, a lower bound for the mean time of fixation is obtained for an effective population size that increases with time, and this is applied to exponentially growing populations. The results obtained in this work show, among other things, that for populations that increase in size, the mean time of fixation can be enhanced, sometimes substantially so, over 4N(e,0) generations, where N(e,0) is the effective population size at the time the mutation arises. Such an enhancement is associated with (i) an increased probability of neutral polymorphism in a population and (ii) an enhanced persistence of high-frequency neutral variation, which is the variation most likely to be observed.
Stable Control of Firing Rate Mean and Variance by Dual Homeostatic Mechanisms.
Cannon, Jonathan; Miller, Paul
2017-12-01
Homeostatic processes that provide negative feedback to regulate neuronal firing rates are essential for normal brain function. Indeed, multiple parameters of individual neurons, including the scale of afferent synapse strengths and the densities of specific ion channels, have been observed to change on homeostatic time scales to oppose the effects of chronic changes in synaptic input. This raises the question of whether these processes are controlled by a single slow feedback variable or multiple slow variables. A single homeostatic process providing negative feedback to a neuron's firing rate naturally maintains a stable homeostatic equilibrium with a characteristic mean firing rate; but the conditions under which multiple slow feedbacks produce a stable homeostatic equilibrium have not yet been explored. Here we study a highly general model of homeostatic firing rate control in which two slow variables provide negative feedback to drive a firing rate toward two different target rates. Using dynamical systems techniques, we show that such a control system can be used to stably maintain a neuron's characteristic firing rate mean and variance in the face of perturbations, and we derive conditions under which this happens. We also derive expressions that clarify the relationship between the homeostatic firing rate targets and the resulting stable firing rate mean and variance. We provide specific examples of neuronal systems that can be effectively regulated by dual homeostasis. One of these examples is a recurrent excitatory network, which a dual feedback system can robustly tune to serve as an integrator.
Advanced concepts in accelerator timing control
International Nuclear Information System (INIS)
Frankel, R.; Salwen, C.
1988-01-01
The control system for the Booster accelerator presently under construction at BNL includes a timing section with serial high speed coded data distribution, computer based encoders for both real time and field driven clocks and a method of easily tracking the performance and reliability of these timing streams. We have developed a simple method for the generation of timing which operates to produce pulses which may be repeated as desired with minimal latency
On the initial conditions of time-dependent mean-field equations of evolution. Pt. 2
International Nuclear Information System (INIS)
Troudet, T.; Paris-11 Univ., 91 - Orsay
1986-01-01
We analyze the problem so far untouched of determining the initial mean-field wavefunction in the context of zero-temperature mean-field descriptions of time-dependent expectation values and quantum fluctuations of nuclear observables. The nucleus, at zero temperature, is taken to be in a low-lying excited many-body eigenstate and is approximated by the corresponding RPA wavefunction as a continuous superposition of coherent states (i.e. Slater determinants). A generating function Gsub(A)(lambda) for time-dependent expectation values and quantum fluctuations is constructed within the formalism of functional integration. By applying the saddle-point method to the functional action of Gsub(A)(lambda) and then taking its lambda-derivatives, we recover the well-known TDHF theory and propose a simple determination of the initial Slater determinant for an appropriate mean-field description of time-dependent expectation values. The analog mean-field description of quadratic-quantum fluctuations proceeds similarly and in addition includes the contribution of the uncorrelated TDHF-RPA phonons coupled to collective excitations of the initial (static) mean-field configuration. When the collective TDHF-RPA excitations are solely taken into account, we obtain an improved version of the Balian-Veneroni dispersion formula by showing how to determine the initial mean-field wavefunction. By first taking the lambda-derivatives of Gsub(A)(lambda) before applying the saddle-point method, the initial mean-field wavefunction is found to be non-linearly coupled to the mean-field dynamics themselves. In return, and in contrast to the first quantization scheme, these both depend non-trivially upon the observable A being measured so that approximations must be proposed to simplify the resulting mean-field equations. (orig.)
Mean-variance Optimal Reinsurance-investment Strategy in Continuous Time
Directory of Open Access Journals (Sweden)
Daheng Peng
2017-10-01
Full Text Available In this paper, Lagrange method is used to solve the continuous-time mean-variance reinsurance-investment problem. Proportional reinsurance, multiple risky assets and risk-free asset are considered synthetically in the optimal strategy for insurers. By solving the backward stochastic differential equation for the Lagrange multiplier, we get the mean-variance optimal reinsurance-investment strategy and its effective frontier in explicit forms.
Mean-variance Optimal Reinsurance-investment Strategy in Continuous Time
Daheng Peng; Fang Zhang
2017-01-01
In this paper, Lagrange method is used to solve the continuous-time mean-variance reinsurance-investment problem. Proportional reinsurance, multiple risky assets and risk-free asset are considered synthetically in the optimal strategy for insurers. By solving the backward stochastic differential equation for the Lagrange multiplier, we get the mean-variance optimal reinsurance-investment strategy and its effective frontier in explicit forms.
[Predictors of mean blood glucose control and its variability in diabetic hospitalized patients].
Sáenz-Abad, Daniel; Gimeno-Orna, José Antonio; Sierra-Bergua, Beatriz; Pérez-Calvo, Juan Ignacio
2015-01-01
This study was intended to assess the effectiveness and predictors factors of inpatient blood glucose control in diabetic patients admitted to medical departments. A retrospective, analytical cohort study was conducted on patients discharged from internal medicine with a diagnosis related to diabetes. Variables collected included demographic characteristics, clinical data and laboratory parameters related to blood glucose control (HbA1c, basal plasma glucose, point-of-care capillary glucose). The cumulative probability of receiving scheduled insulin regimens was evaluated using Kaplan-Meier analysis. Multivariate regression models were used to select predictors of mean inpatient glucose (MHG) and glucose variability (standard deviation [GV]). The study sample consisted of 228 patients (mean age 78.4 (SD 10.1) years, 51% women). Of these, 96 patients (42.1%) were treated with sliding-scale regular insulin only. Median time to start of scheduled insulin therapy was 4 (95% CI, 2-6) days. Blood glucose control measures were: MIG 181.4 (SD 41.7) mg/dL, GV 56.3 (SD 22.6). The best model to predict MIG (R(2): .376; P<.0001) included HbA1c (b=4.96; P=.011), baseline plasma glucose (b=.056; P=.084), mean capillary blood glucose in the first 24hours (b=.154; P<.0001), home treatment (versus oral agents) with basal insulin only (b=13.1; P=.016) or more complex (pre-mixed insulin or basal-bolus) regimens (b=19.1; P=.004), corticoid therapy (b=14.9; P=.002), and fasting on admission (b=10.4; P=.098). Predictors of inpatient blood glucose control which should be considered in the design of DM management protocols include home treatment, HbA1c, basal plasma glucose, mean blood glucose in the first 24hours, fasting, and corticoid therapy. Copyright © 2014 SEEN. Published by Elsevier España, S.L.U. All rights reserved.
Existential Meaning Among First-Time Full-Term and Preterm Mothers
DEFF Research Database (Denmark)
Prinds, Christina; Hvidtjørn, Dorte; Mogensen, Ole
2014-01-01
Research indicates that childbirth is a time when a woman might experience existential disruptions and gain new perspectives on life. The 2-fold aim of this study was to investigate whether attitudes related to existential meaning among first-time mothers intensify and whether they differ between...... mothers who gave birth at full term and those who gave birth preterm. All first-time mothers who gave birth in Denmark in 2010 before the 32nd week of pregnancy and twice that number of full-term mothers (randomly sampled) were invited to participate in a national cross-sectional survey. Five core items...... concerning meaning in life, vulnerability of life, responsibility, thoughts about life and death, and "something bigger than oneself" were analyzed to compare mothers' attitudes on existential meaning. The overall response rate was 57% (517/913). Contrary to the hypothesis, attitudes related to existential...
Time dependent policy-based access control
DEFF Research Database (Denmark)
Vasilikos, Panagiotis; Nielson, Flemming; Nielson, Hanne Riis
2017-01-01
also on other attributes of the environment such as the time. In this paper, we use systems of Timed Automata to model distributed systems and we present a logic in which one can express time-dependent policies for access control. We show how a fragment of our logic can be reduced to a logic......Access control policies are essential to determine who is allowed to access data in a system without compromising the data's security. However, applications inside a distributed environment may require those policies to be dependent on the actual content of the data, the flow of information, while...... that current model checkers for Timed Automata such as UPPAAL can handle and we present a translator that performs this reduction. We then use our translator and UPPAAL to enforce time-dependent policy-based access control on an example application from the aerospace industry....
Time-odd mean fields in covariant density functional theory: Rotating systems
International Nuclear Information System (INIS)
Afanasjev, A. V.; Abusara, H.
2010-01-01
Time-odd mean fields (nuclear magnetism) and their impact on physical observables in rotating nuclei are studied in the framework of covariant density functional theory (CDFT). It is shown that they have profound effect on the dynamic and kinematic moments of inertia. Particle number, configuration, and rotational frequency dependencies of their impact on the moments of inertia have been analyzed in a systematic way. Nuclear magnetism can also considerably modify the band crossing features such as crossing frequencies and the properties of the kinematic and dynamic moments of inertia in the band crossing region. The impact of time-odd mean fields on the moments of inertia in the regions away from band crossing only weakly depends on the relativistic mean-field parametrization, reflecting good localization of the properties of time-odd mean fields in CDFT. The moments of inertia of normal-deformed nuclei considerably deviate from the rigid-body value. On the contrary, superdeformed and hyperdeformed nuclei have the moments of inertia which are close to rigid-body value. The structure of the currents in rotating frame, their microscopic origin, and the relations to the moments of inertia have been systematically analyzed. The phenomenon of signature separation in odd-odd nuclei, induced by time-odd mean fields, has been analyzed in detail.
Time-optimal control of reactor power
International Nuclear Information System (INIS)
Bernard, J.A.
1987-01-01
Control laws that permit adjustments in reactor power to be made in minimum time and without overshoot have been formulated and demonstrated. These control laws which are derived from the standard and alternate dynamic period equations, are closed-form expressions of general applicability. These laws were deduced by noting that if a system is subject to one or more operating constraints, then the time-optimal response is to move the system along these constraints. Given that nuclear reactors are subject to limitations on the allowed reactor period, a time-optimal control law would step the period from infinity to the minimum allowed value, hold the period at that value for the duration of the transient, and then step the period back to infinity. The change in reactor would therefore be accomplished in minimum time. The resulting control laws are superior to other forms of time-optimal control because they are general-purpose, closed-form expressions that are both mathematically tractable and readily implanted. Moreover, these laws include provisions for the use of feedback. The results of simulation studies and actual experiments on the 5 MWt MIT Research Reactor in which these time-optimal control laws were used successfully to adjust the reactor power are presented
Robust Control Charts for Time Series Data
Croux, C.; Gelper, S.; Mahieu, K.
2010-01-01
This article presents a control chart for time series data, based on the one-step- ahead forecast errors of the Holt-Winters forecasting method. We use robust techniques to prevent that outliers affect the estimation of the control limits of the chart. Moreover, robustness is important to maintain
Real-time controller for hydrostatic transmission
2014-01-01
M. Ing. (Electrical and Electronic Engineering) This dissertation describes the development of a modular real-time controller implemented on a personal computer for a hydrostatically driven vehicle. In such a vehicle the conventional mechanical transmission is replaced with a hydrostatic pump and two hydrostatic motors, making use of the secondary control principle. The infinitely variable transmission and wheel pair controller gives the vehicle superior traction and mobility over conventi...
Time-Dependent Mean-Field Games in the Subquadratic Case
Gomes, Diogo A.; Pimentel, Edgard A.; Sá nchez-Morgado, Hé ector
2014-01-01
In this paper we consider time-dependent mean-field games with subquadratic Hamiltonians and power-like local dependence on the measure. We establish existence of classical solutions under a certain set of conditions depending on both the growth of the Hamiltonian and the dimension. This is done by combining regularity estimates for the Hamilton-Jacobi equation based on the Gagliardo-Nirenberg interpolation inequality with polynomial estimates for the Fokker-Planck equation. This technique improves substantially the previous results on the regularity of time-dependent mean-field games.
Time-Dependent Mean-Field Games in the Subquadratic Case
Gomes, Diogo A.
2014-10-14
In this paper we consider time-dependent mean-field games with subquadratic Hamiltonians and power-like local dependence on the measure. We establish existence of classical solutions under a certain set of conditions depending on both the growth of the Hamiltonian and the dimension. This is done by combining regularity estimates for the Hamilton-Jacobi equation based on the Gagliardo-Nirenberg interpolation inequality with polynomial estimates for the Fokker-Planck equation. This technique improves substantially the previous results on the regularity of time-dependent mean-field games.
Meteorological Reference Years of Daily Mean Temperature during the Slighting Time
International Nuclear Information System (INIS)
Marchante Jimenez, M.; Ramirez Santigosa, L.; Navarro Fernandez, A.; Mora Lopez, L.; Sidrach de Cardona Ortin, M.
2002-01-01
In this work the characterization of the daily mean temperature during the sunlight time has been analyzed. An algorithm for the hourly series generation from extreme daily values has been applied to evaluate the daily mean temperature during the sunlight time. A generic algorithm has been enhanced as a function of the sunrise time. This algorithm allows taking into account the fractions related to the sunrise and sunset hours. This methodology has been applied in data from 45 Spanish stations, uniformly distributed in the Iberian Peninsula. Data for a period of 14 years has been used in most of locations, and once the interest variable has been calculated, the meteorological reference year of the daily mean temperature during the sunlight time has been evaluated in each stations. The next step is the evaluation of the daily mean temperature during the sunlight time in any point into the zone of evaluation, not only in the measured stations. From the result data in each measured station, an geographic information system has been used in order to calculate the interpolation, obtaining maps with a data each 5 km. for each of the 365 days of the year. Then, this results can be superposed with the solar radiation evaluation obtaining the input data for the sizing of the photovoltaic grid connected system in any point of the Spanish geography. (Author) 64 refs
Time-Consistent Strategies for a Multiperiod Mean-Variance Portfolio Selection Problem
Directory of Open Access Journals (Sweden)
Huiling Wu
2013-01-01
Full Text Available It remained prevalent in the past years to obtain the precommitment strategies for Markowitz's mean-variance portfolio optimization problems, but not much is known about their time-consistent strategies. This paper takes a step to investigate the time-consistent Nash equilibrium strategies for a multiperiod mean-variance portfolio selection problem. Under the assumption that the risk aversion is, respectively, a constant and a function of current wealth level, we obtain the explicit expressions for the time-consistent Nash equilibrium strategy and the equilibrium value function. Many interesting properties of the time-consistent results are identified through numerical sensitivity analysis and by comparing them with the classical pre-commitment solutions.
Mean-Variance portfolio optimization when each asset has individual uncertain exit-time
Directory of Open Access Journals (Sweden)
Reza Keykhaei
2016-12-01
Full Text Available The standard Markowitz Mean-Variance optimization model is a single-period portfolio selection approach where the exit-time (or the time-horizon is deterministic. In this paper we study the Mean-Variance portfolio selection problem with uncertain exit-time when each has individual uncertain xit-time, which generalizes the Markowitz's model. We provide some conditions under which the optimal portfolio of the generalized problem is independent of the exit-times distributions. Also, it is shown that under some general circumstances, the sets of optimal portfolios in the generalized model and the standard model are the same.
Active controllers and the time duration to learn a task
Repperger, D. W.; Goodyear, C.
1986-01-01
An active controller was used to help train naive subjects involved in a compensatory tracking task. The controller is called active in this context because it moves the subject's hand in a direction to improve tracking. It is of interest here to question whether the active controller helps the subject to learn a task more rapidly than the passive controller. Six subjects, inexperienced to compensatory tracking, were run to asymptote root mean square error tracking levels with an active controller or a passive controller. The time required to learn the task was defined several different ways. The results of the different measures of learning were examined across pools of subjects and across controllers using statistical tests. The comparison between the active controller and the passive controller as to their ability to accelerate the learning process as well as reduce levels of asymptotic tracking error is reported here.
Timing control by redundant inhibitory neuronal circuits
Energy Technology Data Exchange (ETDEWEB)
Tristan, I., E-mail: itristan@ucsd.edu; Rulkov, N. F.; Huerta, R.; Rabinovich, M. [BioCircuits Institute, University of California, San Diego, La Jolla, California 92093-0402 (United States)
2014-03-15
Rhythms and timing control of sequential activity in the brain is fundamental to cognition and behavior. Although experimental and theoretical studies support the understanding that neuronal circuits are intrinsically capable of generating different time intervals, the dynamical origin of the phenomenon of functionally dependent timing control is still unclear. Here, we consider a new mechanism that is related to the multi-neuronal cooperative dynamics in inhibitory brain motifs consisting of a few clusters. It is shown that redundancy and diversity of neurons within each cluster enhances the sensitivity of the timing control with the level of neuronal excitation of the whole network. The generality of the mechanism is shown to work on two different neuronal models: a conductance-based model and a map-based model.
Timing control by redundant inhibitory neuronal circuits
International Nuclear Information System (INIS)
Tristan, I.; Rulkov, N. F.; Huerta, R.; Rabinovich, M.
2014-01-01
Rhythms and timing control of sequential activity in the brain is fundamental to cognition and behavior. Although experimental and theoretical studies support the understanding that neuronal circuits are intrinsically capable of generating different time intervals, the dynamical origin of the phenomenon of functionally dependent timing control is still unclear. Here, we consider a new mechanism that is related to the multi-neuronal cooperative dynamics in inhibitory brain motifs consisting of a few clusters. It is shown that redundancy and diversity of neurons within each cluster enhances the sensitivity of the timing control with the level of neuronal excitation of the whole network. The generality of the mechanism is shown to work on two different neuronal models: a conductance-based model and a map-based model
Timing system control software in the SLC
International Nuclear Information System (INIS)
Thompson, K.; Phinney, N.
1985-04-01
A new timing system that allows precision (approx.1 to 2 ns) control of the trigger times of klystrons, beam position monitors, and other devices on a pulse-to-pulse basis at up to 360 Hz is in operation in the first third of the SLAC linear accelerator. The control software is divided between a central host VAX and local Intel 8086-based microprocessor clusters. Facilities exist to set up and adjust the timing of devices or groups of devices independently for beam pulses having different destinations and purposes, which are run in an interlaced fashion during normal machine operation. Upgrading of the system is currently underway, using a new version of the Programmable Delay Unit CAMAC module to allow pipelining of timing information for three machine pulses. An overview of the current state of the system is presented in this paper, with an emphasis on software control
Testing for Change in Mean of Independent Multivariate Observations with Time Varying Covariance
Directory of Open Access Journals (Sweden)
Mohamed Boutahar
2012-01-01
Full Text Available We consider a nonparametric CUSUM test for change in the mean of multivariate time series with time varying covariance. We prove that under the null, the test statistic has a Kolmogorov limiting distribution. The asymptotic consistency of the test against a large class of alternatives which contains abrupt, smooth and continuous changes is established. We also perform a simulation study to analyze the size distortion and the power of the proposed test.
Estimating space-time mean concentrations of nutrients in surface waters of variable depth
Knotters, M.; Brus, D.J.
2010-01-01
A monitoring scheme has been designed to test whether the space-time mean concentration total Nitrogen (N-total) in the surface water in the Northern Frisian Woodlands (NFW, The Netherlands) complies with standards of the European Water Framework directive. Since in statistical testing for
Short-time existence of solutions for mean-field games with congestion
Gomes, Diogo A.; Voskanyan, Vardan K.
2015-01-01
We consider time-dependent mean-field games with congestion that are given by a Hamilton–Jacobi equation coupled with a Fokker–Planck equation. These models are motivated by crowd dynamics in which agents have difficulty moving in high-density areas
Using the mean approach in pooling cross-section and time series data for regression modelling
International Nuclear Information System (INIS)
Nuamah, N.N.N.N.
1989-12-01
The mean approach is one of the methods for pooling cross section and time series data for mathematical-statistical modelling. Though a simple approach, its results are sometimes paradoxical in nature. However, researchers still continue using it for its simplicity. Here, the paper investigates the nature and source of such unwanted phenomena. (author). 7 refs
International Nuclear Information System (INIS)
Montalto, M.; Giacomelli, R.; Nocente, M.; Bortoluzzi, S.; Spezzano, P.
1990-12-01
Design of automatic system for real time air monitoring of radioactive particulates are relate. Recommendations are made for design and operation of sampling conduits to minimize losses. By means of experimental equipment loss of particles in long sampling conduits, minimum detectable activity and efficiency of gamma radiation detectable are evaluated. (author)
Time Optimal Run-time Evaluation of Distributed Timing Constraints in Process Control Software
DEFF Research Database (Denmark)
Drejer, N.; Kristensen, C.H.
1993-01-01
This paper considers run-time evaluation of an important class of constraints; Timing constraints. These appear extensively in process control systems. Timing constraints are considered in distributed systems, i.e. systems consisting of multiple autonomous nodes......
A time-delayed method for controlling chaotic maps
International Nuclear Information System (INIS)
Chen Maoyin; Zhou Donghua; Shang Yun
2005-01-01
Combining the repetitive learning strategy and the optimality principle, this Letter proposes a time-delayed method to control chaotic maps. This method can effectively stabilize unstable periodic orbits within chaotic attractors in the sense of least mean square. Numerical simulations of some chaotic maps verify the effectiveness of this method
Real-time measurement and control at Jet. Experiment Control
International Nuclear Information System (INIS)
Felton, R.; Zabeo, L.; Sartori, F.; Piccolo, F.; Farthing, J.; Budd, T.; Dorling, S.; McCullen, P.; Harling, J.; Dalley, S.; Goodyear, A.; Stephen, A.; Card, P.; Bright, M.; Lucock, R.; Jones, E.; Griph, S.; Hogben, C.; Beldishevski, M.; Buckley, M.; Davis, J.; Young, I.; Hemming, O.; Wheatley, M.; Heesterman, P.; Lloyd, G.; Walters, M.; Bridge, R.; Leggate, H.; Howell, D.; Zastrow, K.D.; Giroud, C.; Coffey, I.; Hawkes, N.; Stamp, M.; Barnsley, R.; Edlington, T.; Guenther, K.; Gowers, C.; Popovichef, S.; Huber, A.; Ingesson, C.; Joffrin, E.; Mazon, D.; Moreau, D.; Murari, A.; Riva, M.; Barana, O.; Bolzonella, T.; Valisa, M.; Innocente, P.; Zerbini, M.; Bosak, K.; Blum, J.; Vitale, E.; Crisanti, F.; La Luna, E. de; Sanchez, J.
2004-01-01
Over the past few ears, the preparation of ITER-relevant plasma scenarios has been the main focus experimental activity on tokamaks. The development of integrated, simultaneous, real-time controls of plasma shape, current, pressure, temperature, radiation, neutron profiles, and also impurities, ELMs (edge localized modes) and MHD are now seen to be essential for further development of quasi-steady state conditions with feedback, or the stabilisation of transient phenomena with event-driven actions. For this thrust, the EFDA JET Real Time Project has developed a set of real-time plasma measurements, experiment control, and communication facilities. The Plasma Diagnostics used for real-time experiments are Far Infra Red interferometry, polarimetry, visible, UV and X-ray spectroscopy, LIDAR, bolometry, neutron and magnetics. Further analysis systems produce integrated results such as temperature profiles on geometry derived from MHD equilibrium solutions. The Actuators include toroidal, poloidal and divertor coils, gas and pellet fuelling, neutral beam injection, radiofrequency (ICRH) waves and microwaves (LH). The Heating/Fuelling Operators can either define a power or gas request waveform or select the real-time instantaneous power/gas request from the Real Time Experiment Central Control (RTCC) system. The Real Time Experiment Control system provides both a high-level, control-programming environment and interlocks with the actuators. A MATLAB facility is being developed for the development of more complex controllers. The plasma measurement, controller and plant control systems communicate in ATM network. The EFDA Real Time project is essential groundwork for future reactors such as ITER. It involves many staff from several institutions. The facility is now frequently used in experiments. (authors)
On a mean field game optimal control approach modeling fast exit scenarios in human crowds
Burger, Martin; Di Francesco, Marco; Markowich, Peter A.; Wolfram, Marie Therese
2013-01-01
The understanding of fast exit and evacuation situations in crowd motion research has received a lot of scientific interest in the last decades. Security issues in larger facilities, like shopping malls, sports centers, or festivals necessitate a better understanding of the major driving forces in crowd dynamics. In this paper we present an optimal control approach modeling fast exit scenarios in pedestrian crowds. The model is formulated in the framework of mean field games and based on a parabolic optimal control problem. We consider the case of a large human crowd trying to exit a room as fast as possible. The motion of every pedestrian is determined by minimizing a cost functional, which depends on his/her position and velocity, the overall density of people, and the time to exit. This microscopic setup leads in a mean-field formulation to a nonlinear macroscopic optimal control problem, which raises challenging questions for the analysis and numerical simulations.We discuss different aspects of the mathematical modeling and illustrate them with various computational results. ©2013 IEEE.
On a mean field game optimal control approach modeling fast exit scenarios in human crowds
Burger, Martin
2013-12-01
The understanding of fast exit and evacuation situations in crowd motion research has received a lot of scientific interest in the last decades. Security issues in larger facilities, like shopping malls, sports centers, or festivals necessitate a better understanding of the major driving forces in crowd dynamics. In this paper we present an optimal control approach modeling fast exit scenarios in pedestrian crowds. The model is formulated in the framework of mean field games and based on a parabolic optimal control problem. We consider the case of a large human crowd trying to exit a room as fast as possible. The motion of every pedestrian is determined by minimizing a cost functional, which depends on his/her position and velocity, the overall density of people, and the time to exit. This microscopic setup leads in a mean-field formulation to a nonlinear macroscopic optimal control problem, which raises challenging questions for the analysis and numerical simulations.We discuss different aspects of the mathematical modeling and illustrate them with various computational results. ©2013 IEEE.
CONTINUITY OF THE MEANINGS AND FORMS OF PATRIOTISM IN THE CONTEXT OF SOCIAL TIME STUDY
Directory of Open Access Journals (Sweden)
Olga Valerjevna Kashirina
2017-06-01
Full Text Available Purpose. The work objective is to identify the focus of the meanings’ continuity and forms of patriotism in patriotic choice as the frame meaning of main life strategy that each civilized subject has- an individual, a social community of any size. The choice truthfulness is defined by presence of the meaning time continuity and approach of its structure to «the right rate». Methodology. The problem analysis is carried out on the basis of transdisciplinary dialectical and trialectical method of distinction and meaning-making with respect to intellectual technology of civilized and noospheric patriotism continuity. Results. The article regards to the continuity of meanings and forms of patriotism in the context of social time study and searches for the solution to the problem of patriotism in three lines: 1 as the problem of civilized patriotism of Great and Small Motherland, 2 as the problem of noospheric patriotism, 3 as the problem of the continuity of the meanings between them. It highlights the solution flexibility of patriotism problem that is related to the fact that social time study considers patriotism as the culture phenomenon that has the dialectical «nature of existence», and at the same time, it has three way model of civilized reality «existence» meanings – entirety of present, continuity of past and reasonability of future. The article says that the dynamic balance of meanings of civilized and noospheric patriotism in the identity culture of a civilized subject making the culture of his/her behavior and activity provides formation and stability of moral and spiritual immunity that appears by virtue of them in the semantic field of patriotism. Practical implications. The practical implication of the research is in its usability to work out courses on philosophy, culture philosophy, etc. Social time study theory can be realized in teaching practice of the new course unit «The basics of social time study» as a humanity
Markov Chain Model with Catastrophe to Determine Mean Time to Default of Credit Risky Assets
Dharmaraja, Selvamuthu; Pasricha, Puneet; Tardelli, Paola
2017-11-01
This article deals with the problem of probabilistic prediction of the time distance to default for a firm. To model the credit risk, the dynamics of an asset is described as a function of a homogeneous discrete time Markov chain subject to a catastrophe, the default. The behaviour of the Markov chain is investigated and the mean time to the default is expressed in a closed form. The methodology to estimate the parameters is given. Numerical results are provided to illustrate the applicability of the proposed model on real data and their analysis is discussed.
Short-time existence of solutions for mean-field games with congestion
Gomes, Diogo A.
2015-11-20
We consider time-dependent mean-field games with congestion that are given by a Hamilton–Jacobi equation coupled with a Fokker–Planck equation. These models are motivated by crowd dynamics in which agents have difficulty moving in high-density areas. The congestion effects make the Hamilton–Jacobi equation singular. The uniqueness of solutions for this problem is well understood; however, the existence of classical solutions was only known in very special cases, stationary problems with quadratic Hamiltonians and some time-dependent explicit examples. Here, we demonstrate the short-time existence of C∞ solutions for sub-quadratic Hamiltonians.
Mean transit time image - a new method of analyzing brain perfusion studies
Energy Technology Data Exchange (ETDEWEB)
Szabo, Z.; Ritzl, F.
1983-05-01
Point-by-point calculation of the mean transit time based on gamma fit was used to analyze brain perfusion studies in a vertex view. The algorithm and preliminary results in normal brain and in different stages of cerebral perfusion abnormality (ischemia, stroke, migraine, tumor, abscess) are demonstrated. In contrast to the traditional methods using fixed, a priori defined regions of interest this type of mapping of the relative regions cerebral perfusion shows more clearly the irregular outlines of the disturbance. Right to left activity ratios in the arterial part of the time-activity curves showed significant correlation with the mean transit time ratios (Q/sub 1/=1.185-0.192 Qsub(a), n=38, r=0.716, P<0.001).
Mass dispersions in a time-dependent mean-field approach
International Nuclear Information System (INIS)
Balian, R.; Bonche, P.; Flocard, H.; Veneroni, M.
1984-05-01
Characteristic functions for single-particle (s.p.) observables are evaluated by means of a time-dependent variational principle, which involves a state and an observable as conjugate variables. This provides a mean-field expression for fluctuations of s.p. observables, such as mass dispersions. The result differs from TDHF, it requires only the use of existing codes, and it presents attractive theoretical features. First numerical tests are encouraging. In particular, a calculation for 16 O + 16 O provides a significant increase of the predicted mass dispersion
Ponomarenko, V I; Kulminskiy, D D; Prokhorov, M D
2017-08-01
We study the collective dynamics of oscillators in a network of identical bistable time-delayed feedback systems globally coupled via the mean field. The influence of delay and inertial properties of the mean field on the collective behavior of globally coupled oscillators is investigated. A variety of oscillation regimes in the network results from the presence of bistable states with substantially different frequencies in coupled oscillators. In the physical experiment and numerical simulation we demonstrate the existence of chimeralike states, in which some of the oscillators in the network exhibit synchronous oscillations, while all other oscillators remain asynchronous.
Forecasting the Global Mean Sea Level, a Continuous-Time State-Space Approach
DEFF Research Database (Denmark)
Boldrini, Lorenzo
In this paper we propose a continuous-time, Gaussian, linear, state-space system to model the relation between global mean sea level (GMSL) and the global mean temperature (GMT), with the aim of making long-term projections for the GMSL. We provide a justification for the model specification based......) and the temperature reconstruction from Hansen et al. (2010). We compare the forecasting performance of the proposed specification to the procedures developed in Rahmstorf (2007b) and Vermeer and Rahmstorf (2009). Finally, we compute projections for the sea-level rise conditional on the 21st century SRES temperature...
Time Consistent Strategies for Mean-Variance Asset-Liability Management Problems
Directory of Open Access Journals (Sweden)
Hui-qiang Ma
2013-01-01
Full Text Available This paper studies the optimal time consistent investment strategies in multiperiod asset-liability management problems under mean-variance criterion. By applying time consistent model of Chen et al. (2013 and employing dynamic programming technique, we derive two-time consistent policies for asset-liability management problems in a market with and without a riskless asset, respectively. We show that the presence of liability does affect the optimal strategy. More specifically, liability leads a parallel shift of optimal time-consistent investment policy. Moreover, for an arbitrarily risk averse investor (under the variance criterion with liability, the time-diversification effects could be ignored in a market with a riskless asset; however, it should be considered in a market without any riskless asset.
Processing implicit control: evidence from reading times
Directory of Open Access Journals (Sweden)
Michael eMcCourt
2015-10-01
Full Text Available Sentences such as The ship was sunk to collect the insurance exhibit an unusual form of anaphora, implicit control, where neither anaphor nor antecedent is audible. The nonfinite reason clause has an understood subject, PRO, that is anaphoric; here it may be understood as naming the agent of the event of the host clause. Yet since the host is a short passive, this agent is realized by no audible dependent. The putative antecedent to PRO is therefore implicit, which it normally cannot be. What sorts of representations subserve the comprehension of this dependency? Here we present four self-paced reading time studies directed at this question. Previous work showed no processing cost for implicit versus explicit control, and took this to support the view that PRO is linked syntactically to a silent argument in the passive. We challenge this conclusion by reporting that we also find no processing cost for remote implicit control, as in: The ship was sunk. The reason was to collect the insurance. Here the dependency crosses two independent sentences, and so cannot, we argue, be mediated by syntax. Our Experiments 1-4 examined the processing of both implicit (short passive and explicit (active or long passive control in both local and remote configurations. Experiments 3 and 4 added either three days ago or just in order to the local conditions, to control for the distance between the passive and infinitival verbs, and for the predictability of the reason clause, respectively. We replicate the finding that implicit control does not impose an additional processing cost. But critically we show that remote control does not impose a processing cost either. Reading times at the reason clause were never slower when control was remote. In fact they were always faster. Thus efficient processing of local implicit control cannot show that implicit control is mediated by syntax; nor, in turn, that there is a silent but grammatically active argument in passives.
Maximizing the Mean Exit Time of a Brownian Motion from an Interval
Directory of Open Access Journals (Sweden)
Mario Lefebvre
2011-01-01
Full Text Available Let X(t be a controlled one-dimensional standard Brownian motion starting from x∈(−d,d. The problem of optimally controlling X(t until |X(t|=d for the first time is solved explicitly in a particular case. The maximal value that the instantaneous reward given for survival in (−d,d can take is determined.
Availability and mean life time prediction of multistage degraded system with partial repairs
International Nuclear Information System (INIS)
Pham, Hoang; Suprasad, A.; Misra, R.B.
1997-01-01
In some environments, components might not always fail fully, but can degrade, and there can be multiple stages of degradation. In such cases, the efficiency of the system may decrease. After a certain stage of degradation the efficiency of the system may decrease to an unacceptable limit and can be considered as a total failure. However, the system can fail randomly from any stage. and can be repaired. Further, the repair action cannot bring the system to the good stage, but can make it operational and the failure rate of the system will, therefore, remain the same as before the failure. In this study, we present a model for predicting the reliability, availability, mean life time, and mean time to first failure of multistage degraded systems with partial repairs. In the analysis, state dependent transition rates for the degradation process, as well as repair processes, are considered. A numerical example is provided to illustrate the results
Li, Zhengjun; Zang, Yu-Feng; Ding, Jianping; Wang, Ze
2017-04-01
The time-to-time fluctuations (TTFs) of resting-state brain activity as captured by resting-state fMRI (rsfMRI) have been repeatedly shown to be informative of functional brain structures and disease-related alterations. TTFs can be characterized by the mean and the range of successive difference. The former can be measured with the mean squared successive difference (MSSD), which is mathematically similar to standard deviation; the latter can be calculated by the variability of the successive difference (VSD). The purpose of this study was to evaluate both the resting state-MSSD and VSD of rsfMRI regarding their test-retest stability, sensitivity to brain state change, as well as their biological meanings. We hypothesized that MSSD and VSD are reliable in resting brain; both measures are sensitive to brain state changes such as eyes-open compared to eyes-closed condition; both are predictive of age. These hypotheses were tested with three rsfMRI datasets and proven true, suggesting both MSSD and VSD as reliable and useful tools for resting-state studies.
A short note on the mean exit time of the Brownian motion
Cadeddu, Lucio; Farina, Maria Antonietta
We investigate the functional Ω↦ℰ(Ω) where Ω runs through the set of compact domains of fixed volume v in any Riemannian manifold (M,g) and where ℰ(Ω) is the mean exit time from Ω of the Brownian motion. We give an alternative analytical proof of a well-known fact on its critical points proved by McDonald: the critical points of ℰ(Ω) are harmonic domains.
Double giant resonances in time-dependent relativistic mean-field theory
International Nuclear Information System (INIS)
Ring, P.; Podobnik, B.
1996-01-01
Collective vibrations in spherical nuclei are described in the framework of time-dependent relativistic mean-field theory (RMFT). Isoscalar quadrupole and isovector dipole oscillations that correspond to giant resonances are studied, and possible excitations of higher modes are investigated. We find evidence for modes which can be interpreted as double resonances. In a quantized RMFT they correspond to two-phonon states. (orig.)
A comparison of various forecasting techniques applied to mean hourly wind speed time series
Energy Technology Data Exchange (ETDEWEB)
Sfetsos, A. [7 Pirsou Street, Athens (Greece)
2000-09-01
This paper presents a comparison of various forecasting approaches, using time series analysis, on mean hourly wind speed data. In addition to the traditional linear (ARMA) models and the commonly used feed forward and recurrent neural networks, other approaches are also examined including the Adaptive Neuro-Fuzzy Inference Systems (ANFIS) and Neural Logic Networks. The developed models are evaluated for their ability to produce accurate and fast forecasts. (Author)
New information technologies as a means of quality improvement of part-time students’ training
Directory of Open Access Journals (Sweden)
Нестеренко В. В.
2016-09-01
Full Text Available Ways and means aimed at facilitating the quality of part-time students’ training at an institution of higher education are considered in the article. The principles the conditions facilitating quality increase of adult part-time students’ training are based on as well as criteria of their effectiveness assessment are described. The definition of the notion «distance learning» has been given. Tuition by correspondence as a special form of continuous education allowing the use of elements of distance educational technologies is examined. The role of informational technologies in correspondence form of education providing essential improvement of students’ training quality is described.
Time dependent mean field approximation to the many-body S-matrix
International Nuclear Information System (INIS)
Alhassid, Y.; Koonin, S.E.
1980-01-01
Time-dependent Hartree-Fock (TDHF) calculations are a good description of some inclusive properties of deep inelastic heavy-ion collisions. The first steps toward a mean-field theory that approximates specific elements of the many-body S matrix are presented. A many-body system with pairwise interactions excited by an external, time-dependent one-body field is considered. The methods are used to solve the forced Lipkin model. The moduli of elastic and excitation amplitudes are plotted. 3 figures
Mean first passage time for random walk on dual structure of dendrimer
Li, Ling; Guan, Jihong; Zhou, Shuigeng
2014-12-01
The random walk approach has recently been widely employed to study the relations between the underlying structure and dynamic of complex systems. The mean first-passage time (MFPT) for random walks is a key index to evaluate the transport efficiency in a given system. In this paper we study analytically the MFPT in a dual structure of dendrimer network, Husimi cactus, which has different application background and different structure (contains loops) from dendrimer. By making use of the iterative construction, we explicitly determine both the partial mean first-passage time (PMFT, the average of MFPTs to a given target) and the global mean first-passage time (GMFT, the average of MFPTs over all couples of nodes) on Husimi cactus. The obtained closed-form results show that PMFPT and EMFPT follow different scaling with the network order, suggesting that the target location has essential influence on the transport efficiency. Finally, the impact that loop structure could bring is analyzed and discussed.
Existence of optimal controls for systems governed by mean-field ...
African Journals Online (AJOL)
In this paper, we study the existence of an optimal control for systems, governed by stochastic dierential equations of mean-eld type. For non linear systems, we prove the existence of an optimal relaxed control, by using tightness techniques and Skorokhod selection theorem. The optimal control is a measure valued process ...
PEP-II injection timing and controls
International Nuclear Information System (INIS)
Bharadwaj, V.; Browne, M.; Crane, M.; Gromme, T.; Himel, T.; Ross, M.; Stanek, M.; Ronan, M.
1997-07-01
Hardware has been built and software written and incorporated in the existing SLC accelerator control system to control injection of beam pulses from the accelerator into the PEP-II storage rings currently under construction. Hardware includes a CAMAC module to delay the machine timing fiducial in order that a beam pulse extracted from a damping ring will be injected into a selected group of four 476 MHz buckets in a PEP-II ring. Further timing control is accomplished by shifting the phase of the bunches stored in the damping rings before extraction while leaving the phase of the PEP-II stored beam unchanged. The software which drives timing devices on a pulse-to-pulse basis relies on a dedicated communication link on which one scheduling microprocessor broadcasts a 128-bit message to all distributed control microprocessors at 360 Hz. PEP-II injection will be driven by the scheduling microprocessor according to lists specifying bucket numbers in arbitrary order, and according to scheduling constraints maximizing the useful beam delivered to the SLC collider currently in operation. These lists will be generated by a microprocessor monitoring the current stored per bucket in each of the PEP-II rings
Mean transit times in headwater catchments: insights from the Otway Ranges, Australia
Directory of Open Access Journals (Sweden)
W. Howcroft
2018-01-01
Full Text Available Understanding the timescales of water flow through catchments and the sources of stream water at different flow conditions is critical for understanding catchment behaviour and managing water resources. Here, tritium (3H activities, major ion geochemistry and streamflow data were used in conjunction with lumped parameter models (LPMs to investigate mean transit times (MTTs and the stores of water in six headwater catchments in the Otway Ranges of southeastern Australia. 3H activities of stream water ranged from 0.20 to 2.14 TU, which are significantly lower than the annual average 3H activity of modern local rainfall, which is between 2.4 and 3.2 TU. The 3H activities of the stream water are lowest during low summer flows and increase with increasing streamflow. The concentrations of most major ions vary little with streamflow, which together with the low 3H activities imply that there is no significant direct input of recent rainfall at the streamflows sampled in this study. Instead, shallow younger water stores in the soils and regolith are most likely mobilised during the wetter months. MTTs vary from approximately 7 to 230 years. Despite uncertainties of several years in the MTTs that arise from having to assume an appropriate LPM, macroscopic mixing, and uncertainties in the 3H activities of rainfall, the conclusion that they range from years to decades is robust. Additionally, the relative differences in MTTs at different streamflows in the same catchment are estimated with more certainty. The MTTs in these and similar headwater catchments in southeastern Australia are longer than in many catchments globally. These differences may reflect the relatively low rainfall and high evapotranspiration rates in southeastern Australia compared with headwater catchments elsewhere. The long MTTs imply that there is a long-lived store of water in these catchments that can sustain the streams over drought periods lasting several years. However, the
Mean transit times in headwater catchments: insights from the Otway Ranges, Australia
Howcroft, William; Cartwright, Ian; Morgenstern, Uwe
2018-01-01
Understanding the timescales of water flow through catchments and the sources of stream water at different flow conditions is critical for understanding catchment behaviour and managing water resources. Here, tritium (3H) activities, major ion geochemistry and streamflow data were used in conjunction with lumped parameter models (LPMs) to investigate mean transit times (MTTs) and the stores of water in six headwater catchments in the Otway Ranges of southeastern Australia. 3H activities of stream water ranged from 0.20 to 2.14 TU, which are significantly lower than the annual average 3H activity of modern local rainfall, which is between 2.4 and 3.2 TU. The 3H activities of the stream water are lowest during low summer flows and increase with increasing streamflow. The concentrations of most major ions vary little with streamflow, which together with the low 3H activities imply that there is no significant direct input of recent rainfall at the streamflows sampled in this study. Instead, shallow younger water stores in the soils and regolith are most likely mobilised during the wetter months. MTTs vary from approximately 7 to 230 years. Despite uncertainties of several years in the MTTs that arise from having to assume an appropriate LPM, macroscopic mixing, and uncertainties in the 3H activities of rainfall, the conclusion that they range from years to decades is robust. Additionally, the relative differences in MTTs at different streamflows in the same catchment are estimated with more certainty. The MTTs in these and similar headwater catchments in southeastern Australia are longer than in many catchments globally. These differences may reflect the relatively low rainfall and high evapotranspiration rates in southeastern Australia compared with headwater catchments elsewhere. The long MTTs imply that there is a long-lived store of water in these catchments that can sustain the streams over drought periods lasting several years. However, the catchments are likely
Energy Technology Data Exchange (ETDEWEB)
Graber, P. Jameson, E-mail: jameson-graber@baylor.edu [Baylor University, Department of Mathematics (United States)
2016-12-15
We study a general linear quadratic mean field type control problem and connect it to mean field games of a similar type. The solution is given both in terms of a forward/backward system of stochastic differential equations and by a pair of Riccati equations. In certain cases, the solution to the mean field type control is also the equilibrium strategy for a class of mean field games. We use this fact to study an economic model of production of exhaustible resources.
International Nuclear Information System (INIS)
Kim, J.H.; Lee, E.J.; Lee, S.J.; Choi, N.C.; Lim, B.H.; Shin, T.
2002-01-01
Purpose: Perfusion MR imaging offers an easy quantitative evaluation of relative regional cerebral blood volume (rrCBV), relative mean transit time (rMTT) and time-to-peak (TTP). The purpose of this study was to investigate the reliability of these parameters in assessing the hemodynamic disturbance of carotid occlusive disease in comparison with normative data. Material and Methods: Dynamic contrast-enhanced T2*-weighted perfusion MR imaging was performed in 19 patients with symptomatic unilateral internal carotid artery occlusion and 20 control subjects. The three parameters were calculated from the concentration-time curve fitted by gamma-variate function. Lesion-to-contralateral ratios of each parameter were compared between patients and control subjects. Results: Mean±SD of rrCBV, rMTT and TTP ratios of patients were 1.089±0.118, 1.054±0.031 and 1.062±0.039, respectively, and those of control subjects were 1.002±0.045, 1.000±0.006, 1.001±0.006, respectively. The rMTT and TTP ratios of all patients were greater than 2SDs of control data, whereas in only 6 patients (32%), rrCBV ratios were greater than 2SDs of control data. The three parameter ratios of the patients were significantly high compared with those of control subjects, respectively (p<0.01 for rrCBV ratios, p<0.0001 for rMTT ratios, and p<0.0001 for TTP ratios). Conclusion: Our results indicate that rMTT and TTP of patients, in contrast to rrCBV, are distributed in narrow ranges minimally overlapped with control data. The rMTT and TTP could be more reliable parameters than rrCBV in assessing the hemodynamic disturbance in carotid occlusive disease
Regular and chaotic dynamics in time-dependent relativistic mean-field theory
International Nuclear Information System (INIS)
Vretenar, D.; Ring, P.; Lalazissis, G.A.; Poeschl, W.
1997-01-01
Isoscalar and isovector monopole oscillations that correspond to giant resonances in spherical nuclei are described in the framework of time-dependent relativistic mean-field theory. Time-dependent and self-consistent calculations that reproduce experimental data on monopole resonances in 208 Pb show that the motion of the collective coordinate is regular for isoscalar oscillations, and that it becomes chaotic when initial conditions correspond to the isovector mode. Regular collective dynamics coexists with chaotic oscillations on the microscopic level. Time histories, Fourier spectra, state-space plots, Poincare sections, autocorrelation functions, and Lyapunov exponents are used to characterize the nonlinear system and to identify chaotic oscillations. Analogous considerations apply to higher multipolarities. copyright 1997 The American Physical Society
RFX: New tools for real-time MHD control
International Nuclear Information System (INIS)
Gnesotto, F.; Luchetta, A.; Marchiori, G.
2005-01-01
RFX has been recently modified to improve its capability of controlling different MHD phenomena by means of fast, feedback controlled amplifiers and distributed radial field inductors. The paper, after summarizing the principal results obtained in the past by means of active control of magnetic fields in RFX, describes the recent modifications to the machine and the improvements to the power supplies and to the magnetic diagnostics. The old thick shell has been replaced by a much thinner shell, whose electromagnetic time constants are much shorter than pulse duration, and a system of 192 radial field coils has been added, covering the whole torus surface. Then the paper describes the models used to design the new real-time control system of RFX and gives some preliminary results obtained, with the same techniques, on the EXTRAP-T2R device. The basic choices about the technologies adopted for the new RFX control system are discussed with reference to the general problem of real-time control of MHD instabilities in magnetic fusion devices. Finally, the paper defines the main objectives of the RFX scientific programme aimed at exploiting these new tools. (author)
Short-range correlations in an extended time-dependent mean-field theory
International Nuclear Information System (INIS)
Madler, P.
1982-01-01
A generalization is performed of the time-dependent mean-field theory by an explicit inclusion of strong short-range correlations on a level of microscopic reversibility relating them to realistic nucleon-nucleon forces. Invoking a least action principle for correlated trial wave functions, equations of motion for the correlation functions and the single-particle model wave function are derived in lowest order of the FAHT cluster expansion. Higher order effects as well as long-range correlations are consider only to the extent to which they contribute to the mean field via a readjusted phenomenological effective two-body interaction. The corresponding correlated stationary problem is investigated and appropriate initial conditions to describe a heavy ion reaction are proposed. The singleparticle density matrix is evaluated
Mapping absorption processes onto a Markov chain, conserving the mean first passage time
International Nuclear Information System (INIS)
Biswas, Katja
2013-01-01
The dynamics of a multidimensional system is projected onto a discrete state master equation using the transition rates W(k → k′; t, t + dt) between a set of states {k} represented by the regions {ζ k } in phase or discrete state space. Depending on the dynamics Γ i (t) of the original process and the choice of ζ k , the discretized process can be Markovian or non-Markovian. For absorption processes, it is shown that irrespective of these properties of the projection, a master equation with time-independent transition rates W-bar (k→k ' ) can be obtained, which conserves the total occupation time of the partitions of the phase or discrete state space of the original process. An expression for the transition probabilities p-bar (k ' |k) is derived based on either time-discrete measurements {t i } with variable time stepping Δ (i+1)i = t i+1 − t i or the theoretical knowledge at continuous times t. This allows computational methods of absorbing Markov chains to be used to obtain the mean first passage time (MFPT) of the system. To illustrate this approach, the procedure is applied to obtain the MFPT for the overdamped Brownian motion of particles subject to a system with dichotomous noise and the escape from an entropic barrier. The high accuracy of the simulation results confirms with the theory. (paper)
Real time computer controlled weld skate
Wall, W. A., Jr.
1977-01-01
A real time, adaptive control, automatic welding system was developed. This system utilizes the general case geometrical relationships between a weldment and a weld skate to precisely maintain constant weld speed and torch angle along a contoured workplace. The system is compatible with the gas tungsten arc weld process or can be adapted to other weld processes. Heli-arc cutting and machine tool routing operations are possible applications.
Optimal, real-time control--colliders
International Nuclear Information System (INIS)
Spencer, J.E.
1991-05-01
With reasonable definitions, optimal control is possible for both classical and quantal systems with new approaches called PISC(Parallel) and NISC(Neural) from analogy with RISC (Reduced Instruction Set Computing). If control equals interaction, observation and comparison to some figure of merit with interaction via external fields, then optimization comes from varying these fields to give design or operating goals. Structural stability can then give us tolerance and design constraints. But simulations use simplified models, are not in real-time and assume fixed or stationary conditions, so optimal control goes far beyond convergence rates of algorithms. It is inseparable from design and this has many implications for colliders. 12 refs., 3 figs
Rahmat, Mohd Fua'ad; Yazdani, Amir Mehdi; Movahed, Mohammad Ahmadi; Mahmoudzadeh, Somaiyeh
2011-01-01
Continues Stirred Tank Reactor (CSTR) is an important subject in chemical process and offering a diverse range of researches in the area of the chemical and control engineering. Various control approaches have been applied on CSTR to control its parameters. This paper presents two different control strategies based on the combination of a novel socio-political optimization algorithm, called Imperialist Competitive Algorithm (ICA), and concept of the gain scheduling performed by means of the l...
Visually and force controlled opening and closing of doors by means of a mobile robot arm
Milighetti, G.; Hoffmann, E.; Fetzner, Angelika; Kuntze, Helge-Björn
2012-01-01
A multi-sensory discrete-continuous control concept has been developed to realize interactive basic skills for humanoid and mobile service robots. In the upper hierarchy level a discrete task control structure enables the flexible execution of primitive skill sequences. In the lower continuous level a suitable controller is chosen with control parameters adapted to the current primitive skill. The basic skill for the frequently occurring task of unlocking and opening a door by means of a mobi...
Time-delayed autosynchronous swarm control.
Biggs, James D; Bennet, Derek J; Dadzie, S Kokou
2012-01-01
In this paper a general Morse potential model of self-propelling particles is considered in the presence of a time-delayed term and a spring potential. It is shown that the emergent swarm behavior is dependent on the delay term and weights of the time-delayed function, which can be set to induce a stationary swarm, a rotating swarm with uniform translation, and a rotating swarm with a stationary center of mass. An analysis of the mean field equations shows that without a spring potential the motion of the center of mass is determined explicitly by a multivalued function. For a nonzero spring potential the swarm converges to a vortex formation about a stationary center of mass, except at discrete bifurcation points where the center of mass will periodically trace an ellipse. The analytical results defining the behavior of the center of mass are shown to correspond with the numerical swarm simulations.
Simple control law structure for the control of airplanes by means of their engines
Fezans, Nicolas
2011-01-01
In this paper a simple control law structure is presented for the control of airplanes using only the engines' thrust. For the design of such a propulsion controlled aircraft control law, the approach followed in this work is to look for the right level of performance in order to avoid both excessive engines activity and reduction of robustness properties. Another goal is to keep the control law and its tuning as simple as possible: for this a control law structure whose terms can easily be i...
Implicit and explicit timing in oculomotor control.
Directory of Open Access Journals (Sweden)
Ilhame Ameqrane
Full Text Available The passage of time can be estimated either explicitly, e.g. before leaving home in the morning, or implicitly, e.g. when catching a flying ball. In the present study, the latency of saccadic eye movements was used to evaluate differences between implicit and explicit timing. Humans were required to make a saccade between a central and a peripheral position on a computer screen. The delay between the extinction of a central target and the appearance of an eccentric target was the independent variable that could take one out of four different values (400, 900, 1400 or 1900 ms. In target trials, the delay period lasted for one of the four durations randomly. At the end of the delay, a saccade was initiated by the appearance of an eccentric target. Cue&target trials were similar to target trials but the duration of the delay was visually cued. In probe trials, the duration of the upcoming delay was cued, but there was no eccentric target and subjects had to internally generate a saccade at the estimated end of the delay. In target and cue&target trials, the mean and variance of latency distributions decreased as delay duration increased. In cue&target trials latencies were shorter. In probe trials, the variance increased with increasing delay duration and scalar variability was observed. The major differences in saccadic latency distributions were observed between visually-guided (target and cue&target trials and internally-generated saccades (probe trials. In target and cue&target trials the timing of the response was implicit. In probe trials, the timing of the response was internally-generated and explicitly based on the duration of the visual cue. Scalar timing was observed only during probe trials. This study supports the hypothesis that there is no ubiquitous timing system in the brain but independent timing processes active depending on task demands.
Mean transit times as a parameter for optimizing the quantitative brain scintigraphy
International Nuclear Information System (INIS)
Vosberg, H.; Szabo, Z.; Nase, D.; Feinendegen, L.E.
1984-01-01
Cerebral perfusion imaging with non-diffusible Tc-9mm-labelled substances is a simple screening procedure for identifying perfusion deficits, which can easily be applied in all nuclear medicine departments. Gross hypoperfusion can readily be recognized on analog images. To visualize and assess minor changes in limited brain areas, the perfusion phase in each pixel was fitted to a gamma function and the mean transit times were stored as parametric matrix. To examine the diagnostic sensitivity of transit time images versus that of the usual semiquantitative procedures, data of 84 patients with unilateral cerebral blood flow disorders were analyzed. From the pertinent studies parameters of hemispheral flow were computed using 10 different methodes. Data for the normal and the diseased hemisphere and their ratios were subjected to analysis of variance to assess their diagnostic weight. Patient groups with different angiologically verfied stenoses or occlusion were most easily dinstinguished by the time interval carotid artery - hemispheral peak. The values derived from the parametric images of mean transit times showed more or less the same weight, but the special advantage offered by parametric images, i.e. the precise visualization of the hypoperfused area, was not considered in the analysis of variance. Factorial analysis indicated that the parameters examined can be described by 2 factors to the extent of 72%. The first of these factors combines the weights (58%) of those variables which, in one may or the other, reflect the time of perfusion, while the second includes variables which make use of the count rates for differentiation (14%). The analysis of gamma camera data for diagnosing cerebral blood flow disorders is thus improved. (Author)
Modified mean generation time parameter in the neutron point kinetics equations
Energy Technology Data Exchange (ETDEWEB)
Diniz, Rodrigo C.; Gonçalves, Alessandro C.; Rosa, Felipe S.S., E-mail: alessandro@nuclear.ufrj.br, E-mail: frosa@if.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)
2017-07-01
This paper proposes an approximation for the modified point kinetics equations proposed by NUNES et. al, 2015, through the adjustment of a kinetic parameter. This approximation consists of analyzing the terms of the modified point kinetics equations in order to identify the least important ones for the solution, resulting in a modification of the mean generation time parameter that incorporates all influences of the additional terms of the modified kinetics. This approximation is applied on the inverse kinetics, to compare the results with the inverse kinetics from the modified kinetics in order to validate the proposed model. (author)
Modified mean generation time parameter in the neutron point kinetics equations
International Nuclear Information System (INIS)
Diniz, Rodrigo C.; Gonçalves, Alessandro C.; Rosa, Felipe S.S.
2017-01-01
This paper proposes an approximation for the modified point kinetics equations proposed by NUNES et. al, 2015, through the adjustment of a kinetic parameter. This approximation consists of analyzing the terms of the modified point kinetics equations in order to identify the least important ones for the solution, resulting in a modification of the mean generation time parameter that incorporates all influences of the additional terms of the modified kinetics. This approximation is applied on the inverse kinetics, to compare the results with the inverse kinetics from the modified kinetics in order to validate the proposed model. (author)
Rembovskiĭ, V R; Mogilenkova, L A; Savel'eva, E I
2005-01-01
The major unit monitoring chemical weapons destruction objects is a system of chemical analyticcontrol over the technologic process procedures and possibility of environment and workplace pollution withtoxicchemicals and their destruction products. At the same time, physical and chemical control means meet sanitary and hygienic requirements incompletely. To provide efficient control, internationally recognized approaches should be adapted to features of Russian system monitoring pollution of chemical weapons destruction objects with toxic chemicals.
Structural nested mean models for assessing time-varying effect moderation.
Almirall, Daniel; Ten Have, Thomas; Murphy, Susan A
2010-03-01
This article considers the problem of assessing causal effect moderation in longitudinal settings in which treatment (or exposure) is time varying and so are the covariates said to moderate its effect. Intermediate causal effects that describe time-varying causal effects of treatment conditional on past covariate history are introduced and considered as part of Robins' structural nested mean model. Two estimators of the intermediate causal effects, and their standard errors, are presented and discussed: The first is a proposed two-stage regression estimator. The second is Robins' G-estimator. The results of a small simulation study that begins to shed light on the small versus large sample performance of the estimators, and on the bias-variance trade-off between the two estimators are presented. The methodology is illustrated using longitudinal data from a depression study.
Time series modelling of global mean temperature for managerial decision-making.
Romilly, Peter
2005-07-01
Climate change has important implications for business and economic activity. Effective management of climate change impacts will depend on the availability of accurate and cost-effective forecasts. This paper uses univariate time series techniques to model the properties of a global mean temperature dataset in order to develop a parsimonious forecasting model for managerial decision-making over the short-term horizon. Although the model is estimated on global temperature data, the methodology could also be applied to temperature data at more localised levels. The statistical techniques include seasonal and non-seasonal unit root testing with and without structural breaks, as well as ARIMA and GARCH modelling. A forecasting evaluation shows that the chosen model performs well against rival models. The estimation results confirm the findings of a number of previous studies, namely that global mean temperatures increased significantly throughout the 20th century. The use of GARCH modelling also shows the presence of volatility clustering in the temperature data, and a positive association between volatility and global mean temperature.
Time under control: time perspective and desire for control in substance use.
Fieulaine, Nicolas; Martinez, Frederic
2010-08-01
To investigate the role of time perspective and desire for control in self-reported substance use and to test for a moderating effect of desire for control in the relation between time perspective and substance use. A random sample of 240 persons, aged 15 years and over, selected in various public spaces in an urban region in central France. Time perspective was measured using subscales of the Zimbardo Time Perspective Inventory (ZTPI, Zimbardo & Boyd, 1999), Desire for control was measured using a translated version of the Desire for Control Scale (DCS, Burger & Cooper, 1979), and substance use was self-reported. After controlling for age and gender, significant links were found between time perspective and substance use. Desire for control did not appear to be directly related to substance use. The interaction effect between TP and desire for control appeared to be related to substance use. There was evidence that the relation between TP and substance use is buffered by low desire for control. This study converges with previous studies demonstrating the relation between TP and substance use, but provides evidence of the moderating role played by desire for control. Desire for control thus appears as worthy of interest in the analysis of self-regulatory process, and further research on the links between TP and various aspects of control is required. In order to be more effective, the design of future studies and interventions based on time-related issues should consider how desire for control plays a part in establishing vulnerability profiles. Copyright 2010 Elsevier Ltd. All rights reserved.
Flowering time control in European winter wheat
Directory of Open Access Journals (Sweden)
Simon Martin Langer
2014-10-01
Full Text Available Flowering time is an important trait in wheat breeding as it affects adaptation and yield potential. The aim of this study was to investigate the genetic architecture of flowering time in European winter bread wheat cultivars. To this end a population of 410 winter wheat varieties was evaluated in multi-location field trials and genotyped by a genotyping-by-sequencing approach and candidate gene markers. Our analyses revealed that the photoperiod regulator Ppd-D1 is the major factor affecting flowering time in this germplasm set, explaining 58% of the genotypic variance. Copy number variation at the Ppd-B1 locus was present but explains only 3.2% and thus a comparably small proportion of genotypic variance. By contrast, the plant height loci Rht-B1 and Rht-D1 had no effect on flowering time. The genome-wide scan identified six QTL which each explain only a small proportion of genotypic variance and in addition we identified a number of epistatic QTL, also with small effects. Taken together, our results show that flowering time in European winter bread wheat cultivars is mainly controlled by Ppd-D1 while the fine tuning to local climatic conditions is achieved through Ppd-B1 copy number variation and a larger number of QTL with small effects.
A Mean-Variance Criterion for Economic Model Predictive Control of Stochastic Linear Systems
DEFF Research Database (Denmark)
Sokoler, Leo Emil; Dammann, Bernd; Madsen, Henrik
2014-01-01
, the tractability of the resulting optimal control problem is addressed. We use a power management case study to compare different variations of the mean-variance strategy with EMPC based on the certainty equivalence principle. The certainty equivalence strategy is much more computationally efficient than the mean......-variance strategies, but it does not account for the variance of the uncertain parameters. Openloop simulations suggest that a single-stage mean-variance approach yields a significantly lower operating cost than the certainty equivalence strategy. In closed-loop, the single-stage formulation is overly conservative...... be modified to perform almost as well as the two-stage mean-variance formulation. Nevertheless, we argue that the mean-variance approach can be used both as a strategy for evaluating less computational demanding methods such as the certainty equivalence method, and as an individual control strategy when...
DEFF Research Database (Denmark)
Sokoler, Leo Emil; Dammann, Bernd; Madsen, Henrik
2014-01-01
This paper presents a decomposition algorithm for solving the optimal control problem (OCP) that arises in Mean-Variance Economic Model Predictive Control of stochastic linear systems. The algorithm applies the alternating direction method of multipliers to a reformulation of the OCP...
Finite-Time and Fixed-Time Cluster Synchronization With or Without Pinning Control.
Liu, Xiwei; Chen, Tianping
2018-01-01
In this paper, the finite-time and fixed-time cluster synchronization problem for complex networks with or without pinning control are discussed. Finite-time (or fixed-time) synchronization has been a hot topic in recent years, which means that the network can achieve synchronization in finite-time, and the settling time depends on the initial values for finite-time synchronization (or the settling time is bounded by a constant for any initial values for fixed-time synchronization). To realize the finite-time and fixed-time cluster synchronization, some simple distributed protocols with or without pinning control are designed and the effectiveness is rigorously proved. Several sufficient criteria are also obtained to clarify the effects of coupling terms for finite-time and fixed-time cluster synchronization. Especially, when the cluster number is one, the cluster synchronization becomes the complete synchronization problem; when the network has only one node, the coupling term between nodes will disappear, and the synchronization problem becomes the simplest master-slave case, which also includes the stability problem for nonlinear systems like neural networks. All these cases are also discussed. Finally, numerical simulations are presented to demonstrate the correctness of obtained theoretical results.
Hicks, Joshua A; Trent, Jason; Davis, William E; King, Laura A
2012-03-01
Four studies tested the prediction that positive affect (PA) would relate more strongly to meaning in life (MIL) as a function of perceived time limitations. In Study 1 (N = 360), adults completed measures of PA and MIL. As predicted, PA related more strongly to MIL for older, compared to younger, participants. In Studies 2 and 3, adults (N = 514) indicated their current position in their life span, and rated their MIL. PA, whether naturally occurring (Study 2) or induced (Study 3), was a stronger predictor of MIL for individuals who perceived themselves as having a limited amount of time left to live. Finally, in Study 4 (N = 98) students completed a measure of PA, MIL, and future time perspective (FTP). Results showed that PA was more strongly linked to MIL for those who believed they had fewer opportunities left to pursue their goals. Overall, these findings suggest that the experience of PA becomes increasingly associated with the experience of MIL as the perception of future time becomes limited. The contribution of age related processes to judgments of well-being are discussed.
Real-time control of fusion reactors
International Nuclear Information System (INIS)
Goncalves, B.; Sousa, J.; Varandas, C.A.F.
2010-01-01
The next generation fusion experiments, e.g. ITER, will be highly complex and raise new challenges in the field of control and data acquisition systems. The more advanced operation scenarios have to be capable of sustaining long pulse steady-state plasma and to suppress plasma instabilities almost completely. Such scenarios will heavily rely on Multiple-Input-Multiple-Output (MIMO) fast control systems. To ensure safety for the operation these systems have to be robust and resilient to faults while ensuring high availability. Mindful of the importance of such features for future fusion experiments ATCA based systems have been successfully used in fusion experiment as MIMO fast controller. This is the most promising architecture to substantially enhance the performance and capability of existing standard systems delivering well high throughput as well as high availability. The real-time control needs of a fusion experiment, the rational for the presently pursued solutions, the existing problems and the broad scientific and technical questions that need to be addressed on the path to a fusion power plant will be discussed.
Dental X-ray diagnostic facility with means to choose the time of exposure
Energy Technology Data Exchange (ETDEWEB)
Krause, H; Grassme, U
1978-02-16
Equipment for dental X-ray diagnostics with automatic exposure control. In the patient's mouth there is arranged a film carrier containing in a pocket a dental X-ray film. A detector-transmitter assembly touches the pocket. It reacts to the density of the film and wireless transmits a signal to an antenna. This antenna is connected to a receiver shutting off the high voltage of the X-ray tube by means of a circuit if a desired dose value is reached. The detector-transmitter unit is an integrated component. It has got a luminescent layer with a light-sensitive detector or a detector directly sensitive to X-rays.
An application of Mean Escape Time and metapopulation on forestry catastrophe insurance
Li, Jiangcheng; Zhang, Chunmin; Liu, Jifa; Li, Zhen; Yang, Xuan
2018-04-01
A forestry catastrophe insurance model due to forestry pest infestations and disease epidemics is developed by employing metapopulation dynamics and statistics properties of Mean Escape Time (MET). The probability of outbreak of forestry catastrophe loss and the catastrophe loss payment time with MET are respectively investigated. Forestry loss data in China is used for model simulation. Experimental results are concluded as: (1) The model with analytical results is shown to be a better fit; (2) Within the condition of big area of patches and structure of patches, high system factor, low extinction rate, high multiplicative noises, and additive noises with a high cross-correlated strength range, an outbreak of forestry catastrophe loss or catastrophe loss payment due to forestry pest infestations and disease epidemics could occur; (3) An optimal catastrophe loss payment time MET due to forestry pest infestations and disease epidemics can be identified by taking proper value of multiplicative noises and limits the additive noises on a low range of value, and cross-correlated strength at a high range of value.
Real Time Optimal Control of Supercapacitor Operation for Frequency Response
Energy Technology Data Exchange (ETDEWEB)
Luo, Yusheng; Panwar, Mayank; Mohanpurkar, Manish; Hovsapian, Rob
2016-07-01
Supercapacitors are gaining wider applications in power systems due to fast dynamic response. Utilizing supercapacitors by means of power electronics interfaces for power compensation is a proven effective technique. For applications such as requency restoration if the cost of supercapacitors maintenance as well as the energy loss on the power electronics interfaces are addressed. It is infeasible to use traditional optimization control methods to mitigate the impacts of frequent cycling. This paper proposes a Front End Controller (FEC) using Generalized Predictive Control featuring real time receding optimization. The optimization constraints are based on cost and thermal management to enhance to the utilization efficiency of supercapacitors. A rigorous mathematical derivation is conducted and test results acquired from Digital Real Time Simulator are provided to demonstrate effectiveness.
Paraskevopoulou, Sivylla E; Wu, Di; Eftekhar, Amir; Constandinou, Timothy G
2014-09-30
This work presents a novel unsupervised algorithm for real-time adaptive clustering of neural spike data (spike sorting). The proposed Hierarchical Adaptive Means (HAM) clustering method combines centroid-based clustering with hierarchical cluster connectivity to classify incoming spikes using groups of clusters. It is described how the proposed method can adaptively track the incoming spike data without requiring any past history, iteration or training and autonomously determines the number of spike classes. Its performance (classification accuracy) has been tested using multiple datasets (both simulated and recorded) achieving a near-identical accuracy compared to k-means (using 10-iterations and provided with the number of spike classes). Also, its robustness in applying to different feature extraction methods has been demonstrated by achieving classification accuracies above 80% across multiple datasets. Last but crucially, its low complexity, that has been quantified through both memory and computation requirements makes this method hugely attractive for future hardware implementation. Copyright © 2014 Elsevier B.V. All rights reserved.
Must analysis of meaning follow analysis of form? A time course analysis.
Feldman, Laurie B; Milin, Petar; Cho, Kit W; Moscoso Del Prado Martín, Fermín; O'Connor, Patrick A
2015-01-01
Many models of word recognition assume that processing proceeds sequentially from analysis of form to analysis of meaning. In the context of morphological processing, this implies that morphemes are processed as units of form prior to any influence of their meanings. Some interpret the apparent absence of differences in recognition latencies to targets (SNEAK) in form and semantically similar (sneaky-SNEAK) and in form similar and semantically dissimilar (sneaker-SNEAK) prime contexts at a stimulus onset asynchrony (SOA) of 48 ms as consistent with this claim. To determine the time course over which degree of semantic similarity between morphologically structured primes and their targets influences recognition in the forward masked priming variant of the lexical decision paradigm, we compared facilitation for the same targets after semantically similar and dissimilar primes across a range of SOAs (34-100 ms). The effect of shared semantics on recognition latency increased linearly with SOA when long SOAs were intermixed (Experiments 1A and 1B) and latencies were significantly faster after semantically similar than dissimilar primes at homogeneous SOAs of 48 ms (Experiment 2) and 34 ms (Experiment 3). Results limit the scope of form-then-semantics models of recognition and demonstrate that semantics influences even the very early stages of recognition. Finally, once general performance across trials has been accounted for, we fail to provide evidence for individual differences in morphological processing that can be linked to measures of reading proficiency.
Five-hole pitot probe time-mean velocity measurements in confined swirling flows
Yoon, H. K.; Lilley, D. G.
1983-01-01
Nonswirling and swirling nonreacting flows in an axisymmetric test section with an expansion ratio D/d = 2, which may be equipped with contraction nozzles of area ratios 2 and 4, are investigated. The effects of a number of geometric parameters on the flow-field are investigated, among them side-wall expansion angles of 90 and 45 deg, swirl vane angles of 0, 38, 45, 60, and 70 deg, and contraction nozzle locations L/D = 1 and 2 (if present). Data are acquired by means of a five-hole pitot probe enabling three time-mean velocity components in the axial, radial, and azimuthal directions to be measured. The velocities are extensively plotted and artistic impressions of recirculation zones are set forth. The presence of a swirler is found to shorten the corner recirculation zone and to generate a central recirculation zone followed by a precessing vortex core. A gradual inlet expansion has the effect of encouraging the flow to remain close to the sidewall and shortening the extent of the corner recirculation zone in all cases investigated.
Must analysis of meaning follow analysis of form? A time course analysis
Directory of Open Access Journals (Sweden)
Laurie eFeldman
2015-03-01
Full Text Available Many models of word recognition assume that processing proceeds sequentially from analysis of form to analysis of meaning. In the context of morphological processing, this implies that morphemes are processed as units of form prior to any influence of their meanings. Some interpret the apparent absence of differences in recognition latencies to targets (SNEAK in form and semantically similar (sneaky-SNEAK and in form similar and semantically dissimilar (sneaker-SNEAK prime contexts at an SOA of 48 ms as consistent with this claim. To determine the time course over which degree of semantic similarity between morphologically structured primes and their targets influences recognition in the forward masked priming variant of the lexical decision paradigm, we compared facilitation for the same targets after semantically similar and dissimilar primes across a range of SOAs. The effect of shared semantics on recognition latency increased linearly with SOA when long SOAs were intermixed (Exp. 1 and latencies were significantly faster after semantically similar than dissimilar primes at homogeneous SOAs of 48 ms (Exp. 2 and 34 ms (Exp. 3. Results limit the scope of form-then-semantics models of recognition and demonstrate that semantics influences even the very early stages of recognition. Finally, once general behavior across trials has been accounted for, we fail to provide evidence for individual differences in morphological processing that can be linked to measures of reading proficiency.
Gun Launch System: efficient and low-cost means of research and real-time monitoring
Degtyarev, Alexander; Ventskovsky, Oleg; Korostelev, Oleg; Yakovenko, Peter; Kanevsky, Valery; Tselinko, Alexander
2005-08-01
The Gun Launch System with a reusable sub-orbital launch vehicle as a central element is proposed by a consortium of several Ukrainian high-tech companies as an effective, fast-response and low-cost means of research and real-time monitoring. The system is described in details, with the emphasis on its most important advantages. Multiple applications of the system are presented, including ones for the purposes of microgravity research; chemical, bacteriological and radiation monitoring and research of atmosphere and ionosphere; operational monitoring of natural and man-made disasters, as well as for some other areas of great practical interest. The current level of the system development is given, and the way ahead towards full system's implementation is prescribed.
Time-dependent mean-field games in the superquadratic case
Gomes, Diogo A.
2016-04-06
We investigate time-dependent mean-field games with superquadratic Hamiltonians and a power dependence on the measure. Such problems pose substantial mathematical challenges as key techniques used in the subquadratic case, which was studied in a previous publication of the authors, do not extend to the superquadratic setting. The main objective of the present paper is to address these difficulties. Because of the superquadratic structure of the Hamiltonian, Lipschitz estimates for the solutions of the Hamilton−Jacobi equation are obtained here through a novel set of techniques. These explore the parabolic nature of the problem through the nonlinear adjoint method. Well-posedness is proven by combining Lipschitz regularity for the Hamilton−Jacobi equation with polynomial estimates for solutions of the Fokker−Planck equation. Existence of classical solutions is then established under conditions depending only on the growth of the Hamiltonian and the dimension. Our results also add to current understanding of superquadratic Hamilton−Jacobi equations.
Mean first-passage time of an asymmetric bistable system driven by colour-correlated noise
Institute of Scientific and Technical Information of China (English)
Zhang Xiao-Yan; Xu Wei
2007-01-01
In this paper, the effect of every parameter (including p, q,r, λ,τ) on the mean first-passage time (MFPT) is investigated in an asymmetric bistable system driven by colour-correlated noise. The expression of MFPT has been obtained by applying the steepest-descent approximation. Numerical results show that (1) the intensity of multiplicative noise p and the intensity of additive noise q play different roles in the MFPT of the system, (2) suppression appears on the curve of the MFPT with small λ (e.g. λ＜ 0.5) but there is a peak on the curve of the MFPT when λ is big (e.g.λ＞ 0.5), and (3) with different values of r (e.g. r = 0.1, 0.5, 1.5), the effort of τ on the MFPT is diverse.
Time-dependent mean-field games in the superquadratic case
Gomes, Diogo A.; Pimentel, Edgard; Sá nchez-Morgado, Hé ctor
2016-01-01
We investigate time-dependent mean-field games with superquadratic Hamiltonians and a power dependence on the measure. Such problems pose substantial mathematical challenges as key techniques used in the subquadratic case, which was studied in a previous publication of the authors, do not extend to the superquadratic setting. The main objective of the present paper is to address these difficulties. Because of the superquadratic structure of the Hamiltonian, Lipschitz estimates for the solutions of the Hamilton−Jacobi equation are obtained here through a novel set of techniques. These explore the parabolic nature of the problem through the nonlinear adjoint method. Well-posedness is proven by combining Lipschitz regularity for the Hamilton−Jacobi equation with polynomial estimates for solutions of the Fokker−Planck equation. Existence of classical solutions is then established under conditions depending only on the growth of the Hamiltonian and the dimension. Our results also add to current understanding of superquadratic Hamilton−Jacobi equations.
Directory of Open Access Journals (Sweden)
L.V. Artemova
2014-04-01
Full Text Available Development of the students’ competences which consist of the three main groups (general, instrumental, interpersonal provides education of high quality. The instrumental one means “computer skills and information management abilities”. That is the reason why pedagogical staff and students have to master information technologies on the appropriate level. Structural and methodological peculiarities of e-presentations usage on “Early Childhood Education Development in the Times of UNR” topic at lectures, seminars and students’ individual work are considered in the article. The represented methodology of e-presentations usage supplies interactive educational activities of students and teachers. It is considered as a complex of different tasks. It promotes cognitive activities, encourages interest for mastering the content, directs students to use active methods of teaching.
A network of spiking neurons that can represent interval timing: mean field analysis.
Gavornik, Jeffrey P; Shouval, Harel Z
2011-04-01
Despite the vital importance of our ability to accurately process and encode temporal information, the underlying neural mechanisms are largely unknown. We have previously described a theoretical framework that explains how temporal representations, similar to those reported in the visual cortex, can form in locally recurrent cortical networks as a function of reward modulated synaptic plasticity. This framework allows networks of both linear and spiking neurons to learn the temporal interval between a stimulus and paired reward signal presented during training. Here we use a mean field approach to analyze the dynamics of non-linear stochastic spiking neurons in a network trained to encode specific time intervals. This analysis explains how recurrent excitatory feedback allows a network structure to encode temporal representations.
Real-time inspection of metal laminates by means of CNNs
Preciado, Victor M.; Guinea, Domingo; Montufar-Chaveznava, Rodrigo; Vicente, Jose
2001-04-01
Analog CNN array computer arises as an alternative to traditional digital processors in many industrial inspection like visual quality control of metal laminants, capable of make in a single chip Tera equivalent operations per second. A 4096 analog CNN processor array is able to perform complex space-time image analysis, being much faster than a camera- computer system in continuous inspection applications. Both chips have been implemented in CMOS technology and they are managed by a 32-bit high-performance low-cost micro- controller that closes the pan, tilt, lighting, focus and zoom loops required in the implementation of the active vision strategies. Several convolution masks for the Cellular Processors has been selected to detect particular changes in the texture, size, direction or orientation of the image entities, reprogramming `on the fly' the pixel resolution of shape when necessary. Laboratory results present these Cellular Processors and multiple resolution imager circuits as a promising architecture for visual inspection of industrial processes in real time.
The time-dependent relativistic mean-field theory and the random phase approximation
International Nuclear Information System (INIS)
Ring, P.; Ma, Zhong-yu; Van Giai, Nguyen; Vretenar, D.; Wandelt, A.; Cao, Li-gang
2001-01-01
The Relativistic Random Phase Approximation (RRPA) is derived from the Time-Dependent Relativistic Mean-Field (TD RMF) theory in the limit of small amplitude oscillations. In the no-sea approximation of the RMF theory, the RRPA configuration space includes not only the usual particle-hole ph-states, but also αh-configurations, i.e. pairs formed from occupied states in the Fermi sea and empty negative-energy states in the Dirac sea. The contribution of the negative-energy states to the RRPA matrices is examined in a schematic model, and the large effect of Dirac-sea states on isoscalar strength distributions is illustrated for the giant monopole resonance in 116 Sn. It is shown that, because the matrix elements of the time-like component of the vector-meson fields which couple the αh-configurations with the ph-configurations are strongly reduced with respect to the corresponding matrix elements of the isoscalar scalar meson field, the inclusion of states with unperturbed energies more than 1.2 GeV below the Fermi energy has a pronounced effect on giant resonances with excitation energies in the MeV region. The influence of nuclear magnetism, i.e. the effect of the spatial components of the vector fields is examined, and the difference between the nonrelativistic and relativistic RPA predictions for the nuclear matter compression modulus is explained
Microseismic imaging using Geometric-mean Reverse-Time Migration in Hydraulic Fracturing Monitoring
Yin, J.; Ng, R.; Nakata, N.
2017-12-01
Unconventional oil and gas exploration techniques such as hydraulic fracturing are associated with microseismic events related to the generation and development of fractures. For example, hydraulic fracturing, which is popular in Southern Oklahoma, produces earthquakes that are greater than magnitude 2.0. Finding the accurate locations, and mechanisms, of these events provides important information of local stress conditions, fracture distribution, hazard assessment, and economical impact. The accurate source location is also important to separate fracking-induced and wastewater disposal induced seismicity. Here, we implement a wavefield-based imaging method called Geometric-mean Reverse-Time Migration (GmRTM), which takes the advantage of accurate microseismic location based on wavefield back projection. We apply GmRTM to microseismic data collected during hydraulic fracturing for imaging microseismic source locations, and potentially, fractures. Assuming an accurate velocity model, GmRTM can improve the spatial resolution of source locations compared to HypoDD or P/S travel-time based methods. We will discuss the results from GmRTM and HypoDD using this field dataset and synthetic data.
Means and method for controlling the neutron output of a neutron generator tube
International Nuclear Information System (INIS)
1980-01-01
A specification is given for an energizing and regulating circuit for a gas filled neutron generator tube consisting of a target, an ion source and a replenisher, the circuit consisting of a power supply to provide a negative high voltage to the target and a target current corresponding to the neutron output of the tube, a constant current source, and control means connected to the power supply and to the constant current source, the control means being responsive to the target current to provide a portion of the constant current to the replenisher substantially to regulate the neutron output of the tube. (author)
Mean first-passage times in confined media: from Markovian to non-Markovian processes
International Nuclear Information System (INIS)
Bénichou, O; Voituriez, R; Guérin, T
2015-01-01
We review recent theoretical works that enable the accurate evaluation of the mean first passage time (MFPT) of a random walker to a target in confinement for Markovian (memory-less) and non-Markovian walkers. For the Markovian problem, we present a general theory which allows one to accurately evaluate the MFPT and its extensions to related first-passage observables such as splitting probabilities and occupation times. We show that this analytical approach provides a universal scaling dependence of the MFPT on both the volume of the confining domain and the source–target distance in the case of general scale-invariant processes. This analysis is applicable to a broad range of stochastic processes characterized by length scale-invariant properties, and reveals the key role that can be played by the starting position of the random walker. We then present an extension to non-Markovian walks by taking the specific example of a tagged monomer of a polymer chain looking for a target in confinement. We show that the MFPT can be calculated accurately by computing the distribution of the positions of all the monomers in the chain at the instant of reaction. Such a theory can be used to derive asymptotic relations that generalize the scaling dependence with the volume and the initial distance to the target derived for Markovian walks. Finally, we present an application of this theory to the problem of the first contact time between the two ends of a polymer chain, and review the various theoretical approaches of this non- Markovian problem. (topical review)
An on-line modified least-mean-square algorithm for training neurofuzzy controllers.
Tan, Woei Wan
2007-04-01
The problem hindering the use of data-driven modelling methods for training controllers on-line is the lack of control over the amount by which the plant is excited. As the operating schedule determines the information available on-line, the knowledge of the process may degrade if the setpoint remains constant for an extended period. This paper proposes an identification algorithm that alleviates "learning interference" by incorporating fuzzy theory into the normalized least-mean-square update rule. The ability of the proposed methodology to achieve faster learning is examined by employing the algorithm to train a neurofuzzy feedforward controller for controlling a liquid level process. Since the proposed identification strategy has similarities with the normalized least-mean-square update rule and the recursive least-square estimator, the on-line learning rates of these algorithms are also compared.
Autotuning of PID controller by means of human machine interface device
Directory of Open Access Journals (Sweden)
Michał Awtoniuk
2017-06-01
Full Text Available More and more control systems are based on industry microprocessors like PLC controllers (Programmable Logic Controller. The most commonly used control algorithm is PID (Proportional-Integral-Derivative algorithm. Autotuning procedure is not available in every PLC. These controllers are typically used in cooperation with HMI (Human Machine Interface devices. In the study two procedures of autotuning of the PID controller were implemented in the HMI device: step method and relay method. Six tuning rules for step methods and one for relay method were chosen. The autotuning procedures on simulated controlled object and PLC controller without build-in autotuning were tested. The object of control was first order system plus time delay.
Multi-bottle, no compressor, mean pressure control system for a Stirling engine
Corey, John A.
1990-01-01
The invention relates to an apparatus for mean pressure control of a Stirling engine without the need for a compressor. The invention includes a multi-tank system in which there is at least one high pressure level tank and one low pressure level tank wherein gas flows through a maximum pressure and supply line from the engine to the high pressure tank when a first valve is opened until the maximum pressure of the engine drops below that of the high pressure tank opening an inlet regulator to permit gas flow from the engine to the low pressure tank. When gas flows toward the engine it flows through the minimum pressure supply line 2 when a second valve is opened from the low pressure tank until the tank reaches the engine's minimum pressure level at which time the outlet regulator opens permitting gas to be supplied from the high pressure tank to the engine. Check valves between the two tanks prevent any backflow of gas from occurring.
Active flow control on a NACA 23012 airfoil model by means of magnetohydrodynamic plasma actuator
International Nuclear Information System (INIS)
Kazanskiy, P N; Moralev, I A; Bityurin, V A; Efimov, A V
2016-01-01
The paper is devoted to the study of high speed flow control around the airfoil by means of the Lorentz force. The latter is formed by creating the pulsed arc filament, moving in the magnetic field along the upper airfoil surface. The research was performed for the NACA23012 airfoil model at flow velocities up to 60 m/s (134 mph). The dynamic measurement of the aerodynamic forces on the airfoil was made. Changes up to 5% in an average value of lift and pitching moment were obtained at pulse repetition frequency up to 13 Hz and average discharge power less than 200 W. The amplitude of lift force oscillation was obtained as high as 10%, with the integration time of the balance 30 ms. The dynamic flow visualization of an airfoil model after a single discharge ignition was performed. It is shown that interaction of the main flow with the arc-induced disturbance leads to the dramatic changes in the flow structure. It was shown that the upstream movement of the arc channel (I = 40-700 A) leads to the local flow separation and simultaneously to the formation of a high pressure region above the model surface. Current paper presents investigation of previous work. (paper)
Availability Control for Means of Transport in Decisive Semi-Markov Models of Exploitation Process
Migawa, Klaudiusz
2012-12-01
The issues presented in this research paper refer to problems connected with the control process for exploitation implemented in the complex systems of exploitation for technical objects. The article presents the description of the method concerning the control availability for technical objects (means of transport) on the basis of the mathematical model of the exploitation process with the implementation of the decisive processes by semi-Markov. The presented method means focused on the preparing the decisive for the exploitation process for technical objects (semi-Markov model) and after that specifying the best control strategy (optimal strategy) from among possible decisive variants in accordance with the approved criterion (criteria) of the activity evaluation of the system of exploitation for technical objects. In the presented method specifying the optimal strategy for control availability in the technical objects means a choice of a sequence of control decisions made in individual states of modelled exploitation process for which the function being a criterion of evaluation reaches the extreme value. In order to choose the optimal control strategy the implementation of the genetic algorithm was chosen. The opinions were presented on the example of the exploitation process of the means of transport implemented in the real system of the bus municipal transport. The model of the exploitation process for the means of transports was prepared on the basis of the results implemented in the real transport system. The mathematical model of the exploitation process was built taking into consideration the fact that the model of the process constitutes the homogenous semi-Markov process.
Optimization of control parameters of a hot cold controller by means of Simplex type methods
Porte, C.; Caron-Poussin, M.; Carot, S.; Couriol, C.; Moreno, M. Martin; Delacroix, A.
1997-01-01
This paper describes a hot/cold controller for regulating crystallization operations. The system was identified with a common method (the Broida method) and the parameters were obtained by the Ziegler-Nichols method. The paper shows that this empirical method will only allow a qualitative approach to regulation and that, in some instances, the parameters obtained are unreliable and therefore cannot be used to cancel variations between the set point and the actual values. Optimization methods were used to determine the regulation parameters and solve this identcation problem. It was found that the weighted centroid method was the best one. PMID:18924791
BIOLOGICAL CONTROL - AS A MEANS TO CONTROL INSECT PESTS IN AZERBAIJAN
Directory of Open Access Journals (Sweden)
Z. M. Mamedov
2013-01-01
Full Text Available Two hundreds and twenty species parasites and predators of pests of various agricultures are revealed in Azerbaijan. The complex of entomophages of certain pests of agricultures is studied: 48 species of parasites and predators of Chloridea obsoleta 21 species of entomophages of Pectinophora malvella Hb., over 160 species of entomophages of pests of ozehards and vegetables, 34 species of entomophages of pests of forests. The hundreds species of entomophages and some entomophogenous microbes and antagonists are revealed. Biology and ecology of over 60 species of entomophages and useful microorganisims which are prospective as biological control agents are studied.
Non-destructive methods and means for quality control of structural products
International Nuclear Information System (INIS)
Dmitriev, V.V.
1989-01-01
Progressive non-destructive methods (acoustic, magnetic, radiation with liquid penetrants) and means of control of structural product quality, allowing to determine the state of products and structures not only immediately after their production but directly at the erected or reconstructed objects are described
Lee, Jun-Yi; Huang, -Chuan, Jr.
2017-04-01
Mean transit time (MTT) is one of the of fundamental catchment descriptors to advance understanding on hydrological, ecological, and biogeochemical processes and improve water resources management. However, there were few documented the base flow partitioning (BFP) and mean transit time within a mountainous catchment in typhoon alley. We used a unique data set of 18O isotope and conductivity composition of rainfall (136 mm to 778 mm) and streamflow water samples collected for 14 tropical cyclone events (during 2011 to 2015) in a steep relief forested catchment (Pinglin, in northern Taiwan). A lumped hydrological model, HBV, considering dispersion model transit time distribution was used to estimate total flow, base flow, and MTT of stream base flow. Linear regression between MTT and hydrometric (precipitation intensity and antecedent precipitation index) variables were used to explore controls on MTT variation. Results revealed that both the simulation performance of total flow and base flow were satisfactory, and the Nash-Sutcliffe model efficiency coefficient of total flow and base flow was 0.848 and 0.732, respectively. The event magnitude increased with the decrease of estimated MTTs. Meanwhile, the estimated MTTs varied 4-21 days with the increase of BFP between 63-92%. The negative correlation between event magnitude and MTT and BFP showed the forcing controls the MTT and BFP. Besides, a negative relationship between MTT and the antecedent precipitation index was also found. In other words, wetter antecedent moisture content more rapidly active the fast flow paths. This approach is well suited for constraining process-based modeling in a range of high precipitation intensity and steep relief forested environments.
Mean First Passage Time of Preferential Random Walks on Complex Networks with Applications
Directory of Open Access Journals (Sweden)
Zhongtuan Zheng
2017-01-01
Full Text Available This paper investigates, both theoretically and numerically, preferential random walks (PRW on weighted complex networks. By using two different analytical methods, two exact expressions are derived for the mean first passage time (MFPT between two nodes. On one hand, the MFPT is got explicitly in terms of the eigenvalues and eigenvectors of a matrix associated with the transition matrix of PRW. On the other hand, the center-product-degree (CPD is introduced as one measure of node strength and it plays a main role in determining the scaling of the MFPT for the PRW. Comparative studies are also performed on PRW and simple random walks (SRW. Numerical simulations of random walks on paradigmatic network models confirm analytical predictions and deepen discussions in different aspects. The work may provide a comprehensive approach for exploring random walks on complex networks, especially biased random walks, which may also help to better understand and tackle some practical problems such as search and routing on networks.
Bhattacharya, Tinish; Gupta, Ankesh; Singh, Salam ThoiThoi; Roy, Sitikantha; Prasad, Anamika
2017-07-01
Cuff-less and non-invasive methods of Blood Pressure (BP) monitoring have faced a lot of challenges like stability, noise, motion artefact and requirement for calibration. These factors are the major reasons why such devices do not get approval from the medical community easily. One such method is calculating Blood Pressure indirectly from pulse transit time (PTT) obtained from electrocardiogram (ECG) and Photoplethysmogram (PPG). In this paper we have proposed two novel analog signal conditioning circuits for ECG and PPG that increase stability, remove motion artefacts, remove the sinusoidal wavering of the ECG baseline due to respiration and provide consistent digital pulses corresponding to blood pulses/heart-beat. We have combined these two systems to obtain the PTT and then correlated it with the Mean Arterial Pressure (MAP). The aim was to perform major part of the processing in analog domain to decrease processing load over microcontroller so as to reduce cost and make it simple and robust. We have found from our experiments that the proposed circuits can calculate the Heart Rate (HR) with a maximum error of ~3.0% and MAP with a maximum error of ~2.4% at rest and ~4.6% in motion.
Time and spatial concentration profile inside a membrane by means of a memory formalism
Caputo, Michele; Cametti, Cesare; Ruggero, Vittorio
2008-03-01
In this note, the profile concentration of diffusing particles inside a membrane has been calculated on the basis of the Fick diffusion equation modified by introducing a memory formalism. In highly heterogeneous systems, such as biological membranes, the intrinsic structural complexity of the medium restricts the applicability of continuum diffusion models and suggests that diffusion parameters could depend at a certain time or position on what happens at preceding times (diffusion with memory). Here, we deal with two particular cases, the diffusion of glucose across an erythrocyte membrane, when the concentration at both sides of the membrane are assigned, and the permeation transport of small molecular weight solute through an artificial hydrogel polymeric membrane. However, the present procedure can be easily extended to more general conditions. The knowledge of the concentration profile within a membranous structure, which is usually not easily experimentally accessible, completes the description of the rather complex phenomenon of the transport across a highly structured confined medium and can also lead to an improvement in controlled drug-delivery systems.
International Nuclear Information System (INIS)
Sinitsyn, V.E.; Sergienko, V.B.; Ostroumov, E.N.; Mareev, V.Yu.
1991-01-01
Diagnostic value of mean pulmonary 99m Tc-pertechnetate passage time was studied in 27 patients with different types of hypertension disturbances. It was shown that the parameters of mean indicator passage time can be used for noninvasive determination of diastolic pressure in pulmonary artery
Real time control engineering systems and automation
Ng, Tian Seng
2016-01-01
This book covers the two broad areas of the electronics and electrical aspects of control applications, highlighting the many different types of control systems of relevance to real-life control system design. The control techniques presented are state-of-the-art. In the electronics section, readers will find essential information on microprocessor, microcontroller, mechatronics and electronics control. The low-level assembly programming language performs basic input/output control techniques as well as controlling the stepper motor and PWM dc motor. In the electrical section, the book addresses the complete elevator PLC system design, neural network plant control, load flow analysis, and process control, as well as machine vision topics. Illustrative diagrams, circuits and programming examples and algorithms help to explain the details of the system function design. Readers will find a wealth of computer control and industrial automation practices and applications for modern industries, as well as the educat...
Luo, Yi; Zhang, Tao; Li, Xiao-song
2016-05-01
To explore the application of fuzzy time series model based on fuzzy c-means clustering in forecasting monthly incidence of Hepatitis E in mainland China. Apredictive model (fuzzy time series method based on fuzzy c-means clustering) was developed using Hepatitis E incidence data in mainland China between January 2004 and July 2014. The incidence datafrom August 2014 to November 2014 were used to test the fitness of the predictive model. The forecasting results were compared with those resulted from traditional fuzzy time series models. The fuzzy time series model based on fuzzy c-means clustering had 0.001 1 mean squared error (MSE) of fitting and 6.977 5 x 10⁻⁴ MSE of forecasting, compared with 0.0017 and 0.0014 from the traditional forecasting model. The results indicate that the fuzzy time series model based on fuzzy c-means clustering has a better performance in forecasting incidence of Hepatitis E.
On Discrete Time Control of Continuous Time Systems
DEFF Research Database (Denmark)
Poulsen, Niels Kjølstad
This report is meant as a supplement or an extension to the material used in connection to or after the courses Stochastic Adaptive Control (02421) and Static and Dynamic Optimization (02711) given at the department Department of Informatics and Mathematical Modelling, The Technical University...
Risk-sensitivity and the mean-variance trade-off: decision making in sensorimotor control.
Nagengast, Arne J; Braun, Daniel A; Wolpert, Daniel M
2011-08-07
Numerous psychophysical studies suggest that the sensorimotor system chooses actions that optimize the average cost associated with a movement. Recently, however, violations of this hypothesis have been reported in line with economic theories of decision-making that not only consider the mean payoff, but are also sensitive to risk, that is the variability of the payoff. Here, we examine the hypothesis that risk-sensitivity in sensorimotor control arises as a mean-variance trade-off in movement costs. We designed a motor task in which participants could choose between a sure motor action that resulted in a fixed amount of effort and a risky motor action that resulted in a variable amount of effort that could be either lower or higher than the fixed effort. By changing the mean effort of the risky action while experimentally fixing its variance, we determined indifference points at which participants chose equiprobably between the sure, fixed amount of effort option and the risky, variable effort option. Depending on whether participants accepted a variable effort with a mean that was higher, lower or equal to the fixed effort, they could be classified as risk-seeking, risk-averse or risk-neutral. Most subjects were risk-sensitive in our task consistent with a mean-variance trade-off in effort, thereby, underlining the importance of risk-sensitivity in computational models of sensorimotor control.
Symbolic approximate time-optimal control
Mazo, Manuel; Tabuada, Paulo
There is an increasing demand for controller design techniques capable of addressing the complex requirements of today's embedded applications. This demand has sparked the interest in symbolic control where lower complexity models of control systems are used to cater for complex specifications given
Directory of Open Access Journals (Sweden)
Yu Chang
2015-09-01
Full Text Available Fire frequency and size are two important parameters describing fire characteristics. Exploring the spatial variation of fire characteristics and understanding the environmental controls are indispensable to fire prediction and sustainable forest landscape management. To illustrate the spatial variation of forest fire characteristics over China and to quantitatively determine the relative contribution of each of the environmental controls to this variation, forest fire characteristic data (mean number of forest fires and mean burned forest area and environmental data (climate, land use, vegetation type and topography at provincial level were derived. These data sets can potentially serve as a foundation for future studies relating to fire risk assessment, carbon emission by forest fires, and the impact of climate change on fire characteristics. This data article contains data related to the research article entitled “Environmental controls on the characteristics of mean number of forest fires and mean forest area burned (1987–2007 in China” by chang et al. [1].
Discrete Time McKean–Vlasov Control Problem: A Dynamic Programming Approach
Energy Technology Data Exchange (ETDEWEB)
Pham, Huyên, E-mail: pham@math.univ-paris-diderot.fr; Wei, Xiaoli, E-mail: tyswxl@gmail.com [Laboratoire de Probabilités et Modèles Aléatoires, CNRS, UMR 7599, Université Paris Diderot (France)
2016-12-15
We consider the stochastic optimal control problem of nonlinear mean-field systems in discrete time. We reformulate the problem into a deterministic control problem with marginal distribution as controlled state variable, and prove that dynamic programming principle holds in its general form. We apply our method for solving explicitly the mean-variance portfolio selection and the multivariate linear-quadratic McKean–Vlasov control problem.
Discrete Time McKean–Vlasov Control Problem: A Dynamic Programming Approach
International Nuclear Information System (INIS)
Pham, Huyên; Wei, Xiaoli
2016-01-01
We consider the stochastic optimal control problem of nonlinear mean-field systems in discrete time. We reformulate the problem into a deterministic control problem with marginal distribution as controlled state variable, and prove that dynamic programming principle holds in its general form. We apply our method for solving explicitly the mean-variance portfolio selection and the multivariate linear-quadratic McKean–Vlasov control problem.
Control of beam size and polarization time in PEP
International Nuclear Information System (INIS)
Paterson, J.M.; Rees, J.R.; Wiedemann, H.
1975-07-01
In this report we describe a method of controlling beam size in which the focusing functions are not altered with beam energy but the curvature function is drastically altered in a few locations which comprise only a very small fraction of the circumference. As will be described in the following paper we are proposing to control the quantum excitation and radiation damping of the particles by means of special excitation magnets or /open quotes/wigglers/close quotes/. Since the mean square energy deviation and radial beam emittance are proportional approximately to E/sup 2//l angle/G/sup 3//r angle//l angle/G/sup 2//r angle//sup /minus/1 while the damping times are proportional to (E/sup 3//l angle/G/sup 2//r angle/)/sup /minus/1/, it is possible to achieve constant beam size in a constant focusing configuration while the damping times vary roughly as E/sup /minus/2/. In addition, it is possible to reduce the beam polarization time with these devices. A scheme for beam-size and damping control based on the same principle was described by M. Bassetti about a year ago, in which all of the storage-ring bending magnets were involved as wigglers, and a substantial increase in magnet cost resulted. The consequences for polarization times were not explored. The design formulae are derived and two specific applications to the PEP design in which the wigglers are installed in three of the six 5-m straight sections are described with attention given to practical magnet design, synchrotron radiation handling and other matters. 5 refs., 4 figs., 1 tab
DEFF Research Database (Denmark)
Dyre, Jeppe; Jacobsen, Jacob M.
1995-01-01
This paper presents a calculation of the time dependence of the mean-square displacement for symmetric random energy barrier hopping models at low temperatures, where the frequency dependence of the normalized diffusion constant D-tilde becomes universal, i.e., independent of the energy barrier...... probability distribution [J. C. Dyre, Phys. Rev. B 49, 11 709 (1994)]. The universal time dependence of the mean-square displacement is calculated from the effective medium approximation (EMA) universality equation, D-tilde lnD-tilde=s-tilde, where s-tilde is the dimensionless imaginary frequency, as well...... as for the approximation to the EMA universality equation D-tilde~=s-tilde/ln(1+s-tilde). At long times the universal mean-square displacement is linear in time, corresponding to ordinary diffusion, whereas the mean-square displacement at short times t in dimensionless units varies as 2/ln(t-1)....
Performance Improvement of tilting-pad journal bearings by means of controllable lubrication
DEFF Research Database (Denmark)
Cerda, Alejandro; Santos, Ilmar
2012-01-01
Tilting-Pad Journal Bearings (TPJB) are commonly used on high-performance turbomachinery due to their excellent stability properties at high speed when compared to other designs for oil film bearings. Hence, efforts have been made to improve the accuracy for the available models for these mechani...... is used to show the benefits of applying a controllable lubrication regime, by means of the modification of the thermal and dynamic behaviour of the bearing....
Robust control of time-delay chaotic systems
International Nuclear Information System (INIS)
Hua Changchun; Guan Xinping
2003-01-01
Robust control problem of nonlinear time-delay chaotic systems is investigated. For such uncertain systems, we propose adaptive feedback controller and novel nonlinear feedback controller. They are both independent of the time delay and can render the corresponding closed-loop systems globally uniformly ultimately bounded stable. The simulations on controlling logistic system are made and the results show the controllers are feasible
Chiu, Mei Choi; Pun, Chi Seng; Wong, Hoi Ying
2017-08-01
Investors interested in the global financial market must analyze financial securities internationally. Making an optimal global investment decision involves processing a huge amount of data for a high-dimensional portfolio. This article investigates the big data challenges of two mean-variance optimal portfolios: continuous-time precommitment and constant-rebalancing strategies. We show that both optimized portfolios implemented with the traditional sample estimates converge to the worst performing portfolio when the portfolio size becomes large. The crux of the problem is the estimation error accumulated from the huge dimension of stock data. We then propose a linear programming optimal (LPO) portfolio framework, which applies a constrained ℓ 1 minimization to the theoretical optimal control to mitigate the risk associated with the dimensionality issue. The resulting portfolio becomes a sparse portfolio that selects stocks with a data-driven procedure and hence offers a stable mean-variance portfolio in practice. When the number of observations becomes large, the LPO portfolio converges to the oracle optimal portfolio, which is free of estimation error, even though the number of stocks grows faster than the number of observations. Our numerical and empirical studies demonstrate the superiority of the proposed approach. © 2017 Society for Risk Analysis.
Modern linear control design a time-domain approach
Caravani, Paolo
2013-01-01
This book offers a compact introduction to modern linear control design. The simplified overview presented of linear time-domain methodology paves the road for the study of more advanced non-linear techniques. Only rudimentary knowledge of linear systems theory is assumed - no use of Laplace transforms or frequency design tools is required. Emphasis is placed on assumptions and logical implications, rather than abstract completeness; on interpretation and physical meaning, rather than theoretical formalism; on results and solutions, rather than derivation or solvability. The topics covered include transient performance and stabilization via state or output feedback; disturbance attenuation and robust control; regional eigenvalue assignment and constraints on input or output variables; asymptotic regulation and disturbance rejection. Lyapunov theory and Linear Matrix Inequalities (LMI) are discussed as key design methods. All methods are demonstrated with MATLAB to promote practical use and comprehension. ...
Soeryana, E.; Fadhlina, N.; Sukono; Rusyaman, E.; Supian, S.
2017-01-01
Investments in stocks investors are also faced with the issue of risk, due to daily price of stock also fluctuate. For minimize the level of risk, investors usually forming an investment portfolio. Establishment of a portfolio consisting of several stocks are intended to get the optimal composition of the investment portfolio. This paper discussed about optimizing investment portfolio of Mean-Variance to stocks by using mean and volatility is not constant based on logarithmic utility function. Non constant mean analysed using models Autoregressive Moving Average (ARMA), while non constant volatility models are analysed using the Generalized Autoregressive Conditional heteroscedastic (GARCH). Optimization process is performed by using the Lagrangian multiplier technique. As a numerical illustration, the method is used to analyse some Islamic stocks in Indonesia. The expected result is to get the proportion of investment in each Islamic stock analysed.
Mean time for the development of large workloads and large queue lengths in the GI/G/1 queue
Directory of Open Access Journals (Sweden)
Charles Knessl
1996-01-01
Full Text Available We consider the GI/G/1 queue described by either the workload U(t (unfinished work or the number of customers N(t in the system. We compute the mean time until U(t reaches excess of the level K, and also the mean time until N(t reaches N0. For the M/G/1 and GI/M/1 models, we obtain exact contour integral representations for these mean first passage times. We then compute the mean times asymptotically, as K and N0→∞, by evaluating these contour integrals. For the general GI/G/1 model, we obtain asymptotic results by a singular perturbation analysis of the appropriate backward Kolmogorov equation(s. Numerical comparisons show that the asymptotic formulas are very accurate even for moderate values of K and N0.
Identification and disruption of bacteria associated with sheep scab mites-novel means of control?
Hall, S A; Mack, K; Blackwell, A; Evans, K A
2015-10-01
Psoroptes ovis mites, which cause psoroptic mange (sheep scab), were investigated to identify potential bacterial targets for endosymbiont control of sheep scab. In addition, transmission of bacteria to the sheep skin was investigated through the characterisation of bacteria present in P. ovis faecal trails and on the fleece environment by internal transcribed spacer (ITS) sequencing. A diverse range of bacteria was identified in addition to a potential endosymbiont candidate, Comamonas sp, which was detected in P. ovis by both ITS PCR and endosymbiont-specific PCR. Disruption of these bacteria within P. ovis, through the use of antibiotics, was explored; with significant reduction in mean mite survival when administered antibiotic diets compared with controls (LR4 = 23.12, P bacteria associated with P. ovis should be further investigated for novel control. Copyright © 2015 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Francesco Ferri
2014-04-01
Full Text Available In order to reduce the cost of electricity produced by wave energy converters (WECs, the benefit of selling electricity as well as the investment costs of the structure has to be considered. This paper presents a methodology for assessing the control strategy for a WEC with respect to both energy output and structural fatigue loads. Different active and passive control strategies are implemented (proportional (P controller, proportional-integral (PI controller, proportional-integral-derivative with memory compensation (PID controller, model predictive control (MPC and maximum energy controller (MEC, and load time-series resulting from numerical simulations are used to design structural parts based on fatigue analysis using rain-flow counting, Stress-Number (SN curves and Miner’s rule. The objective of the methodology is to obtain a cost-effective WEC with a more comprehensive analysis of a WEC based on a combination of well known control strategies and standardised fatigue methods. The presented method is then applied to a particular case study, the Wavestar WEC, for a specific location in the North Sea. Results, which are based on numerical simulations, show the importance of balancing the gained power against structural fatigue. Based on a simple cost model, the PI controller is shown as a viable solution.
Motor control by precisely timed spike patterns
DEFF Research Database (Denmark)
Srivastava, Kyle H; Holmes, Caroline M; Vellema, Michiel
2017-01-01
whether the information in spike timing actually plays a role in brain function. By examining the activity of individual motor units (the muscle fibers innervated by a single motor neuron) and manipulating patterns of activation of these neurons, we provide both correlative and causal evidence......A fundamental problem in neuroscience is understanding how sequences of action potentials ("spikes") encode information about sensory signals and motor outputs. Although traditional theories assume that this information is conveyed by the total number of spikes fired within a specified time...... interval (spike rate), recent studies have shown that additional information is carried by the millisecond-scale timing patterns of action potentials (spike timing). However, it is unknown whether or how subtle differences in spike timing drive differences in perception or behavior, leaving it unclear...
Generator coordinate representation of the time independent mean field theory of collisions
International Nuclear Information System (INIS)
Giraud, B.G.; Lemm, J.; Weiguny, A.; Wierling, A.
1991-01-01
We show how matrix elements of the T-matrix can be easily estimated on a basis of Slater determinants, with a mean field approximation. Linear superpositions of these Slater determinants then generate plane waves, or distorted (Coulomb) waves. This provides physical matrix elements of T
Entering medical practice for the very first time : emotional talk, meaning and identity development
Helmich, Esther; Bolhuis, Sanneke; Dornan, Tim; Laan, Roland; Koopmans, Raymond
2012-01-01
Medical Education 2012: 46: 10741087 CONTEXT During early clinical exposure, medical students have many emotive experiences. Through participation in social practice, they learn to give personal meaning to their emotional states. This meaningful social act of participation may lead to a sense of
Entering medical practice for the very first time: emotional talk, meaning and identity development
Helmich, E.; Bolhuis, S.; Dornan, T.; Laan, R.F.; Koopmans, R.T.
2012-01-01
Medical Education 2012: 46: 1074-1087 CONTEXT During early clinical exposure, medical students have many emotive experiences. Through participation in social practice, they learn to give personal meaning to their emotional states. This meaningful social act of participation may lead to a sense of
The Time Has Come to Create Meaning-Making Centers on College Campuses
Nash, Robert J.; Jang, Jennifer J. J.
2013-01-01
Robert J. Nash and Jennifer J. J. Jang argue that students have a great need to find a "meaning to live for," à la Victor Frankl, and make a case for creating a space for students and educators to contextualize learning experiences dealing with the universal, existential questions of life.
Energy Technology Data Exchange (ETDEWEB)
Odrich, T.; Koenig, H. [Jaeggi/Guentner (Schweiz) AG, Trimbach (Switzerland)
2007-07-01
Due to its functional principle and design, the hybrid dry cooler holds a high potential for saving water and energy. Purely convective heat discharge during dry operation in the case of a high annual rate of utilisation, evaporative cooling during the wetting cycle at peak load times or high ambient temperatures and infinitely adjustable fan speed in both operating modes permit a very substantial recooling performance at low operating costs and with little space requirement. However, the efficiency of hybrid dry coolers depends to a large degree on how intelligently the cooling functions are controlled and on the control strategy. The present article demonstrates that the control strategy contributes decisively to minimising water and energy consumption and costs. Besides describing the actual functions of a hybrid cooler control system it presents a control strategy for automatic lowering of the setpoint and hence optimisation of the refrigeration process. It discusses the option of operating multiple hybrid coolers by means of a hydraulic network and presents an optimised control concept for this purpose which is based on a master control unit. In conclusion the study shows that hybrid coolers need their own optimised control unit if maximum savings in energy and water are to be achieved.
Entering medical practice for the very first time: emotional talk, meaning and identity development.
Helmich, Esther; Bolhuis, Sanneke; Dornan, Tim; Laan, Roland; Koopmans, Raymond
2012-11-01
During early clinical exposure, medical students have many emotive experiences. Through participation in social practice, they learn to give personal meaning to their emotional states. This meaningful social act of participation may lead to a sense of belonging and identity construction. The aim of this study was to broaden and deepen our understanding of the interplay between those experiences and students' identity development. Our research questions asked how medical students give meaning to early clinical experiences and how that affects their professional identity development. Our method was phenomenology. Within that framework we used a narrative interviewing technique. Interviews with 17 medical students on Year 1 attachments to nurses in hospitals and nursing homes were analysed by listening to audio-recordings and reading transcripts. Nine transcripts, which best exemplified the students' range of experiences, were purposively sampled for deeper analysis. Two researchers carried out a systematic analysis using qualitative research software. Finally, cases representing four paradigms were chosen to exemplify the study findings. Students experienced their relationships with the people they met during early clinical experiences in very different ways, particularly in terms of feeling and displaying emotions, adjusting, role finding and participation. The interplay among emotions, meaning and identity was complex and four different 'paradigms' of lived experience were apparent: feeling insecure; complying; developing, and participating. We found large differences in the way students related to other people and gave meaning to their first experiences as doctors-to-be. They differed in their ability to engage in ward practices, the way they experienced their roles as medical students and future doctors, and how they experienced and expressed their emotions. Medical educators should help students to be sensitive to their emotions, offer space to explore different
Genetic control of flowering time in legumes
Directory of Open Access Journals (Sweden)
James L Weller
2015-04-01
Full Text Available The timing of flowering, and in particular the degree to which it is responsive to the environment, is a key factor in the adaptation of a given species to various eco-geographic locations and agricultural practices. Flowering time variation has been documented in many crop legumes, and selection for specific variants has permitted significant expansion and improvement in cultivation, from prehistoric times to the present day. Recent advances in legume genomics have accelerated the process of gene identification and functional analysis, and opened up new prospects for a molecular understanding of flowering time adaptation in this important crop group. Within the legumes, two species have been prominent in flowering time studies; the vernalization-responsive long-day species pea (Pisum sativum and the warm-season short-day plant soybean (Glycine max. Analysis of flowering in these species is now being complemented by reverse genetics capabilities in the model legumes Medicago truncatula and Lotus japonicus, and the emergence of genome-scale resources in a range of other legumes. This review will outline the insights gained from detailed forward genetic analysis of flowering time in pea and soybean, highlighting the importance of light perception, the circadian clock and the FT family of flowering integrators. It discusses the current state of knowledge on genetic mechanisms for photoperiod and vernalization response, and concludes with a broader discussion of flowering time adaptation across legumes generally.
Time Series Analysis Forecasting and Control
Box, George E P; Reinsel, Gregory C
2011-01-01
A modernized new edition of one of the most trusted books on time series analysis. Since publication of the first edition in 1970, Time Series Analysis has served as one of the most influential and prominent works on the subject. This new edition maintains its balanced presentation of the tools for modeling and analyzing time series and also introduces the latest developments that have occurred n the field over the past decade through applications from areas such as business, finance, and engineering. The Fourth Edition provides a clearly written exploration of the key methods for building, cl
Administrative Lead Time at Navy Inventory Control Points
National Research Council Canada - National Science Library
Granetto, Paul
1994-01-01
.... We also evaluated the internal controls established for administrative lead time and the adequacy of management's implementation of the DoD Internal Management Control Program for monitoring administrative lead time...
Control of the beam-internal target interaction at the nuclotron by means of light radiation
Energy Technology Data Exchange (ETDEWEB)
Artiomov, A.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)]. E-mail: artiomov@moonhe.jinr.ru; Anisimov, Yu.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Afanasiev, S.V. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Bazilev, S.N. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Zolin, L.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Issinsky, I.B. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kliman, J. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia); Malakhov, A.I. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Matousek, V. [Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia); Morhac, M. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia); Nikitin, V.A. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Nikiforov, A.S. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Nomokonov, P.V. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Pilyar, A.V. [Laboratory of High Energies, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Turzo, I. [Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia)
2005-02-11
The light radiation from various internal targets at the nuclotron can be utilized for the operative control and time optimization of the interaction intensity of the beam. The examples presented in the paper illustrate information about the space characteristics of the circulating beam during one cycle of the accelerator run at the stages of injection, acceleration and during the physical experiments, respectively.
Exploring Time-Lapse Photography as a Means for Qualitative Data Collection
Persohn, Lindsay
2015-01-01
Collecting information via time-lapse photography is nothing new. Scientists and artists have been using this kind of data since the late 1800s. However, my research and experiments with time-lapse have shown that great potential may lie in its application to educational and social scientific research methods. This article is part history, part…
Failure modes and natural control time for distributed vibrating systems
International Nuclear Information System (INIS)
Reid, R.M.
1994-01-01
The eigenstructure of the Gram matrix of frequency exponentials is used to study linear vibrating systems of hyperbolic type with distributed control. Using control norm as a practical measure of controllability and the vibrating string as a prototype, it is demonstrated that hyperbolic systems have a natural control time, even when only finitely many modes are excited. For shorter control times there are identifiable control failure modes which can be steered to zero only with very high cost in control norm. Both natural control time and the associated failure modes are constructed for linear fluids, strings, and beams, making note of the essential algorithms and Mathematica code, and displaying results graphically
Menenti, M.; Azzali, S.; Verhoef, W.; Van Swol, R.
1993-01-01
Examples are presented of applications of a fast Fourier transform algorithm to analyze time series of images of Normalized Difference Vegetation Index values. The results obtained for a case study on Zambia indicated that differences in vegetation development among map units of an existing agroclimatic map were not significant, while reliable differences were observed among the map units obtained using the Fourier analysis.
The need to control for regression to the mean in social psychology studies
Directory of Open Access Journals (Sweden)
Rongjun eYu
2015-01-01
Full Text Available It is common in repeated measurements for extreme values at the first measurement to approach the mean at the subsequent measurement, a phenomenon called regression to the mean (RTM. If RTM is not fully controlled, it will lead to erroneous conclusions. The wide use of repeated measurements in social psychology creates a risk that an RTM effect will influence results. However, insufficient attention is paid to RTM in most social psychological research. Notable cases include studies on the phenomena of social conformity and unrealistic optimism. In Study 1, 13 university students rated and re-rated the facial attractiveness of a series of female faces as a test of the social conformity effect. In Study 2, 15 university students estimated and re-estimated their risk of experiencing a series of adverse life events as a test of the unrealistic optimism effect. Although these studies used methodologies similar to those used in earlier research, the social conformity and unrealistic optimism effects were no longer evident after controlling for RTM. Based on these findings we suggest several ways to control for the RTM effect in social psychology studies.
Improvements in brain activation detection using time-resolved diffuse optical means
Montcel, Bruno; Chabrier, Renee; Poulet, Patrick
2005-08-01
An experimental method based on time-resolved absorbance difference is described. The absorbance difference is calculated over each temporal step of the optical signal with the time-resolved Beer-Lambert law. Finite element simulations show that each step corresponds to a different scanned zone and that cerebral contribution increases with the arrival time of photons. Experiments are conducted at 690 and 830 nm with a time-resolved system consisting of picosecond laser diodes, micro-channel plate photo-multiplier tube and photon counting modules. The hemodynamic response to a short finger tapping stimulus is measured over the motor cortex. Time-resolved absorbance difference maps show that variations in the optical signals are not localized in superficial regions of the head, which testify for their cerebral origin. Furthermore improvements in the detection of cerebral activation is achieved through the increase of variations in absorbance by a factor of almost 5 for time-resolved measurements as compared to non-time-resolved measurements.
Rypdal, Martin; Sirnes, Espen; Løvsletten, Ola; Rypdal, Kristoffer
2013-08-01
Maximum likelihood estimation techniques for multifractal processes are applied to high-frequency data in order to quantify intermittency in the fluctuations of asset prices. From time records as short as one month these methods permit extraction of a meaningful intermittency parameter λ characterising the degree of volatility clustering. We can therefore study the time evolution of volatility clustering and test the statistical significance of this variability. By analysing data from the Oslo Stock Exchange, and comparing the results with the investment grade spread, we find that the estimates of λ are lower at times of high market uncertainty.
Means and method for controlling the neutron output of a neutron generator tube
International Nuclear Information System (INIS)
Langford, O.M.; Peelman, H.E.
1978-01-01
Means and method are described for energizing and regulating a neutron generator tube having a target, an ion source and a replenisher. It providing a negative high voltage to the target and monitoring the target current. A constant current from a constant current source is divided into a shunt current and a replenisher current in accordence with the target current. The replenisher current is applied to the replenisher in a neutron generator tube so as to control the neutron output in accordance with the target current
Means and method for controlling the neutron output of a neutron generator tube
International Nuclear Information System (INIS)
1977-01-01
A means and method for energizing and regulating a neutron generator tube is described. It has a target, an ion source and a replenisher. A negative high voltage is applied to the target and the target current monitored. A constant current from a constant current source is divided into a shunt current and a replenisher current in accordance with the target current. The replenisher current is applied to the replenisher in a neutron generator tube so as to control the neutron output in accordance with the target current. (C.F.)
Means of control of the public authorities as participants in public limited energy supply companies
International Nuclear Information System (INIS)
Kermel, C.
1994-01-01
Despite the fundamental studies by Emmerich and Puettner, the control of publicly owned companies by the state as a majority shareholder has not evolved to a generally accepted form. With a mind to the discussion on a nuclear phase-out at Hamburgische Electrizitaetswerke AG the author examines the scope offered by the law on public limited companies for realising the interests of the state as a shareholder. She arrives at interesting conclusions regarding the means to this end and the legal consequences of a phase-out decision. Lower supply companies are an ideal object of study for the purposes of this work. (orig./UA) [de
Controlling gain one photon at a time
Schwartz, Gregory W; Rieke, Fred
2013-01-01
Adaptation is a salient property of sensory processing. All adaptational or gain control mechanisms face the challenge of obtaining a reliable estimate of the property of the input to be adapted to and obtaining this estimate sufficiently rapidly to be useful. Here, we explore how the primate retina balances the need to change gain rapidly and reliably when photons arrive rarely at individual rod photoreceptors. We find that the weakest backgrounds that decrease the gain of the retinal output signals are similar to those that increase human behavioral threshold, and identify a novel site of gain control in the retinal circuitry. Thus, surprisingly, the gain of retinal signals begins to decrease essentially as soon as background lights are detectable; under these conditions, gain control does not rely on a highly averaged estimate of the photon count, but instead signals from individual photon absorptions trigger changes in gain. DOI: http://dx.doi.org/10.7554/eLife.00467.001 PMID:23682314
MacDonald, Sarah; Murphy, Simon; Elliott, Eva
2018-04-06
Potential merits of a social practice perspective for examining the meanings and dynamics of family food include moving beyond individual behaviour, and exploring how practices emerge, develop and change. However, researchers have struggled to encourage reflection on mundane practices, and how to understand associated meanings. Drawing on a study of families in South Wales, this article reflects on the value of the diary-interview approach in addressing these methodological challenges, and aims to explore and understand the dynamics of control across family contexts. Contemporary practice theories distinguish between practices as 'performances' and practices as 'entities' and the diary-interview method facilitated an examination of these dimensions. Detailed accounts of daily 'performances' (through diaries), alongside reflection on underlying contexts and 'entities' (through interviews), illustrated the entanglement of control, practices and context. The article adds further complexity to the concept of practice 'bundles' which facilitated an understanding of how food was interrelated with other practices - across family contexts and across generations. Sociological approaches with a practices perspective at the core, offer potential for developing public health interventions by acknowledging: the relational meaning of food; the embeddedness of food within everyday practices; and the need to consider interventions across a range of policy areas. © 2018 Foundation for the Sociology of Health & Illness.
Vo, Kathy; Smollin, Craig
2015-06-01
Online social networking services such as Facebook provide a novel medium for the dissemination of public health information by poison control centers in the United States. We performed a cross-sectional study of poison control center Facebook pages to describe and assess the use of this medium. Facebook pages associated with poison control centers were identified during a continuous two-week period from December 24, 2012 to January 7, 2013. Data were extracted from each page, including affiliated poison control center; page duration, measured in years since registration; number of subscribers; number of postings by general toxicological category; and measures of user-generated activity including "likes", "shares", and comments per posting. Among the 56 US poison control centers, 39 Facebook pages were identified, of which 29 were currently active. The total number of active pages has increased by 140% from 2009 to 2013 (average of 25% per year). The total number of all subscribers to active pages was 11,211, ranging from 40 to 2,456 (mean 387, SD 523), equal to 0.006% of all Facebook users in the United States. The number of subscribers per page was associated with page duration, number of postings, and type of postings. The types of toxicological postings were public education (45%), self-promotion (28%), childhood safety (12%), drugs of abuse (8%), environmental poisonings (6%), and general overdoses (1%). Slightly over half of all poison control centers in the United States are supplementing their outreach and education efforts through Facebook. In general, the more active the poison control center on Facebook, the more page followers and follower engagement gained.
Quality Control Procedure Based on Partitioning of NMR Time Series
Directory of Open Access Journals (Sweden)
Michał Staniszewski
2018-03-01
Full Text Available The quality of the magnetic resonance spectroscopy (MRS depends on the stability of magnetic resonance (MR system performance and optimal hardware functioning, which ensure adequate levels of signal-to-noise ratios (SNR as well as good spectral resolution and minimal artifacts in the spectral data. MRS quality control (QC protocols and methodologies are based on phantom measurements that are repeated regularly. In this work, a signal partitioning algorithm based on a dynamic programming (DP method for QC assessment of the spectral data is described. The proposed algorithm allows detection of the change points—the abrupt variations in the time series data. The proposed QC method was tested using the simulated and real phantom data. Simulated data were randomly generated time series distorted by white noise. The real data were taken from the phantom quality control studies of the MRS scanner collected for four and a half years and analyzed by LCModel software. Along with the proposed algorithm, performance of various literature methods was evaluated for the predefined number of change points based on the error values calculated by subtracting the mean values calculated for the periods between the change-points from the original data points. The time series were checked using external software, a set of external methods and the proposed tool, and the obtained results were comparable. The application of dynamic programming in the analysis of the phantom MRS data is a novel approach to QC. The obtained results confirm that the presented change-point-detection tool can be used either for independent analysis of MRS time series (or any other or as a part of quality control.
Computing the Skewness of the Phylogenetic Mean Pairwise Distance in Linear Time
DEFF Research Database (Denmark)
Tsirogiannis, Constantinos; Sandel, Brody Steven
2014-01-01
The phylogenetic Mean Pairwise Distance (MPD) is one of the most popular measures for computing the phylogenetic distance between a given group of species. More specifically, for a phylogenetic tree and for a set of species R represented by a subset of the leaf nodes of , the MPD of R is equal...... to the average cost of all possible simple paths in that connect pairs of nodes in R. Among other phylogenetic measures, the MPD is used as a tool for deciding if the species of a given group R are closely related. To do this, it is important to compute not only the value of the MPD for this group but also...
Energy Technology Data Exchange (ETDEWEB)
Hengevoss, Charly [Weatherford Ukraine LLC, Kiev (Ukraine); Homrighausen, Reiner [BAUER Resources GmbH, Schrobenhausen (Germany)
2013-03-01
Today, the most modern directional drilling technology not only is used in case of very deep drillings (deeper or longer than 2,000 meter) by means of deep-level drilling rigs, but also with small, highly mobile universal drilling rigs. Thus, drilling costs are reduced, and unconventional hydrocarbons (methane gas - oil shale and shale gas) deposits are explores economically. Furthermore, known near-surface petroleum deposits in Northern Germany as well as in other parts of the Earth (such as in Romania, the U.S.A. or in Canada) which extraction of petroleum is very low already are interesting economically. Furthermore, today it is possible to investigate with controlled drillings more economically and with more safe sites for a possibly final storage of highly radioactive wastes. Controlled drillings may give an answer to geotechnical questions on highly inaccessible on optimum points for drilling wells in order to plan underground cavities or to investigate tunnel axes geotechnical or hydrological.
Poncet, A; Parma, V; Strubin, P; Tock, JP; Tommasini, D
2007-01-01
In 2001, the project management decided to perform at CERN the final assembly of the LHC superconducting magnets with cryostat parts and cold masses produced by European Industry in large series. This industrial-like production has required a very significant investment in tooling, production facilities, engineering and quality control efforts, in contractual partnership with a consortium of firms. This unusual endeavour of a limited lifetime represented more than 850,000 working hours spanning over five years, the work being done on a result-oriented basis by the contractor. This paper presents the reasons for having conducted this project at CERN, summarizes the work breakdown structure, the production means and methods, the infrastructure specially developed, the tooling, logistics and quality control aspects of the work performed and the results achieved, in analytical form. Finally, the lessons learnt are outlined.
A Time Series of Mean Global Sea Surface Temperature from the Along-Track Scanning Radiometers
Veal, Karen L.; Corlett, Gary; Remedios, John; Llewellyn-Jones, David
2010-12-01
A climate data set requires a long time series of consistently processed data with suitably long periods of overlap of different instruments which allows characterization of any inter-instrument biases. The data obtained from ESA's three Along-Track Scanning Radiometers (ATSRs) together comprise an 18 year record of SST with overlap periods of at least 6 months. The data from all three ATSRs has been consistently processed. These factors together with the stability of the instruments and the precision of the derived SST makes this data set eminently suitable for the construction of a time series of SST that complies with many of the GCOS requirements for a climate data set. A time series of global and regional average SST anomalies has been constructed from the ATSR version 2 data set. An analysis of the overlap periods of successive instruments was used to remove intra-series biases and align the series to a common reference. An ATSR climatology has been developed and has been used to calculate the SST anomalies. The ATSR-1 time series and the AATSR time series have been aligned to ATSR-2. The largest adjustment is ~0.2 K between ATSR-2 and AATSR which is suspected to be due to a shift of the 12 μm filter function for AATSR. An uncertainty of 0.06 K is assigned to the relative anomaly record that is derived from the dual three-channel night-time data. A relative uncertainty of 0.07 K is assigned to the dual night-time two-channel record, except in the ATSR-1 period (1994-1996) where it is larger.
A metronome for controlling the mean velocity during the bench press exercise.
Moras, Gerard; Rodríguez-Jiménez, Sergio; Busquets, Albert; Tous-Fajardo, Julio; Pozzo, Marco; Mujika, Iñigo
2009-05-01
Lifting velocity may have a great impact on strength training-induced adaptations. The purpose of this study was to validate a method including a metronome and a measurement tape as inexpensive tools for the estimation of mean lifting velocity during the bench press exercise. Fifteen subjects participated in this study. After determining their one repetition maximum (1RM) load, we estimated the maximum metronome rhythm (R) that each subject could maintain in the concentric phase for loads of 40 and 60% of 1RM. To estimate R, the 3 repetitions with highest concentric power, as measured by means of a linear encoder, were selected, and their average duration was calculated and converted to lifting rhythm in beats per minute (bpm) for each subject. The range of motion was measured using a regular tape and kept constant during all exercises. Subjects were instructed to begin with the barbell at arm lengths and lower it in correspondence with the metronome beep. They subsequently performed 5 repetitions at 3 different rhythms relative to R (50, 70, and 90% R) for each training load (40 and 60% of 1RM). A linear encoder was attached to the bar and used as a criterion to measure the vertical displacement over time. For each rhythm, the mean velocity was calculated with the metronome (time) and the reference distance and compared with that recorded by the linear encoder. The SEM for velocity between both testing methods ranged from 0.02 to 0.05 m.s (coefficient of variation, 4.0-6.4%; Pearson's correlation, 0.8-0.95). The present results showed that the use of a metronome and a measurement tape may be a valid method to estimate the mean velocity of execution during the bench press exercise. This simple method could help coaches and athletes achieve their strength training goals, which are partly determined by lifting velocity.
Space and time optimization of nuclear reactors by means of the Pontryagin principle
International Nuclear Information System (INIS)
Anton, V.
1979-01-01
A numerical method is being presented for solving space dependent optimization problems concerning a functional for one dimensional geometries in the few group diffusion approximation. General dimensional analysis was applied to derive relations for the maximum of a functional and the limiting values of the constraints. Two procedures were given for calculating the anisotropic diffusion coefficients in order to improve the results of the diffusion approximation. In this work two procedures were presented for collapsing the microscopic multigroup cross sections, one general and another specific to the space dependent optimization problems solved by means of the Pontryagin maximum principle. Neutron spectrum optimization is performed to ensure the burnup of Pu 239 isotope produced in a thermal nuclear reactor. A procedure is also given for the minimization of finite functional set by means of the Pontryagin maximum principle. A method for determining the characteristics of fission Pseudo products is formulated in one group and multigroup cases. This method is applied in the optimization of the burnup in nuclear reactors with fuel electric cells. A procedure to mjnimze the number of the fuel burnup equations is described. The optimization problems presented and solved in this work point to the efficiency of the maximum principle. Each problem on method presented in the various chapters is accompanied by considerations concerning dual problems and possibilities of further research development. (author)
More does not always mean better – the problem of working time in the European Union
Directory of Open Access Journals (Sweden)
Ewa Ignaciuk
2010-12-01
Full Text Available The introduction of an eight-hour working day and forty eight-hour working week was the result of many years of struggle of the workers of Europe and America, demanding respect for their rights, including the right to leisure and family life. Currently, in many European countries, average working time is shorter than that established by the International Labour Conference in the Convention of 1919. The longest – 40 hour working time – valid in Greece, Malta and in most countries of the former socialist bloc (with the exception of Slovakia and the Czech Republic. In the so-called fifteen countries (EU-15 average weekly working hours (excluding overtime in 2007 was 37.9 hours. According to official statistics in all countries of the European Union, the actual working time is longer than that specified in collective agreements. Employees work the longest in Austria, Greece, Great Britain, the Czech Republic and Poland, while the shortest is in Luxembourg.It was observed that there is an inverse relationship between working time and work efficiency. In countries, where workers have the most days off from work and/or shortest time, labor productivity is the largest (eg, Luxembourg, Sweden, Ireland, France and Germany. The effects of fatigue for workers not only have an impact on staff competencies, but also imprint their mark on the sphere of social life and the whole economy. Therefore, the concern should be treated any ideas for extending working hours.
Time and Control in Teachers’ Work
DEFF Research Database (Denmark)
Lund, Henrik Lambrecht
2017-01-01
to changes in the temporal order of work among teachers in Denmark. A 2014 change in Danish legislation forced teachers to conduct all their work at their school. This caused the largest labor marked conflict seen in Denmark for many years, and the largest ever seen in the public sector. Before this change...... relationship between different types of tasks, division of labor, rhythms of time for socializing, communication practices, coordination, synchronization, etc....
Directory of Open Access Journals (Sweden)
M. Finizio
Full Text Available Starting from a number of observables in the form of time-series of meteorological elements in various areas of the northern hemisphere, a model capable of fitting past records and predicting monthly vorticity time changes in the western Mediterranean is implemented. A new powerful statistical methodology is introduced (MARS in order to capture the non-linear dynamics of time-series representing the available 40-year history of the hemispheric circulation. The developed model is tested on a suitable independent data set. An ensemble forecast exercise is also carried out to check model stability in reference to the uncertainty of input quantities.
Key words. Meteorology and atmospheric dynamics · General circulation ocean-atmosphere interactions · Synoptic-scale meteorology
Controlling flow time delays in flexible manufacturing cells
Slomp, J.; Caprihan, R.; Bokhorst, J. A. C.
2009-01-01
Flow time delays in Flexible Manufacturing Cells (FMCs) are caused by transport and clamping/reclamping activities. This paper shows how dynamic scheduling parameters may control the flow times of jobs and the available task windows for flow time delays.
Controlling the structure of forced convective flow by means of rotating magnetic-field inductors
International Nuclear Information System (INIS)
Sorkin, M.Z.; Mozgirs, O.Kh.
1993-01-01
The forced convective flow generated by a rotating magnetic-field inductor is used in a melt as a means of controlling the transfer of mass and heat in the case of directed crystallization. An obvious advantage in using a rotating field is the generation of azimuthal twisting of the fluid, this providing for an evening out of the crystallization conditions in the azimuthal direction under nonsymmetrical boundary conditions in an actual technological process. From the standpoint of affecting the crystallization processes it would be preferable to use an inductor which would allow alteration of the intensity and of the direction of the meridional flow. Mixing in the form of velocity pulsations generated by the inductor within the melt would be if interest from the standpoint of affecting the crystallization processes, in particular to intensify the crystallization purification. The authors propose the use of a double magnetohydrodynmic rotator which consists of two rotating magnetic-field inductors, separated in altitude, with separate power supplies. The supply of power to the inductors with various current loads allows the generation of a controllable nonuniformity in field distribution and in the azimuthal velocity through the altitude and thus allows control of both the intensity and configuration of the meridional flows. The dual rotator makes it possible to purposefully control the structure of the meridional flows and the pulsation component of velocity and can be recommended for use in processes of directed crystallization as well as in crystallization purification. 4 refs., 3 figs
Radiographic findings after pubic symphysiotomy: mean time to follow-up of 41.6 years.
LENUS (Irish Health Repository)
Galbraith, John G
2014-01-01
Pubic symphysiotomy is a rarely performed procedure in which the pubic symphysis is divided to facilitate vaginal delivery in cases of obstructed labor. Recently, many obstetricians have shown renewed interest in this procedure. The purpose of this paper is to report the long-term radiographic findings for patients who had undergone pubic symphysiotomy compared with the radiographic appearance of a group of age-matched and parity-matched controls.
Time domain passivity controller for 4-channel time-delay bilateral teleoperation.
Rebelo, Joao; Schiele, Andre
2015-01-01
This paper presents an extension of the time-domain passivity control approach to a four-channel bilateral controller under the effects of time delays. Time-domain passivity control has been used successfully to stabilize teleoperation systems with position-force and position-position controllers; however, the performance with such control architectures is sub-optimal both with and without time delays. This work extends the network representation of the time-domain passivity controller to the four-channel architecture, which provides perfect transparency to the user without time delay. The proposed architecture is based on modelling the controllers as dependent voltage sources and using only series passivity controllers. The obtained results are shown on a one degree-of-freedom setup and illustrate the stabilization behaviour of the proposed controller when time delay is present in the communication channel.
A study on the pulmonary mean transit time and the pulmonary blood volume by RI-cardiogram
International Nuclear Information System (INIS)
Ushio, Norio
1987-01-01
The pulmonary mean transit time and the pulmonary blood volume in cases of cardio-pulmonary disease were measured using Giuntini's method which is considered the most appropriate among radiocardiographic methods. The errors in this method were confirmed to be almost negligible. The results obtained were as follows: 1) The pulmonary mean transit time was related to the systemic mean transit time and markedly prolonged in left heart failure. On the other hand, it was markedly shortened in some cases of chronic pulmonary disease, particularly pulmonary emphysema. 2) The pulmonary blood volume tended to increase in left heart disorders and mitral valve disease and tended to decrease in the chronic pulmonary disease. The decrease was conspicuous particularly in some cases of pulmonary emphysema. 3) A structural change of the pulmonary vascular system in the chronic pulmonary disease appeared to bring about shortening of the pulmonary mean transit time and a decrease in the pulmonary blood volume. The pathophysiology of cardio-pulmonary disease can be more clarified by the RI-cardiogram used in this study, in which the pulmonary mean transit time and the pulmonary blood volume are used as the indicator. (author)
Methods and means for improving the man-machine systems for NPP control
International Nuclear Information System (INIS)
Konstantinov, L.V.; Rakitin, I.D.
1984-01-01
Consideration is being given to the role of ''human factors'' and the ways of improving the man-machine interaction in NPP control and safety systems (CSS). Simulators and tAaining equipment on the basis of dynamic power unit models used for training and improving skill of NPP operatoAs, as well as for mastering collective actions of personnel under accidental conditions are considered in detail. The most perfect program complexes for fast NPP diagnostics and theiA pealization in the Federal Republic of Germany, Japan, Canada, the USA and other countries are described. A special attention is paid to the means and methods of videoterminal dialogue operator interaction with an object both in normal and extreme situations. It is noted that the problems of the man-machine interaction have become the subject of study only in the end of 70s after analyzing the causes of the Three-Mile-Island accident (USA). Publications dealing with the development of perspective control rooms for NPP were analyzed. It was concluded that radical changes both in equipment and principles of organizing the personnel activity will take place in the nearest future. They will be based on the progress in creating dialogue means and computers of the fourth and fifth generations as well as on engineering and psychological and technical aspects of designing
Mean sojourn times for phase-type discriminatory processor sharing systems
Haviv, M.; van der Wal, J.
2008-01-01
In a discriminatory processor sharing (DPS) queueing model, each job (or customer) belongs to one out of finitely many classes. The arrival processes are Poisson. Classes differ with respect to arrival rates and service time distributions. Moreover, classes have different priority levels. All jobs
The effects of disjunct sampling and averaging time on maximum mean wind speeds
DEFF Research Database (Denmark)
Larsén, Xiaoli Guo; Mann, J.
2006-01-01
Conventionally, the 50-year wind is calculated on basis of the annual maxima of consecutive 10-min averages. Very often, however, the averages are saved with a temporal spacing of several hours. We call it disjunct sampling. It may also happen that the wind speeds are averaged over a longer time...
A time to pause and ponder - will to meaning in education
DEFF Research Database (Denmark)
Daugbjerg, Peer; Spencer, Christopher
Worries about the effect of trade and globalisation on the workforce are “a staple of politics in the US and Europe” (Financial Times 2016). There would appear to be a general global movement towards isolation and protectionism (see Brexit, Trump, Putin). Europa was the battle field for conflicts...
Mean residence time of kaolinite and smectite-bound organic matter in mozambiquan soils
Wattel-Koekkoek, E.J.W.; Buurman, P.
2004-01-01
To gain understanding about the process of global warming, it is essential to study the global C cycle. In the global C cycle, soil organic matter (SOM) is a major source and sink of atmospheric C. Turnover times of C in these soil organic compounds vary from hours to thousands of years. Clay
Su, Yu
2013-01-01
The No Child Left Behind Act of 2001 increases school accountability and requires educators to improve student academic outcomes using evidence-based practice. One factor that contributes to desirable school outcomes is principals' instructional leadership behaviors. Principals who allocate more time to instructional leadership behaviors are more…
Energy Technology Data Exchange (ETDEWEB)
Kasperl, St.; Franz, M. [Fraunhofer Development Center for X-ray Technology EZRT, a cooperative dept. of the Fraunhofer Institutes IZFP Saarbrucken and IIS Erlangen, Furth (Germany)
2007-07-01
This article deals with the enhancement of accuracy in CT by just-in-time correction of artefacts (beam hardening, scattered radiation) caused by the interaction of X-rays with matter. The so called EAR method needs for simulation a registration of the object. Therefore the article presents two different registration concepts. (authors)
International Nuclear Information System (INIS)
Kasperl, St.; Franz, M.
2007-01-01
This article deals with the enhancement of accuracy in CT by just-in-time correction of artefacts (beam hardening, scattered radiation) caused by the interaction of X-rays with matter. The so called EAR method needs for simulation a registration of the object. Therefore the article presents two different registration concepts. (authors)
Particle correlation based measurement of the mean time between the deuteron and proton emissions
International Nuclear Information System (INIS)
Ghisalberti, C.; Lebrun, C.; Sezac, L.; Ardouin, D.; Erazmus, B.; Eudes, P.; Ghuilbault, F.; Lautridou, P.; Rahmani, J.A.; Reposeur, T.; Chbihi, A.; Galin, J.; Guerreau, D.; Morjean, M.; Peghaire, A.; Lednicky, R.; Pluta, J.; Quebert, J.; Siemssen, R.
1997-01-01
Proton-deuteron correlations at small relative momenta have been measured with the reaction 208 Pb + 93 Nb at 29 MeV per nucleon at GANIL using the ORION neutron calorimeter. By selecting the proton-deuteron pairs according to the angle between their relative velocity and the pair center of mass velocity of the emitting source one can determine the average value of the time delay between the emission of these particles. The results reported in this paper for the first time at GANIL energies agree with the values published before in the literature i.e. 600 and 1500 fm/c for deuteron and proton emission times, respectively, as obtained in the reactions Ar + Ag at E/A = 17 MeV. At higher energies measurements with a B.U.U. calorimeter recording the collisions 14 N + 27 Al at E/A = 75 MeV show that in this case the proton emission begins at 15 fm/c and decreases slowly in time, while the deuterons are emitted at 50 fm/c and present a steep falling. This result agrees with a negative average value of d - t p >. Thus, the method presented in this report for determining the order of emission is of great interest for checking the theoretical description of the particle emission all the way in the collision dynamical process
Kim, Byungyeon; Park, Byungjun; Lee, Seungrag; Won, Youngjae
2016-01-01
We demonstrated GPU accelerated real-time confocal fluorescence lifetime imaging microscopy (FLIM) based on the analog mean-delay (AMD) method. Our algorithm was verified for various fluorescence lifetimes and photon numbers. The GPU processing time was faster than the physical scanning time for images up to 800 × 800, and more than 149 times faster than a single core CPU. The frame rate of our system was demonstrated to be 13 fps for a 200 × 200 pixel image when observing maize vascular tissue. This system can be utilized for observing dynamic biological reactions, medical diagnosis, and real-time industrial inspection. PMID:28018724
Almirall, Daniel; Griffin, Beth Ann; McCaffrey, Daniel F.; Ramchand, Rajeev; Yuen, Robert A.; Murphy, Susan A.
2014-01-01
This article considers the problem of examining time-varying causal effect moderation using observational, longitudinal data in which treatment, candidate moderators, and possible confounders are time varying. The structural nested mean model (SNMM) is used to specify the moderated time-varying causal effects of interest in a conditional mean model for a continuous response given time-varying treatments and moderators. We present an easy-to-use estimator of the SNMM that combines an existing regression-with-residuals (RR) approach with an inverse-probability-of-treatment weighting (IPTW) strategy. The RR approach has been shown to identify the moderated time-varying causal effects if the time-varying moderators are also the sole time-varying confounders. The proposed IPTW+RR approach provides estimators of the moderated time-varying causal effects in the SNMM in the presence of an additional, auxiliary set of known and measured time-varying confounders. We use a small simulation experiment to compare IPTW+RR versus the traditional regression approach and to compare small and large sample properties of asymptotic versus bootstrap estimators of the standard errors for the IPTW+RR approach. This article clarifies the distinction between time-varying moderators and time-varying confounders. We illustrate the methodology in a case study to assess if time-varying substance use moderates treatment effects on future substance use. PMID:23873437
Control and ad ustment system of the BIS-2 spectrometer by means of a minicomputer
International Nuclear Information System (INIS)
Eichner, G.; Aleev, A.N.; Aref'ev, V.A.
1980-01-01
Control and adjustment system of the BIS-2 spectrometer apparatus is desribed. The work was intented to adjust time losses during the apparatus preparation and obtaing detailed information on the operation of basic parts of the spectrometer. To solve this problem the program-controlled electronic circuits working on-line with the TPA-1001/i computer were used and corresponding software was created. The flexibility and comparative simplicity of program designing was achieved by using the combination of FOKAL and SLAG1 programming languages. The examples of programs serving for the apparatus adjustment are given. The use of this control and adjustment system allows one to accelerate the preparation of the spectrometer for operation. The hardware-software complex can be used for various setups of experimental apparatus
Empiric model for mean generation time adjustment factor for classic point kinetics equations
Energy Technology Data Exchange (ETDEWEB)
Goes, David A.B.V. de; Martinez, Aquilino S.; Goncalves, Alessandro da C., E-mail: david.goes@poli.ufrj.br, E-mail: aquilino@lmp.ufrj.br, E-mail: alessandro@con.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Engenharia Nuclear
2017-11-01
Point reactor kinetics equations are the easiest way to observe the neutron production time behavior in a nuclear reactor. These equations are derived from the neutron transport equation using an approximation called Fick's law leading to a set of first order differential equations. The main objective of this study is to review classic point kinetics equation in order to approximate its results to the case when it is considered the time variation of the neutron currents. The computational modeling used for the calculations is based on the finite difference method. The results obtained with this model are compared with the reference model and then it is determined an empirical adjustment factor that modifies the point reactor kinetics equation to the real scenario. (author)
Empiric model for mean generation time adjustment factor for classic point kinetics equations
International Nuclear Information System (INIS)
Goes, David A.B.V. de; Martinez, Aquilino S.; Goncalves, Alessandro da C.
2017-01-01
Point reactor kinetics equations are the easiest way to observe the neutron production time behavior in a nuclear reactor. These equations are derived from the neutron transport equation using an approximation called Fick's law leading to a set of first order differential equations. The main objective of this study is to review classic point kinetics equation in order to approximate its results to the case when it is considered the time variation of the neutron currents. The computational modeling used for the calculations is based on the finite difference method. The results obtained with this model are compared with the reference model and then it is determined an empirical adjustment factor that modifies the point reactor kinetics equation to the real scenario. (author)
Measuring the diameter of rising gas bubbles by means of the ultrasound transit time technique
Energy Technology Data Exchange (ETDEWEB)
Richter, T., E-mail: Thomas.Richter6@tu-dresden.de; Eckert, K., E-mail: Kerstin.Eckert@tu-dresden.de; Yang, X.; Odenbach, S.
2015-09-15
Highlights: • Ultrasound transit time technique (UTTT) is applied to the zig-zag raise of gas bubble. • Comparison of bubble diameter and tilt, measured by UTTT, with high-speed imaging. • Uncertainty in the determination of the bubble diameter by UTTT is less than 7%. • UTTT is able to measure dynamic changes in bubble size in opaque liquids and vessels. • UTTT can be applied to liquid metal loops. - Abstract: This study presents ultrasound transit time technique (UTTT) measurements of the diameter variations of single argon bubbles rising in a zig-zag trajectory in water. Simultaneous size measurements with a high-speed camera show that UTTT resolves both the apparent diameter and the tilt of the bubble axis with an accuracy of better than 7%. This qualifies UTTT for the measurement of bubble sizes in opaque liquids, such as liquid metals, or vessels.
Rúa-Uribe, Guillermo L; Suárez-Acosta, Carolina; Chauca, José; Ventosilla, Palmira; Almanza, Rita
2013-09-01
Dengue fever is a major impact on public health vector-borne disease, and its transmission is influenced by entomological, sociocultural and economic factors. Additionally, climate variability plays an important role in the transmission dynamics. A large scientific consensus has indicated that the strong association between climatic variables and disease could be used to develop models to explain the incidence of the disease. To develop a model that provides a better understanding of dengue transmission dynamics in Medellin and predicts increases in the incidence of the disease. The incidence of dengue fever was used as dependent variable, and weekly climatic factors (maximum, mean and minimum temperature, relative humidity and precipitation) as independent variables. Expert Modeler was used to develop a model to better explain the behavior of the disease. Climatic variables with significant association to the dependent variable were selected through ARIMA models. The model explains 34% of observed variability. Precipitation was the climatic variable showing statistically significant association with the incidence of dengue fever, but with a 20 weeks delay. In Medellin, the transmission of dengue fever was influenced by climate variability, especially precipitation. The strong association dengue fever/precipitation allowed the construction of a model to help understand dengue transmission dynamics. This information will be useful to develop appropriate and timely strategies for dengue control.
Active cancellation - A means to zero dead-time pulse EPR.
Franck, John M; Barnes, Ryan P; Keller, Timothy J; Kaufmann, Thomas; Han, Songi
2015-12-01
The necessary resonator employed in pulse electron paramagnetic resonance (EPR) rings after the excitation pulse and creates a finite detector dead-time that ultimately prevents the detection of signal from fast relaxing spin systems, hindering the application of pulse EPR to room temperature measurements of interesting chemical or biological systems. We employ a recently available high bandwidth arbitrary waveform generator (AWG) to produce a cancellation pulse that precisely destructively interferes with the resonant cavity ring-down. We find that we can faithfully detect EPR signal at all times immediately after, as well as during, the excitation pulse. This is a proof of concept study showcasing the capability of AWG pulses to precisely cancel out the resonator ring-down, and allow for the detection of EPR signal during the pulse itself, as well as the dead-time of the resonator. However, the applicability of this approach to conventional EPR experiments is not immediate, as it hinges on either (1) the availability of low-noise microwave sources and amplifiers to produce the necessary power for pulse EPR experiment or (2) the availability of very high conversion factor micro coil resonators that allow for pulse EPR experiments at modest microwave power. Copyright © 2015 Elsevier Inc. All rights reserved.
Image enhancement in photoemission electron microscopy by means of imaging time-of-flight analysis
International Nuclear Information System (INIS)
Oelsner, A.; Krasyuk, A.; Fecher, G.H.; Schneider, C.M.; Schoenhense, G.
2004-01-01
Photoemission electron microscopy (PEEM) is widely used in combination with synchrotron sources as a powerful tool to observe chemical and magnetic properties of metal and semiconductor surfaces. Presently, the resolution limit of these instruments using soft-X-ray excitation is limited to about 50 nm, because of the chromatic aberration of the electron optics used. Various sophisticated approaches have thus been reported for enhancing the spatial resolution in photoemission electron microscopy. This work demonstrates the use of a simple imaging energy filter based on electron time-of-flight (ToF) selection. The spatial resolution could be improved dramatically, even though the instrument was optimized using a rather large contrast aperture of 50 μm. A special (x, y, t)-resolving delayline detector was used as the imaging unit of this ToF-PEEM. It is operated in phase with the time structure of the synchrotron source, cutting time intervals from the raw image-forming data set in order to reduce the electron energy width contributing to the final images
Waadeland, Carl Haakon
2017-01-01
Results from different empirical investigations on gestural aspects of timed rhythmic movements indicate that the production of asymmetric movement trajectories is a feature that seems to be a common characteristic of various performances of repetitive rhythmic patterns. The behavioural or neural origin of these asymmetrical trajectories is, however, not identified. In the present study we outline a theoretical model that is capable of producing syntheses of asymmetric movement trajectories documented in empirical investigations by Balasubramaniam et al. (2004). Characteristic qualities of the extension/flexion profiles in the observed asymmetric trajectories are reproduced, and we conduct an experiment similar to Balasubramaniam et al. (2004) to show that the empirically documented movement trajectories and our modelled approximations share the same spectral components. The model is based on an application of frequency modulated movements, and a theoretical interpretation offered by the model is to view paced rhythmic movements as a result of an unpaced movement being "stretched" and "compressed", caused by the presence of a metronome. We discuss our model construction within the framework of event-based and emergent timing, and argue that a change between these timing modes might be reflected by the strength of the modulation in our model. Copyright © 2016 Elsevier B.V. All rights reserved.
Time Stamp Synchronization of PEFP Distributed Control Systems
International Nuclear Information System (INIS)
Song, Young Gi; An, Eun Mi; Kwon, Hyeok Jung; Cho, Yong Sub
2010-01-01
Proton Engineering Frontier Project (PEFP) proton linac consists of several types of control systems, such as soft Input Output Controllers (IOC) and embedded IOC based on Experimental Physics Industrial Control System (EPICS) for each subsection of PEFP facility. One of the important factors is that IOC's time clock is synchronized. The synchronized time and time stamp can be achieved with Network Time Protocol (NTP) and EPICS time stamp record without timing hardware. The requirement of the time accuracy of IOCs is less than 1 second. The main objective of this study is to configure a master clock and produce Process Variable (PV) time stamps using local CPU time synchronized from the master clock. The distributed control systems are attached on PEFP control network
Sex 'n' drugs 'n' rock 'n' roll: the meaning and social consequences of pubertal timing.
Waylen, Andrea; Wolke, Dieter
2004-11-01
This is a brief review of the normal changes in adolescent behaviour and the interplay between biology and social factors that occur at and around puberty, in an attempt to explain when this transition may become problematic The onset of puberty is a biological marker for an individual's transition from a non-reproductive to a reproductive state. Adolescence is a normal developmental transition associated with clearly visible physical changes, reorganization and pruning of neuronal circuits in the brain and the occurrence of new behaviours and interests. It is a time when new life tasks (orientation towards peers of the other sex, romantic and sexual involvement and mastering an educational career) need to be mastered. Parent-child conflict increases and becomes more intense as the adolescent struggles for more independence while still requiring support. These normal changes can become problematic if biological and social expectations diverge e.g. entering puberty very early or very late. While early pubertal onset in boys is likely to have beneficial effects, in girls precocious pubertal timing may have a negative impact on body-image, affect (or emotional well-being) and sex-role expectations. Other individual biological predispositions and genetic endowment may interact with social factors (e.g. peers, parenting style, neighbourhood) making adolescence either an adaptive or a challenging transition. There is a lack of sufficiently large longitudinal studies that have been able to study this interaction between genetics, biology and social environment on adolescent development. The Avon Longitudinal Study of Parents and Children (ALSPAC) cohort provides a unique opportunity to investigate the impact of pubertal timing on social behaviour. Planned assessments and concepts are outlined.
Cybersecurity through Real-Time Distributed Control Systems
Energy Technology Data Exchange (ETDEWEB)
Kisner, Roger A [ORNL; Manges, Wayne W [ORNL; MacIntyre, Lawrence Paul [ORNL; Nutaro, James J [ORNL; Munro Jr, John K [ORNL; Ewing, Paul D [ORNL; Howlader, Mostofa [ORNL; Kuruganti, Phani Teja [ORNL; Wallace, Richard M [ORNL; Olama, Mohammed M [ORNL
2010-04-01
Critical infrastructure sites and facilities are becoming increasingly dependent on interconnected physical and cyber-based real-time distributed control systems (RTDCSs). A mounting cybersecurity threat results from the nature of these ubiquitous and sometimes unrestrained communications interconnections. Much work is under way in numerous organizations to characterize the cyber threat, determine means to minimize risk, and develop mitigation strategies to address potential consequences. While it seems natural that a simple application of cyber-protection methods derived from corporate business information technology (IT) domain would lead to an acceptable solution, the reality is that the characteristics of RTDCSs make many of those methods inadequate and unsatisfactory or even harmful. A solution lies in developing a defense-in-depth approach that ranges from protection at communications interconnect levels ultimately to the control system s functional characteristics that are designed to maintain control in the face of malicious intrusion. This paper summarizes the nature of RTDCSs from a cybersecurity perspec tive and discusses issues, vulnerabilities, candidate mitigation approaches, and metrics.
Discrete-time inverse optimal control for nonlinear systems
Sanchez, Edgar N
2013-01-01
Discrete-Time Inverse Optimal Control for Nonlinear Systems proposes a novel inverse optimal control scheme for stabilization and trajectory tracking of discrete-time nonlinear systems. This avoids the need to solve the associated Hamilton-Jacobi-Bellman equation and minimizes a cost functional, resulting in a more efficient controller. Design More Efficient Controllers for Stabilization and Trajectory Tracking of Discrete-Time Nonlinear Systems The book presents two approaches for controller synthesis: the first based on passivity theory and the second on a control Lyapunov function (CLF). Th
The Timing and Fast Control Demonstrator
Chen, Jiheng; Gustafsson, Leif
In this thesis, the feasibility of an FPGA to host a system for generating and distributing clocks as well as distributing synchronous and asynchronous commands is tested. This system will be an imitation of the SHiP (Search for Hidden Particle) DAQ (Data Acquisition) system led by CERN. The practical implementation is to mainly apply Altera Cyclone V GT development board attached with SFP+ daughter card to achieve accurate timing and high speed performance. Experiments include three loopback test implementations. Loopback test is the simplest technique to assess a channel’s integration. The first one is the Ethernet loopback test. An Ethernet card daughter board is inserted to the HSMC port of the Cyclone V GT development board. After that, a SFP card is applied alternatively on the same port to do the similar loopback test but at a much higher speed via optical fibers. And finally, a more advanced XAUI to SFP+ card daughter board will be used to replace the previous SFP card in order to get a further spee...
Barnett, M C; McFarlane, J R; Hegarty, R S
2015-06-01
Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T3 ), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T3 concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T3 concentration, CO2 production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T3 concentration (p < 0.05), CO2 production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T3 could be used as an indirect selection tool for genetic selection of low enteric methane-producing ruminants. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.
Martínez-Carreras, N.; Fenicia, F.; Frentress, J.; Wrede, S.; Pfister, L.
2012-04-01
In recent years, stable isotopes have been increasingly used to characterize important aspects of catchment hydrological functioning, such as water storage dynamics, flow pathways and water sources. These characteristics are often synthesized by the Mean Residence Time (MRT), which is a simple catchment descriptor that employ the relation of distinct stable isotopic signatures in the rainfall input and streamflow output of a catchment that are significantly dampened through sub-surface propagation. In this preliminary study, MRT was estimated in the Attert River catchment (NW Luxembourg), where previous studies have shown that lithology exerts a major control on runoff generation. The Attert catchment lies at the transition zone of contrasting bedrock lithology: the Northern part is characterized by Devonian schist of the Ardennes massif, while sedimentary deposits of sandstone and marls dominate in the south of the catchment. As a consequence of differing lithologic characteristics, hydrological processes change across scales. The schistose catchments exhibit a delayed shallow groundwater component, sandstone catchments have slow-responding year-round groundwater component, whereas flashy runoff regimes prevails in the marly catchments. Under these circumstances, the MRTs are expected to vary significantly according to lithology, and provide additional understanding in internal catchment processes and their scale dependencies. In order to test this, bi-weekly monitoring of rainfall and discharge stable water isotope composition (oxygen-18 and deuterium) has been carried out since 2007 in 10 nested sub-catchments ranging in size from 0.4 to 247 km2 in the Attert catchment. MRT was estimated using different lumped convolution integral models and sine wave functions with varying transit times distributions (TTDs). TTDs were evaluated through calibration. Further research efforts will deal with the application of conceptual models to simulate and compare TTD, using
Ophem, S. van; Berkhoff, A.P.
2012-01-01
Tracking behavior and the rate of convergence are critical properties in active noise control applications with time-varying disturbance spectra. As compared to the standard filtered-reference Least Mean Square (LMS) algorithm, improved convergence can be obtained with schemes based on
Directory of Open Access Journals (Sweden)
U. Morgenstern
2010-11-01
Full Text Available Tritium measurements of streamwater draining the Toenepi catchment, a small dairy farming area in Waikato, New Zealand, have shown that the mean transit time of the water varies with the flow rate of the stream. Mean transit times through the catchment are 2–5 years during high baseflow conditions in winter, increasing to 30–40 years as baseflow decreases in summer, and then dramatically older water during drought conditions with mean transit time of more than 100 years. Older water is gained in the lower reaches of the stream, compared to younger water in the headwater catchment. The groundwater store supplying baseflow was estimated from the mean transit time and average baseflow to be 15.4 × 10^{6} m^{3} of water, about 1 m water equivalent over the catchment and 2.3 times total annual streamflow. Nitrate is relatively high at higher flow rates in winter, but is low at times of low flow with old water. This reflects both lower nitrate loading in the catchment several decades ago as compared to current intensive dairy farming, and denitrification processes occurring in the older groundwater. Silica, leached from the aquifer material and accumulating in the water in proportion to contact time, is high at times of low streamflow with old water. There was a good correlation between silica concentration and streamwater age, which potentially allows silica concentrations to be used as a proxy for age when calibrated by tritium measurements. This study shows that tritium dating of stream water is possible with single tritium measurements now that bomb-test tritium has effectively disappeared from hydrological systems in New Zealand, without the need for time-series data.
DEFF Research Database (Denmark)
Dou, Chun-Xia; Yue, Dong; Guerrero, Josep M.
2017-01-01
This paper focuses on a multi-agent based distributed coordinated control for radial DC microgrid considering trans-mission time delays. Firstly, a two-level multi-agent system is constructed, where local control is formulated based on local states and executed by means of the first-level agent......, and dis-tributed coordinated control law is formulated based on wide-area information and executed by means of the secondary- level agent in order to improve the voltage control performances. Afterwards, the research mainly focuses on designing the local controller and the distributed coordinated...
Simulation of acoustic streaming by means of the finite-difference time-domain method
DEFF Research Database (Denmark)
Santillan, Arturo Orozco
2012-01-01
Numerical simulations of acoustic streaming generated by a standing wave in a narrow twodimensional cavity are presented. In this case, acoustic streaming arises from the viscous boundary layers set up at the surfaces of the walls. It is known that streaming vortices inside the boundary layer have...... directions of rotation that are opposite to those of the outer streaming vortices (Rayleigh streaming). The general objective of the work described in this paper has been to study the extent to which it is possible to simulate both the outer streaming vortices and the inner boundary layer vortices using...... the finite-difference time-domain method. To simplify the problem, thermal effects are not considered. The motivation of the described investigation has been the possibility of using the numerical method to study acoustic streaming, particularly under non-steady conditions. Results are discussed for channels...
Measurement of residual strain in composites by means of time-of- flight neutron diffraction
International Nuclear Information System (INIS)
Kupperman, D.S.; Majumdar, S.; Richardson, J.; Saigal, A.
1993-01-01
Neutron diffraction time-of-flight measurements using the Intense Pulsed Neutron Source at Argonne National Laboratory have been employed to study strain in various metal- and ceramic-matrix composites. For example, measurements carried out to 900 C on a composite composed of a titanium alloy matrix and silicon carbide fibers have been used to validate theoretical assumptions in the prediction of fabrication-induced residual stress. Sapphire reinforced nickel aluminide composites have also been studied. Studies of a high-temperature ceramic superconducting composite consisting of yttrium barium copper oxide and silver with various volume fractions of silver have also been carried out. The results of these studies have provided information on the effect of Ag content on interface bonding. In addition, ceramic-matrix composites with randomly dispersed ceramic whiskers with varying fiber content have been investigated
Energy Technology Data Exchange (ETDEWEB)
Pettersen, Bjoernar Hauknes
1997-12-31
Many problems in offshore oil production and multiphase transport are related to surface and colloid chemistry. This thesis applies dielectric spectroscopy as an experimental technique to study the behaviour of particle suspensions in polar media. The thesis opens with an introduction to suspensions and time domain dielectric spectroscopy. It then investigates the dielectric properties of silica and alumina dispersed in polar solvents. It is found that theoretical models can be used to calculate the volume fraction disperse phase in the suspension and that the particle sedimentation depends on the wetting of the particles, charge on the particle surface and viscosity of the solvent, and that this dependency can be measured by time domain dielectric spectroscopy. When the surface properties of silica and alumina particles were modified by coating them with a non-ionic polymer and a non-ionic surfactant, then different degrees of packing in the sedimented phase at the bottom of the sedimentation vessel occurred. Chemometrical methods on the synthesis of monodisperse silica particles were used to investigate what factors influence the particle size. It turned out that it is insufficient to consider only main variables when discussing the results of the synthesis. By introducing interaction terms, the author could explain the variation in the size of particles synthesized. The difference in the sedimentation rate of monodisperse silica particles upon variation of volume fraction particles, pH, salinity, amount of silanol groups at the particle surface and temperature was studied. The cross interactions play an important role and a model explaining the variation in sedimentation is introduced. Finally, magnetic particles dispersed in water and in an external magnetic field were used to study the impact on the sedimentation due to the induced flocculation. 209 refs., 90 figs., 9 tabs.
Mean-cluster approach indicates cell sorting time scales are determined by collective dynamics
Beatrici, Carine P.; de Almeida, Rita M. C.; Brunnet, Leonardo G.
2017-03-01
Cell migration is essential to cell segregation, playing a central role in tissue formation, wound healing, and tumor evolution. Considering random mixtures of two cell types, it is still not clear which cell characteristics define clustering time scales. The mass of diffusing clusters merging with one another is expected to grow as td /d +2 when the diffusion constant scales with the inverse of the cluster mass. Cell segregation experiments deviate from that behavior. Explanations for that could arise from specific microscopic mechanisms or from collective effects, typical of active matter. Here we consider a power law connecting diffusion constant and cluster mass to propose an analytic approach to model cell segregation where we explicitly take into account finite-size corrections. The results are compared with active matter model simulations and experiments available in the literature. To investigate the role played by different mechanisms we considered different hypotheses describing cell-cell interaction: differential adhesion hypothesis and different velocities hypothesis. We find that the simulations yield normal diffusion for long time intervals. Analytic and simulation results show that (i) cluster evolution clearly tends to a scaling regime, disrupted only at finite-size limits; (ii) cluster diffusion is greatly enhanced by cell collective behavior, such that for high enough tendency to follow the neighbors, cluster diffusion may become independent of cluster size; (iii) the scaling exponent for cluster growth depends only on the mass-diffusion relation, not on the detailed local segregation mechanism. These results apply for active matter systems in general and, in particular, the mechanisms found underlying the increase in cell sorting speed certainly have deep implications in biological evolution as a selection mechanism.
Murcott, W J
2014-09-01
A young person's transition of care from child and adolescent mental health services to adult mental health services can be an uncertain and distressing event that can have serious ramifications for their recovery. Recognition of this across many countries and recent UK media interest in the dangers of mental health services failing young people has led practitioners to question the existing processes. This paper reviews the current theories and research into potential failings of services and encourages exploration for a deeper understanding of when and how care should be managed in the transition process for young people. Mental health nurses can play a vital role in this process and, by adopting the assumptions of this paradigm, look at transition from this unique perspective. By reviewing the current ideas related to age boundaries, service thresholds, service philosophy and service design, it is argued that the importance of the therapeutic relationship, the understanding of the cultural context of the young person and the placing of the young person in a position of autonomy and control should be central to any decision and process of transfer between two mental health services. © 2014 John Wiley & Sons Ltd.
Pneumatic oscillator circuits for timing and control of integrated microfluidics.
Duncan, Philip N; Nguyen, Transon V; Hui, Elliot E
2013-11-05
Frequency references are fundamental to most digital systems, providing the basis for process synchronization, timing of outputs, and waveform synthesis. Recently, there has been growing interest in digital logic systems that are constructed out of microfluidics rather than electronics, as a possible means toward fully integrated laboratory-on-a-chip systems that do not require any external control apparatus. However, the full realization of this goal has not been possible due to the lack of on-chip frequency references, thus requiring timing signals to be provided from off-chip. Although microfluidic oscillators have been demonstrated, there have been no reported efforts to characterize, model, or optimize timing accuracy, which is the fundamental metric of a clock. Here, we report pneumatic ring oscillator circuits built from microfluidic valves and channels. Further, we present a compressible-flow analysis that differs fundamentally from conventional circuit theory, and we show the utility of this physically based model for the optimization of oscillator stability. Finally, we leverage microfluidic clocks to demonstrate circuits for the generation of phase-shifted waveforms, self-driving peristaltic pumps, and frequency division. Thus, pneumatic oscillators can serve as on-chip frequency references for microfluidic digital logic circuits. On-chip clocks and pumps both constitute critical building blocks on the path toward achieving autonomous laboratory-on-a-chip devices.
Energy Technology Data Exchange (ETDEWEB)
MacKinnon, Robert J.; Kuhlman, Kristopher L
2016-05-01
We present a method of control variates for calculating improved estimates for mean performance quantities of interest, E(PQI) , computed from Monte Carlo probabilistic simulations. An example of a PQI is the concentration of a contaminant at a particular location in a problem domain computed from simulations of transport in porous media. To simplify the presentation, the method is described in the setting of a one- dimensional elliptical model problem involving a single uncertain parameter represented by a probability distribution. The approach can be easily implemented for more complex problems involving multiple uncertain parameters and in particular for application to probabilistic performance assessment of deep geologic nuclear waste repository systems. Numerical results indicate the method can produce estimates of E(PQI)having superior accuracy on coarser meshes and reduce the required number of simulations needed to achieve an acceptable estimate.
Fog-computing concept usage as means to enhance information and control system reliability
Melnik, E. V.; Klimenko, A. B.; Ivanov, D. Ya
2018-05-01
This paper focuses on the reliability issue of information and control systems (ICS). The authors propose using the elements of the fog-computing concept to enhance the reliability function. The key idea of fog-computing is to shift computations to the fog-layer of the network, and thus to decrease the workload of the communication environment and data processing components. As for ICS, workload also can be distributed among sensors, actuators and network infrastructure facilities near the sources of data. The authors simulated typical workload distribution situations for the “traditional” ICS architecture and for the one with fogcomputing concept elements usage. The paper contains some models, selected simulation results and conclusion about the prospects of the fog-computing as a means to enhance ICS reliability.
Mean Field Type Control with Congestion (II): An Augmented Lagrangian Method
Energy Technology Data Exchange (ETDEWEB)
Achdou, Yves, E-mail: achdou@ljll.univ-paris-diderot.fr; Laurière, Mathieu [Univ. Paris Diderot, Sorbonne Paris Cité, Laboratoire Jacques-Louis Lions, UMR 7598, UPMC, CNRS (France)
2016-12-15
This work deals with a numerical method for solving a mean-field type control problem with congestion. It is the continuation of an article by the same authors, in which suitably defined weak solutions of the system of partial differential equations arising from the model were discussed and existence and uniqueness were proved. Here, the focus is put on numerical methods: a monotone finite difference scheme is proposed and shown to have a variational interpretation. Then an Alternating Direction Method of Multipliers for solving the variational problem is addressed. It is based on an augmented Lagrangian. Two kinds of boundary conditions are considered: periodic conditions and more realistic boundary conditions associated to state constrained problems. Various test cases and numerical results are presented.
2010-04-01
... controlled substances by means of the Internet. 1300.04 Section 1300.04 Food and Drugs DRUG ENFORCEMENT... substances by means of the Internet. (a) Any term not defined in this part or elsewhere in this chapter shall... evaluation of the patient. (c) The term deliver, distribute, or dispense by means of the Internet refers...
Directory of Open Access Journals (Sweden)
Ling Zhang
2012-01-01
Full Text Available We study a multi-period mean-variance portfolio selection problem with an uncertain time horizon and serial correlations. Firstly, we embed the nonseparable multi-period optimization problem into a separable quadratic optimization problem with uncertain exit time by employing the embedding technique of Li and Ng (2000. Then we convert the later into an optimization problem with deterministic exit time. Finally, using the dynamic programming approach, we explicitly derive the optimal strategy and the efficient frontier for the dynamic mean-variance optimization problem. A numerical example with AR(1 return process is also presented, which shows that both the uncertainty of exit time and the serial correlations of returns have significant impacts on the optimal strategy and the efficient frontier.
Garcia, Rolando R.; Boville, Byron A.
1994-01-01
According to the 'downward control' principle, the extratropical mean vertical velocity on a given pressure level is approximately proportional to the meridional gradient of the vertically integrated zonal force per unit mass exerted by waves above that level. In this paper, a simple numerical model that includes parameterizations of both planetary and gravity wave breaking is used to explore the influence of gravity wave breaking in the mesosphere on the mean meridional circulation and temperature distribution at lower levels in the polar winter stratosphere. The results of these calculations suggest that gravity wave drag in the mesosphere can affect the state of the polar winter stratosphere down to altitudes below 30 km. The effect is most important when planetary wave driving is relatively weak: that is, during southern winter and in early northern winter. In southern winter, downwelling weakens by a factor of 2 near the stratospause and by 20% at 30 km when gravity wave drag is not included in the calculations. As a consequence, temperatures decrease considerably throughout the polar winter stratosphere (over 20 K above 40 km and as much as 8 K at 30 km, where the effect is enhanced by the long radiative relaxation timescale). The polar winter states obtained when gravity wave drag is omitted in this simple model resemble the results of simulations with some general circulation models and suggest that some of the shortcomings of the latter may be due to a deficit in mesospheric momentum deposition by small-scale gravity waves.
Orthogonal control of expression mean and variance by epigenetic features at different genomic loci.
Dey, Siddharth S; Foley, Jonathan E; Limsirichai, Prajit; Schaffer, David V; Arkin, Adam P
2015-05-05
While gene expression noise has been shown to drive dramatic phenotypic variations, the molecular basis for this variability in mammalian systems is not well understood. Gene expression has been shown to be regulated by promoter architecture and the associated chromatin environment. However, the exact contribution of these two factors in regulating expression noise has not been explored. Using a dual-reporter lentiviral model system, we deconvolved the influence of the promoter sequence to systematically study the contribution of the chromatin environment at different genomic locations in regulating expression noise. By integrating a large-scale analysis to quantify mRNA levels by smFISH and protein levels by flow cytometry in single cells, we found that mean expression and noise are uncorrelated across genomic locations. Furthermore, we showed that this independence could be explained by the orthogonal control of mean expression by the transcript burst size and noise by the burst frequency. Finally, we showed that genomic locations displaying higher expression noise are associated with more repressed chromatin, thereby indicating the contribution of the chromatin environment in regulating expression noise. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.
Pacheco, P.; Álvarez, J.; Sarmiento, R.; Bredice, F.; Sánchez-Aké, C.; Villagrán-Muniz, M.; Palleschi, V.
2018-04-01
A Nd:YAG ns-pulsed laser was used to ablate Al, Cd and Zn targets, which were placed between the plates of a planar charged capacitor. The plasma generates a transient redistribution of the electrical charges on the plates that can be measured as a voltage drop across a resistor connected to the ground plate. This signal is proportional to the capacitor applied voltage, the distance between the plates and the total number of ions produced in the ablation process which in turn is related to the laser energy and the ablated mass. After a series of pulses, the targets were weighed on a thermogravimetric balance to measure the ablated mass. Our results show that the electrical signal measured on the resistor is univocally related to the ablated mass from the target. Therefore, after a proper calibration depending on the material and the experimental geometry, the electrical signal can be used for real time quantitative measurement of the ablated mass in pulsed laser generated plasma experiments. The experiments were repeated on an aluminum target, with and without the presence of the external electric field in order to determine the possible influence of the applied electric field on the ablated mass.
An attempt to model the timing of magma formation by means of radioactive disequilibria
International Nuclear Information System (INIS)
Cortini, M.
1985-01-01
In order to quantitatively determine the timing of magma formation, the Th series radioactive disequilibria for the Etna and Stromboli volcanoes have been re-examined in the light of new isotopic evidence that shows that magma formation is a chemically open-system process. This aim was but partially reached. It is shown that single-stage models of magma formation are not consistent with the experimental data. Short-life disequilibria require that magma formation undergoes: (1) a Th and Ra enrichment stage (a few years long); (2) a closed-system stage (a few tens to some hundreds years long); (3) a second Th and Ra enrichment stage (a few years long), different from the former in terms of Ra/Th ratio. The whole process can be described by a group of equations, derived from open-system non-equilibrium thermodynamics, which were integrated with numerical methods. However, too many unknowns are involved to allow a one-to-one solution based on the available data. (orig.)
Alternative strategies: A means for saving money and time on the Yucca Mountain Project
International Nuclear Information System (INIS)
Wilder, D.G.
1993-01-01
The United States Department of Energy (DOE) is undertaking studies to determine the suitability of Yucca Mountain (YM) as a potential site for disposal of high level nuclear waste. Yucca Mountain is located in an arid environment. Many processes that could contribute to mobilization of radionuclides are either absent or minimized in a dry site. Therefore, Yucca Mountain should have the potential of being a veryfavorable site for disposal of waste. The determination of suitability has no precedence, and the characterization of an and site is complex, requiring intensive studies to determine suitability. The studies undertaken by the Yucca Mountain Site Characterization Project (YMP) are very costly. By a process called performance allocation, the YMP determined strategies to satisfy regulations or meet performance while minimizing costs and schedules. Those involved recognized that allocations should be reviewed as additional information became available. The allocation has not been reviewed nor revised since the initial allocation in the Site Characterization Plan (SCP). The purpose of this paper is to outline alternative allocations that the author feels should be considered based on the additional information that is available at this time
First-time observation of Mastro Giorgio masterpieces by means of non-destructive techniques
Padeletti, G.; Ingo, G. M.; Bouquillon, A.; Pages-Camagna, S.; Aucouturier, M.; Roehrs, S.; Fermo, P.
2006-06-01
For the first time some excellent pieces belonging to the majolica production of the great master Giorgio Andreoli from Gubbio (Central Italy) have been characterized from a chemical and structural point of view with the aim to identify the composition of both pigments and lustres. A series of particle-induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and Raman analyses have been performed on some plates coming from Museo del Palazzo dei Consoli (Gubbio) and several French museums (Louvre, Musée National de la Céramique, Musée National de la Renaissance) lustred by Giorgio Andreoli and decorated by famous majolica painters such as Francesco Xanto Avelli. The three techniques are complementary and useful in the investigation of art objects since they are non-destructive. Furthermore, the low detection limits allow the identification of all elements and compounds present, and RBS allows concentration profiling, too. It is worth noticing that the examined objects are characterized by the presence of both gold and ruby-red lustres, a peculiarity of Mastro Giorgio’s technique. The measurements by PIXE and RBS have been carried out on the AGLAE accelerator at C2RMF, Louvre Palace.
International Nuclear Information System (INIS)
Li Dongxi; Xu Wei; Guo Yongfeng; Li Gaojie
2008-01-01
The mean first-passage time of a bistable system with time-delayed feedback driven by multiplicative non-Gaussian noise and additive Gaussian white noise is investigated. Firstly, the non-Markov process is reduced to the Markov process through a path-integral approach; Secondly, the approximate Fokker-Planck equation is obtained by applying the unified coloured noise approximation, the small time delay approximation and the Novikov Theorem. The functional analysis and simplification are employed to obtain the approximate expressions of MFPT. The effects of non-Gaussian parameter (measures deviation from Gaussian character) r, the delay time τ, the noise correlation time τ 0 , the intensities D and α of noise on the MFPT are discussed. It is found that the escape time could be reduced by increasing the delay time τ, the noise correlation time τ 0 , or by reducing the intensities D and α. As far as we know, this is the first time to consider the effect of delay time on the mean first-passage time in the stochastic dynamical system
International Nuclear Information System (INIS)
Frank, T D; Mongkolsakulvong, S
2015-01-01
In a previous study strongly nonlinear autoregressive (SNAR) models have been introduced as a generalization of the widely-used time-discrete autoregressive models that are known to apply both to Markov and non-Markovian systems. In contrast to conventional autoregressive models, SNAR models depend on process mean values. So far, only linear dependences have been studied. We consider the case in which process mean values can have a nonlinear impact on the processes under consideration. It is shown that such models describe Markov and non-Markovian many-body systems with mean field forces that exhibit a nonlinear impact on single subsystems. We exemplify that such nonlinear dependences can describe order-disorder phase transitions of time-discrete Markovian and non-Markovian many-body systems. The relevant order parameter equations are derived and issues of stability and stationarity are studied. (paper)
International Nuclear Information System (INIS)
Wang, J.; Cao, L.; Wu, D.J.
2003-01-01
We present an analytic investigation of the mean first passage time in two opposite directions (from the left well to the right well and from right to left) by studying symmetrical bistable systems driven by correlated Gaussian white noises, and prove that the mean first passage time in two opposite directions is not symmetrical any more when noises are correlated. As examples, the mean first passage time in the quartic bistable model and the sawtooth bistable model are calculated, respectively. From the analytic results of the mean first passage time, we testify further the relation T(from x - to x + ,λ)≠T(from x + to x - ,λ) in the same area of the parameter plan. Moreover, it is found that the dependences of T + (i.e., T(from x - to x + ,λ)) and T - (i.e., T(from x + to x - ,λ)) upon the multiplicative noise intensity Q and the additive noise intensity D exhibit entirely different properties. For same areas of the parameter plan: in the quartic bistable system, when the T + vs. Q curve exhibits a maximum, while the T - vs. Q curve is monotonous; when the T + vs. D curve is monotonous, while the T - vs. D curve experiences a phase transition from decreasing monotonously to possessing one minimum. Increasing Q, when the T + vs. D curve experiences a phase transition from decreasing monotonously to possessing one maximum, while the T - vs. D curve only increases monotonously. Similar behaviours also exist in the sawtooth bistable model
On robust multi-period pre-commitment and time-consistent mean-variance portfolio optimization
F. Cong (Fei); C.W. Oosterlee (Kees)
2017-01-01
textabstractWe consider robust pre-commitment and time-consistent mean-variance optimal asset allocation strategies, that are required to perform well also in a worst-case scenario regarding the development of the asset price. We show that worst-case scenarios for both strategies can be found by
Discrete-Time LPV Current Control of an Induction Motor
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2003-01-01
In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...... further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop...
Grape juice quality control by means of {sup 1}H NMR spectroscopy and chemometric analyses
Energy Technology Data Exchange (ETDEWEB)
Grandizoli, Caroline Werner Pereira da Silva; Campos, Francinete Ramos; Simonelli, Fabio; Barison, Andersson [Universidade Federal do Paraná (UFPR), Curitiba (Brazil). Departamento de Química
2014-07-01
This work shows the application of {sup 1}H NMR spectroscopy and chemometrics for quality control of grape juice. A wide range of quality assurance parameters were assessed by single {sup 1}H NMR experiments acquired directly from juice. The investigation revealed that conditions and time of storage should be revised and indicated on all labels. The sterilization process of homemade grape juices was efficient, making it possible to store them for long periods without additives. Furthermore, chemometric analysis classified the best commercial grape juices to be similar to homemade grape juices, indicating that this approach can be used to determine the authenticity after adulteration. (author)
CAMAC module control from the TPA-1001/i by means of the FOCAL programming language
International Nuclear Information System (INIS)
Angelov, A.Kh.; Dubovik, L.V.
1977-01-01
The possibility of using FOCAL programming language to control CAMAC modules by minicomputer is considered. This language allows to make effective changes in the program and reduce the time necessary for writing and running programmes. To address CAMAC modules a packet of CAMAC subroutines from the CAMAC-tr A/i software is included into FOCAL language, its operational possibilities and linguistic peculiarities being completely preserved. A big fast memory enables one to add three additional functions to the function list of FOCAL language. An example is given illustrating the use of these functions
Stamopoulos, D.; Zeibekis, M.; Zhang, S. J.
2018-01-01
The controlled modification of superconductivity by any means, specifically in hybrid systems, has attracted much interest in the recent decades. Here, we present experimental data and phenomenological modeling on the control of TC of superconducting (SC) Nb thin films, with thickness 3 nm ≤ dN b≤50 nm, under the application of in-plane strain, S(Eex) induced by an external out-of-plane electric field, Eex to piezoelectric (PE) single crystals, namely, ( 1 -x )Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT), with x = 0.27 and 0.31. We report experimental modification of TC of Nb by Eex, accurately described by a phenomenological model that incorporates the constitutive relation S(Eex) of PMN-xPT. The systematic experimental-phenomenological modeling approach introduced here is generic and paves the way for an understanding of the underlying physical mechanisms in any SC/PE hybrid.
Mechanisms Controlling Global Mean Sea Surface Temperature Determined From a State Estimate
Ponte, R. M.; Piecuch, C. G.
2018-04-01
Global mean sea surface temperature (T¯) is a variable of primary interest in studies of climate variability and change. The temporal evolution of T¯ can be influenced by surface heat fluxes (F¯) and by diffusion (D¯) and advection (A¯) processes internal to the ocean, but quantifying the contribution of these different factors from data alone is prone to substantial uncertainties. Here we derive a closed T¯ budget for the period 1993-2015 based on a global ocean state estimate, which is an exact solution of a general circulation model constrained to most extant ocean observations through advanced optimization methods. The estimated average temperature of the top (10-m thick) level in the model, taken to represent T¯, shows relatively small variability at most time scales compared to F¯, D¯, or A¯, reflecting the tendency for largely balancing effects from all the latter terms. The seasonal cycle in T¯ is mostly determined by small imbalances between F¯ and D¯, with negligible contributions from A¯. While D¯ seems to simply damp F¯ at the annual period, a different dynamical role for D¯ at semiannual period is suggested by it being larger than F¯. At periods longer than annual, A¯ contributes importantly to T¯ variability, pointing to the direct influence of the variable ocean circulation on T¯ and mean surface climate.
A distributed timing system for synchronizing control and data correlation
International Nuclear Information System (INIS)
Stettler, M.; Thuot, M.; Dalesio, L.R.; Cole, R.; Fite, C.; Slentz, G.; Warren, D.
1992-01-01
Synchronization is necessary in experimental physics machines to provide positive control over related events. The Ground Test Accelerator (GTA) timing system provides this function through a distributed control system, known as the Experimental Physics and Industrial Control System (EPICS). The EPICS timing system was designed to take advantage of a distributed architecture, and provides time stamping for synchronous data correlation as well as event control. The system has been successfully demonstrated on over a dozen controller nodes for operation and data analysis. The design of the hardware, software, and operational results are discussed. (author). 2 refs., 4 figs
A distributed timing system for sychronizing control and data correlation
International Nuclear Information System (INIS)
Stettler, M.; Thout, M.; Dalesio, L.R.; Cole, R.; Fite, C.; Slentz, G.; Warren, D.
1992-01-01
Synchronization is necessary in experimental physics machines to provide positive control over related events. The Ground Test Accelerator (GTA) timing system provides this function through a distributed control system, known as the Experimental Physics and Industrial Control System (EPICS). The EPICS timing system was designed to take advantage of a distributed architecture, and provides time stamping for synchronous data correlation as well as event control. The system has been successfully demonstrated on over a dozen controller nodes for operation and data analysis. The design of the hardware, software, and operational results are discussed
Discrete-Time LPV Current Control of an Induction Motor
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2001-01-01
In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... without further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as experimentally on the actual induction motor, both in open-loop current control and when an outer...... speed control loop is closed around the current loop...
Discrete-Time LPV Current Control of an Induction Motor
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2003-01-01
In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop...... is closed around the current loop....
Foundation for a Time Interval Access Control Model
National Research Council Canada - National Science Library
Afinidad, Francis B; Levin, Timothy E; Irvine, Cynthia E; Nguyen, Thuy D
2005-01-01
A new model for representing temporal access control policies is introduced. In this model, temporal authorizations are represented by time attributes associated with both subjects and objects, and a time interval access graph...
Real-time control of Tokamak plasmas: from control of physics to physics-based control
International Nuclear Information System (INIS)
Felici, F. A. A.
2011-11-01
Stable, high-performance operation of a tokamak requires several plasma control problems to be handled simultaneously. Moreover, the complex physics which governs the tokamak plasma evolution must be studied and understood to make correct choices in controller design. In this thesis, the two subjects have been merged, using control solutions as experimental tool for physics studies, and using physics knowledge for developing new advanced control solutions. The TCV tokamak at CRPP-EPFL is ideally placed to explore issues at the interface between plasma physics and plasma control, by combining a digital realtime control system with a flexible and powerful set of actuators, in particular the electron cyclotron heating and current drive system (ECRH/ECCD). This experimental platform has been used to develop and test new control strategies for three plasma physics instabilities: sawtooth, edge localized mode (ELM) and neoclassical tearing mode (NTM). The period of the sawtooth crash, a periodic MHD instability in the core of a tokamak plasma, can be varied by localized deposition of ECRH/ECCD near the q = 1 surface (q: safety factor). A sawtooth pacing controller was developed which is able to control the time of appearance of the next sawtooth crash. Each individual sawtooth period can be controlled in real-time. A similar scheme is applied to H-mode plasmas with type-I ELMs, where it is shown that pacing regularizes the ELM period. The regular, reproducible and therefore predictable sawtooth crashes have been used to study the relationship between sawteeth and NTMs. Postcrash MHD activity can provide the ‘seed’ island for an NTM, which then grows under its neoclassical bootstrap drive. The seeding of 3/2 NTMs by long sawtooth crashes can be avoided by preemptive, crash-synchronized EC power injection pulses at the q = 3/2 rational surface location. NTM stabilization experiments in which the ECRH deposition location is moved in real-time with steerable mirrors have
Sansosti, Laura E; Spiess, Kerianne E; Meyr, Andrew J
We have previously demonstrated an abnormally delayed mean brake response time and an increased frequency of abnormally delayed brake responses in a group of neuropathic diabetic drivers compared with a control group of drivers with neither diabetes nor lower extremity neuropathy. The objective of the present case-control study was to compare the mean brake response time between neuropathic diabetic drivers with and without specific diabetic foot pathology. The braking performances of the participants were evaluated using a computerized driving simulator with specific measurement of the mean brake response time and the frequency of abnormally delayed brake responses. We analyzed a control group of 20 active drivers with type 2 diabetes, lower extremity neuropathy, and no history of diabetic foot pathology and an experimental group of 20 active drivers with type 2 diabetes, lower extremity neuropathy, and a history of diabetic foot pathology (ulceration, amputation, and/or Charcot neuroarthropathy) from an urban U.S. podiatric medical clinic. Neuropathic diabetic drivers without a history of specific foot pathology demonstrated an 11.11% slower mean brake response time (0.790 ± 0.223 versus 0.711 ± 0.135 second; p time slower than a suggested threshold of 0.70 second. The results of the present investigation provide evidence that diabetic patients across a spectrum of lower extremity sensorimotor neuropathy and foot pathology demonstrate abnormal automobile brake responses and might be at risk of impaired driving function. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.
Low-complexity controllers for time-delay systems
Özbay, Hitay; Bonnet, Catherine; Mounier, Hugues
2014-01-01
This volume in the newly established series Advances in Delays and Dynamics (ADD@S) provides a collection of recent results on the design and analysis of Low Complexity Controllers for Time Delay Systems. A widely used indirect method to obtain low order controllers for time delay systems is to design a controller for the reduced order model of the plant. In the dual indirect approach, an infinite dimensional controller is designed first for the original plant model; then, the controller is approximated by keeping track of the degradation in performance and stability robustness measures. The present volume includes new techniques used at different stages of the indirect approach. It also includes new direct design methods for fixed structure and low order controllers. On the other hand, what is meant by low complexity controller is not necessarily low order controller. For example, Smith predictor or similar type of controllers include a copy of the plant internally in the controller, so they are technically ...
Integrals of Motion for Discrete-Time Optimal Control Problems
Torres, Delfim F. M.
2003-01-01
We obtain a discrete time analog of E. Noether's theorem in Optimal Control, asserting that integrals of motion associated to the discrete time Pontryagin Maximum Principle can be computed from the quasi-invariance properties of the discrete time Lagrangian and discrete time control system. As corollaries, results for first-order and higher-order discrete problems of the calculus of variations are obtained.
Rahman, P. A.; D'K Novikova Freyre Shavier, G.
2018-03-01
This scientific paper is devoted to the analysis of the mean time to data loss of redundant disk arrays RAID-6 with alternation of data considering different failure rates of disks both in normal state of the disk array and in degraded and rebuild states, and also nonzero time of the disk replacement. The reliability model developed by the authors on the basis of the Markov chain and obtained calculation formula for estimation of the mean time to data loss (MTTDL) of the RAID-6 disk arrays are also presented. At last, the technique of estimation of the initial reliability parameters and examples of calculation of the MTTDL of the RAID-6 disk arrays for the different numbers of disks are also given.
Hygienic quality control of chicken (thighs) by means of ionizing radiations
International Nuclear Information System (INIS)
Lescano, G.; Kairiyama, E.; Narvaiz, P.; Kaupert, N.L.
1990-01-01
High quality chicken thighs, packed in polystyrene trays covered with PVC films, were treated with ionizing energy provided by a semiindustrial 60 Co facility, with a dose of 2.5 kGy, at the temperature of melting ice. Control and irradiated samples were stored at 2 deg C ± 2 deg C and RH: 89 % ± 6 %. Microbiological, chemical and sensory evaluations were performed. This treatment improved significantly the hygienic quality of the product, and reduced in two log cycles the initial number of aerobic bacteria, which led to a 2.5 times extension of the commercialization period. A diminished water content was observed after irradiation. Decreasing values were also found in every sample as storage time went by; the irradiated sample, on day 23, had values 9 % lower than that of the control sample on day 2. Rancidity, measured as peroxide number, increased their values after irradiation, but in such extent that was not noticed organoleptically. It was never higher than 10 meg/kg of fat (specification of the Argentine Alimentary Codex for oils). The commercial quality of the irradiated samples was acceptable until day 22. (Author) [es
[Internal audit in medical laboratory: what means of control for an effective audit process?].
Garcia-Hejl, Carine; Chianéa, Denis; Dedome, Emmanuel; Sanmartin, Nancy; Bugier, Sarah; Linard, Cyril; Foissaud, Vincent; Vest, Philippe
2013-01-01
To prepare the French Accreditation Committee (COFRAC) visit for initial certification of our medical laboratory, our direction evaluated its quality management system (QMS) and all its technical activities. This evaluation was performed owing an internal audit. This audit was outsourced. Auditors had an expertise in audit, a whole knowledge of biological standards and were independent. Several nonconformities were identified at that time, including a lack of control of several steps of the internal audit process. Hence, necessary corrective actions were taken in order to meet the requirements of standards, in particular, the formalization of all stages, from the audit program, to the implementation, review and follow-up of the corrective actions taken, and also the implementation of the resources needed to carry out audits in a pre-established timing. To ensure an optimum control of each step, the main concepts of risk management were applied: process approach, root cause analysis, effects and criticality analysis (FMECA). After a critical analysis of our practices, this methodology allowed us to define our "internal audit" process, then to formalize it and to follow it up, with a whole documentary system.
International Nuclear Information System (INIS)
Keles, Dogan; Genoese, Massimo; Möst, Dominik; Fichtner, Wolf
2012-01-01
This paper evaluates different financial price and time series models, such as mean reversion, autoregressive moving average (ARMA), integrated ARMA (ARIMA) and general autoregressive conditional heteroscedasticity (GARCH) process, usually applied for electricity price simulations. However, as these models are developed to describe the stochastic behaviour of electricity prices, they are extended by a separate data treatment for the deterministic components (trend, daily, weekly and annual cycles) of electricity spot prices. Furthermore price jumps are considered and implemented within a regime-switching model. Since 2008 market design allows for negative prices at the European Energy Exchange, which also occurred for several hours in the last years. Up to now, only a few financial and time series approaches exist, which are able to capture negative prices. This paper presents a new approach incorporating negative prices. The evaluation of the different approaches presented points out that the mean reversion and the ARMA models deliver the lowest mean root square error between simulated and historical electricity spot prices gained from the European Energy Exchange. These models posses also lower mean average errors than GARCH models. Hence, they are more suitable to simulate well-fitting price paths. Furthermore it is shown that the daily structure of historical price curves is better captured applying ARMA or ARIMA processes instead of mean-reversion or GARCH models. Another important outcome of the paper is that the regime-switching approach and the consideration of negative prices via the new proposed approach lead to a significant improvement of the electricity price simulation. - Highlights: ► Considering negative prices improves the results of time-series and financial models for electricity prices. ► Regime-switching approach captures the jumps and base prices quite well. ► Removing and separate modelling of deterministic annual, weekly and daily
Computational investigation of flow control by means of tubercles on Darrieus wind turbine blades
Sevinç, K.; Özdamar, G.; Şentürk, U.; Özdamar, A.
2015-09-01
This work presents the current status of the computational study of the boundary layer control of a vertical axis wind turbine blade by modifying the blade geometry for use in wind energy conversion. The control method is a passive method which comprises the implementation of the tubercle geometry of a humpback whale flipper onto the leading edge of the blades. The baseline design is an H-type, three-bladed Darrieus turbine with a NACA 0015 cross-section. Finite-volume based software ANSYS Fluent was used in the simulations. Using the optimum control parameters for a NACA 634-021 profile given by Johari et al. (2006), turbine blades were modified. Three dimensional, unsteady, turbulent simulations for the blade were conducted to look for a possible improvement on the performance. The flow structure on the blades was investigated and flow phenomena such as separation and stall were examined to understand their impact on the overall performance. For a tip speed ratio of 2.12, good agreement was obtained in the validation of the baseline model with a relative error in time- averaged power coefficient of 1.05%. Modified turbine simulations with a less expensive but less accurate turbulence model yielded a decrease in power coefficient. Results are shown comparatively.
Directory of Open Access Journals (Sweden)
John Cortés-Romero
2013-01-01
Full Text Available The problem of active disturbance rejection control of induction motors is tackled by means of a generalized PI observer based discrete-time control, using the delta operator approach as the methodology of analyzing the sampled time process. In this scheme, model uncertainties and external disturbances are included in a general additive disturbance input which is to be online estimated and subsequently rejected via the controller actions. The observer carries out the disturbance estimation, thus reducing the complexity of the controller design. The controller efficiency is tested via some experimental results, performing a trajectory tracking task under load variations.
Conditions for settling liquid levels by means of gamma-ray relay control
Energy Technology Data Exchange (ETDEWEB)
Wakabayashi, N [Kobe Univ. (Japan). Faculty of Engineering
1976-03-01
Using a control action which consists of infusion and exhaust at constant speeds and a neutral zone to maintain liquid levels within a given range, a gamma-ray source, a detector, and two relays at the upper and lower limits of the counting rate were provided. The optimum condition in this case is discussed and confirmed experimentally. Since a counting rate-meter has a time constant and its output is subject to the statistical fluctuation, the liquid level may overrun the opposite limit, move again after settling within the range, or drift far out of the range by a load before actuation of the relay. Formulas are derived providing the conditions such that these phenomena will not occur more frequently than a tolerant probability. These give the relations between the counting rates at the upper and lower limits, the time constant of the rate-meter, the multipliers of the standard deviations of the counting rates, the infusing and exhausting speeds, and the hysteresis widths of the limiting relays. Since it can be said that the first two of the five quantities should be smaller and the next two greater, the optimum condition can be determined from the formulas. When the infusing and exhausting speeds are the same and the hysteresis widths are equal, the formulas show that the optimum is a case where the ratio of the counting rates at the two limits, which is taken smaller than unity, is small, and where each hysteresis width is equal to 0.34 times the difference between the two counting rates, almost regardless of the value of their ratio. The above-mentioned deductions were examined in a system constructed with a backscattered gamma-ray type level gauge and a controller for infusion and exhaust of water. Its results almost agreed with those of the deductions when the multipliers of the standard deviations are substituted for by 2.
Directory of Open Access Journals (Sweden)
Giuseppe Cannistraro
2015-08-01
Full Text Available The hygrothermal comfort indoor conditions are defined as: those environmental conditions in which an individual exposed, expresses a state of satisfaction. These conditions cannot always be achieved anywhere in an optimal way and economically; in some cases they can be obtained only in work environments specific areas. This could be explained because of air conditioning systems designing is generally performed both on the basis of the fundamental parameters’ average values, such as temperature, velocity and relative humidity (Ta, va e φa and derived parameters such as operating temperature and mean radiant one (Top eTmr. However, in some specific cases - large open-spaces or in case of radiating surfaces - the descriptors defining indoor comfort conditions, based on average values, do not provide the optimum values required during the air conditioning systems design phase. This is largely due to the variability of real environmental parameters values compared to the average ones taken as input in the calculation. The results obtained in previous scientific papers on the thermal comfort have been the driving element of this work. It offers a simple, original and clever way of thinking about the new domotic systems for air conditioning, based on the “local mean radiant temperature.” This is a very important parameter when one wants to analyze comfort in environments characterized by the presence of radiating surfaces, as will be seen hereinafter. In order to take into account the effects of radiative exchanges in the open-space workplace, where any occupant may find themselves in different temperature and humidity conditions, this paper proposes an action on the domotic climate control, with ducts and vents air distribution placed in different zones. Comparisons were performed between the parameters values representing the punctual thermal comfort, with the Predicted Mean Vote PMV, in an environment marked by radiating surfaces (i
Shen, Gang; Zhu, Zhencai; Zhao, Jinsong; Zhu, Weidong; Tang, Yu; Li, Xiang
2017-03-01
This paper focuses on an application of an electro-hydraulic force tracking controller combined with an offline designed feedback controller (ODFC) and an online adaptive compensator in order to improve force tracking performance of an electro-hydraulic force servo system (EHFS). A proportional-integral controller has been employed and a parameter-based force closed-loop transfer function of the EHFS is identified by a continuous system identification algorithm. By taking the identified system model as a nominal plant model, an H ∞ offline design method is employed to establish an optimized feedback controller with consideration of the performance, control efforts, and robustness of the EHFS. In order to overcome the disadvantage of the offline designed controller and cope with the varying dynamics of the EHFS, an online adaptive compensator with a normalized least-mean-square algorithm is cascaded to the force closed-loop system of the EHFS compensated by the ODFC. Some comparative experiments are carried out on a real-time EHFS using an xPC rapid prototype technology, and the proposed controller yields a better force tracking performance improvement. Copyright © 2016. Published by Elsevier Ltd.
Calculation method for control rod dropping time in reactor
International Nuclear Information System (INIS)
Nogami, Takeki; Kato, Yoshifumi; Ishino, Jun-ichi; Doi, Isamu.
1996-01-01
If a control rod starts dropping, the dropping speed is rapidly increased, then settled substantially constant, rapidly decreased when it reaches a dash pot. A second detection signal generated by removing an AC component from a first detection signal is differentiated twice. The time when the maximum value among the twice differentiated values is generated is determined as a time when the control rods starts dropping. The time when minimum value among the twice differentiated values is generated is determined as a time when the control rod reaches the dash pot of the reactor. The measuring time within a range from the time when the control rod starts dropping to the time when the control rod reaches the dash pot of the reactor is determined. As a result, processing for the calculation of the dropping start time and dash pot reaching time of the control rod can be automatized. Further, it is suffice to conduct differentiation twice till the reaching time, which can facilitate the processing thereby enabling to determine a reliable time range. (N.H.)
Evaluation of Real-Time Hand Motion Tracking Using a Range Camera and the Mean-Shift Algorithm
Lahamy, H.; Lichti, D.
2011-09-01
Several sensors have been tested for improving the interaction between humans and machines including traditional web cameras, special gloves, haptic devices, cameras providing stereo pairs of images and range cameras. Meanwhile, several methods are described in the literature for tracking hand motion: the Kalman filter, the mean-shift algorithm and the condensation algorithm. In this research, the combination of a range camera and the simple version of the mean-shift algorithm has been evaluated for its capability for hand motion tracking. The evaluation was assessed in terms of position accuracy of the tracking trajectory in x, y and z directions in the camera space and the time difference between image acquisition and image display. Three parameters have been analyzed regarding their influence on the tracking process: the speed of the hand movement, the distance between the camera and the hand and finally the integration time of the camera. Prior to the evaluation, the required warm-up time of the camera has been measured. This study has demonstrated the suitability of the range camera used in combination with the mean-shift algorithm for real-time hand motion tracking but for very high speed hand movement in the traverse plane with respect to the camera, the tracking accuracy is low and requires improvement.
Real time control of plasmas and ECRH systems on TCV
Paley, J.I.; Felici, F.; Berrino, J.; Coda, S.; Cruz, N.; Duval, B.P.; Goodman, T.P.; Martin, Y.; Moret, J.-M.; Piras, F.; Rodrigues, A.P.; Santos, B.; Varandas, C.A.F.
2008-01-01
Developments in the real time control hardware on TCV paired with the flexibility of plasma shaping and ECRH actuators are opening many opportunities to perform real time experiments and develop algorithms and methods for fusion applications. The ability to control MHD instabilities is particularly
On the application of Discrete Time Optimal Control Concepts to ...
African Journals Online (AJOL)
On the application of Discrete Time Optimal Control Concepts to Economic Problems. ... Journal of the Nigerian Association of Mathematical Physics ... Abstract. An extension of the use of the maximum principle to solve Discrete-time Optimal Control Problems (DTOCP), in which the state equations are in the form of general ...
Direct output feedback control of discrete-time systems
International Nuclear Information System (INIS)
Lin, C.C.; Chung, L.L.; Lu, K.H.
1993-01-01
An optimal direct output feedback control algorithm is developed for discrete-time systems with the consideration of time delay in control force action. Optimal constant output feedback gains are obtained through variational process such that certain prescribed quadratic performance index is minimized. Discrete-time control forces are then calculated from the multiplication of output measurements by these pre-calculated feedback gains. According to the proposed algorithm, structural system is assured to remain stable even in the presence of time delay. The number of sensors and controllers may be very small as compared with the dimension of states. Numerical results show that direct velocity feedback control is more sensitive to time delay than state feedback but, is still quite effective in reducing the dynamic responses under earthquake excitation. (author)
Discrete-time optimal control and games on large intervals
Zaslavski, Alexander J
2017-01-01
Devoted to the structure of approximate solutions of discrete-time optimal control problems and approximate solutions of dynamic discrete-time two-player zero-sum games, this book presents results on properties of approximate solutions in an interval that is independent lengthwise, for all sufficiently large intervals. Results concerning the so-called turnpike property of optimal control problems and zero-sum games in the regions close to the endpoints of the time intervals are the main focus of this book. The description of the structure of approximate solutions on sufficiently large intervals and its stability will interest graduate students and mathematicians in optimal control and game theory, engineering, and economics. This book begins with a brief overview and moves on to analyze the structure of approximate solutions of autonomous nonconcave discrete-time optimal control Lagrange problems.Next the structures of approximate solutions of autonomous discrete-time optimal control problems that are discret...
A simple time-delayed method to control chaotic systems
International Nuclear Information System (INIS)
Chen Maoyin; Zhou Donghua; Shang Yun
2004-01-01
Based on the adaptive iterative learning strategy, a simple time-delayed controller is proposed to stabilize unstable periodic orbits (UPOs) embedded in chaotic attractors. This controller includes two parts: one is a linear feedback part; the other is an adaptive iterative learning estimation part. Theoretical analysis and numerical simulation show the effectiveness of this controller
Landing-Time-Controlled Management Of Air Traffic
Erzberger, Heinz; Tobias, Leonard
1988-01-01
Conceptual system controls aircraft with old and new guidance equipment. Report begins with overview of concept, then reviews controller-interactive simulations. Describes fuel-conservative-trajectory algorithm, based on equations of motion for controlling landing time. Finally, presents results of piloted simulations.
Predicting timing performance of advanced mechatronics control systems
Voeten, J.P.M.; Hendriks, T.; Theelen, B.D.; Schuddemat, J.; Tabingh Suermondt, W.; Gemei, J.; Kotterink, C.; Huet, van J.; Eichler, G.; Kuepper, A.; Schau, V.; Fouchal, H.; Unger, H.
2011-01-01
Embedded control is a key product technology differentiator for many high-tech industries, including ASML. The strong increase in complexity of embedded control systems, combined with the occurrence of late changes in control requirements, results in many timing performance problems showing up only
Controlling shareholders and market timing in share issuance
Urzua Infante, F.; Larrain, B.
2013-01-01
We examine market timing in the equity issuance of firms controlled by large shareholders using a hand-collected data set of controlling shareholders' ownership stakes in Chile between 1990 and 2009. When a firm issues shares, the controlling shareholder can either maintain or change his ownership
Real-time control systems: feedback, scheduling and robustness
Simon, Daniel; Seuret, Alexandre; Sename, Olivier
2017-08-01
The efficient control of real-time distributed systems, where continuous components are governed through digital devices and communication networks, needs a careful examination of the constraints arising from the different involved domains inside co-design approaches. Thanks to the robustness of feedback control, both new control methodologies and slackened real-time scheduling schemes are proposed beyond the frontiers between these traditionally separated fields. A methodology to design robust aperiodic controllers is provided, where the sampling interval is considered as a control variable of the system. Promising experimental results are provided to show the feasibility and robustness of the approach.
International Nuclear Information System (INIS)
Preuss, W.; Eggerdinger, C.; Sieber, R.
1982-01-01
This report describes the findings of an investigation into selected communication means for control room personnel in nuclear power stations. The study can be seen as a contribution to the systematic analysis of major problem areas which were identified in the general study 'Human factors in the nuclear power plant'. The subjects under investigation were the 'Shift book', 'Simulation book', and 'Technical and organisational changes and their records'. It was intended to analyse both the communication, processes and the associated written documentation in order to determine areas for potential improvement and possibilities for standardization. Information was obtained by interviewing shift members and their supervisors, by general observation, and by compilation and evaluation of the extensive dokumentation. Assessment criteria were developed on a scientific basis and in the course of the investigation, in particular from ergonomic findings, as well as from standards and regulations and comparison between the plants. General practical suggestions were developed for the improvement of the communication forms and the formal design of the documents and their contents. The transfer of the recommendations to practical use in the plants presupposes the consideration of plant-specific frames of reference. The report includes a compilation and listing of suggestions for improvement in topical subdivisions. (orig.) [de
Engineering applications of discrete-time optimal control
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui; Ravn, Hans V.
1990-01-01
Many problems of design and operation of engineering systems can be formulated as optimal control problems where time has been discretisized. This is also true even if 'time' is not involved in the formulation of the problem, but rather another one-dimensional parameter. This paper gives a review...... of some well-known and new results in discrete time optimal control methods applicable to practical problem solving within engineering. Emphasis is placed on dynamic programming, the classical maximum principle and generalized versions of the maximum principle for optimal control of discrete time systems...
Discrete-Time Nonlinear Control of VSC-HVDC System
Directory of Open Access Journals (Sweden)
TianTian Qian
2015-01-01
Full Text Available Because VSC-HVDC is a kind of strong nonlinear, coupling, and multi-input multioutput (MIMO system, its control problem is always attracting much attention from scholars. And a lot of papers have done research on its control strategy in the continuous-time domain. But the control system is implemented through the computer discrete sampling in practical engineering. It is necessary to study the mathematical model and control algorithm in the discrete-time domain. The discrete mathematical model based on output feedback linearization and discrete sliding mode control algorithm is proposed in this paper. And to ensure the effectiveness of the control system in the quasi sliding mode state, the fast output sampling method is used in the output feedback. The results from simulation experiment in MATLAB/SIMULINK prove that the proposed discrete control algorithm can make the VSC-HVDC system have good static, dynamic, and robust characteristics in discrete-time domain.
Attributing Meanings to Representations of Data: The Case of Statistical Process Control
Hoyles, Celia; Bakker, Arthur; Kent, Phillip; Noss, Richard
2007-01-01
This article is concerned with the meanings that employees in industry attribute to representations of data and the contingencies of these meanings in context. Our primary concern is to more precisely characterize how the context of the industrial process is constitutive of the meaning of graphs of data derived from this process. We draw on data…
International Nuclear Information System (INIS)
Aguiar, Lais A. de; Frutuoso e Melo, P.F.; Alvim, Antonio C.M.
2007-01-01
This work aims at estimating the mean time to failure (MTTF) of each barrier of a near surface radioactive waste repository. It is assumed that surface water infiltrates through the barriers, reaching the matrix where radionuclides are contained, releasing them to the environment. Radioactive wastes considered in this work are low and medium level wastes (produced during operation of a PWR nuclear power station) fixed on cement. The repository consists of 6 saturated porous media barriers (top cover, upper layer, packages, basis, repository walls and geosphere). It has been verified that the mean time to failure (MTTF) of each barrier increases for radionuclides having higher retardation factor (Fr) and also that the MTTF for concrete is larger for Nickel , while for the geosphere, Plutonium gives the largest MTTF. (author)
Estimate of the global-scale joule heating rates in the thermosphere due to time mean currents
International Nuclear Information System (INIS)
Roble, R.G.; Matsushita, S.
1975-01-01
An estimate of the global-scale joule heating rates in the thermosphere is made based on derived global equivalent overhead electric current systems in the dynamo region during geomagnetically quiet and disturbed periods. The equivalent total electric field distribution is calculated from Ohm's law. The global-scale joule heating rates are calculated for various monthly average periods in 1965. The calculated joule heating rates maximize at high latitudes in the early evening and postmidnight sectors. During geomagnetically quiet times the daytime joule heating rates are considerably lower than heating by solar EUV radiation. However, during geomagnetically disturbed periods the estimated joule heating rates increase by an order of magnitude and can locally exceed the solar EUV heating rates. The results show that joule heating is an important and at times the dominant energy source at high latitudes. However, the global mean joule heating rates calculated near solar minimum are generally small compared to the global mean solar EUV heating rates. (auth)
Decentralized control of discrete-time linear time invariant systems with input saturation
Deliu, Ciprian; Deliu, C.; Malek, Babak; Roy, Sandip; Saberi, Ali; Stoorvogel, Antonie Arij
2009-01-01
We study decentralized stabilization of discrete time linear time invariant (LTI) systems subject to actuator saturation, using LTI controllers. The requirement of stabilization under both saturation constraints and decentralization impose obvious necessary conditions on the open-loop plant, namely
Ferreira, Aline S; Silva-Paes-Leme, Annelisa F; Raposo, Nádia R B; da Silva, Sílvio S
2015-01-01
Xylitol is an important polyalcohol suitable for use in odontological, medical and pharmaceutical products and as an additive in food. The first studies on the efficacy of xylitol in the control and treatment of infections started in the late 1970s and it is still applied for this purpose, with safety and very little contribution to resistance. Xylitol seems to act against microorganisms exerting an anti-adherence effect. Some research studies have demonstrated its action against Gram-positive and Gram-negative bacteria and yeasts. However, a clear explanation of how xylitol is effective has not been completely established yet. Some evidence shows that xylitol acts on gene expression, down-regulating the ones which are involved in the microorganisms' virulence, such as capsule formation. Another possible clarification is that xylitol blocks lectin-like receptors. The most important aspect is that, over time, xylitol bypasses microbial resistance and succeeds in controlling infection, either alone or combined with another compound. In this review, the effect of xylitol in inhibiting the growth of a different microorganism is described, focusing on studies in which such an anti-adherent property was highlighted. This is the first mini-review to describe xylitol as an anti-adherent compound and take into consideration how it exerts such action.
Remote control of data acquisition devices by means of message oriented middleware
International Nuclear Information System (INIS)
Sanchez, E.; Portas, A.; Pereira, A.; Vega, J.; Kirpitchev, I.
2007-01-01
The TJ-II autonomous acquisition systems are computers running dedicated applications for programming and controlling data acquisition channels and also integrating acquired data into the central database. These computers are located in the experimental hall and have to be remotely controlled during plasma discharges. A remote control for these systems has been implemented by taking advantage of the message-oriented middleware recently introduced into the TJ-II data acquisition system. Java Message Service (JMS) is used as the messaging application program interface. All the acquisition actions that are available through the system console of the data acquisition computers (starting or aborting an acquisition, restarting the system or updating the acquisition application) can now be initiated remotely. Command messages are sent to the acquisition systems located in the experimental hall close to the TJ-II device by using the messaging software, without having to use a remote desktop application that produces heavy network traffic and requires manual operation. Action commands can be sent to only one or to several/many acquisition systems at the same time. This software is integrated into the TJ-II remote participation system and the acquisition systems can be commanded from inside or outside the laboratory. All this software is integrated into the security framework provided by PAPI, thus preventing non-authorized users commanding the acquisition computers. In order to dimension and distribute messaging services some performance tests of the message oriented middleware software have been carried out. Results of the tests are presented. As suggested by the tests results different transport connectors are used: TCP transport protocol is used for the local environment, while HTTP protocol is used for remote accesses, thereby allowing the system performance to be optimized
Remote control of data acquisition devices by means of message oriented middleware
Energy Technology Data Exchange (ETDEWEB)
Sanchez, E. [Asociacion EURATOM/CIEMAT para Fusion, Madrid (Spain)], E-mail: edi.sanchez@ciemat.es; Portas, A.; Pereira, A.; Vega, J.; Kirpitchev, I. [Asociacion EURATOM/CIEMAT para Fusion, Madrid (Spain)
2007-10-15
The TJ-II autonomous acquisition systems are computers running dedicated applications for programming and controlling data acquisition channels and also integrating acquired data into the central database. These computers are located in the experimental hall and have to be remotely controlled during plasma discharges. A remote control for these systems has been implemented by taking advantage of the message-oriented middleware recently introduced into the TJ-II data acquisition system. Java Message Service (JMS) is used as the messaging application program interface. All the acquisition actions that are available through the system console of the data acquisition computers (starting or aborting an acquisition, restarting the system or updating the acquisition application) can now be initiated remotely. Command messages are sent to the acquisition systems located in the experimental hall close to the TJ-II device by using the messaging software, without having to use a remote desktop application that produces heavy network traffic and requires manual operation. Action commands can be sent to only one or to several/many acquisition systems at the same time. This software is integrated into the TJ-II remote participation system and the acquisition systems can be commanded from inside or outside the laboratory. All this software is integrated into the security framework provided by PAPI, thus preventing non-authorized users commanding the acquisition computers. In order to dimension and distribute messaging services some performance tests of the message oriented middleware software have been carried out. Results of the tests are presented. As suggested by the tests results different transport connectors are used: TCP transport protocol is used for the local environment, while HTTP protocol is used for remote accesses, thereby allowing the system performance to be optimized.
Research on classified real-time flood forecasting framework based on K-means cluster and rough set.
Xu, Wei; Peng, Yong
2015-01-01
This research presents a new classified real-time flood forecasting framework. In this framework, historical floods are classified by a K-means cluster according to the spatial and temporal distribution of precipitation, the time variance of precipitation intensity and other hydrological factors. Based on the classified results, a rough set is used to extract the identification rules for real-time flood forecasting. Then, the parameters of different categories within the conceptual hydrological model are calibrated using a genetic algorithm. In real-time forecasting, the corresponding category of parameters is selected for flood forecasting according to the obtained flood information. This research tests the new classified framework on Guanyinge Reservoir and compares the framework with the traditional flood forecasting method. It finds that the performance of the new classified framework is significantly better in terms of accuracy. Furthermore, the framework can be considered in a catchment with fewer historical floods.
Neural Feedback Scheduling of Real-Time Control Tasks
Xia, Feng; Tian, Yu-Chu; Sun, Youxian; Dong, Jinxiang
2008-01-01
Many embedded real-time control systems suffer from resource constraints and dynamic workload variations. Although optimal feedback scheduling schemes are in principle capable of maximizing the overall control performance of multitasking control systems, most of them induce excessively large computational overheads associated with the mathematical optimization routines involved and hence are not directly applicable to practical systems. To optimize the overall control performance while minimi...
Analysis of Time Delay Simulation in Networked Control System
Nyan Phyo Aung; Zaw Min Naing; Hla Myo Tun
2016-01-01
The paper presents a PD controller for the Networked Control Systems (NCS) with delay. The major challenges in this networked control system (NCS) are the delay of the data transmission throughout the communication network. The comparative performance analysis is carried out for different delays network medium. In this paper, simulation is carried out on Ac servo motor control system using CAN Bus as communication network medium. The True Time toolbox of MATLAB is used for simulation to analy...
Engine control system having speed-based timing
Willi, Martin L [Dunlap, IL; Fiveland, Scott B [Metamora, IL; Montgomery, David T [Edelstein, IL; Gong, Weidong [Dunlap, IL
2012-02-14
A control system for an engine having a cylinder is disclosed having an engine valve movable to regulate a fluid flow of the cylinder and an actuator associated with the engine valve. The control system also has a controller in communication with the actuator. The controller is configured to receive a signal indicative of engine speed and compare the engine speed signal with a desired engine speed. The controller is also configured to selectively regulate the actuator to adjust a timing of the engine valve to control an amount of air/fuel mixture delivered to the cylinder based on the comparison.
Directory of Open Access Journals (Sweden)
Krasnykh V.Yu.
2017-06-01
Full Text Available the article describes the main system requirements of software of finished products for implementation of an automatic control system by technical means at the garage consumer cooperative.
Real time neutral beam power control on MAST
Energy Technology Data Exchange (ETDEWEB)
Homfray, David A., E-mail: david.homfray@ccfe.ac.uk [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Benn, A.; Ciric, D.; Day, I.; Dunkley, V.; Keeling, D.; Khilar, S.; King, D.; King, R. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Kurutz, U. [Department of Experimental Plasma Physics, University of Augsburg, Augsburg (Germany); Payne, D.; Simmonds, M.; Stevenson, P.; Tame, C. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon (United Kingdom)
2011-10-15
Real time power control of neutral beam provides an excellent tool for many different plasma physics studies. Power control at a better resolution than the level of a single injector is usually achieved by modulating individual power supplies. However, the short beam slowing down time on MAST is such that the plasma would be sensitive to modulating the neutral beam using this 100% on-off pulse-width modulation method. A novel alternative method of power control has been demonstrated, where the arc current, and hence beam current, has been controlled in real time allowing variations in neutral beam power. This has been demonstrated in a MAST plasma with almost no loss of transmission as a consequence of the optical properties of the high perveance MAST neutral beam system. This paper will detail the methodology, experiment and results and discuss the full implementation of this method that will allow MAST to control the beam power in real time.
Tas, Ibrahim; Iskender, Murat
2018-01-01
The aim of this study is to examine meaning in life, satisfaction with life, self-concept and locus of control among teachers by several variables. The research group was composed of 363 teachers (114 [40%] women, 219 [60%] men) working in several districts of Istanbul. The data were collected with Meaning in Life Scale (MLS), Satisfaction with…
Time-optimal control of infinite order distributed parabolic systems involving time lags
Directory of Open Access Journals (Sweden)
G.M. Bahaa
2014-06-01
Full Text Available A time-optimal control problem for linear infinite order distributed parabolic systems involving constant time lags appear both in the state equation and in the boundary condition is presented. Some particular properties of the optimal control are discussed.
Concepts of real time and semi-real time material control
International Nuclear Information System (INIS)
Lovett, J.E.
1975-01-01
After a brief consideration of the traditional material balance accounting on an MBA basis, this paper explores the basic concepts of real time and semi-real time material control, together with some of the major problems to be solved. Three types of short-term material control are discussed: storage, batch processing, and continuous processing. (DLC)
Prototyping Real-Time Control in the SPS
Andersson, J; Jensen, L; Jones, R; Lamont, M; Wenninger, J; Wijnands, Thijs; CERN. Geneva. AB Department
2003-01-01
Real-time control of beam related parameters will be required in the LHC. In order to gain experience of the issues involved in implementing distributed real-time control over large distances, a prototype local orbit feedback system is being developed in the SPS. This will use 6 pickups, each equipped with the full LHC acquisition electronics chain and linked to a real-time communication and feedback system. This reports summarises the .rst tests performed with this system in October 2002, where the data from four pickups was successfully acquired and displayed at 10 Hz in the control room.
Time-varying linear control for tiltrotor aircraft
Directory of Open Access Journals (Sweden)
Jing ZHANG
2018-04-01
Full Text Available Tiltrotor aircraft have three flight modes: helicopter mode, airplane mode, and transition mode. A tiltrotor has characteristics of highly nonlinear, time-varying flight dynamics and inertial/control couplings in its transition mode. It can transit from the helicopter mode to the airplane mode by tilting its nacelles, and an effective controller is crucial to accomplish tilting transition missions. Longitudinal dynamic characteristics of the tiltrotor are described by a nonlinear Lagrange-form model, which takes into account inertial/control couplings and aerodynamic interferences. Reference commands for airspeed velocity and attitude in the transition mode are calculated dynamically by visiting a command library which is founded in advance by analyzing the flight envelope of the tiltrotor. A Time-Varying Linear (TVL model is obtained using a Taylor-expansion based online linearization technique from the nonlinear model. Subsequently, based on an optimal control concept, an online optimization based control method with input constraints considered is proposed. To validate the proposed control method, three typical tilting transition missions are simulated using the nonlinear model of XV-15 tiltrotor aircraft. Simulation results show that the controller can be used to control the tiltrotor throughout its operating envelop which includes a transition flight, and can also deal with vertical gust disturbances. Keywords: Constrained optimal control, Inertia/control couplings, Tiltrotor aircraft, Time-varying control, Transition mode
Microcomputer-controlled world time display for public area viewing
Yep, S.; Rashidian, M.
1982-05-01
The design, development, and implementation of a microcomputer-controlled world clock is discussed. The system, designated international Time Display System (ITDS), integrates a Geochron Calendar Map and a microcomputer-based digital display to automatically compensate for daylight savings time, leap year, and time zone differences. An in-depth technical description of the design and development of the electronic hardware, firmware, and software systems is provided. Reference material on the time zones, fabrication techniques, and electronic subsystems are also provided.
Real-time software for the COMPASS tokamak plasma control
International Nuclear Information System (INIS)
Valcarcel, D.F.; Duarte, A.S.; Neto, A.; Carvalho, I.S.; Carvalho, B.B.; Fernandes, H.; Sousa, J.; Sartori, F.; Janky, F.; Cahyna, P.; Hron, M.; Panek, R.
2010-01-01
The COMPASS tokamak has started its operation recently in Prague and to meet the necessary operation parameters its real-time system, for data processing and control, must be designed for both flexibility and performance, allowing the easy integration of code from several developers and to guarantee the desired time cycle. For this purpose an Advanced Telecommunications Computing Architecture based real-time system has been deployed with a solution built on a multi-core x86 processor. It makes use of two software components: the BaseLib2 and the MARTe (Multithreaded Application Real-Time executor) real-time frameworks. The BaseLib2 framework is a generic real-time library with optimized objects for the implementation of real-time algorithms. This allowed to build a library of modules that process the acquired data and execute control algorithms. MARTe executes these modules in kernel space Real-Time Application Interface allowing to attain the required cycle time and a jitter of less than 1.5 μs. MARTe configuration and data storage are accomplished through a Java hardware client that connects to the FireSignal control and data acquisition software. This article details the implementation of the real-time system for the COMPASS tokamak, in particular the organization of the control code, the design and implementation of the communications with the actuators and how MARTe integrates with the FireSignal software.
Real-time software for the COMPASS tokamak plasma control
Energy Technology Data Exchange (ETDEWEB)
Valcarcel, D.F., E-mail: danielv@ipfn.ist.utl.p [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Duarte, A.S.; Neto, A.; Carvalho, I.S.; Carvalho, B.B.; Fernandes, H.; Sousa, J. [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Sartori, F. [Euratom-UKAEA, Culham Science Centre, Abingdon, OX14 3DB Oxon (United Kingdom); Janky, F.; Cahyna, P.; Hron, M.; Panek, R. [Institute of Plasma Physics AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 182 00 Prague (Czech Republic)
2010-07-15
The COMPASS tokamak has started its operation recently in Prague and to meet the necessary operation parameters its real-time system, for data processing and control, must be designed for both flexibility and performance, allowing the easy integration of code from several developers and to guarantee the desired time cycle. For this purpose an Advanced Telecommunications Computing Architecture based real-time system has been deployed with a solution built on a multi-core x86 processor. It makes use of two software components: the BaseLib2 and the MARTe (Multithreaded Application Real-Time executor) real-time frameworks. The BaseLib2 framework is a generic real-time library with optimized objects for the implementation of real-time algorithms. This allowed to build a library of modules that process the acquired data and execute control algorithms. MARTe executes these modules in kernel space Real-Time Application Interface allowing to attain the required cycle time and a jitter of less than 1.5 {mu}s. MARTe configuration and data storage are accomplished through a Java hardware client that connects to the FireSignal control and data acquisition software. This article details the implementation of the real-time system for the COMPASS tokamak, in particular the organization of the control code, the design and implementation of the communications with the actuators and how MARTe integrates with the FireSignal software.
A General Theory of Markovian Time Inconsistent Stochastic Control Problems
DEFF Research Database (Denmark)
Björk, Tomas; Murgochi, Agatha
We develop a theory for stochastic control problems which, in various ways, are time inconsistent in the sense that they do not admit a Bellman optimality principle. We attach these problems by viewing them within a game theoretic framework, and we look for Nash subgame perfect equilibrium points...... examples of time inconsistency in the literature are easily seen to be special cases of the present theory. We also prove that for every time inconsistent problem, there exists an associated time consistent problem such that the optimal control and the optimal value function for the consistent problem...
Real-Time Software for the Compass Tokamak Plasma Control
Energy Technology Data Exchange (ETDEWEB)
Valcarcel, D.F.; Duarte, A.S.; Neto, A.; Carvalho, I.S.; Carvalho, B.B.; Fernandes, H.; Sousa, J. [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Lisboa (Portugal); Sartori, F. [Euratom-UKAEA, Culham Science Centre, Abingdon, OX14 3DB Oxon (United Kingdom); Janky, F.; Cahyna, P.; Hron, M.; Panek, R. [Institute of Plasma Physics AS CR, v.v.i., Association EURATOM / IPP.CR, Prague (Costa Rica)
2009-07-01
This poster presents the flexible and high-performance real time system that guarantees the desired time cycles for plasma control on the COMPASS tokamak: 500 {mu}s for toroidal field, current, equilibrium and shaping; 50 {mu}s for fast control of the equilibrium and vertical instability. This system was developed on top of a high-performance processor and a software framework (MARTe) tailored for real-time. The preliminary measurements indicate that the time constraints will be met on the final solution. The system allows the making of modifications in the future to improve software components. (A.C.)
Control of epileptic seizures in WAG/Rij rats by means of brain-computer interface
Makarov, Vladimir V.; Maksimenko, Vladimir A.; van Luijtelaar, Gilles; Lüttjohann, Annika; Hramov, Alexander E.
2018-02-01
The main issue of epileptology is the elimination of epileptic events. This can be achieved by a system that predicts the emergence of seizures in conjunction with a system that interferes with the process that leads to the onset of seizure. The prediction of seizures remains, for the present, unresolved in the absence epilepsy, due to the sudden onset of seizures. We developed an algorithm for predicting seizures in real time, evaluated it and implemented it into an online closed-loop brain stimulation system designed to prevent typical for the absence of epilepsy of spike waves (SWD) in the genetic rat model. The algorithm correctly predicts more than 85% of the seizures and the rest were successfully detected. Unlike the old beliefs that SWDs are unpredictable, current results show that they can be predicted and that the development of systems for predicting and preventing closed-loop capture is a feasible step on the way to intervention to achieve control and freedom from epileptic seizures.
Real-time communication for distributed plasma control systems
Energy Technology Data Exchange (ETDEWEB)
Luchetta, A. [Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Corso Stati Uniti 4, Padova 35127 (Italy)], E-mail: adriano.luchetta@igi.cnr.it; Barbalace, A.; Manduchi, G.; Soppelsa, A.; Taliercio, C. [Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Corso Stati Uniti 4, Padova 35127 (Italy)
2008-04-15
Real-time control applications will benefit in the near future from the enhanced performance provided by multi-core processor architectures. Nevertheless real-time communication will continue to be critical in distributed plasma control systems where the plant under control typically is distributed over a wide area. At RFX-mod real-time communication is crucial for hard real-time plasma control, due to the distributed architecture of the system, which consists of several VMEbus stations. The system runs under VxWorks and uses Gigabit Ethernet for sub-millisecond real-time communication. To optimize communication in the system, a set of detailed measurements has been carried out on the target platforms (Motorola MVME5100 and MVME5500) using either the VxWorks User Datagram Protocol (UDP) stack or raw communication based on the data link layer. Measurements have been carried out also under Linux, using its UDP stack or, in alternative, RTnet, an open source hard real-time network protocol stack. RTnet runs under Xenomai or RTAI, two popular real-time extensions based on the Linux kernel. The paper reports on the measurements carried out and compares the results, showing that the performance obtained by using open source code is suitable for sub-millisecond real-time communication in plasma control.
Real-time Control Mediation in Agile Distributed Software Development
DEFF Research Database (Denmark)
Persson, John Stouby; Aaen, Ivan; Mathiassen, Lars
2008-01-01
Agile distributed environments pose particular challenges related to control of quality and collaboration in software development. Moreover, while face-to-face interaction is fundamental in agile development, distributed environments must rely extensively on mediated interactions. On this backdrop...... control was mediated over distance by technology through real-time exchanges. Contrary to previous research, the analysis suggests that both formal and informal elements of real-time mediated control were used; that evolving goals and adjustment of expectations were two of the main issues in real......-time mediated control exchanges; and, that the actors, despite distances in space and culture, developed a clan-like pattern mediated by technology to help control quality and collaboration in software development....
Real-Time Application Performance Steering and Adaptive Control
National Research Council Canada - National Science Library
Reed, Daniel
2002-01-01
.... The objective of the Real-time Application Performance Steering and Adaptive Control project is to replace ad hoc, post-mortem performance optimization with an extensible, portable, and distributed...
FPGA Implementation of Real-Time Ethernet for Motion Control
Directory of Open Access Journals (Sweden)
Chen Youdong
2013-01-01
Full Text Available This paper provides an applicable implementation of real-time Ethernet named CASNET, which modifies the Ethernet medium access control (MAC to achieve the real-time requirement for motion control. CASNET is the communication protocol used for motion control system. Verilog hardware description language (VHDL has been used in the MAC logic design. The designed MAC serves as one of the intellectual properties (IPs and is applicable to various industrial controllers. The interface of the physical layer is RJ45. The other layers have been implemented by using C programs. The real-time Ethernet has been implemented by using field programmable gate array (FPGA technology and the proposed solution has been tested through the cycle time, synchronization accuracy, and Wireshark testing.
Takeover Time in Highly Automated Vehicles: Noncritical Transitions to and From Manual Control.
Eriksson, Alexander; Stanton, Neville A
2017-06-01
The aim of this study was to review existing research into driver control transitions and to determine the time it takes drivers to resume control from a highly automated vehicle in noncritical scenarios. Contemporary research has moved from an inclusive design approach to adhering only to mean/median values when designing control transitions in automated driving. Research into control transitions in highly automated driving has focused on urgent scenarios where drivers are given a relatively short time span to respond to a request to resume manual control. We found a paucity in research into more frequent scenarios for control transitions, such as planned exits from highway systems. Twenty-six drivers drove two scenarios with an automated driving feature activated. Drivers were asked to read a newspaper, or to monitor the system, and to relinquish, or resume, control from the automation when prompted by vehicle systems. Significantly longer control transition times were found between driving with and without secondary tasks. Control transition times were substantially longer than those reported in the peer-reviewed literature. We found that drivers take longer to resume control when under no time pressure compared with that reported in the literature. Moreover, we found that drivers occupied by a secondary task exhibit larger variance and slower responses to requests to resume control. Workload scores implied optimal workload. Intra- and interindividual differences need to be accommodated by vehicle manufacturers and policy makers alike to ensure inclusive design of contemporary systems and safety during control transitions.
Partial Finite-Time Synchronization of Switched Stochastic Chua's Circuits via Sliding-Mode Control
Directory of Open Access Journals (Sweden)
Zhang-Lin Wan
2011-01-01
Full Text Available This paper considers the problem of partial finite-time synchronization between switched stochastic Chua's circuits accompanied by a time-driven switching law. Based on the Ito formula and Lyapunov stability theory, a sliding-mode controller is developed to guarantee the synchronization of switched stochastic master-slave Chua's circuits and for the mean of error states to obtain the partial finite-time stability. Numerical simulations demonstrate the effectiveness of the proposed methods.
Real-time control for long ohmic alternate current discharges
International Nuclear Information System (INIS)
Carvalho, Ivo S.; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Hekkert, Tiago; Carvalho, Bernardo B.; Gomes, Rui B.
2014-01-01
Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks
Real-time control for long ohmic alternate current discharges
Energy Technology Data Exchange (ETDEWEB)
Carvalho, Ivo S., E-mail: ivoc@ipfn.ist.utl.pt; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Hekkert, Tiago; Carvalho, Bernardo B.; Gomes, Rui B.
2014-05-15
Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks.
Finite-Time Reentry Attitude Control Using Time-Varying Sliding Mode and Disturbance Observer
Directory of Open Access Journals (Sweden)
Xuzhong Wu
2015-01-01
Full Text Available This paper presents the finite-time attitude control problem for reentry vehicle with redundant actuators in consideration of planet uncertainties and external disturbances. Firstly, feedback linearization technique is used to cancel the nonlinearities of equations of motion to construct a basic mode for attitude controller. Secondly, two kinds of time-varying sliding mode control methods with disturbance observer are integrated with the basic mode in order to enhance the control performance and system robustness. One method is designed based on boundary layer technique and the other is a novel second-order sliding model control method. The finite-time stability analyses of both resultant closed-loop systems are carried out. Furthermore, after attitude controller produces the torque commands, an optimization control allocation approach is introduced to allocate them into aerodynamic surface deflections and on-off reaction control system thrusts. Finally, the numerical simulation results demonstrate that both of the time-varying sliding mode control methods are robust to uncertainties and disturbances without chattering phenomenon. Moreover, the proposed second-order sliding mode control method possesses better control accuracy.
The evolution of real-time control systems at JET
Energy Technology Data Exchange (ETDEWEB)
Goodyear, A.; Dorling, S.; Felton, R
2001-07-01
Real-time feedback control of the JET experiment is based upon a collection of diagnostics providing signals which are processed by various controllers that manipulate actuator parameters for plasma current, shape and heating. The real-time data network (RTDN) connects the diagnostic, controller and actuator systems to form a flexible feedback and protection system for plasma monitoring and control. The controllers are mainly VME systems based on the Motorola 680X0 (68K) processor with some computationally intensive systems utilising Texas Instruments TMS320C40 (C40) digital signal processors (DSP), though lately there has been a move towards PowerPC 750 based processors. The majority of 68K VME systems use VxWorks, a hard real time operating system. There is an ongoing requirement to improve the efficiency of the real-time control systems at JET. This is driven by a desire to either add more input signals, reduce the feedback cycle time or increase algorithm complexity. New technology has a major role to play in the upgrade of the real-time control systems but the novel redeployment of existing equipment can also be used to enhance performance. This paper examines the configuration of existing systems, both hardware and software, and how new technology can be gradually integrated without jeopardising the current functionality. The adoption of Asynchronous Transfer Mode (ATM) as the connection medium for the RTDN is key to the evolutional development of the control systems. The ATM network is extremely flexible to configure and benefits from low message latency and deterministic delivery time, essential properties for a real-time network. (author)
Real-time control environment for the RFX experiment
International Nuclear Information System (INIS)
Barana, O.; Cavinato, M.; Luchetta, A.; Manduchi, G.; Taliercio, C.
2005-01-01
A comprehensive set of control schemes can be presently implemented on RFX due to the enhanced load assembly and renewed power supply system. The schemes include: plasma equilibrium control and resistive wall mode stabilization, aiming at controlling actively the discharge when the passive action of the shell vanishes; the rotation of the localised helical deformation to minimize the enhanced plasma-wall interaction; the MHD mode control and the 'intelligent shell', aiming at achieving a better comprehension of the underlying physics. To the purpose, an integrated, distributed, digital system has been developed consisting of a set of computing nodes. Each node can act either as pre-processing or control station, the former acquiring raw data and computing intermediate control parameters, the latter executing control algorithms and driving the power amplifiers. An overview of the system architecture is presented in the paper with reference to the software real-time environment providing both basic functions, such as data read-out and real-time communication, and useful tools to program control algorithms, to perform simulations and to commission the system. To simulate the control schemes, the real-time environment is extended to include a so called 'simulation mode', in which the real-time nodes exchange their input/output signals with one station running a suitable model of the experiment, for instance the two dimensional FEM code MAXFEA in the case of the equilibrium control. In this way the control system can be tested offline and the time needed for the commissioning of algorithms reduced
Self-control mediates the relationship between time perspective and BMI.
Price, Menna; Higgs, Suzanne; Lee, Michelle
2017-01-01
Trait future time perspective measures the extent to which behaviour is dominated by a striving for future goals and rewards. Trait present time perspective measures orientation towards immediate pleasure. Previous research has explored the relationship between future and present time perspective and BMI with mixed findings. In addition, the psychological mechanism underlying this relationship is unclear. Self-control is a likely candidate, as it has been related to both BMI and time perspective, but the relationship between all of these concepts has not been examined in a single study. Therefore, the aim of this study was to examine if trait self-control mediates the relationship between time perspective (future and present) and BMI. Self-report time perspective (ZTPI), self-control (SCS) and height/weight data were collected using an online survey from a mixed student and community sample (N = 218) with wide ranging age (mean 29, SD 11, range 18-73 years) and BMI (mean 24, SD 4, range 15-43). The results of a structural equation model including both facets of time perspective suggested that the traits are related yet distinct measures that independently predict BMI through changes in self-control. Bootstrap mediation analysis showed that self-control mediated the relationship between both future time perspective (95% CI, -0.10 to -0.02) and present time perspective (95% CI, 0.03 to 0.17), and BMI in opposite directions. Participants with higher future time perspective scores (higher present time perspective scores) had higher (lower) self-control, which predicted lower (higher) BMI. These results are consistent with previous research suggesting an important role for time perspective in health outcomes. Self-control likely mediates the relationship between temporal perspectives and BMI, suggesting that time perspective may be a target for individualised interventions. Copyright Â© 2016 Elsevier Ltd. All rights reserved.
The hybrid UNIX controller for real-time data acquisition
International Nuclear Information System (INIS)
Huesman, R.H.; Klein, G.J.; Fleming, T.K.
1996-01-01
The authors describe a hybrid data acquisition architecture integrating a conventional UNIX workstation with CAMAC-based real-time hardware. The system combines the high-level programming simplicity and user interface of a UNIX workstation with the low-level timing control available from conventional real-time hardware. They detail this architecture as it has been implemented for control of the Donner 600-Crystal Positron Tomograph (PET600). Low-level data acquisition is carried out in this system using eight LeCroy 3588 histogrammers, which together after derandomization, acquire events at rates up to 4 MHz, and two dedicated Motorola 6809 microprocessors, which arbitrate fine timing control during acquisition. A SUN Microsystems UNIX workstation is used for high-level control, allowing an easily extensible user interface in an X-Windows environment, as well as real-time communications to the low-level acquisition units. Communication between the high- and low-level units is carried out via a Jorway 73A SCSI-CAMAC crate controller and a serial interface. For this application, the hybrid configuration segments low from high-level control for ease of maintenance and provided a low-cost upgrade from dated high-level control hardware
An adaptive robust controller for time delay maglev transportation systems
Milani, Reza Hamidi; Zarabadipour, Hassan; Shahnazi, Reza
2012-12-01
For engineering systems, uncertainties and time delays are two important issues that must be considered in control design. Uncertainties are often encountered in various dynamical systems due to modeling errors, measurement noises, linearization and approximations. Time delays have always been among the most difficult problems encountered in process control. In practical applications of feedback control, time delay arises frequently and can severely degrade closed-loop system performance and in some cases, drives the system to instability. Therefore, stability analysis and controller synthesis for uncertain nonlinear time-delay systems are important both in theory and in practice and many analytical techniques have been developed using delay-dependent Lyapunov function. In the past decade the magnetic and levitation (maglev) transportation system as a new system with high functionality has been the focus of numerous studies. However, maglev transportation systems are highly nonlinear and thus designing controller for those are challenging. The main topic of this paper is to design an adaptive robust controller for maglev transportation systems with time-delay, parametric uncertainties and external disturbances. In this paper, an adaptive robust control (ARC) is designed for this purpose. It should be noted that the adaptive gain is derived from Lyapunov-Krasovskii synthesis method, therefore asymptotic stability is guaranteed.
Time-optimal feedback control for linear systems
International Nuclear Information System (INIS)
Mirica, S.
1976-01-01
The paper deals with the results of qualitative investigations of the time-optimal feedback control for linear systems with constant coefficients. In the first section, after some definitions and notations, two examples are given and it is shown that even the time-optimal control problem for linear systems with constant coefficients which looked like ''completely solved'' requires a further qualitative investigation of the stability to ''permanent perturbations'' of optimal feedback control. In the second section some basic results of the linear time-optimal control problem are reviewed. The third section deals with the definition of Boltyanskii's ''regular synthesis'' and its connection to Filippov's theory of right-hand side discontinuous differential equations. In the fourth section a theorem is proved concerning the stability to perturbations of time-optimal feedback control for linear systems with scalar control. In the last two sections it is proved that, if the matrix which defines the system has only real eigenvalues or is three-dimensional, the time-optimal feedback control defines a regular synthesis and therefore is stable to perturbations. (author)
Infrared wireless data transfer for real-time motion control
Gajdusek, M.; Overboom, T.T.; Damen, A.A.H.; Bosch, van den P.P.J.
2009-01-01
In this paper several wireless solution are compared for their suitability for real-time control of a fast motion system. From the comparison, Very Fast Infrared (VFIR) communication link has been found to be an attractive solution for presented wirelessly controlled manipulator. Because standard
Auxiliary controller for time-to-digital converter module readout
International Nuclear Information System (INIS)
Ermolin, Yu.V.
1992-01-01
The KD-225 auxiliary controller for time-to-digital converter module readout in the SUMMA crate is described. After readout and preliminary processing the data are written in the P-140 buffer memory module. The controller is used in the FODS-2 experimental setup data acquisition system. 12 refs.; 1 fig
Real time control of the SSC string magnets
International Nuclear Information System (INIS)
Calvo, O.; Flora, R.; MacPherson, M.
1987-01-01
The system described in this paper, called SECAR, was designed to control the excitation of a test string of magnets for the proposed Superconducting Super Collider (SSC) and will be used to upgrade the present Tevatron Excitation, Control and Regulation (TECAR) hardware and software. It resides in a VME orate and is controlled by a 68020/68881 based CPU running the application software under a real time operating system named VRTX
Guaranteed cost control of time-delay chaotic systems
International Nuclear Information System (INIS)
Park, Ju H.; Kwon, O.M.
2006-01-01
This article studies a guaranteed cost control problem for a class of time-delay chaotic systems. Attention is focused on the design of memory state feedback controllers such that the resulting closed-loop system is asymptotically stable and an adequate level of performance is also guaranteed. Using the Lyapunov method and LMI (linear matrix inequality) framework, two criteria for the existence of the controller are derived in terms of LMIs. A numerical example is given to illustrate the proposed method
Real-Time Control of a Video Game Using Eye Movements and Two Temporal EEG Sensors
Directory of Open Access Journals (Sweden)
Abdelkader Nasreddine Belkacem
2015-01-01
Full Text Available EEG-controlled gaming applications range widely from strictly medical to completely nonmedical applications. Games can provide not only entertainment but also strong motivation for practicing, thereby achieving better control with rehabilitation system. In this paper we present real-time control of video game with eye movements for asynchronous and noninvasive communication system using two temporal EEG sensors. We used wavelets to detect the instance of eye movement and time-series characteristics to distinguish between six classes of eye movement. A control interface was developed to test the proposed algorithm in real-time experiments with opened and closed eyes. Using visual feedback, a mean classification accuracy of 77.3% was obtained for control with six commands. And a mean classification accuracy of 80.2% was obtained using auditory feedback for control with five commands. The algorithm was then applied for controlling direction and speed of character movement in two-dimensional video game. Results showed that the proposed algorithm had an efficient response speed and timing with a bit rate of 30 bits/min, demonstrating its efficacy and robustness in real-time control.
Real-Time Control of a Video Game Using Eye Movements and Two Temporal EEG Sensors.
Belkacem, Abdelkader Nasreddine; Saetia, Supat; Zintus-art, Kalanyu; Shin, Duk; Kambara, Hiroyuki; Yoshimura, Natsue; Berrached, Nasreddine; Koike, Yasuharu
2015-01-01
EEG-controlled gaming applications range widely from strictly medical to completely nonmedical applications. Games can provide not only entertainment but also strong motivation for practicing, thereby achieving better control with rehabilitation system. In this paper we present real-time control of video game with eye movements for asynchronous and noninvasive communication system using two temporal EEG sensors. We used wavelets to detect the instance of eye movement and time-series characteristics to distinguish between six classes of eye movement. A control interface was developed to test the proposed algorithm in real-time experiments with opened and closed eyes. Using visual feedback, a mean classification accuracy of 77.3% was obtained for control with six commands. And a mean classification accuracy of 80.2% was obtained using auditory feedback for control with five commands. The algorithm was then applied for controlling direction and speed of character movement in two-dimensional video game. Results showed that the proposed algorithm had an efficient response speed and timing with a bit rate of 30 bits/min, demonstrating its efficacy and robustness in real-time control.
Shen, Lu; Decker, Caitlin G; Maynard, Heather D; Levine, Alex J
2016-09-01
We present here the calculation of the mean time to capture of a tethered ligand to the receptor. This calculation is then used to determine the shift in the partitioning between (1) free, (2) singly bound, and (3) doubly bound ligands in chemical equilibrium as a function of the length of the tether. These calculations are used in the research article Fibroblast Growth Factor 2 Dimer with Superagonist in vitro Activity Improves Granulation Tissue Formation During Wound Healing (Decker et al., in press [1]) to explain quantitatively how changes in polymeric linker length in the ligand dimers modifies the efficacy of these molecules relative to that of free ligands.
Assessment of variations in control of asthma over time.
Combescure, C; Chanez, P; Saint-Pierre, P; Daurès, J P; Proudhon, H; Godard, P
2003-08-01
Control and severity of asthma are two different but complementary concepts. The severity of asthma could influence the control over time. The aim of this study was to demonstrate this relationship. A total 365 patients with persistent asthma (severity) were enrolled and followed-up prospectively. Data were analysed using a continuous time homogeneous Markov model of the natural history of asthma. Control of asthma was defined according to three health states which were qualified: optimal, suboptimal and unacceptable control (states 1, 2 and 3). Transition forces (denoted lambda(ij) from state i to state j) and transition probabilities between control states were assessed and the results stratified by asthma severity were compared. Models were validated by comparing expected and observed numbers of patients in the different states. Transition probabilities stabilised between 100-250 days and more rapidly in patients with mild-to-moderate asthma. Patients with mild-to-moderate asthma in suboptimal or unacceptable control had a high probability of transition directly to optimal control. Patients with severe asthma had a tendency to remain in unacceptable control. A Markov model is a useful tool to model the control of asthma over time. Severity modified clearly the health states. It could be used to compare the performance of different approaches to asthma management.
International Nuclear Information System (INIS)
Oelsner, Andreas; Rohmer, Martin; Schneider, Christian; Bayer, Daniela; Schoenhense, Gerd; Aeschlimann, Martin
2010-01-01
The present work enlightens the developments in time- and energy resolved photoemission electron microscopy over the past few years. We describe basic principles of the technique and demonstrate different applications. An energy- and time-filtering photoemission electron microscopy (PEEM) for real-time spectroscopic imaging can be realized either by a retarding field or hemispherical energy analyzer or by using time-of-flight optics with a delay line detector. The latter method has the advantage of no data loss at all as all randomly incoming particles are measured not only by position but also by time. This is of particular interest for pump-probe experiments in the femtosecond and attosecond time scale where space charge processes drastically limit the maximum number of photoemitted electrons per laser pulse. This work focuses particularly on time-of-flight analysis using a novel delay line detector. Time and energy resolved PEEM instruments with delay line detectors enable 4D imaging (x, y, Δt, E Kin ) on a true counting basis. This allows a broad range of applications from real-time observation of dynamic phenomena at surfaces to fs time-of-flight spectro-microscopy and even aberration correction. By now, these time-of-flight analysis instruments achieve intrinsic time resolutions of 108 ps absolute and 13.5 ps relative. Very high permanent measurement speeds of more than 4 million events per second in random detection regimes have been realized using a standard USB2.0 interface. By means of this performance, the time-resolved PEEM technique enables to display evolutions of spatially resolved (<25 nm) and temporal sliced images life on any modern computer. The method allows dynamics investigations of variable electrical, magnetic, and optical near fields at surfaces and great prospects in dynamical adaptive photoelectron optics. For dynamical processes in the ps time scale such as magnetic domain wall movements, the time resolution of the delay line detectors
Combs, Dennis R; Chapman, Dustin; Waguspack, Jace; Basso, Michael R; Penn, David L
2011-04-01
Deficits in emotion perception are common in people with schizophrenia and current research has focused on improving these deficits. In our previous research, we demonstrated that directing attention to salient facial features via attention shaping can improve these deficits among inpatients. In this study, we examined the efficacy of an enhanced attention shaping program that contains 192 emotional expressions from which 25 are randomly presented for training. We extended our previous work by using repeated administrations of the shaping intervention and testing its effect in outpatients with schizophrenia and impaired controls. Fifteen participants with schizophrenia and fourteen college student controls with emotion perception deficits were randomly assigned to 1, 3 or 5 sessions of attention shaping. Participants completed 2 outcome measures of emotion perception, the FEIT and BLERT, not presented during the training, and underwent eye tracking at pre and post-tests. All conditions and groups improved, but the largest improvements on the BLERT and FEIT were found for persons assigned to the 5 session condition. Performance on the shaping program was positively correlated with the two outcome measures of emotion perception. There was less support for changes in visual scanning of faces as there was a relative reduction in total scanning time from pre-test to post-test. Results are interpreted in terms of the efficacy of attention shaping as a means to improve emotion perception deficits. Copyright © 2010 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Galdiz Batxi
2004-09-01
Full Text Available Abstract Background Non-invasive monitoring of respiratory muscle function is an area of increasing research interest, resulting in the appearance of new monitoring devices, one of these being piezoelectric contact sensors. The present study was designed to test whether the use of piezoelectric contact (non-invasive sensors could be useful in respiratory monitoring, in particular in measuring the timing of diaphragmatic contraction. Methods Experiments were performed in an animal model: three pentobarbital anesthetized mongrel dogs. The motion of the thoracic cage was acquired by means of a piezoelectric contact sensor placed on the costal wall. This signal is compared with direct measurements of the diaphragmatic muscle length, made by sonomicrometry. Furthermore, to assess the diaphragmatic function other respiratory signals were acquired: respiratory airflow and transdiaphragmatic pressure. Diaphragm contraction time was estimated with these four signals. Using diaphragm length signal as reference, contraction times estimated with the other three signals were compared with the contraction time estimated with diaphragm length signal. Results The contraction time estimated with the TM signal tends to give a reading 0.06 seconds lower than the measure made with the DL signal (-0.21 and 0.00 for FL and DP signals, respectively, with a standard deviation of 0.05 seconds (0.08 and 0.06 for FL and DP signals, respectively. Correlation coefficients indicated a close link between time contraction estimated with TM signal and contraction time estimated with DL signal (a Pearson correlation coefficient of 0.98, a reliability coefficient of 0.95, a slope of 1.01 and a Spearman's rank-order coefficient of 0.98. In general, correlation coefficients and mean and standard deviation of the difference were better in the inspiratory load respiratory test than in spontaneous ventilation tests. Conclusion The technique presented in this work provides a non
Time-delay effects and simplified control fields in quantum Lyapunov control
International Nuclear Information System (INIS)
Yi, X X; Wu, S L; Wu, Chunfeng; Feng, X L; Oh, C H
2011-01-01
Lyapunov-based quantum control has the advantage that it is free from the measurement-induced decoherence and it includes the instantaneous information of the system in the control. The Lyapunov control is often confronted with time delay in the control fields and difficulty in practical implementations of the control. In this paper, we study the effect of time delay on the Lyapunov control and explore the possibility of replacing the control field with a pulse train or a bang-bang signal. The efficiency of the Lyapunov control is also presented through examining the convergence time of the system. These results suggest that the Lyapunov control is robust against time delay, easy to realize and effective for high-dimensional quantum systems.
Meier, Laurenz L; Semmer, Norbert K; Elfering, Achim; Jacobshagen, Nicola
2008-07-01
The Job Demand-Control model postulates that job control attenuates the effects of job demands on health and well-being. Support for this interactive effect is rather weak. Conceivably, it holds only when there is a match between job control and individual characteristics that relate to exercising control options, such as locus of control, or self-efficacy. This three-way interaction was tested in a sample of 96 service employees, with affective strain and musculoskeletal pain as dependent variables. As hypothesized, job control attenuated the effects of stressors only for people with an internal locus of control. For people with an external locus of control, job control actually predicted poorer well-being and health as stressors increased. For self-efficacy, the corresponding three-way interaction was significant with regard to affective strain. Copyright (c) 2008 APA, all rights reserved.
Forman, Evan M; Shaw, Jena A; Goldstein, Stephanie P; Butryn, Meghan L; Martin, Lindsay M; Meiran, Nachshon; Crosby, Ross D; Manasse, Stephanie M
2016-08-01
Obesity is largely attributable to excess caloric intake, in particular from "junk" foods, including salty snack foods. Evidence suggests that neurobiological preferences to consume highly hedonic foods translate (via implicit processes) into poor eating choices, unless overturned by inhibitory mechanisms or interrupted by explicit processes. The primary aim of the current study was to test the independent and combinatory effects of a computerized inhibitory control training (ICT) and a mindful decision-making training (MDT) designed to facilitate de-automatization. We randomized 119 habitual salty snack food eaters to one of four short, training conditions: MDT, ICT, both MDT and ICT, or neither (i.e., psychoeducation). For 7 days prior to the intervention and 7 days following the intervention, participants reported on their salty snack food consumption 2 times per day, on 3 portions of their days, using a smartphone-based ecological momentary assessment system. Susceptibility to emotional eating cues was measured at baseline. Results indicated that the effect of MDT was consistent across levels of trait emotional eating, whereas the benefit of ICT was apparent only at lower levels of emotional eating. No synergistic effect of MDT and ICT was detected. These results provide qualified support for the efficacy of both types of training for decreasing hedonically-motivated eating. Moderation effects suggest that those who eat snack foods for reasons unconnected to affective experiences (i.e., lower in emotional eating) may derive benefit from a combination of ICT and MDT. Future research should investigate the additive benefit of de-automization training to standard weight loss interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.
A continuous-time control model on production planning network ...
African Journals Online (AJOL)
A continuous-time control model on production planning network. DEA Omorogbe, MIU Okunsebor. Abstract. In this paper, we give a slightly detailed review of Graves and Hollywood model on constant inventory tactical planning model for a job shop. The limitations of this model are pointed out and a continuous time ...
Real-Time Plasma Control Tools for Advanced Tokamak Operation
International Nuclear Information System (INIS)
Varandas, C. A. F.; Sousa, J.; Rodrigues, A. P.; Carvalho, B. B.; Fernandes, H.; Batista, A. J.; Cruz, N.; Combo, A.; Pereira, R. C.
2006-01-01
Real-time control will play an important role in the operation and scientific exploitation of the new generation fusion devices. This paper summarizes the real-time systems and diagnostics developed by the Portuguese Fusion Euratom Association based on digital signal processors and field programmable gate arrays
Controlling traffic jams by time modulating the safety distance
DEFF Research Database (Denmark)
Gaididei, Yu B.; Gorria, C.; Berkemer, R.
2013-01-01
The possibility of controlling traffic dynamics by applying high-frequency time modulation of traffic flow parameters is studied. It is shown that the region of the car density where the uniform (free) flow is unstable changes in the presence of time modulation compared with the unmodulated case....
Real time control of plasmas and ECRH systems on TCV
Paley, J.I.; Berrino, J.; Coda, S.; Cruz, N.; Duval, B.P.; Felici, F.; Goodman, T.P.; Martin, Y.; Moret, J.-M.; Piras, F.; Rodriques, A.P.; Santos, B.; Varandas, C.A.F.
2009-01-01
Developments in the real time control hardware on Tokamak Configuration Variable (TCV) coupled with the flexibility of plasma shaping and electron cyclotron (EC) heating and current drive actuators are opening many opportunities to perform real time experiments and develop algorithms and methods for
Time-lapse controlled-source electromagnetics using interferometry
Hunziker, J.W.; Slob, E.C.; Wapenaar, C.P.A.
In time-lapse controlled-source electromagnetics, it is crucial that the source and the receivers are positioned at exactly the same location at all times of measurement. We use interferometry by multidimensional deconvolution (MDD) to overcome problems in repeatability of the source location.
Simulation of Simple Controlled Processes with Dead-Time.
Watson, Keith R.; And Others
1985-01-01
The determination of closed-loop response of processes containing dead-time is typically not covered in undergraduate process control, possibly because the solution by Laplace transforms requires the use of Pade approximation for dead-time, which makes the procedure lengthy and tedious. A computer-aided method is described which simplifies the…
Ni, Fang; Nakatsukasa, Takashi
2018-04-01
To describe quantal collective phenomena, it is useful to requantize the time-dependent mean-field dynamics. We study the time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory for the two-level pairing Hamiltonian, and compare results of different quantization methods. The one constructing microscopic wave functions, using the TDHFB trajectories fulfilling the Einstein-Brillouin-Keller quantization condition, turns out to be the most accurate. The method is based on the stationary-phase approximation to the path integral. We also examine the performance of the collective model which assumes that the pairing gap parameter is the collective coordinate. The applicability of the collective model is limited for the nuclear pairing with a small number of single-particle levels, because the pairing gap parameter represents only a half of the pairing collective space.
Real-time operating system timing jitter and its impact on motor control
Proctor, Frederick M.; Shackleford, William P.
2001-12-01
General-purpose microprocessors are increasingly being used for control applications due to their widespread availability and software support for non-control functions like networking and operator interfaces. Two classes of real-time operating systems (RTOS) exist for these systems. The traditional RTOS serves as the sole operating system, and provides all OS services. Examples include ETS, LynxOS, QNX, Windows CE and VxWorks. RTOS extensions add real-time scheduling capabilities to non-real-time OSes, and provide minimal services needed for the time-critical portions of an application. Examples include RTAI and RTL for Linux, and HyperKernel, OnTime and RTX for Windows NT. Timing jitter is an issue in these systems, due to hardware effects such as bus locking, caches and pipelines, and software effects from mutual exclusion resource locks, non-preemtible critical sections, disabled interrupts, and multiple code paths in the scheduler. Jitter is typically on the order of a microsecond to a few tens of microseconds for hard real-time operating systems, and ranges from milliseconds to seconds in the worst case for soft real-time operating systems. The question of its significance on the performance of a controller arises. Naturally, the smaller the scheduling period required for a control task, the more significant is the impact of timing jitter. Aside from this intuitive relationship is the greater significance of timing on open-loop control, such as for stepper motors, than for closed-loop control, such as for servo motors. Techniques for measuring timing jitter are discussed, and comparisons between various platforms are presented. Techniques to reduce jitter or mitigate its effects are presented. The impact of jitter on stepper motor control is analyzed.
Advanced Map For Real-Time Process Control
Shiobara, Yasuhisa; Matsudaira, Takayuki; Sashida, Yoshio; Chikuma, Makoto
1987-10-01
MAP, a communications protocol for factory automation proposed by General Motors [1], has been accepted by users throughout the world and is rapidly becoming a user standard. In fact, it is now a LAN standard for factory automation. MAP is intended to interconnect different devices, such as computers and programmable devices, made by different manufacturers, enabling them to exchange information. It is based on the OSI intercomputer com-munications protocol standard under development by the ISO. With progress and standardization, MAP is being investigated for application to process control fields other than factory automation [2]. The transmission response time of the network system and centralized management of data exchanged with various devices for distributed control are import-ant in the case of a real-time process control with programmable controllers, computers, and instruments connected to a LAN system. MAP/EPA and MINI MAP aim at reduced overhead in protocol processing and enhanced transmission response. If applied to real-time process control, a protocol based on point-to-point and request-response transactions limits throughput and transmission response. This paper describes an advanced MAP LAN system applied to real-time process control by adding a new data transmission control that performs multicasting communication voluntarily and periodically in the priority order of data to be exchanged.
He, Yuning
2015-01-01
Safety of unmanned aerial systems (UAS) is paramount, but the large number of dynamically changing controller parameters makes it hard to determine if the system is currently stable, and the time before loss of control if not. We propose a hierarchical statistical model using Treed Gaussian Processes to predict (i) whether a flight will be stable (success) or become unstable (failure), (ii) the time-to-failure if unstable, and (iii) time series outputs for flight variables. We first classify the current flight input into success or failure types, and then use separate models for each class to predict the time-to-failure and time series outputs. As different inputs may cause failures at different times, we have to model variable length output curves. We use a basis representation for curves and learn the mappings from input to basis coefficients. We demonstrate the effectiveness of our prediction methods on a NASA neuro-adaptive flight control system.
Time scaling internal state predictive control of a solar plant
Energy Technology Data Exchange (ETDEWEB)
Silva, R.N. [DEE-FCT/UNL, Caparica (Portugal); Rato, L.M. [INESC-ID/University, Evora (Portugal); Lemos, J.M. [INESC-ID/IST, Lisboa (Portugal)
2003-12-01
The control of a distributed collector solar field is addressed in this work, exploiting the plant's transport characteristic. The plant is modeled by a hyperbolic type partial differential equation (PDE) where the transport speed is the manipulated flow, i.e. the controller output. The model has an external distributed source, which is the solar radiation captured along the collector, approximated to depend only of time. From the solution of the PDE, a linear discrete state space model is obtained by using time-scaling and the redefinition of the control input. This method allows overcoming the dependency of the time constants with the operating point. A model-based predictive adaptive controller is derived with the internal temperature distribution estimated with a state observer. Experimental results at the solar power plant are presented, illustrating the advantages of the approach under consideration. (author)
Real time control of plasmas and ECRH systems on TCV
International Nuclear Information System (INIS)
Paley, J.I.; Berrino, J.; Coda, S.; Duval, B.P.; Felici, F.; Goodman, T.P.; Martin, Y.; Moret, J.M.; Piras, F.; Cruz, N.; Rodriques, A.P.; Santos, B.; Varandas, C.A.F.
2009-01-01
Developments in the real time control hardware on Tokamak a Configuration Variable (TCV) coupled with the flexibility of plasma shaping and electron cyclotron (EC) heating and current drive actuators are opening many opportunities to perform real time experiments and develop algorithms and methods for fusion applications. The ability to control magnetohydrodynamic instabilities is particularly important for achieving high performance fusion plasmas and EC is envisaged as a key actuator in maintaining high performance. We have successfully demonstrated control of the sawtooth instability using the EC launcher injection angle to modify the current profile around the q =1 surface. This paper presents an overview of recent real time control experiments on TCV, developments in the hardware and algorithms together with plans for the future.
Application of Skype API to Control Working Time
Directory of Open Access Journals (Sweden)
Julian Vasilev
2013-11-01
Full Text Available The purpose of this article is to present an innovative approach to monitor and control working time. A special software program is developed by Delphi implementing Skype API functions. This article shows three different approaches to control working time using the Skype_API program. It automatically detects when an employee goes to his working place and when he leaves work. Moreover it can check periodically weather an employee is at work. The proposed ideas are written for the first time. They may be applied easily in many enterprises with very low costs.
Model-Checking Real-Time Control Programs
DEFF Research Database (Denmark)
Iversen, T. K.; Kristoffersen, K. J.; Larsen, Kim Guldstrand
2000-01-01
In this paper, we present a method for automatic verification of real-time control programs running on LEGO(R) RCX(TM) bricks using the verification tool UPPALL. The control programs, consisting of a number of tasks running concurrently, are automatically translated into the mixed automata model...... of UPPAAL. The fixed scheduling algorithm used by the LEGO(R) RCX(TM) processor is modeled in UPPALL, and supply of similar (sufficient) timed automata models for the environment allows analysis of the overall real-time system using the tools of UPPALL. To illustrate our technique for sorting LEGO(R) bricks...
Response times of operators in a control room
International Nuclear Information System (INIS)
Platz, O.; Rasmussen, J.; Skanborg, P.Z.
1982-12-01
A statistical analysis was made of operator response times recorded in the control room of a research reactor during the years 1972-1974. A homogeneity test revealed that the data consist of a mixture of populations. A small but statistically significant difference is found between day and night response times. Lognormal distributions are found to provide the best fit of the day and the night response times. (author)
Adaptive control of discrete-time chaotic systems: a fuzzy control approach
International Nuclear Information System (INIS)
Feng Gang; Chen Guanrong
2005-01-01
This paper discusses adaptive control of a class of discrete-time chaotic systems from a fuzzy control approach. Using the T-S model of discrete-time chaotic systems, an adaptive control algorithm is developed based on some conventional adaptive control techniques. The resulting adaptively controlled chaotic system is shown to be globally stable, and its robustness is discussed. A simulation example of the chaotic Henon map control is finally presented, to illustrate an application and the performance of the proposed control algorithm
Sikora, Grzegorz; Teuerle, Marek; Wyłomańska, Agnieszka; Grebenkov, Denis
2017-08-01
The most common way of estimating the anomalous scaling exponent from single-particle trajectories consists of a linear fit of the dependence of the time-averaged mean-square displacement on the lag time at the log-log scale. We investigate the statistical properties of this estimator in the case of fractional Brownian motion (FBM). We determine the mean value, the variance, and the distribution of the estimator. Our theoretical results are confirmed by Monte Carlo simulations. In the limit of long trajectories, the estimator is shown to be asymptotically unbiased, consistent, and with vanishing variance. These properties ensure an accurate estimation of the scaling exponent even from a single (long enough) trajectory. As a consequence, we prove that the usual way to estimate the diffusion exponent of FBM is correct from the statistical point of view. Moreover, the knowledge of the estimator distribution is the first step toward new statistical tests of FBM and toward a more reliable interpretation of the experimental histograms of scaling exponents in microbiology.
Jin, Tian; Yuan, Heliang; Zhao, Na; Qin, Honglei; Sun, Kewen; Ji, Yuanfa
2017-12-04
Frequency-locked detector (FLD) has been widely utilized in tracking loops of Global Positioning System (GPS) receivers to indicate their locking status. The relation between FLD and lock status has been seldom discussed. The traditional PLL experience is not suitable for FLL. In this paper, the threshold setting criteria for frequency-locked detector in the GPS receiver has been proposed by analyzing statistical characteristic of FLD output. The approximate probability distribution of frequency-locked detector is theoretically derived by using a statistical approach, which reveals the relationship between probabilities of frequency-locked detector and the carrier-to-noise ratio ( C / N ₀) of the received GPS signal. The relationship among mean-time-to-lose-lock (MTLL), detection threshold and lock probability related to C / N ₀ can be further discovered by utilizing this probability. Therefore, a theoretical basis for threshold setting criteria in frequency locked loops for GPS receivers is provided based on mean-time-to-lose-lock analysis.
Cai, Shuiming; Hao, Junjun; Liu, Zengrong
2011-06-01
This paper studies the synchronization of coupled chaotic systems with time-varying delays in the presence of parameter mismatches by means of periodically intermittent control. Some novel and useful quasisynchronization criteria are obtained by using the methods which are different from the techniques employed in the existing works, and the derived results are less conservative. Especially, a strong constraint on the control width that the control width should be larger than the time delay imposed by the current references is released in this paper. Moreover, our results show that the synchronization criteria depend on the ratio of control width to control period, but not the control width or the control period. Finally, some numerical simulations are given to show the effectiveness of the theoretical results.
Engine control system having pressure-based timing
Willi, Martin L [Dunlap, IL; Fiveland, Scott B [Metamora, IL; Montgomery, David T [Edelstein, IL; Gong, Weidong [Dunlap, IL
2011-10-04
A control system for an engine having a first cylinder and a second cylinder is disclosed having a first engine valve movable to regulate a fluid flow of the first cylinder and a first actuator associated with the first engine valve. The control system also has a second engine valve movable to regulate a fluid flow of the second cylinder and a sensor configured to generate a signal indicative of a pressure within the first cylinder. The control system also has a controller that is in communication with the first actuator and the sensor. The controller is configured to compare the pressure within the first cylinder with a desired pressure and selectively regulate the first actuator to adjust a timing of the first engine valve independently of the timing of the second engine valve based on the comparison.
Optimal control for parabolic-hyperbolic system with time delay
International Nuclear Information System (INIS)
Kowalewski, A.
1985-07-01
In this paper we consider an optimal control problem for a system described by a linear partial differential equation of the parabolic-hyperbolic type with time delay in the state. The right-hand side of this equation and the initial conditions are not continuous functions usually, but they are measurable functions belonging to L 2 or Lsup(infinity) spaces. Therefore, the solution of this equation is given by a certain Sobolev space. The time delay in the state is constant, but it can be also a function of time. The control time T is fixed in our problem. Making use of the Milutin-Dubovicki theorem, necessary and sufficient conditions of optimality with the quadratic performance functional and constrained control are derived for the Dirichlet problem. The flow chart of the algorithm which can be used in the numerical solving of certain optimization problems for distributed systems is also presented. (author)
Real time equilibrium reconstruction for tokamak discharge control
International Nuclear Information System (INIS)
Ferron, J.R.; Walker, M.L.; Lao, L.L.; St John, H.E.; Humphreys, D.A.; Leuer, J.A.
1998-01-01
A practical method for performing a tokamak equilibrium reconstruction in real time for arbitrary time varying discharge shapes and current profiles is described. An approximate solution to the Grad-Shafranov equilibrium relation is found which best fits the diagnostic measurements. Thus, a solution for the spatial distribution of poloidal flux and toroidal current density is available in real time that is consistent with plasma force balance, allowing accurate evaluation of parameters such as discharge shape and safety factor profile. The equilibrium solutions are produced at a rate sufficient for discharge control. This equilibrium reconstruction algorithm has been implemented on the digital plasma control system for the DIII-D tokamak. The first application of real time equilibrium reconstruction to discharge shape control is described. (author)
Engine control system having fuel-based timing
Willi, Martin L [Dunlap, IL; Fiveland, Scott B [Metamora, IL; Montgomery, David T [Edelstein, IL; Gong, Weidong [Dunlap, IL
2012-04-03
A control system for an engine having a cylinder is disclosed having an engine valve movable to regulate a fluid flow of the cylinder and an actuator associated with the engine valve. The control system also has a sensor configured to generate a signal indicative of an amount of an air/fuel mixture remaining within the cylinder after completion of a first combustion event and a controller in communication with the actuator and the sensor. The controller may be configured to compare the amount with a desired amount, and to selectively regulate the actuator to adjust a timing of the engine valve associated with a subsequent combustion event based on the comparison.
Directory of Open Access Journals (Sweden)
Mailys Lopes
2017-07-01
Full Text Available This paper deals with the classification of grasslands using high resolution satellite image time series. Grasslands considered in this work are semi-natural elements in fragmented landscapes, i.e., they are heterogeneous and small elements. The first contribution of this study is to account for grassland heterogeneity while working at the object level by modeling its pixels distributions by a Gaussian distribution. To measure the similarity between two grasslands, a new kernel is proposed as a second contribution: the α -Gaussian mean kernel. It allows one to weight the influence of the covariance matrix when comparing two Gaussian distributions. This kernel is introduced in support vector machines for the supervised classification of grasslands from southwest France. A dense intra-annual multispectral time series of the Formosat-2 satellite is used for the classification of grasslands’ management practices, while an inter-annual NDVI time series of Formosat-2 is used for old and young grasslands’ discrimination. Results are compared to other existing pixel- and object-based approaches in terms of classification accuracy and processing time. The proposed method is shown to be a good compromise between processing speed and classification accuracy. It can adapt to the classification constraints, and it encompasses several similarity measures known in the literature. It is appropriate for the classification of small and heterogeneous objects such as grasslands.
Ameli, Ali; McDonnell, Jeffrey; Laudon, Hjalmar; Bishop, Kevin
2017-04-01
The stable isotopes of water have served science well as hydrological tracers which have demonstrated that there is often a large component of "old" water in stream runoff. It has been more problematic to define the full transit time distribution of that stream water. Non-linear mixing of previous precipitation signals that is stored for extended periods and slowly travel through the subsurface before reaching the stream results in a large range of possible transit times. It difficult to find tracers can represent this, especially if all that one has is data on the precipitation input and the stream runoff. In this paper, we explicitly characterize this "old water" displacement using a novel quasi-steady physically-based flow and transport model in the well-studied S-Transect hillslope in Sweden where the concentration of hydrological tracers in the subsurface and stream has been measured. We explore how subsurface conductivity profile impacts the characteristics of old water displacement, and then test these scenarios against the observed dynamics of conservative hydrological tracers in both the stream and subsurface. This work explores the efficiency of convolution-based approaches in the estimation of stream "young water" fraction and time-variant mean transit times. We also suggest how celerity and velocity differ with landscape structure
Developing infrared array controller with software real time operating system
Sako, Shigeyuki; Miyata, Takashi; Nakamura, Tomohiko; Motohara, Kentaro; Uchimoto, Yuka Katsuno; Onaka, Takashi; Kataza, Hirokazu
2008-07-01
Real-time capabilities are required for a controller of a large format array to reduce a dead-time attributed by readout and data transfer. The real-time processing has been achieved by dedicated processors including DSP, CPLD, and FPGA devices. However, the dedicated processors have problems with memory resources, inflexibility, and high cost. Meanwhile, a recent PC has sufficient resources of CPUs and memories to control the infrared array and to process a large amount of frame data in real-time. In this study, we have developed an infrared array controller with a software real-time operating system (RTOS) instead of the dedicated processors. A Linux PC equipped with a RTAI extension and a dual-core CPU is used as a main computer, and one of the CPU cores is allocated to the real-time processing. A digital I/O board with DMA functions is used for an I/O interface. The signal-processing cores are integrated in the OS kernel as a real-time driver module, which is composed of two virtual devices of the clock processor and the frame processor tasks. The array controller with the RTOS realizes complicated operations easily, flexibly, and at a low cost.
Kuypers, Dirk R J; Vanrenterghem, Yves
2004-11-01
The aims of this study were to determine whether disposition-related pharmacokinetic parameters such as T(max) and mean residence time (MRT) could be used as predictors of clinical efficacy of tacrolimus in renal transplant recipients, and to what extent these parameters would be influenced by clinical variables. We previously demonstrated, in a prospective pharmacokinetic study in de novo renal allograft recipients, that patients who experienced early acute rejection did not differ from patients free from rejection in terms of tacrolimus pharmacokinetic exposure parameters (dose interval AUC, preadministration trough blood concentration, C(max), dose). However, recipients with acute rejection reached mean (SD) tacrolimus T(max) significantly faster than those who were free from rejection (0.96 [0.56] hour vs 1.77 [1.06] hours; P clearance nor T(1/2) could explain this unusual finding, we used data from the previous study to calculate MRT from the concentration-time curves. As part of the previous study, 100 patients (59 male, 41 female; mean [SD] age, 51.4 [13.8] years;age range, 20-75 years) were enrolled in the study The calculated MRT was significantly shorter in recipients with acute allograft rejection (11.32 [031] hours vs 11.52 [028] hours; P = 0.02), just like T(max) was an independent risk factor for acute rejection in a multivariate logistic regression model (odds ratio, 0.092 [95% CI, 0.014-0.629]; P = 0.01). Analyzing the impact of demographic, transplantation-related, and biochemical variables on MRT, we found that increasing serum albumin and hematocrit concentrations were associated with a prolonged MRT (P calculated MRT were associated with a higher incidence of early acute graft rejection. These findings suggest that a shorter transit time of tacrolimus in certain tissue compartments, rather than failure to obtain a maximum absolute tacrolimus blood concentration, might lead to inadequate immunosuppression early after transplantation.
Horiguchi, Miki; Cronin, Angel M; Takeuchi, Masahiro; Uno, Hajime
2018-04-22
In randomized clinical trials where time-to-event is the primary outcome, almost routinely, the logrank test is prespecified as the primary test and the hazard ratio is used to quantify treatment effect. If the ratio of 2 hazard functions is not constant, the logrank test is not optimal and the interpretation of hazard ratio is not obvious. When such a nonproportional hazards case is expected at the design stage, the conventional practice is to prespecify another member of weighted logrank tests, eg, Peto-Prentice-Wilcoxon test. Alternatively, one may specify a robust test as the primary test, which can capture various patterns of difference between 2 event time distributions. However, most of those tests do not have companion procedures to quantify the treatment difference, and investigators have fallen back on reporting treatment effect estimates not associated with the primary test. Such incoherence in the "test/estimation" procedure may potentially mislead clinicians/patients who have to balance risk-benefit for treatment decision. To address this, we propose a flexible and coherent test/estimation procedure based on restricted mean survival time, where the truncation time τ is selected data dependently. The proposed procedure is composed of a prespecified test and an estimation of corresponding robust and interpretable quantitative treatment effect. The utility of the new procedure is demonstrated by numerical studies based on 2 randomized cancer clinical trials; the test is dramatically more powerful than the logrank, Wilcoxon tests, and the restricted mean survival time-based test with a fixed τ, for the patterns of difference seen in these cancer clinical trials. Copyright © 2018 John Wiley & Sons, Ltd.
Oudejans, R.R.D.; Coolen, H.
2003-01-01
In human movement and sports science, manipulations of perception and action are common and often comprise the control of events, such as opening or closing liquid crystal goggles. Most of these events are externally controlled, independent of the actions of the participants. Less common, although
Using Control Heuristics as a Means to Explore the Educational Potential of Robotics Kits
Gaudiello, Ilaria; Zibetti, Elisabetta
2013-01-01
The educational potential of robotics kits as a form of control technology will remain undervalued until meaningful observation parameters are identified to enable a better understanding of children?s control strategies. For this reason, this paper aims primarily to identify and classify the heuristics spontaneously applied by 6-10 year old…
Low average blister-rust infection rates may mean high control costs
Robert Marty
1965-01-01
The Northeastern Forest Experiment Station, in cooperation with Federal and State forest-pest-control agencies, undertook a survey of blister-rust infection rates in the white pine region of the East during 1962 and 1963. Those engaged in blister-rust-control activities will not be surprised at the survey's results. We found that infection rates were significantly...
Controlling microwave signals by means of slow and fast light effects in SOA-EA structures
DEFF Research Database (Denmark)
Sales, Salvador; Öhman, Filip; Capmany, José
2007-01-01
We present a novel scheme for the control of microwave signals in the optical domain. We propose the use of alternating amplifying and absorbing sections to implement phase control by using fast and slow light effects in semiconductors. The potential benefits from the proposed semiconductor optic...
Visualization of differences across port state control regimes by means of correspondence analysis
S. Knapp (Sabine); M. van de Velden (Michel)
2007-01-01
textabstractThis article is based on a combined dataset of 183,819 port state control (PSC) inspections from various port state control regimes around the world. In theory, there should be no differences in treatments of inspections to determine if a vessel is substandard or not no matter where the
Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks
Zaal, Peter M. T.; Sweet, Barbara T.
2012-01-01
Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.
Controller synthesis for dynamic hierarchical real-time plants using timed automata
DEFF Research Database (Denmark)
Bin Waez, Md Tawhid; Wasowski, Andrzej; Dingel, Juergen
2017-01-01
We use timed I/O automata based timed games to synthesize task-level reconfiguration services for cost-effective fault tolerance in a case study. The case study shows that state-space explosion is a severe problem for timed games. By applying suitable abstractions, we dramatically improve...... the scalability. However, timed I/O automata do not facilitate algorithmic abstraction generation techniques. The case study motivates the development of timed process automata to improve modeling and analysis for controller synthesis of time-critical plants which can be hierarchical and dynamic. The model offers...
Precise control of the drug kinetics by means of non-invasive magnetic drug delivery system
International Nuclear Information System (INIS)
Chuzawa, M.; Mishima, F.; Akiyama, Y.; Nishijima, S.
2013-01-01
Highlights: ► We examined the kinetics of ferromagnetic drugs by simulation. ► We tried to accumulate the magnetic drug in the target part by rotating a magnet. ► Ferromagnetic drugs were accumulated in the target part along the rotating axis. ► Ferromagnetic drugs could be swept downstream in the off-axis part. -- Abstract: In order to solve the problems of the side effects and medical lowering, has been advanced a study on the drug delivery system (DDS) to accumulate the drugs locally in the body with minimum dosage. The DDS is a system that controls the drug kinetics in the body precisely and accumulates the drug locally at the target part, keeping the drugs at high density. Among the DDS, the magnetic drug delivery system (MDDS) is the one that we studied. This is a technique to accumulate drugs by using the magnetic force as the physical driving force. Our previous researches showed the possibility of the technique of MDDS to accumulate the drugs with higher accumulation rate and locality than the traditional methods. It is necessary to apply a strong external magnetic field and a high magnetic gradient to accumulate the ferromagnetic drugs at a deep diseased part non-invasively. However, by applying a static magnetic field from one direction, the drug accumulates only at the surface of the body locates near the magnet. In this study, we tried to change the magnetic field applied by a superconducting bulk magnet with time, in order to make a constant and strong magnetic field applied in the center of the body and to accumulate the ferromagnetic drugs at the deep target part in the body. First of all, the effect of the surface treatment of the ferromagnetic drugs to prevent its absorption in the normal tissue was examined. Then, to increase the accumulation rate of the ferromagnetic drugs at the target part, the distribution of magnetic field was changed, and the optimum spatial and temporal conditions of magnetic field were examined
Energy Technology Data Exchange (ETDEWEB)
Ozyurt, Nur N. [Department of Geological Engineering, Hacettepe University, 06800 Ankara (Turkey); Lutz, Hans O. [Stable Isotope Laboratory, Medical Faculty, Rijeka University, 51000 Rijeka (Croatia); Faculty of Physics, Bielefeld University, 33615 Bielefeld (Germany); Hunjak, Tamara; Mance, Diana [Stable Isotope Laboratory, Medical Faculty, Rijeka University, 51000 Rijeka (Croatia); Roller-Lutz, Zvjezdana, E-mail: roller@medri.uniri.hr [Stable Isotope Laboratory, Medical Faculty, Rijeka University, 51000 Rijeka (Croatia)
2014-07-01
The Gacka River basin aquifer is a highly-developed karst system, located in the Croatian Dinarides. It is mostly composed of permeable Jurassic and Cretaceous carbonate rocks, and clastic sedimentary rocks of Paleogene age. Gacka River provides high quality water for the town of Otočac and several villages; together with the neighboring Lika River, the water is used for the Hydroelectric Power Plant at Senj on the coast. About 10 perennial and over 20 seasonal springs are located at 450 to 460 m a.s.l. (above sea level). Three major springs (Pećina, Majerovo and Tonkovića) provide 57% of the mean annual river flow. Similarities between the average groundwater temperatures as well as between the average specific electrical conductivity values (9.0 °C-328 μS/cm, 9.6 °C-350 μS/cm and 8.9 °C-312 μS/cm) of the springs imply that they are fed from aquifers with similar mean residence times (MRTs). The mean δ{sup 18}O contents of Majerovo, Tonkovića, and Pećina are around − 10.1‰, − 9.2‰ and − 8.9‰, respectively, revealing differences in the mean recharge area elevations. Compared to the temporal amplitude of the{sup 18}O signal of precipitation, the {sup 18}O signal variations of the springs are substantially attenuated because the recharges occurring at different times are well mixed within the aquifers. This indicates MRTs of more than just a few years. The average tritium contents of Pećina, Majerovo and Tonkovića are 5.48 TU, 6.13 TU and 6.17 TU, respectively. Serially connected exponential-plug type unsteady lumped-parameter models run on an annual time scale resulted in rather satisfactory matches between the observed and calculated tritium contents for all studied springs. The models revealed similar MRTs (and corresponding reservoir volumes) for Pećina, Tonkovića and Majerovo of 12 years (470 Mm{sup 3}), 12 years (1190 Mm{sup 3}), and 12.2 years (1210 Mm{sup 3}), respectively. Plug flow conditions dominate in about 90% of the total
THE COMPUTER SIMULATOR-CONTROLLER FOR LEARNING SIGN AND SYMBOLIC MEANS OF PHYSICS
Directory of Open Access Journals (Sweden)
N.I. Tikhonskaya
2012-10-01
Full Text Available The promising application of information technology for learning sign and symbolic means of physics is proposed and theoretically proved in this article. This direction is connected with the idea of training students the presentation of information in different forms.
Time-division-multiplex control scheme for voltage multiplier rectifiers
Directory of Open Access Journals (Sweden)
Bin-Han Liu
2017-03-01
Full Text Available A voltage multiplier rectifier with a novel time-division-multiplexing (TDM control scheme for high step-up converters is proposed in this study. In the proposed TDM control scheme, two full-wave voltage doubler rectifiers can be combined to realise a voltage quadrupler rectifier. The proposed voltage quadrupler rectifier can reduce transformer turn ratio and transformer size for high step-up converters and also reduce voltage stress for the output capacitors and rectifier diodes. An N-times voltage rectifier can be straightforwardly produced by extending the concepts from the proposed TDM control scheme. A phase-shift full-bridge (PSFB converter is adopted in the primary side of the proposed voltage quadrupler rectifier to construct a PSFB quadrupler converter. Experimental results for the PSFB quadrupler converter demonstrate the performance of the proposed TDM control scheme for voltage quadrupler rectifiers. An 8-times voltage rectifier is simulated to determine the validity of extending the proposed TDM control scheme to realise an N-times voltage rectifier. Experimental and simulation results show that the proposed TDM control scheme has great potential to be used in high step-up converters.
Measurement and control of cement set times in waste solidification
International Nuclear Information System (INIS)
Stone, J.A.; d'Entremont, P.D.
1976-09-01
Fixation of radioactive waste in concrete was investigated on laboratory scale. Some cement formulations containing simulated or actual sludges from the Savannah River Plant had set times that would be too short for reliable handling in plant equipment. Set times could be controlled by use of excess water, but the concrete forms produced had inferior strength. A commercial organic retarder was found to be effective for increasing set times of cement-sludge formulations. However, the dosage of retarder required to control set times of high-alumina cement formulations was 1.0 to 1.5 wt percent of dry solids, which is 5 to 10 times the normal dosage for Portland cements. Data were obtained to predict the optimum content of retarder and water
Continuous-time mean-variance portfolio selection with value-at-risk and no-shorting constraints
Yan, Wei
2012-01-01
An investment problem is considered with dynamic mean-variance(M-V) portfolio criterion under discontinuous prices which follow jump-diffusion processes according to the actual prices of stocks and the normality and stability of the financial market. The short-selling of stocks is prohibited in this mathematical model. Then, the corresponding stochastic Hamilton-Jacobi-Bellman(HJB) equation of the problem is presented and the solution of the stochastic HJB equation based on the theory of stochastic LQ control and viscosity solution is obtained. The efficient frontier and optimal strategies of the original dynamic M-V portfolio selection problem are also provided. And then, the effects on efficient frontier under the value-at-risk constraint are illustrated. Finally, an example illustrating the discontinuous prices based on M-V portfolio selection is presented.
Upgrade of the COMPASS tokamak real-time control system
Energy Technology Data Exchange (ETDEWEB)
Janky, F., E-mail: filip.janky.work@gmail.com [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague (Czech Republic); Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague (Czech Republic); Havlicek, J. [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague (Czech Republic); Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague (Czech Republic); Batista, A.J.N. [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa (Portugal); Kudlacek, O.; Seidl, J. [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague (Czech Republic); Neto, A.C. [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa (Portugal); Pipek, J.; Hron, M. [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague (Czech Republic); Mikulin, O. [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague (Czech Republic); Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, V Holesovickach 2, 18000 Prague (Czech Republic); and others
2014-03-15
Highlights: • An upgrade of the COMPASS real-time system has been made to generally improve the plasma performance. • Stability of discharges in SNT configuration has been increased. • Plasma flat-top phase length has been extended. • Central solenoid protection has been developed. • Plasma position estimation has been improved. - Abstract: The COMPASS plasma control system is based on the MARTe real-time framework. Thanks to MARTe modularity and flexibility new algorithms have been developed for plasma diagnostic (plasma position calculation), control (shaping field control), and protection systems (central solenoid protection). Moreover, the MARTe framework itself was modified to broaden the communication capabilities via Aurora. This paper presents the recent upgrades and improvements made to the COMPASS real-time plasma control system, focusing on the issues related to precision of the real-time calculations, and discussing the improvements in terms of discharge parameters and stability. In particular, the new real-time system has given the possibility to analyze and to minimize the transport delays of each control loop.
Guay, M.; Beerens, R.; Nijmeijer, H.
2014-01-01
This paper considers the solution of a real-time optimization problem using adaptive extremum seeking control for a class of unknown discrete-time nonlinear systems. It is assumed that the equations describing the dynamics of the nonlinear system and the cost function to be minimized are unknown and
Missing data in clinical trials: control-based mean imputation and sensitivity analysis.
Mehrotra, Devan V; Liu, Fang; Permutt, Thomas
2017-09-01
In some randomized (drug versus placebo) clinical trials, the estimand of interest is the between-treatment difference in population means of a clinical endpoint that is free from the confounding effects of "rescue" medication (e.g., HbA1c change from baseline at 24 weeks that would be observed without rescue medication regardless of whether or when the assigned treatment was discontinued). In such settings, a missing data problem arises if some patients prematurely discontinue from the trial or initiate rescue medication while in the trial, the latter necessitating the discarding of post-rescue data. We caution that the commonly used mixed-effects model repeated measures analysis with the embedded missing at random assumption can deliver an exaggerated estimate of the aforementioned estimand of interest. This happens, in part, due to implicit imputation of an overly optimistic mean for "dropouts" (i.e., patients with missing endpoint data of interest) in the drug arm. We propose an alternative approach in which the missing mean for the drug arm dropouts is explicitly replaced with either the estimated mean of the entire endpoint distribution under placebo (primary analysis) or a sequence of increasingly more conservative means within a tipping point framework (sensitivity analysis); patient-level imputation is not required. A supplemental "dropout = failure" analysis is considered in which a common poor outcome is imputed for all dropouts followed by a between-treatment comparison using quantile regression. All analyses address the same estimand and can adjust for baseline covariates. Three examples and simulation results are used to support our recommendations. Copyright © 2017 John Wiley & Sons, Ltd.
Real-time control of internal transport barriers in JET
Energy Technology Data Exchange (ETDEWEB)
Mazon, D.; Litaudon, X.; Moreau, D. [Association Euratom-CEA, CEA Cadarache, St. Paul lez Durance (France)] [and others
2002-07-01
We present the results of recent experiments related to real-time control of internal transport barriers (ITBs) in JET. Using a simple criterion to characterize the ITB existence, location and strength, we have successfully controlled for the first time the radial electron temperature profile within the ITB. The dimensionless variable used in the real-time algorithm - ratio of the ion gyro-radius to the local gradient scale length of the electron temperature - is a measure of the normalized electron temperature gradient and characterizes satisfactorily the main ITB features with a relatively low computational cost. We show several examples of control of this variable in various experimental conditions of toroidal field and plasma current, using different heating systems as control actuators. We also present a double-loop feedback scheme where both the global neutron rate from D-D reactions and the ITB strength are controlled simultaneously. In this case the ITB is sustained in a fully non-inductive current drive regime during several seconds. With the proposed control method, disruptions are avoided by holding the plasma performance at a prescribed target and this opens the route towards stationary operation of tokamak plasmas with ITBs. Initial results suggest that the additional control of the current profile is an important issue for achieving steady-state operation, in particular in the triggering and the sustainment of the ITB. (author)
Time-dependent switched discrete-time linear systems control and filtering
Zhang, Lixian; Shi, Peng; Lu, Qiugang
2016-01-01
This book focuses on the basic control and filtering synthesis problems for discrete-time switched linear systems under time-dependent switching signals. Chapter 1, as an introduction of the book, gives the backgrounds and motivations of switched systems, the definitions of the typical time-dependent switching signals, the differences and links to other types of systems with hybrid characteristics and a literature review mainly on the control and filtering for the underlying systems. By summarizing the multiple Lyapunov-like functions (MLFs) approach in which different requirements on comparisons of Lyapunov function values at switching instants, a series of methodologies are developed for the issues on stability and stabilization, and l2-gain performance or tube-based robustness for l∞ disturbance, respectively, in Chapters 2 and 3. Chapters 4 and 5 are devoted to the control and filtering problems for the time-dependent switched linear systems with either polytopic uncertainties or measurable time-varying...
International Nuclear Information System (INIS)
Gottlieb, I.; Agop, M.; Jarcau, M.
2004-01-01
One builds the vacuum metrics of the stationary electromagnetic field through the complex potential model. There are thus emphasized both a variational principle, independent on the Ricci tensor, and some internal symmetries of the vacuum solutions. One shows that similar results may be obtained using the Barbiliant's group. By analytical continuation of a Barbilian transformation the link between the fixed points of the modular groups of the vacuum and the golden mean PHI=(1/(1+PHI))=(√5-1)/2 of ε (∞) space-time is established. Finally, a Cantorian fractal axiomatic model of the space-time is presented. The model is explained using a set of coupled equations which may describe the self organizing processes at the solid-liquid, plasma-plasma, and superconductor-superconductor interfaces
Control of photon storage time using phase locking.
Ham, Byoung S
2010-01-18
A photon echo storage-time extension protocol is presented by using a phase locking method in a three-level backward propagation scheme, where phase locking serves as a conditional stopper of the rephasing process in conventional two-pulse photon echoes. The backward propagation scheme solves the critical problems of extremely low retrieval efficiency and pi rephasing pulse-caused spontaneous emission noise in photon echo based quantum memories. The physics of the storage time extension lies in the imminent population transfer from the excited state to an auxiliary spin state by a phase locking control pulse. We numerically demonstrate that the storage time is lengthened by spin dephasing time.
Time-delayed feedback control of diffusion in random walkers
Ando, Hiroyasu; Takehara, Kohta; Kobayashi, Miki U.
2017-07-01
Time delay in general leads to instability in some systems, while specific feedback with delay can control fluctuated motion in nonlinear deterministic systems to a stable state. In this paper, we consider a stochastic process, i.e., a random walk, and observe its diffusion phenomenon with time-delayed feedback. As a result, the diffusion coefficient decreases with increasing delay time. We analytically illustrate this suppression of diffusion by using stochastic delay differential equations and justify the feasibility of this suppression by applying time-delayed feedback to a molecular dynamics model.
DEFF Research Database (Denmark)
Mørkholt, Jakob; Elliott, S.J.; Sors, T.C.
1997-01-01
with a piezoceramic patch control actuator and a point velocity sensor and excited by a point force driven by white noise acting as the primary source. The design objective has been to suppress the effect of the primary disturbance on the output by minimising the mean square value of the output. Apart from comparing......A comparison of three ways of designing optimal discrete time feedback controllers has been carried out via computer simulations. The three design methods are similar in that they are all based on the minimisation of a quadratic cost function under certain assumptions about the disturbance noise...... and sensor noise in the system to be controlled. They are also based on (different) models of the plant under control and the disturbance to be suppressed by the controllers. Controllers based on the three methods have been designed from a model of a lightly damped, rectangular plate fitted...
RETIMAC: a real-time material control concept for strategic special nuclear material
International Nuclear Information System (INIS)
Shea, T.E.
1975-01-01
As one possible means to upgrade licensee safeguards systems, the NRC is exploring a real-time material control concept. The concept incorporates process controls, material containment provisions, and extensive instrumentation. Plants incorporating this concept would be better able to prevent, deter, and detect diversion, and to assure that diversion has not gone undetected. A substantial methods development, evaluation, and preliminary standards development program is under way to develop the basis for future policy decisions
Energy management in a domestic microgrid by means of model predictive controllers
International Nuclear Information System (INIS)
Bruni, G.; Cordiner, S.; Mulone, V.; Sinisi, V.; Spagnolo, F.
2016-01-01
The need to increase renewable energy sources deployment and to reduce consumption of fossil fuels has led to the diffusion of small-scale DG (Distributed Generation) systems, which may be effectively integrated in micro-grids. The role of control logic in defining microgrid performances and reliability is predominant and can be improved by using advanced control logics such as the ones based on MPC (Model Predictive Control). In a previous paper, a MPC logic, based on the use of weather forecasts to improve the performances, has been applied to the analysis of power management in a domestic micro-grid system composed by: PV (Photovoltaic panels), FC (Fuel Cells) and a battery pack; in that case, the system was not affected by real uncertainties. In this paper the same system has been considered for domestic microgrid applications. The system control logic has been implemented by assuming real weather forecast as input data. DMPC and SMPC (Deterministic and Stochastic Model Predictive Control) concepts have been applied to the system and results have been compared to both MPC and to a standard RBC (Rule Based Control) logic. The impact of forecast uncertainties has been evaluated showing the advantages of a stochastic approach. In that case, the SMPC showed encouraging performances compared to standard control logics, primarily in terms of primary energy savings and downsizing potential of the power-delivering sub-systems using programmable energy sources. - Highlights: • A Model Predictive Controller has been used to optimize the behaviour of a microgrid. • A stochastic approach has been used to model weather forecast uncertainties. • 10% savings of HVAC required energy have been demonstrated. • Savings in primary fossil energy range between 10% and 30%. • Power sub-systems using programmable sources can be consistently downsized.
Advanced discrete-time control designs and applications
Abidi, Khalid
2015-01-01
This book covers a wide spectrum of systems such as linear and nonlinear multivariable systems as well as control problems such as disturbance, uncertainty and time-delays. The purpose of this book is to provide researchers and practitioners a manual for the design and application of advanced discrete-time controllers. The book presents six different control approaches depending on the type of system and control problem. The first and second approaches are based on Sliding Mode control (SMC) theory and are intended for linear systems with exogenous disturbances. The third and fourth approaches are based on adaptive control theory and are aimed at linear/nonlinear systems with periodically varying parametric uncertainty or systems with input delay. The fifth approach is based on Iterative learning control (ILC) theory and is aimed at uncertain linear/nonlinear systems with repeatable tasks and the final approach is based on fuzzy logic control (FLC) and is intended for highly uncertain systems with heuristi...
Cyranka, Jacek; Mucha, Piotr B.; Titi, Edriss S.; Zgliczyński, Piotr
2018-04-01
The paper studies the issue of stability of solutions to the forced Navier-Stokes and damped Euler systems in periodic boxes. It is shown that for large, but fixed, Grashoff (Reynolds) number the turbulent behavior of all Leray-Hopf weak solutions of the three-dimensional Navier-Stokes equations, in periodic box, is suppressed, when viewed in the right frame of reference, by large enough average flow of the initial data; a phenomenon that is similar in spirit to the Landau damping. Specifically, we consider an initial data which have large enough spatial average, then by means of the Galilean transformation, and thanks to the periodic boundary conditions, the large time independent forcing term changes into a highly oscillatory force; which then allows us to employ some averaging principles to establish our result. Moreover, we also show that under the action of fast oscillatory-in-time external forces all two-dimensional regular solutions of the Navier-Stokes and the damped Euler equations converge to a unique time-periodic solution.
Directory of Open Access Journals (Sweden)
M. K. Stewart
2017-09-01
Full Text Available Kirchner (2016a demonstrated that aggregation errors due to spatial heterogeneity, represented by two homogeneous subcatchments, could cause severe underestimation of the mean transit times (MTTs of water travelling through catchments when simple lumped parameter models were applied to interpret seasonal tracer cycle data. Here we examine the effects of such errors on the MTTs and young water fractions estimated using tritium concentrations in two-part hydrological systems. We find that MTTs derived from tritium concentrations in streamflow are just as susceptible to aggregation bias as those from seasonal tracer cycles. Likewise, groundwater wells or springs fed by two or more water sources with different MTTs will also have aggregation bias. However, the transit times over which the biases are manifested are different because the two methods are applicable over different time ranges, up to 5 years for seasonal tracer cycles and up to 200 years for tritium concentrations. Our virtual experiments with two water components show that the aggregation errors are larger when the MTT differences between the components are larger and the amounts of the components are each close to 50 % of the mixture. We also find that young water fractions derived from tritium (based on a young water threshold of 18 years are almost immune to aggregation errors as were those derived from seasonal tracer cycles with a threshold of about 2 months.
Stewart, Michael K.; Morgenstern, Uwe; Gusyev, Maksym A.; Małoszewski, Piotr
2017-09-01
Kirchner (2016a) demonstrated that aggregation errors due to spatial heterogeneity, represented by two homogeneous subcatchments, could cause severe underestimation of the mean transit times (MTTs) of water travelling through catchments when simple lumped parameter models were applied to interpret seasonal tracer cycle data. Here we examine the effects of such errors on the MTTs and young water fractions estimated using tritium concentrations in two-part hydrological systems. We find that MTTs derived from tritium concentrations in streamflow are just as susceptible to aggregation bias as those from seasonal tracer cycles. Likewise, groundwater wells or springs fed by two or more water sources with different MTTs will also have aggregation bias. However, the transit times over which the biases are manifested are different because the two methods are applicable over different time ranges, up to 5 years for seasonal tracer cycles and up to 200 years for tritium concentrations. Our virtual experiments with two water components show that the aggregation errors are larger when the MTT differences between the components are larger and the amounts of the components are each close to 50 % of the mixture. We also find that young water fractions derived from tritium (based on a young water threshold of 18 years) are almost immune to aggregation errors as were those derived from seasonal tracer cycles with a threshold of about 2 months.
A discrete-time adaptive control scheme for robot manipulators
Tarokh, M.
1990-01-01
A discrete-time model reference adaptive control scheme is developed for trajectory tracking of robot manipulators. The scheme utilizes feedback, feedforward, and auxiliary signals, obtained from joint angle measurement through simple expressions. Hyperstability theory is utilized to derive the adaptation laws for the controller gain matrices. It is shown that trajectory tracking is achieved despite gross robot parameter variation and uncertainties. The method offers considerable design flexibility and enables the designer to improve the performance of the control system by adjusting free design parameters. The discrete-time adaptation algorithm is extremely simple and is therefore suitable for real-time implementation. Simulations and experimental results are given to demonstrate the performance of the scheme.
Evaluation of Real-time operating systems for FGC controls
Chalas, Konstantinos
2015-01-01
Power Converter Control for various experiments at CERN, is con- ducted using a machine called Function Generator Controller. The cur- rent generation of FGCs being deployed is FGC3. A certain number of FGCs require very fast and precise control, and for these systems, there is uncertainty of whether the existing hardware will be able to provide the level of determinism required. I have worked in the CCS section as a summer student on a project to study the potential of ARM-based CPUs to provide a real time behaviour fit for a future high-performance FGC4. In this paper, i will present the results of my research into real-time vari- ants of Linux and other real-time operating systems on two different ARM CPUs.
Inherent limitations of fixed time servo-controlled radiometric calorimetry
International Nuclear Information System (INIS)
Wetzel, J.R.; Duff, M.F.; Lemming, J.F.
1987-01-01
There has been some interest in low precision, short run time calorimetry measurements. This type of calorimetry measurement has been proposed for use when high precision measurements are not required, for example, to screen scrap containers to determine if there is enough material to be measured more accurately of for confirmatory measurements that only require low precision results. The equipment needed to make these measurements is a servo-controlled calorimeter with a sample preequilibration bath. The preequilibration bath temperature is set to the internal temperature of the calorimeter running at a fixed servo-controlled wattage level. The sample power value is determined at a fixed time form the sample loading into the calorimeter. There are some limitations and areas of uncertainties in the use of data obtained by this method. Data collected under controlled conditions demonstrate the limitations. Sample packaging, preequilibration time, and item wattage were chosen as the variables most likely to be encountered in a plant environment
Timing and control monitor system upgrade design document. Version 4
International Nuclear Information System (INIS)
Brandt, J.J.
1984-01-01
This is a design document for the Timing and Control Monitor System Upgrade Project. This project is intended to provide a replacement system for the existing user Encoder Monitor Systems and Varian 72 Control Room computer systems. All of these systems reside at the Nevada Test Site. The function of the T and C Monitor System is to gather real-time statistics and data on user defined key variables from control, communication, data acquistion systems, and from the monitoring system itself. The control, communication, and data acquisition systems each operate separately from the monitor system. The T and C Monitor System gathers this data in order to verify the readiness of an event to begin countdown. This includes setup, verification, calibration, and peripheral services, report any failures that may occur during the countdown, verify detonation and containment, and assist reentry activities after the event
Computation of reactor control rod drop time under accident conditions
International Nuclear Information System (INIS)
Dou Yikang; Yao Weida; Yang Renan; Jiang Nanyan
1998-01-01
The computational method of reactor control rod drop time under accident conditions lies mainly in establishing forced vibration equations for the components under action of outside forces on control rod driven line and motion equation for the control rod moving in vertical direction. The above two kinds of equations are connected by considering the impact effects between control rod and its outside components. Finite difference method is adopted to make discretization of the vibration equations and Wilson-θ method is applied to deal with the time history problem. The non-linearity caused by impact is iteratively treated with modified Newton method. Some experimental results are used to validate the validity and reliability of the computational method. Theoretical and experimental testing problems show that the computer program based on the computational method is applicable and reliable. The program can act as an effective tool of design by analysis and safety analysis for the relevant components
Sassen, S.A.E.; Wal, van der J.
1997-01-01
For a real-time shared-memory database with optimistic concurrency control, an approximation for the transaction response-time distribution is obtained. The model assumes that transactions arrive at the database according to a Poisson process, that every transaction uses an equal number of
Sassen, S.A.E.; Wal, van der J.
1997-01-01
For a real-time shared-memory database with optimistic concurrency control, an approximation for the transaction response-time distribution is obtained. The model assumes that transactions arrive at the database according to a Poisson process, that every transaction takes an exponential execution
A theory of Markovian time-inconsistent stochastic control in discrete time
DEFF Research Database (Denmark)
Bjork, Tomas; Murgoci, Agatha
2014-01-01
We develop a theory for a general class of discrete-time stochastic control problems that, in various ways, are time-inconsistent in the sense that they do not admit a Bellman optimality principle. We attack these problems by viewing them within a game theoretic framework, and we look for subgame...
The response time distribution in a real-time database with optimistic concurrency control
Sassen, S.A.E.; Wal, van der J.
1996-01-01
For a real-time shared-memory database with optimistic concurrency control, an approximation for the transaction response time distribution is obtained. The model assumes that transactions arrive at the database according to a Poisson process, that every transaction uses an equal number of
Decentralized control of discrete-time linear time invariant systems with input saturation
Deliu, C.; Deliu, Ciprian; Malek, Babak; Roy, Sandip; Saberi, Ali; Stoorvogel, Antonie Arij
We study decentralized stabilization of discrete-time linear time invariant (LTI) systems subject to actuator saturation, using LTI controllers. The requirement of stabilization under both saturation constraints and decentralization impose obvious necessary conditions on the open-loop plant, namely
Energy Technology Data Exchange (ETDEWEB)
Sato, H. [Public Works Research Inst., Tsukuba (Japan); Takeda, T.; Mukai, H. [Kajima Corp., Tokyo (Japan); Oikawa, K. [SE Corp., Tokyo (Japan)
1996-01-30
In recent years, the techniques for the typical PC bridges shown in the title have been considerably developed in Japan. However, occurrence of characteristic vibrations of the parallel cables even at relatively low wind speeds are observed in many cases, for which an effective control means is inevitably required. In this report, an investigation of tests on effectiveness of 4 kinds of vibration control means carried out in a wind tunnel and its results are described. In the test, an elastic model of 3-dimension was used for 5 test cases including a case without any control means, and each case was explained and examined in detail. It was revealed that for a damping system, a considerably large damping effect was necessary to restraint the wake galloping, and the cable distance selected to be 1.5 times smaller or 6 times larger than the cable diameter was effective, and while vibration control wires were effective, the adjustment of the cable vibration frequency was ineffective. It was also pointed out that a further verification would be necessary for the latter 2 control systems as no enough experience was yet accumulated in the actual service. 13 refs., 16 figs., 6 tabs.
Soft Real-Time PID Control on a VME Computer
Karayan, Vahag; Sander, Stanley; Cageao, Richard
2007-01-01
microPID (uPID) is a computer program for real-time proportional + integral + derivative (PID) control of a translation stage in a Fourier-transform ultraviolet spectrometer. microPID implements a PID control loop over a position profile at sampling rate of 8 kHz (sampling period 125microseconds). The software runs in a strippeddown Linux operating system on a VersaModule Eurocard (VME) computer operating in real-time priority queue using an embedded controller, a 16-bit digital-to-analog converter (D/A) board, and a laser-positioning board (LPB). microPID consists of three main parts: (1) VME device-driver routines, (2) software that administers a custom protocol for serial communication with a control computer, and (3) a loop section that obtains the current position from an LPB-driver routine, calculates the ideal position from the profile, and calculates a new voltage command by use of an embedded PID routine all within each sampling period. The voltage command is sent to the D/A board to control the stage. microPID uses special kernel headers to obtain microsecond timing resolution. Inasmuch as microPID implements a single-threaded process and all other processes are disabled, the Linux operating system acts as a soft real-time system.
Discrete-time control system design with applications
Rabbath, C A
2014-01-01
This book presents practical techniques of discrete-time control system design. In general, the design techniques lead to low-order dynamic compensators that ensure satisfactory closed-loop performance for a wide range of sampling rates. The theory is given in the form of theorems, lemmas, and propositions. The design of the control systems is presented as step-by-step procedures and algorithms. The proposed feedback control schemes are applied to well-known dynamic system models. This book also discusses: Closed-loop performance of generic models of mobile robot and airborne pursuer dynamic systems under discrete-time feedback control with limited computing capabilities Concepts of discrete-time models and sampled-data models of continuous-time systems, for both single- and dual-rate operation Local versus global digital redesign Optimal, closed-loop digital redesign methods Plant input mapping design Generalized holds and samplers for use in feedback control loops, Numerical simulation of fixed-point arithm...
Online Self-Organizing Network Control with Time Averaged Weighted Throughput Objective
Directory of Open Access Journals (Sweden)
Zhicong Zhang
2018-01-01
Full Text Available We study an online multisource multisink queueing network control problem characterized with self-organizing network structure and self-organizing job routing. We decompose the self-organizing queueing network control problem into a series of interrelated Markov Decision Processes and construct a control decision model for them based on the coupled reinforcement learning (RL architecture. To maximize the mean time averaged weighted throughput of the jobs through the network, we propose a reinforcement learning algorithm with time averaged reward to deal with the control decision model and obtain a control policy integrating the jobs routing selection strategy and the jobs sequencing strategy. Computational experiments verify the learning ability and the effectiveness of the proposed reinforcement learning algorithm applied in the investigated self-organizing network control problem.
Guaranteed Cost Finite-Time Control of Discrete-Time Positive Impulsive Switched Systems
Directory of Open Access Journals (Sweden)
Leipo Liu
2018-01-01
Full Text Available This paper considers the guaranteed cost finite-time boundedness of discrete-time positive impulsive switched systems. Firstly, the definition of guaranteed cost finite-time boundedness is introduced. By using the multiple linear copositive Lyapunov function (MLCLF and average dwell time (ADT approach, a state feedback controller is designed and sufficient conditions are obtained to guarantee that the corresponding closed-loop system is guaranteed cost finite-time boundedness (GCFTB. Such conditions can be solved by linear programming. Finally, a numerical example is provided to show the effectiveness of the proposed method.
Energy Technology Data Exchange (ETDEWEB)
Kimura, K; Hasegawa, T; Watanabe, H; Hasegawa, S; Oshima, M [Tsukuba Univ., Sakura, Ibaraki (Japan)
1981-04-01
Ventilatory steady state measurement with /sup 133/Xe, using Ventil-Con (Radx) and a large area scintillation camera (Searle, LFOV) combined with a mini-computer system (Shimadzu, Scintipac 230) was employed to evaluate regional pulmonary function of 94 patients with chronic obstructive lung disease (COLD), fibrosis, carcinoma and other lung diseases. In the patients with COLD, mean washout times (anti t) were markedly prolonged in whole lung fields (anti m 130 +- 33 sec.) and ventilation indices (V*/V) (*: radical) and perfusion indices (Q*/V) (*: radical) were reduced in regional zones, especially in bilateral lower lung zones. For the patients with lung fibrosis, anti t values were short and the distribution of ventilation indices were uniform, and in contrast perfusion indices were reduced in the lower lung fields. In the area most affected by carcinoma, lung volumes (V) were reduced in parallel with the regional ventilation (V*) (*: radical) and perfusion (Q*) (*: radical). As the tumor approached the hilum, the relative ventilation and perfusion of cancerous side decreased remarkably in patients with obstructive findings on bronchoscopy. The mean washout times (anti t) for /sup 133/Xe, calculated by a modified height over area method without background subtraction, were significantly longer than indicated by the data yielded by the least squares curve fitting of initial washout curve after background subtraction. Although the accuracy of these data was limited, it appeared that the prolonged anti t is a good parameter of regional ventilatory disturbance because significant correlations were found between the whole lung anti t in patients with lung diseases and their FEV 1.0% r = -0.66, RV/TLC r = 0.64, % TLC r = 0.43, PaCO/sub 2/ r = 0.41, PaO/sub 2/ r = -0.35.
Distributed digital real-time control system for TCV tokamak
Energy Technology Data Exchange (ETDEWEB)
Le, H.B. [École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association EURATOM-Confédération Suisse, CH-1015 Lausanne (Switzerland); Felici, F. [Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Paley, J.I.; Duval, B.P.; Moret, J.-M.; Coda, S.; Sauter, O.; Fasel, D.; Marmillod, P. [École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association EURATOM-Confédération Suisse, CH-1015 Lausanne (Switzerland)
2014-03-15
Highlights: • A new distributed digital control system for the TCV tokamak has been commissioned. • Data is shared in real-time between all nodes using the reflective memory. • The customised Linux OS allows achieving deterministic and low latency behaviour. • The control algorithm design in Simulink together with the automatic code generation using Embedded Coder allow rapid algorithm development. • Controllers designed outside the TCV environment can be ported easily. • The previous control system functions have been emulated and improved. • New capabilities include MHD control, profile control, equilibrium reconstruction. - Abstract: A new digital feedback control system (named the SCD “Système de Contrôle Distribué”) has been developed, integrated and used successfully to control TCV (Tokamak à Configuration Variable) plasmas. The system is designed to be modular, distributed, and scalable, accommodating hundreds of diagnostic inputs and actuator outputs. With many more inputs and outputs available than previously possible, it offers the possibility to design advanced control algorithms with better knowledge of the plasma state and to coherently control all TCV actuators, including poloidal field (PF) coils, gas valves, the gyrotron powers and launcher angles of the electron cyclotron heating and current drive system (ECRH/ECCD) together with diagnostic triggering signals. The system consists of multiple nodes; each is a customised Linux desktop or embedded PC which may have local ADC and DAC cards. Each node is also connected to a memory network (reflective memory) providing a reliable, deterministic method of sharing memory between all nodes. Control algorithms are programmed as block diagrams in Matlab-Simulink providing a powerful environment for modelling and control design. The C code is generated automatically from the Simulink block diagram and compiled, with the Simulink Embedded Coder (SEC, formerly Real-Time Workshop Embedded
Veeger, C.P.L.; Etman, L.F.P.; Herk, van J.; Rooda, J.E.
2009-01-01
Predicting the mean cycle time as a function of throughput and product mix is helpful in making the production planning for cluster tools. To predict the mean cycle time, detailed simulation models may be used. However, detailed models require much development time, and it may not be possible to
Dynamical control of matter-wave splitting using time-dependent optical lattices
DEFF Research Database (Denmark)
Park, Sung Jong; Andersen, Henrik Kjær; Mai, Sune
2012-01-01
We report on measurements of splitting Bose-Einstein condensates (BEC) by using a time-dependent optical lattice potential. First, we demonstrate the division of a BEC into a set of equally populated components by means of time-dependent control of Landau-Zener tunneling in a vertical lattice....... Finally, a combination of multiple Bragg reflections and Landau-Zener tunneling allows for the generation of macroscopic arrays of condensates with potential applications in atom optics and atom interferometry....