WorldWideScience

Sample records for time-varying electricity production

  1. Electricity Futures Prices : Time Varying Sensitivity to Fundamentals

    NARCIS (Netherlands)

    S-E. Fleten (Stein-Erik); R. Huisman (Ronald); M. Kilic (Mehtap); H.P.G. Pennings (Enrico); S. Westgaard (Sjur)

    2014-01-01

    textabstractThis paper provides insight in the time-varying relation between electricity futures prices and fundamentals in the form of prices of contracts for fossil fuels. As supply curves are not constant and different producers have different marginal costs of production, we argue that the

  2. Time-varying value of electric energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Mims, Natalie A.; Eckman, Tom; Goldman, Charles

    2017-06-30

    Electric energy efficiency resources save energy and may reduce peak demand. Historically, quantification of energy efficiency benefits has largely focused on the economic value of energy savings during the first year and lifetime of the installed measures. Due in part to the lack of publicly available research on end-use load shapes (i.e., the hourly or seasonal timing of electricity savings) and energy savings shapes, consideration of the impact of energy efficiency on peak demand reduction (i.e., capacity savings) has been more limited. End-use load research and the hourly valuation of efficiency savings are used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity and demand response planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service. This study reviews existing literature on the time-varying value of energy efficiency savings, provides examples in four geographically diverse locations of how consideration of the time-varying value of efficiency savings impacts the calculation of power system benefits, and identifies future research needs to enhance the consideration of the time-varying value of energy efficiency in cost-effectiveness screening analysis. Findings from this study include: -The time-varying value of individual energy efficiency measures varies across the locations studied because of the physical and operational characteristics of the individual utility system (e.g., summer or winter peaking, load factor, reserve margin) as well as the time periods during which savings from measures occur. -Across the four locations studied, some of the largest capacity benefits from energy efficiency are derived from the deferral of transmission and distribution system infrastructure upgrades. However, the deferred cost of such upgrades also exhibited the greatest range

  3. Modeling of Electricity Demand for Azerbaijan: Time-Varying Coefficient Cointegration Approach

    Directory of Open Access Journals (Sweden)

    Jeyhun I. Mikayilov

    2017-11-01

    Full Text Available Recent literature has shown that electricity demand elasticities may not be constant over time and this has investigated using time-varying estimation methods. As accurate modeling of electricity demand is very important in Azerbaijan, which is a transitional country facing significant change in its economic outlook, we analyze whether the response of electricity demand to income and price is varying over time in this economy. We employed the Time-Varying Coefficient cointegration approach, a cutting-edge time-varying estimation method. We find evidence that income elasticity demonstrates sizeable variation for the period of investigation ranging from 0.48% to 0.56%. The study has some useful policy implications related to the income and price aspects of the electricity consumption in Azerbaijan.

  4. Resonant e+e- production by time-varying electromagnetic field

    International Nuclear Information System (INIS)

    Farakos, K.; Koutsoumbas, G.; Tiktopoulos, G.

    1990-01-01

    As pointed out by Cornwall and Tiktopoulos (CT) strong, time-varying electric fields may produce e + e - pairs in a resonant fashion. This effect could be related to the sharp peaks in the e + e - spectrum observed in the GSI heavy-ion collision experiments. We attempt to go beyond the case of spatially uniform fields discussed by CT. We find that resonant e + e - production indeed takes place for electric fields derived from four-potentials of the form A 1 =A 2 =A 0 =0, A 3 =δ(t)b(x 3 ) provided by b(x) has discontinuities with a jump at least equal to π. (orig.)

  5. Citrate-capped gold nanoparticle electrophoretic heat production in response to a time-varying radiofrequency electric-field.

    Science.gov (United States)

    Corr, Stuart J; Raoof, Mustafa; Mackeyev, Yuri; Phounsavath, Sophia; Cheney, Matthew A; Cisneros, Brandon T; Shur, Michael; Gozin, Michael; McNally, Patrick J; Wilson, Lon J; Curley, Steven A

    2012-11-15

    The evaluation of heat production from gold nanoparticles (AuNPs) irradiated with radiofrequency (RF) energy has been problematic due to Joule heating of their background ionic buffer suspensions. Insights into the physical heating mechanism of nanomaterials under RF excitations must be obtained if they are to have applications in fields such as nanoparticle-targeted hyperthermia for cancer therapy. By developing a purification protocol which allows for highly-stable and concentrated solutions of citrate-capped AuNPs to be suspended in high-resistivity water, we show herein, for the first time, that heat production is only evident for AuNPs of diameters ≤ 10 nm, indicating a unique size-dependent heating behavior not previously observed. Heat production has also shown to be linearly dependent on both AuNP concentration and total surface area, and severely attenuated upon AuNP aggregation. These relationships have been further validated using permittivity analysis across a frequency range of 10 MHz to 3 GHz, as well as static conductivity measurements. Theoretical evaluations suggest that the heating mechanism can be modeled by the electrophoretic oscillation of charged AuNPs across finite length scales in response to a time-varying electric field. It is anticipated these results will assist future development of nanoparticle-assisted heat production by RF fields for applications such as targeted cancer hyperthermia.

  6. Consumer responses to time varying prices for electricity

    International Nuclear Information System (INIS)

    Thorsnes, Paul; Williams, John; Lawson, Rob

    2012-01-01

    We report new experimental evidence of the household response to weekday differentials in peak and off-peak electricity prices. The data come from Auckland, New Zealand, where peak residential electricity consumption occurs in winter for heating. Peak/off-peak price differentials ranged over four randomly selected groups from 1.0 to 3.5. On average, there was no response except in winter. In winter, participant households reduced electricity consumption by at least 10%, took advantage of lower off-peak prices but did not respond to the peak price differentials. Response varied with house and household size, time spent away from home, and whether water was heated with electricity. - Highlights: ► Seasonal effects in winter. ► High conservation effect from information. ► Higher peak prices no effect on peak use. ► Low off-peak prices encourage less conservation off-peak.

  7. Line shapes and time dynamics of the Förster resonances between two Rydberg atoms in a time-varying electric field

    KAUST Repository

    Yakshina, E. A.

    2016-10-21

    The observation of the Stark-tuned Förster resonances between Rydberg atoms excited by narrowband cw laser radiation requires usage of a Stark-switching technique in order to excite the atoms first in a fixed electric field and then to induce the interactions in a varied electric field, which is scanned across the Förster resonance. In our experiments with a few cold Rb Rydberg atoms, we have found that the transients at the edges of the electric pulses strongly affect the line shapes of the Förster resonances, since the population transfer at the resonances occurs on a time scale of ∼100 ns, which is comparable with the duration of the transients. For example, a short-term ringing at a certain frequency causes additional radio-frequency-assisted Förster resonances, while nonsharp edges lead to asymmetry. The intentional application of the radio-frequency field induces transitions between collective states, whose line shape depends on the interaction strengths and time. Spatial averaging over the atom positions in a single interaction volume yields a cusped line shape of the Förster resonance. We present a detailed experimental and theoretical analysis of the line shape and time dynamics of the Stark-tuned Förster resonances Rb(nP3/2)+Rb(nP3/2)→Rb(nS1/2)+Rb([n+1]S1/2) for two Rb Rydberg atoms interacting in a time-varying electric field.

  8. Line shapes and time dynamics of the Förster resonances between two Rydberg atoms in a time-varying electric field

    KAUST Repository

    Yakshina, E. A.; Tretyakov, D. B.; Beterov, I. I.; Entin, V. M.; Andreeva, C.; Cinins, A.; Markovski, A.; Iftikhar, Z.; Ekers, Aigars; Ryabtsev, I. I.

    2016-01-01

    The observation of the Stark-tuned Förster resonances between Rydberg atoms excited by narrowband cw laser radiation requires usage of a Stark-switching technique in order to excite the atoms first in a fixed electric field and then to induce the interactions in a varied electric field, which is scanned across the Förster resonance. In our experiments with a few cold Rb Rydberg atoms, we have found that the transients at the edges of the electric pulses strongly affect the line shapes of the Förster resonances, since the population transfer at the resonances occurs on a time scale of ∼100 ns, which is comparable with the duration of the transients. For example, a short-term ringing at a certain frequency causes additional radio-frequency-assisted Förster resonances, while nonsharp edges lead to asymmetry. The intentional application of the radio-frequency field induces transitions between collective states, whose line shape depends on the interaction strengths and time. Spatial averaging over the atom positions in a single interaction volume yields a cusped line shape of the Förster resonance. We present a detailed experimental and theoretical analysis of the line shape and time dynamics of the Stark-tuned Förster resonances Rb(nP3/2)+Rb(nP3/2)→Rb(nS1/2)+Rb([n+1]S1/2) for two Rb Rydberg atoms interacting in a time-varying electric field.

  9. Time-Varying Value of Energy Efficiency in Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Mims, Natalie; Eckman, Tom; Schwartz, Lisa C.

    2018-04-02

    Quantifying the time-varying value of energy efficiency is necessary to properly account for all of its benefits and costs and to identify and implement efficiency resources that contribute to a low-cost, reliable electric system. Historically, most quantification of the benefits of efficiency has focused largely on the economic value of annual energy reduction. Due to the lack of statistically representative metered end-use load shape data in Michigan (i.e., the hourly or seasonal timing of electricity savings), the ability to confidently characterize the time-varying value of energy efficiency savings in the state, especially for weather-sensitive measures such as central air conditioning, is limited. Still, electric utilities in Michigan can take advantage of opportunities to incorporate the time-varying value of efficiency into their planning. For example, end-use load research and hourly valuation of efficiency savings can be used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service (KEMA 2012). In addition, accurately calculating the time-varying value of efficiency may help energy efficiency program administrators prioritize existing offerings, set incentive or rebate levels that reflect the full value of efficiency, and design new programs.

  10. Vesicle biomechanics in a time-varying magnetic field.

    Science.gov (United States)

    Ye, Hui; Curcuru, Austen

    2015-01-01

    Cells exhibit distortion when exposed to a strong electric field, suggesting that the field imposes control over cellular biomechanics. Closed pure lipid bilayer membranes (vesicles) have been widely used for the experimental and theoretical studies of cellular biomechanics under this electrodeformation. An alternative method used to generate an electric field is by electromagnetic induction with a time-varying magnetic field. References reporting the magnetic control of cellular mechanics have recently emerged. However, theoretical analysis of the cellular mechanics under a time-varying magnetic field is inadequate. We developed an analytical theory to investigate the biomechanics of a modeled vesicle under a time-varying magnetic field. Following previous publications and to simplify the calculation, this model treated the inner and suspending media as lossy dielectrics, the membrane thickness set at zero, and the electric resistance of the membrane assumed to be negligible. This work provided the first analytical solutions for the surface charges, electric field, radial pressure, overall translational forces, and rotational torques introduced on a vesicle by the time-varying magnetic field. Frequency responses of these measures were analyzed, particularly the frequency used clinically by transcranial magnetic stimulation (TMS). The induced surface charges interacted with the electric field to produce a biomechanical impact upon the vesicle. The distribution of the induced surface charges depended on the orientation of the coil and field frequency. The densities of these charges were trivial at low frequency ranges, but significant at high frequency ranges. The direction of the radial force on the vesicle was dependent on the conductivity ratio between the vesicle and the medium. At relatively low frequencies (biomechanics under a time-varying magnetic field. Biological effects of clinical TMS are not likely to occur via alteration of the biomechanics of brain

  11. Pair production in an electric field in a time-dependent gauge

    International Nuclear Information System (INIS)

    Barut, A.O.; Duru, I.H.

    1989-07-01

    A new nonperturbative method of calculation of the pair production in a constant electric field is presented in which the propagator is evaluated entirely by path-integration in a time-dependent potential. This gauge and the path integration correctly define all the normalizations. As a by-product we get also the Unruh formula since the constant electric field provides an accelerated frame. (author). 11 refs

  12. Electron dynamics in solid state via time varying wavevectors

    Science.gov (United States)

    Khaneja, Navin

    2018-06-01

    In this paper, we study electron wavepacket dynamics in electric and magnetic fields. We rigorously derive the semiclassical equations of electron dynamics in electric and magnetic fields. We do it both for free electron and electron in a periodic potential. We do this by introducing time varying wavevectors k(t). In the presence of magnetic field, our wavepacket reproduces the classical cyclotron orbits once the origin of the Schröedinger equation is correctly chosen to be center of cyclotron orbit. In the presence of both electric and magnetic fields, our equations for wavepacket dynamics differ from classical Lorentz force equations. We show that in a periodic potential, on application of electric field, the electron wave function adiabatically follows the wavefunction of a time varying Bloch wavevector k(t), with its energies suitably shifted with time. We derive the effective mass equation and discuss conduction in conductors and insulators.

  13. Time varying voltage combustion control and diagnostics sensor

    Science.gov (United States)

    Chorpening, Benjamin T [Morgantown, WV; Thornton, Jimmy D [Morgantown, WV; Huckaby, E David [Morgantown, WV; Fincham, William [Fairmont, WV

    2011-04-19

    A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

  14. Guidelines for limiting exposure to time-varying electric and magnetic fields (1 Hz to 100 kHz)

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    This paper is the French translation of an article from the International Commission on Non-Ionizing Radiation Protection (ICNIRP) Guidelines, entitled 'Guidelines for Limiting Exposure to Time-Varying Electric and Magnetic Fields (1 Hz To 100 kHz)'. In This document, guidelines are established for the protection of humans exposed to electric and magnetic fields in the low-frequency range of the electromagnetic spectrum. The general principles for the development of ICNIRP guidelines are published elsewhere (ICNIRP 2002). For the purpose of this document, the low-frequency range extends from 1 Hz to 100 kHz. Above 100 kHz, effects such as heating need to be considered, which are covered by other ICNIRP guidelines. However, in the frequency range from 100 kHz up to approximately 10 MHz protection from both, low frequency effects on the nervous system as well as high frequency effects need to be considered depending on exposure conditions. Therefore, some guidance in this document is extended to 10 MHz to cover the nervous system effects in this frequency range. Guidelines for static magnetic fields have been issued in a separate document (ICNIRP 2009). Guidelines applicable to movement-induced electric fields or time-varying magnetic fields up to 1 Hz will be published separately. This publication replaces the low-frequency part of the 1998 guidelines (ICNIRP 1998). ICNIRP is currently revising the guidelines for the high-frequency portion of the spectrum (above 100 kHz). (authors)

  15. Time-varying convergence in European electricity spot markets and their association with carbon and fuel prices

    International Nuclear Information System (INIS)

    Menezes, Lilian M. de; Houllier, Melanie A.; Tamvakis, Michael

    2016-01-01

    Long-run dynamics of electricity prices are expected to reflect fuel price developments, since fuels generally account for a large share in the cost of generation. As an integrated European market for electricity develops, wholesale electricity prices should be converging as a result of market coupling and increased interconnectivity. Electricity mixes are also changing, spurred by a drive to significantly increase the share of renewables. Consequently, the electricity wholesale price dynamics are evolving, and the fuel–electricity price nexus that has been described in the literature is likely to reflect this evolution. This study investigates associations between spot prices from the British, French and Nordpool markets with those in connected electricity markets and fuel input prices, from December 2005 to October 2013. In order to assess the time-varying dynamics of electricity spot price series, localized autocorrelation functions are used. Electricity spot prices in the three markets are found to have stationary and non-stationary periods. When a trend in spot prices is observed, it is likely to reflect the trend in fuel prices. Cointegration analysis is then used to assess co-movement between electricity spot prices and fuel inputs to generation. The results show that British electricity spot prices are associated with fuel prices and not with price developments in connected markets, while the opposite is observed in the French and Nordpool day-ahead markets. - Highlights: • Electricity market integration policies may have altered EU spot electricity prices. • LACF is used to assess the changing nature of electricity spot prices. • EU electricity spot prices show both stationary and non-stationary periods. • Carbon and fuel prices have greater impact on British spot prices. • In continental Europe, electricity prices have decoupled from fuel prices.

  16. Visualizing time-varying harmonics using filter banks

    NARCIS (Netherlands)

    Duque, C.A.; Da Silveira, P.M.; Ribeiro, P.F.

    2011-01-01

    Although it is well known that Fourier analysis is in reality only accurately applicable to steady state waveforms, it is a widely used tool to study and monitor time-varying signals, such as are commonplace in electrical power systems. The disadvantages of Fourier analysis, such as frequency

  17. An Explicit MOT-TD-VIE Solver for Time Varying Media

    KAUST Repository

    Sayed, Sadeed Bin; Ulku, Huseyin Arda; Bagci, Hakan

    2016-01-01

    An explicit marching on-in-time (MOT) scheme for solving the time domain electric field integral equation enforced on volumes with time varying dielectric permittivity is proposed. Unknowns of the integral equation and the constitutive relation, i

  18. Electrical resistance imaging of a time-varying interface in stratified flows using an unscented Kalman filter

    International Nuclear Information System (INIS)

    Ijaz, Umer Zeeshan; Khambampati, Anil Kumar; Kim, Kyung Youn; Chung, Soon Il; Kim, Sin

    2008-01-01

    In this paper, we estimate a time-varying interfacial boundary in stratified flows of two immiscible liquids using electrical resistance tomography. The interfacial boundary is approximated with front points spaced discretely along the interface. The design variables to be estimated are the locations of the front points, which are varying with the moving interface. The inverse problem is treated as a stochastic nonlinear state estimation problem with the nonstationary phase boundary (state) being estimated with the aid of an unscented Kalman filter. Numerical experiments are performed to evaluate the performance of an unscented Kalman filter. Specifically, a detailed analysis has been done on the effect of the number of front points and contrast ratio on the reconstruction performance. The reconstruction results show that an unscented Kalman filter is better suited for estimation in comparison to the conventional extended Kalman filter

  19. An Economic Evaluation of Binary Cycle Geothermal Electricity Production

    National Research Council Canada - National Science Library

    Fitzgerald, Crissie

    2003-01-01

    .... Variables such as well flow rate, geothermal gradient and electricity prices were varied to study their influence on the economic payback period for binary cycle geothermal electricity production...

  20. Time-varying output performances of piezoelectric vibration energy harvesting under nonstationary random vibrations

    Science.gov (United States)

    Yoon, Heonjun; Kim, Miso; Park, Choon-Su; Youn, Byeng D.

    2018-01-01

    Piezoelectric vibration energy harvesting (PVEH) has received much attention as a potential solution that could ultimately realize self-powered wireless sensor networks. Since most ambient vibrations in nature are inherently random and nonstationary, the output performances of PVEH devices also randomly change with time. However, little attention has been paid to investigating the randomly time-varying electroelastic behaviors of PVEH systems both analytically and experimentally. The objective of this study is thus to make a step forward towards a deep understanding of the time-varying performances of PVEH devices under nonstationary random vibrations. Two typical cases of nonstationary random vibration signals are considered: (1) randomly-varying amplitude (amplitude modulation; AM) and (2) randomly-varying amplitude with randomly-varying instantaneous frequency (amplitude and frequency modulation; AM-FM). In both cases, this study pursues well-balanced correlations of analytical predictions and experimental observations to deduce the relationships between the time-varying output performances of the PVEH device and two primary input parameters, such as a central frequency and an external electrical resistance. We introduce three correlation metrics to quantitatively compare analytical prediction and experimental observation, including the normalized root mean square error, the correlation coefficient, and the weighted integrated factor. Analytical predictions are in an excellent agreement with experimental observations both mechanically and electrically. This study provides insightful guidelines for designing PVEH devices to reliably generate electric power under nonstationary random vibrations.

  1. Regionally-varying and regionally-uniform electricity pricing policies compared across four usage categories

    International Nuclear Information System (INIS)

    Cho, Seong-Hoon; Kim, Taeyoung; Kim, Hyun Jae; Park, Kihyun; Roberts, Roland K.

    2015-01-01

    The objective of our research is to predict how electricity demand varies spatially between status quo regionally-uniform electricity pricing and hypothetical regionally-varying electricity pricing across usage categories. We summarize the empirical results of a case study of electricity demand in South Korea with three key findings and their related implications. First, the price elasticities of electricity demand differ across usage categories. Specifically, electricity demands for manufacturing and retail uses are price inelastic and close to unit elastic, respectively, while those for agricultural and residential uses are not statistically significant. This information is important in designing energy policy, because higher electricity prices could reduce electricity demands for manufacturing and retail uses, resulting in slower growth in those sectors. Second, spatial spillovers in electricity demand vary across uses. Understanding the spatial structure of electricity demand provides useful information to energy policy makers for anticipating changes in demand across regions via regionally-varying electricity pricing for different uses. Third, simulation results suggest that spatial variations among electricity demands by usage category under a regionally-varying electricity-pricing policy differ from those under a regionally-uniform electricity-pricing policy. Differences in spatial changes between the policies provide information for developing a realistic regionally-varying electricity-pricing policy according to usage category. - Highlights: • We compare regionally-varying and regionally-uniform electricity pricing policies. • We summarize empirical results of a case study of electricity demand in South Korea. • We confirm that spatial spillovers in electricity demands vary across different uses. • We find positive spatial spillovers in the manufacturing and residential sectors. • Our methods help policy makers evaluate regionally-varying pricing

  2. Simulations of hybrid system varying solar radiation and microturbine response time

    Directory of Open Access Journals (Sweden)

    Yolanda Fernández Ribaya

    2015-07-01

    Full Text Available Hybrid power systems, such as combinations of renewable power sources with intermittent power production and non-renewable power sources, theoretically increase the reliability and thus integration of renewable sources in the electrical system. However, a recent increase in the number of hybrid installations has sparked interest in the effects of their connection to the grid, especially in remote areas. This paper analyses a photovoltaic-gas microturbine hybrid system dimensioned to be installed in La Paz (Mexico.The research presented in this paper studies and quantifies the effects on the total electric power produced, varying both the solar radiation and the gas microturbine response time. The gas microturbine and the photovoltaic panels are modelled using Matlab/Simulink software, obtaining a platform where different tests to simulate real conditions have been executed. They consist of diverse ramps of irradiance that replicate solar radiation variations, and different microturbine response times reproduced by the time constants of a first order transfer function that models the microturbine dynamic response. The results obtained show that when radiation varies quickly it does not produce significant differences in the power guarantee or the microturbine gas consumption, to any microturbine response time. However, these two parameters are highly variable with smooth radiance variations. The maximum total power variation decreases greatly as the radiation variation gets lower. In addition, by decreasing the microturbine response time, it is possible to appreciably increase the power guarantee although the maximum power variation and gas consumption increase. Only in cases of low radiation variation is there no appreciable difference in the maximum power variation obtained by the different turbine response times.

  3. Simulations of hybrid system varying solar radiation and microturbine response time

    Energy Technology Data Exchange (ETDEWEB)

    Fernández Ribaya, Yolanda, E-mail: fernandezryolanda@uniovi.es; Álvarez, Eduardo; Paredes Sánchez, José Pablo; Xiberta Bernat, Jorge [Department of Energy E.I.M.E.M., University of Oviedo. 13 Independencia Street 2" n" d floor, 36004, Oviedo (Spain)

    2015-07-15

    Hybrid power systems, such as combinations of renewable power sources with intermittent power production and non-renewable power sources, theoretically increase the reliability and thus integration of renewable sources in the electrical system. However, a recent increase in the number of hybrid installations has sparked interest in the effects of their connection to the grid, especially in remote areas. This paper analyses a photovoltaic-gas microturbine hybrid system dimensioned to be installed in La Paz (Mexico).The research presented in this paper studies and quantifies the effects on the total electric power produced, varying both the solar radiation and the gas microturbine response time. The gas microturbine and the photovoltaic panels are modelled using Matlab/Simulink software, obtaining a platform where different tests to simulate real conditions have been executed. They consist of diverse ramps of irradiance that replicate solar radiation variations, and different microturbine response times reproduced by the time constants of a first order transfer function that models the microturbine dynamic response. The results obtained show that when radiation varies quickly it does not produce significant differences in the power guarantee or the microturbine gas consumption, to any microturbine response time. However, these two parameters are highly variable with smooth radiance variations. The maximum total power variation decreases greatly as the radiation variation gets lower. In addition, by decreasing the microturbine response time, it is possible to appreciably increase the power guarantee although the maximum power variation and gas consumption increase. Only in cases of low radiation variation is there no appreciable difference in the maximum power variation obtained by the different turbine response times.

  4. The effect of utility time-varying pricing and load control strategies on residential summer peak electricity use. A review

    International Nuclear Information System (INIS)

    Newsham, Guy R.; Bowker, Brent G.

    2010-01-01

    Peak demand for electricity in North America is expected to grow, challenging electrical utilities to supply this demand in a cost-effective, reliable manner. Therefore, there is growing interest in strategies to reduce peak demand by eliminating electricity use, or shifting it to non-peak times. This strategy is commonly called 'demand response'. In households, common strategies are time-varying pricing, which charge more for energy use on peak, or direct load control, which allows utilities to curtail certain loads during high demand periods. We reviewed recent North American studies of these strategies. The data suggest that the most effective strategy is a critical peak price (CPP) program with enabling technology to automatically curtail loads on event days. There is little evidence that this causes substantial hardship for occupants, particularly if they have input into which loads are controlled and how, and have an override option. In such cases, a peak load reduction of at least 30% is a reasonable expectation. It might be possible to attain such load reductions without enabling technology by focusing on household types more likely to respond, and providing them with excellent support. A simple time-of-use (TOU) program can only expect to realise on-peak reductions of 5%. (author)

  5. Co-production of hydrogen and electricity with CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Arienti, S.; Cotone, P.; Davison, J. [Foster Wheeler Italiana (Italy)

    2007-07-01

    This paper summarizes the results of a study carried out by Foster Wheeler for the IEA Greenhouse Gas R & D Programme that focused on different IGCC configurations with CO{sub 2} capture and H{sub 2} production. The three following main cases are compared: production of hydrogen, with minimum amount of electricity for a stand-alone plant production; co-production of the optimum hydrogen/electricity ratio; and co-production of hydrogen and electricity in a flexible plant that varies the hydrogen/electricity ratio. The paper reviews three available gasification technologies and presents the results of a more detailed evaluation of the selected one. The scope of this paper is to underline possible advantages of hydrogen and electricity co-production from coal, that is likely going to replace natural gas and petroleum as a source of hydrogen in the long term. Expected advantage of co-production will be the ability to vary the hydrogen/electricity ratio to meet market demands. A natural gas, diesel and gasoline demand market analysis has been performed for the Netherlands and the USA to determine the expected future hydrogen demand. Plant performance and costs are established and electric power production costs are evaluated. Electricity and hydrogen co-production plants are compared to plants that produce electricity only, with and without CO{sub 2} capture, to evaluate the costs of CO{sub 2} avoidance. 4 refs., 8 figs., 4 tabs.

  6. Modeling polar cap F-region patches using time varying convection

    International Nuclear Information System (INIS)

    Sojka, J.J.; Bowline, M.D.; Schunk, R.W.; Decker, D.T.; Valladares, C.E.; Sheehan, R.; Anderson, D.N.; Heelis, R.A.

    1993-01-01

    Here the authors present the results of computerized simulations of the polar cap regions which were able to model the formation of polar cap patches. They used the Utah State University Time-Dependent Ionospheric Model (TDIM) and the Phillips Laboratory (PL) F-region models in this work. By allowing a time varying magnetospheric electric field in the models, they were able to generate the patches. This time varying field generates a convection in the ionosphere. This convection is similar to convective changes observed in the ionosphere at times of southward pointing interplanetary magnetic field, due to changes in the B y component of the IMF

  7. Simple Model with Time-Varying Fine-Structure ``Constant''

    Science.gov (United States)

    Berman, M. S.

    2009-10-01

    Extending the original version written in colaboration with L.A. Trevisan, we study the generalisation of Dirac's LNH, so that time-variation of the fine-structure constant, due to varying electrical and magnetic permittivities is included along with other variations (cosmological and gravitational ``constants''), etc. We consider the present Universe, and also an inflationary scenario. Rotation of the Universe is a given possibility in this model.

  8. A time-varying magnetic flux concentrator

    International Nuclear Information System (INIS)

    Kibret, B; Premaratne, M; Lewis, P M; Thomson, R; Fitzgerald, P B

    2016-01-01

    It is known that diverse technological applications require the use of focused magnetic fields. This has driven the quest for controlling the magnetic field. Recently, the principles in transformation optics and metamaterials have allowed the realization of practical static magnetic flux concentrators. Extending such progress, here, we propose a time-varying magnetic flux concentrator cylindrical shell that uses electric conductors and ferromagnetic materials to guide magnetic flux to its center. Its performance is discussed based on finite-element simulation results. Our proposed design has potential applications in magnetic sensors, medical devices, wireless power transfer, and near-field wireless communications. (paper)

  9. Electrical Programming of Soft Matter: Using Temporally Varying Electrical Inputs To Spatially Control Self Assembly.

    Science.gov (United States)

    Yan, Kun; Liu, Yi; Zhang, Jitao; Correa, Santiago O; Shang, Wu; Tsai, Cheng-Chieh; Bentley, William E; Shen, Jana; Scarcelli, Giuliano; Raub, Christopher B; Shi, Xiao-Wen; Payne, Gregory F

    2018-02-12

    The growing importance of hydrogels in translational medicine has stimulated the development of top-down fabrication methods, yet often these methods lack the capabilities to generate the complex matrix architectures observed in biology. Here we show that temporally varying electrical signals can cue a self-assembling polysaccharide to controllably form a hydrogel with complex internal patterns. Evidence from theory and experiment indicate that internal structure emerges through a subtle interplay between the electrical current that triggers self-assembly and the electrical potential (or electric field) that recruits and appears to orient the polysaccharide chains at the growing gel front. These studies demonstrate that short sequences (minutes) of low-power (∼1 V) electrical inputs can provide the program to guide self-assembly that yields hydrogels with stable, complex, and spatially varying structure and properties.

  10. Optimizing Greenhouse Lighting for Advanced Agriculture Based on Real Time Electricity Market Price

    Directory of Open Access Journals (Sweden)

    Mehdi Mahdavian

    2017-01-01

    Full Text Available The world’s growing demand for food can be met by agricultural technology. Use of artificial light to supplement natural sunlight in greenhouse cultivation is one of the most common techniques to increase greenhouse production of food crops. However, artificial light requires significant electrical energy, which increases the cost of greenhouse production and can reduce profit. This paper models the increments to greenhouse productivity as well as the increases in cost from supplemental electric lighting, in a situation where the greenhouse is one of the elements of a smart grid, a system where the electric energy market is dynamic and prices vary over time. We used our models to calculate the optimum values for supplemental light and the required electrical energy for HPS lamps in the greenhouse environment, using cherry tomato cultivation as a case study crop. We considered two optimization techniques: iterative search (IS and genetic algorithm (GA. The two approaches produced similar results, although the GA method was much faster. Both approaches verify the advantages of using optimal supplemental light in terms of increasing production and hence profit.

  11. Time-varying BRDFs.

    Science.gov (United States)

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

  12. Electricity economics. Production functions with electricity

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Zhaoguang [State Grid Energy Research Institute, Beijing (China); Hu, Zheng [Delaware Univ., Newark, DE (United States)

    2013-07-01

    The first book studies on the economics of electricity consumption. Compares the sector production functions with electricity and the commercial production functions with electricity. Introduces the global E-GDP function, the European E-GDP function and 12 national E-GDP functions. Presents the gene characters of EAI production functions and E-GDP functions for USA to see why USA's economy is entering an up-industrialization period. Discusses China's economic growth by production functions with electricity. Electricity Economics: Production Functions with Electricity studies the production output from analyzing patterns of electricity consumption. Since electricity data can be used to measure scenarios of economic performance due to its accuracy and reliability, it could therefore also be used to help scholars explore new research frontiers that directly and indirectly benefits human society. Our research initially explores a similar pattern to substitute the Cobb-Douglas function with the production function with electricity to track and forecast economic activities. The book systematically introduces the theoretical frameworks and mathematical models of economics from the perspective of electricity consumption. The E-GDP functions are presented for case studies of more than 20 developed and developing countries. These functions also demonstrate substantial similarities between human DNA and production functions with electricity in terms of four major characteristics, namely replication, mutation, uniqueness, and evolution. Furthermore, the book includes extensive data and case studies on the U.S., China, Japan, etc. It is intended for scientists, engineers, financial professionals, policy makers, consultants, and anyone else with a desire to study electricity economics as well as related applications.

  13. Electricity economics. Production functions with electricity

    International Nuclear Information System (INIS)

    Hu, Zhaoguang; Hu, Zheng

    2013-01-01

    The first book studies on the economics of electricity consumption. Compares the sector production functions with electricity and the commercial production functions with electricity. Introduces the global E-GDP function, the European E-GDP function and 12 national E-GDP functions. Presents the gene characters of EAI production functions and E-GDP functions for USA to see why USA's economy is entering an up-industrialization period. Discusses China's economic growth by production functions with electricity. Electricity Economics: Production Functions with Electricity studies the production output from analyzing patterns of electricity consumption. Since electricity data can be used to measure scenarios of economic performance due to its accuracy and reliability, it could therefore also be used to help scholars explore new research frontiers that directly and indirectly benefits human society. Our research initially explores a similar pattern to substitute the Cobb-Douglas function with the production function with electricity to track and forecast economic activities. The book systematically introduces the theoretical frameworks and mathematical models of economics from the perspective of electricity consumption. The E-GDP functions are presented for case studies of more than 20 developed and developing countries. These functions also demonstrate substantial similarities between human DNA and production functions with electricity in terms of four major characteristics, namely replication, mutation, uniqueness, and evolution. Furthermore, the book includes extensive data and case studies on the U.S., China, Japan, etc. It is intended for scientists, engineers, financial professionals, policy makers, consultants, and anyone else with a desire to study electricity economics as well as related applications.

  14. Time variation in European carbon pass-through rates in electricity futures prices

    International Nuclear Information System (INIS)

    Huisman, Ronald; Kiliç, Mehtap

    2015-01-01

    The European Union Emissions Trading Scheme is a means to price emission allowances. Electricity market prices should reflect these market prices of emission allowances as they are a cost factor for power producers. The pass-through rate is the fraction of the emission allowance price that is passed through to electricity market prices. It is often measured and presented as an average or a fixed estimate over some time period. However, we expect that the pass-through rates should actually vary over time as electricity supply curves reflect the marginal costs of different producers that differ in emission intensity. We apply a Kalman Filter approach to observe pass-through rates in Germany and U.K. and find strong support for time varying instead of fixed pass-through rates. Although policy makers are interested in the impact of a policy on average, our results indicate that one needs to be careful with the time-frame over which pass-through rates are measured for policy evaluation, as an incorrect chosen evaluation period could cause an under- or overestimation of the pass-through rate. In addition, our model helps to provide policy makers with insight in the development of pass-through rates when market circumstances change with respect to power production. - Highlights: • We analyse the time-variation of the emission pass-through rate in power prices. • We examine historical futures prices for Germany and the U.K. • We test the hypothesis by using the Kalman Filter methodology. • Strong support is found that pass-through rates vary over time. • The chosen time-frame for pass-through rates is important for policy evaluation.

  15. Direct prediction of spatially and temporally varying physical properties from time-lapse electrical resistance data

    Science.gov (United States)

    Hermans, Thomas; Oware, Erasmus; Caers, Jef

    2016-09-01

    Time-lapse applications of electrical methods have grown significantly over the last decade. However, the quantitative interpretation of tomograms in terms of physical properties, such as salinity, temperature or saturation, remains difficult. In many applications, geophysical models are transformed into hydrological models, but this transformation suffers from spatially and temporally varying resolution resulting from the regularization used by the deterministic inversion. In this study, we investigate a prediction-focused approach (PFA) to directly estimate subsurface physical properties with electrical resistance data, circumventing the need for classic tomographic inversions. First, we generate a prior set of resistance data and physical property forecast through hydrogeological and geophysical simulations mimicking the field experiment. We reduce the dimension of both the data and the forecast through principal component analysis in order to keep the most informative part of both sets in a reduced dimension space. Then, we apply canonical correlation analysis to explore the relationship between the data and the forecast in their reduced dimension space. If a linear relationship can be established, the posterior distribution of the forecast can be directly sampled using a Gaussian process regression where the field data scores are the conditioning data. In this paper, we demonstrate PFA for various physical property distributions. We also develop a framework to propagate the estimated noise level in the reduced dimension space. We validate the results by a Monte Carlo study on the posterior distribution and demonstrate that PFA yields accurate uncertainty for the cases studied.

  16. Dynamic linear modeling of monthly electricity demand in Japan: Time variation of electricity conservation effect.

    Science.gov (United States)

    Honjo, Keita; Shiraki, Hiroto; Ashina, Shuichi

    2018-01-01

    After the severe nuclear disaster in Fukushima, which was triggered by the Great East Japan earthquake in March 2011, nuclear power plants in Japan were temporarily shut down for mandatory inspections. To prevent large-scale blackouts, the Japanese government requested companies and households to reduce electricity consumption in summer and winter. It is reported that the domestic electricity demand had a structural decrease because of the electricity conservation effect (ECE). However, quantitative analysis of the ECE is not sufficient, and especially time variation of the ECE remains unclear. Understanding the ECE is important because Japan's NDC (nationally determined contribution) assumes the reduction of CO2 emissions through aggressive energy conservation. In this study, we develop a time series model of monthly electricity demand in Japan and estimate time variation of the ECE. Moreover, we evaluate the impact of electricity conservation on CO2 emissions from power plants. The dynamic linear model is used to separate the ECE from the effects of other irrelevant factors (e.g. air temperature, economic production, and electricity price). Our result clearly shows that consumers' electricity conservation behavior after the earthquake was not temporary but became established as a habit. Between March 2011 and March 2016, the ECE on industrial electricity demand ranged from 3.9% to 5.4%, and the ECE on residential electricity demand ranged from 1.6% to 7.6%. The ECE on the total electricity demand was estimated at 3.2%-6.0%. We found a seasonal pattern that the residential ECE in summer is higher than that in winter. The emissions increase from the shutdown of nuclear power plants was mitigated by electricity conservation. The emissions reduction effect was estimated at 0.82 MtCO2-2.26 MtCO2 (-4.5% on average compared to the zero-ECE case). The time-varying ECE is necessary for predicting Japan's electricity demand and CO2 emissions after the earthquake.

  17. Dynamic linear modeling of monthly electricity demand in Japan: Time variation of electricity conservation effect.

    Directory of Open Access Journals (Sweden)

    Keita Honjo

    Full Text Available After the severe nuclear disaster in Fukushima, which was triggered by the Great East Japan earthquake in March 2011, nuclear power plants in Japan were temporarily shut down for mandatory inspections. To prevent large-scale blackouts, the Japanese government requested companies and households to reduce electricity consumption in summer and winter. It is reported that the domestic electricity demand had a structural decrease because of the electricity conservation effect (ECE. However, quantitative analysis of the ECE is not sufficient, and especially time variation of the ECE remains unclear. Understanding the ECE is important because Japan's NDC (nationally determined contribution assumes the reduction of CO2 emissions through aggressive energy conservation. In this study, we develop a time series model of monthly electricity demand in Japan and estimate time variation of the ECE. Moreover, we evaluate the impact of electricity conservation on CO2 emissions from power plants. The dynamic linear model is used to separate the ECE from the effects of other irrelevant factors (e.g. air temperature, economic production, and electricity price. Our result clearly shows that consumers' electricity conservation behavior after the earthquake was not temporary but became established as a habit. Between March 2011 and March 2016, the ECE on industrial electricity demand ranged from 3.9% to 5.4%, and the ECE on residential electricity demand ranged from 1.6% to 7.6%. The ECE on the total electricity demand was estimated at 3.2%-6.0%. We found a seasonal pattern that the residential ECE in summer is higher than that in winter. The emissions increase from the shutdown of nuclear power plants was mitigated by electricity conservation. The emissions reduction effect was estimated at 0.82 MtCO2-2.26 MtCO2 (-4.5% on average compared to the zero-ECE case. The time-varying ECE is necessary for predicting Japan's electricity demand and CO2 emissions after the

  18. Dynamic linear modeling of monthly electricity demand in Japan: Time variation of electricity conservation effect

    Science.gov (United States)

    Shiraki, Hiroto; Ashina, Shuichi

    2018-01-01

    After the severe nuclear disaster in Fukushima, which was triggered by the Great East Japan earthquake in March 2011, nuclear power plants in Japan were temporarily shut down for mandatory inspections. To prevent large-scale blackouts, the Japanese government requested companies and households to reduce electricity consumption in summer and winter. It is reported that the domestic electricity demand had a structural decrease because of the electricity conservation effect (ECE). However, quantitative analysis of the ECE is not sufficient, and especially time variation of the ECE remains unclear. Understanding the ECE is important because Japan’s NDC (nationally determined contribution) assumes the reduction of CO2 emissions through aggressive energy conservation. In this study, we develop a time series model of monthly electricity demand in Japan and estimate time variation of the ECE. Moreover, we evaluate the impact of electricity conservation on CO2 emissions from power plants. The dynamic linear model is used to separate the ECE from the effects of other irrelevant factors (e.g. air temperature, economic production, and electricity price). Our result clearly shows that consumers’ electricity conservation behavior after the earthquake was not temporary but became established as a habit. Between March 2011 and March 2016, the ECE on industrial electricity demand ranged from 3.9% to 5.4%, and the ECE on residential electricity demand ranged from 1.6% to 7.6%. The ECE on the total electricity demand was estimated at 3.2%–6.0%. We found a seasonal pattern that the residential ECE in summer is higher than that in winter. The emissions increase from the shutdown of nuclear power plants was mitigated by electricity conservation. The emissions reduction effect was estimated at 0.82 MtCO2–2.26 MtCO2 (−4.5% on average compared to the zero-ECE case). The time-varying ECE is necessary for predicting Japan’s electricity demand and CO2 emissions after the

  19. Time horizons and electricity futures: An application of Nicholas Georgescu-Roegen's general theory of economic production

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, Katharine N. [Department of Economics, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Gibson Institute for Land, Food and Environment, Queen' s University of Belfast, Northern Ireland (United Kingdom); Mayumi, Kozo [Faculty of Integrated Arts and Sciences, The University of Tokushima (Japan)

    2009-03-15

    This paper reports theoretical economic production work and uses electricity futures trading to illustrate its argument. The focus is relationships between time, production and tradition both in Nicholas Georgescu-Roegen's analytical representation of the production process (i.e., flow/fund model) and in his dialectical scheme dealing with the evolutionary changes in the economic process. Our main arguments are (1) the flow/fund model is designed to be employed in conjunction with attention to how the boundaries of a given process are determined and (2) process boundaries are dialectical distinctions - between process and not-process - that are strongly related to time and tradition. We propose that Georgescu-Roegen's The Entropy Law and the Economic Process is best understood as the elaboration of a general theory of economic production and we developed two conceptual tools (time {open_square} and meta-funds), both of which are related to the dialectical distinction between process and not-process, which we use to operationalise this general theory. Finally, we demonstrate that, although trading in electricity futures is surprising if one uses a stock/flow vs services distinction (because electricity supply is classed as a service) it appears perfectly logical under Georgescu-Roegen's general theory: shortening time horizons, combined with a shift in the relationship between raw fuel supplies and power production procedures, lead to a shift in the status of electricity supply, from fund to flow. (author)

  20. Controlling Electricity Consumption by Forecasting its Response to Varying Prices

    DEFF Research Database (Denmark)

    Corradi, Olivier; Ochsenfeld, Henning Peter; Madsen, Henrik

    2013-01-01

    electricity consumption using a one-way price signal. Estimation of the price-response is based on data measurable at grid level, removing the need to install sensors and communication devices between each individual consumer and the price-generating entity. An application for price-responsive heating systems......In a real-time electricity pricing context where consumers are sensitive to varying prices, having the ability to anticipate their response to a price change is valuable. This paper proposes models for the dynamics of such price-response, and shows how these dynamics can be used to control...... is studied based on real data, before conducting a control by price experiment using a mixture of real and synthetic data. With the control objective of following a constant consumption reference, peak heating consumption is reduced by nearly 5%, and 11% of the mean daily heating consumption is shifted....

  1. The optimal manufacturing batch size with rework under time-varying demand process for a finite time horizon

    Science.gov (United States)

    Musa, Sarah; Supadi, Siti Suzlin; Omar, Mohd

    2014-07-01

    Rework is one of the solutions to some of the main issues in reverse logistic and green supply chain as it reduces production cost and environmental problem. Many researchers focus on developing rework model, but to the knowledge of the author, none of them has developed a model for time-varying demand rate. In this paper, we extend previous works and develop multiple batch production system for time-varying demand rate with rework. In this model, the rework is done within the same production cycle.

  2. Reduced dielectric response in spatially varying electric fields

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt

    2015-01-01

    relations between the flux and the gradient of the polarization. Comparison between the theory and molecular dynamics simulations confirms this effect. The effect is significant for small length scale electric field variations and the inclusion of the flux is thus important in nanoscale modeling......In this paper, the dynamical equation for polarization is derived. From this the dielectric response to a spatially varying electric field is analyzed showing a reduced response due to flux of polarization in the material. This flux is modeled as a diffusive process through linear constitutive...

  3. Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser

    Science.gov (United States)

    Decker, A. J.

    1982-01-01

    The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

  4. Flexible Demand Management under Time-Varying Prices

    Science.gov (United States)

    Liang, Yong

    In this dissertation, the problem of flexible demand management under time-varying prices is studied. This generic problem has many applications, which usually have multiple periods in which decisions on satisfying demand need to be made, and prices in these periods are time-varying. Examples of such applications include multi-period procurement problem, operating room scheduling, and user-end demand scheduling in the Smart Grid, where the last application is used as the main motivating story throughout the dissertation. The current grid is experiencing an upgrade with lots of new designs. What is of particular interest is the idea of passing time-varying prices that reflect electricity market conditions to end users as incentives for load shifting. One key component, consequently, is the demand management system at the user-end. The objective of the system is to find the optimal trade-off between cost saving and discomfort increment resulted from load shifting. In this dissertation, we approach this problem from the following aspects: (1) construct a generic model, solve for Pareto optimal solutions, and analyze the robust solution that optimizes the worst-case payoffs, (2) extend to a distribution-free model for multiple types of demand (appliances), for which an approximate dynamic programming (ADP) approach is developed, and (3) design other efficient algorithms for practical purposes of the flexible demand management system. We first construct a novel multi-objective flexible demand management model, in which there are a finite number of periods with time-varying prices, and demand arrives in each period. In each period, the decision maker chooses to either satisfy or defer outstanding demand to minimize costs and discomfort over a certain number of periods. We consider both the deterministic model, models with stochastic demand or prices, and when only partial information about the stochastic demand or prices is known. We first analyze the stochastic

  5. An Explicit MOT-TD-VIE Solver for Time Varying Media

    KAUST Repository

    Sayed, Sadeed Bin

    2016-03-15

    An explicit marching on-in-time (MOT) scheme for solving the time domain electric field integral equation enforced on volumes with time varying dielectric permittivity is proposed. Unknowns of the integral equation and the constitutive relation, i.e., flux density and field intensity, are discretized using full and half Schaubert-Wilton-Glisson functions in space. Temporal interpolation is carried out using band limited approximate prolate spherical wave functions. The discretized coupled system of integral equation and constitutive relation is integrated in time using a PE(CE)m type linear multistep scheme. Unlike the existing MOT methods, the resulting explicit MOT scheme allows for straightforward incorporation of the time variation in the dielectric permittivity.

  6. On Schwinger mechanism for gluon pair production in the presence of arbitrary time dependent chromo-electric field

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilov, S.P. [Herzen State Pedagogical University of Russia, Department of General and Experimental Physics, St. Petersburg (Russian Federation); Gitman, D.M. [University of Sao Paulo, Institute of Physics, CP 66318, Sao Paulo, SP (Brazil)

    2009-11-15

    Recently the paper ''Schwinger mechanism for gluon pair production in the presence of arbitrary time dependent chromo-electric field'' by G. C. Nayak was published [Eur. Phys. J. C. 59: 715, 2009; arXiv: 0708.2439]. Its aim is to obtain an exact expression for the probability of non-perturbative gluon pair production per unit time per unit volume and per unit transverse momentum in an arbitrary time-dependent chromo-electric background field. We believe that the obtained expression is open to question. We demonstrate its inconsistency on some well-known examples. We think that this is a consequence of using the so-called ''shift theorem'' [arXiv: hep-th/0609192 ] in deriving the expression for the probability. We make some critical comments on the theorem and its applicability to the problem in question. (orig.)

  7. Consequences of reduced production of electricity in nuclear power plants

    International Nuclear Information System (INIS)

    The Swedish Power Administration has assessed the possibilities of expanding electric power sources other than nuclear power plants for the years 1980 and 1985. Reports on costs in the form of loss of capital and increased operating costs involved in the dismantling of nuclear power plants are made in Supplement 1. The economics division of the Finance Department, starting with a long-range study model of the Swedish economy, has calculated the consequences of a cutback in electric power up to 1980 for Sweden's economy and employment in that year. The consequences of reduction of electricity supplies up to 1985 are summarized in Supplement 2 in this report. It is concluded that in order to be able to manage the problem of supplying electricity by 1985, it will be necessary to increase oil power above what was assumed in the energy policy program. There will have to be new oil-based power as well. According to the Power Administration, oil-power facilities can be expanded to varying degrees, depending upon when the decision is made. The Power Administration's calculations show that 125 TWh is possible in 1985 without nuclear power only if a decision for discontinuation is made in the fall of 1976. This is based on very optimistic assumptions about the time of execution of a program for oil-steam operation, and also on the assumption that extreme measures will be initiated to force expansion of both district-heating distribution and power + heat facilities. Oil consumption for production of electricity in such an electric power system would be about 9 million m 3 , which is about 5 times more than at present and about one-third of the present total consumption of petroleum products in Sweden

  8. Multiscale response of ionic systems to a spatially varying electric field

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt

    2017-01-01

    In this paper the response of ionic systems subjected to a spatially varying electric field is studied. Following the Nernst-Planck equation, two forces driving the mass flux are present, namely, the concentration gradient and the electric potential gradient. The mass flux due to the concentratio...

  9. Electricity production of Slovakia

    International Nuclear Information System (INIS)

    Czodor, T.

    2003-01-01

    Here is examined the spatial structure of electric energy production divided in hydropower plants (through-flow and re-pumping), thermal power plants as the most expensive way of electric energy production and nuclear power plants where high difficulty and long-term realisation of construction projects and spent financial resources are pointed out. Work describes present structure of electric energy production and consumption and refers to alternative electric energy sources

  10. Production function application attempt in electricity generation forecasting

    International Nuclear Information System (INIS)

    Kamrat, W.; Augusiak, A.

    1996-01-01

    A modified Cobb-Douglas production function is applied to evaluate level of electricity generation for medium and long term prognosis (up to 2010) in an easy and simple way. The test calculations have been done for hard coal fired power plants, based on generation data supplied in Main Statistical Office of Poland publications.The model of electricity generation is defined using data on capital of a typical productivity power plant and its employment for time series 1980-90. The test calculation results based on the parameters of Rosenbroock's optimization procedure of electricity generation model are presented. The method described is distinguished for its high accuracy as compared to classical methods despite the relatively short time series. It is suitable for studies in electricity generation policy . 1 tab

  11. Electric energy production and environmental licensing: citizenship in Brazil in time of ecological crisis

    International Nuclear Information System (INIS)

    Bettencourt, Marcia Pires da Luz

    2017-01-01

    The choices of energy sources gain relevance in the face of the ecological crisis which has a central questioning on the modes of production and consumption and that stems from a system which changes everything into merchandise. On one hand, brazilian electricity generation has the advantage of using clean energy in great part of its composition, at least in discourse. On the other hand, though, there are high social and environmental costs, especially for communities living near the regions where projects for the electricity sector are built. This research aimed to identify and analyse different modes society takes part in the process of choosing energy sources for electricity generation in Brazil. It discusses the links between the ecological crisis and the production of electrical energy; how the institutional mechanisms for social participation on issues related to the production of electric power in Brazil work; and, how civil society participates in environmental licensing in the National Environment Council (CONAMA). A set of related approaches to the nature of the ecological crisis and the forms of social participation was adopted in the theoretical framework and an analysis of the electric sector panorama in Brazil has been drawn up. In order to investigate the forms society participates in issues related to the composition of the brazilian electricity matrix, the methodology comprised a documentary analysis and a case study. They included three categories of actors: (1) CONAMA's councilors, (2) experts from the Field; and (3) actors involved in the diagnosis study, planning and management of the electricity sector. The research identified inconsistencies, ambiguities and other relevant issues about the participation of society in the production of electrical energy. Such issues are related to: deficiencies in the mechanisms for information access; lack of transparency and patterns in internal documents; lack of social participation in the elaboration of

  12. Zhang neural network for online solution of time-varying convex quadratic program subject to time-varying linear-equality constraints

    International Nuclear Information System (INIS)

    Zhang Yunong; Li Zhan

    2009-01-01

    In this Letter, by following Zhang et al.'s method, a recurrent neural network (termed as Zhang neural network, ZNN) is developed and analyzed for solving online the time-varying convex quadratic-programming problem subject to time-varying linear-equality constraints. Different from conventional gradient-based neural networks (GNN), such a ZNN model makes full use of the time-derivative information of time-varying coefficient. The resultant ZNN model is theoretically proved to have global exponential convergence to the time-varying theoretical optimal solution of the investigated time-varying convex quadratic program. Computer-simulation results further substantiate the effectiveness, efficiency and novelty of such ZNN model and method.

  13. Magnetohydrodynamic flow of a rarefied gas near a time-varying accelerated plate

    International Nuclear Information System (INIS)

    Mishra, S.P.; Mohapatra, Priti

    1975-01-01

    The flow of an electrically conducting rarefied gas due to the time-varying motion of an infinite flat plate has been studied in the presence of a uniform magnetic field. The magnetic lines of force are taken to be fixed relative to the fluid. General expressions of the velocity and the skin friction have been compared by means of some qraphs and tables. (author)

  14. Economic costs of electricity production in Poland

    International Nuclear Information System (INIS)

    Beeldman, M.; Solinski, J.

    1994-02-01

    This study presents a methodology for the calculation of the economic costs of the production of electricity. This methodology is applied to assess electricity production cost in Poland by type of power station for the years 1995 and 2000. In addition, an overview is presented of the methods used by the OECD countries, particularly in the Netherlands. The main conclusions of the study are: 1) the real economic costs to generate electricity in Poland are about two times higher compared with the traditional book-keeping data; 2) the investment costs will become the most important cost component in the near future; and 3) there are considerables differences in production cost per kWh for the different types of power plants in Poland. 4 appendices, 14 refs

  15. Short and long-term carbon balance of bioenergy electricity production fueled by forest treatments.

    Science.gov (United States)

    Kelsey, Katharine C; Barnes, Kallie L; Ryan, Michael G; Neff, Jason C

    2014-01-01

    Forests store large amounts of carbon in forest biomass, and this carbon can be released to the atmosphere following forest disturbance or management. In the western US, forest fuel reduction treatments designed to reduce the risk of high severity wildfire can change forest carbon balance by removing carbon in the form of biomass, and by altering future potential wildfire behavior in the treated stand. Forest treatment carbon balance is further affected by the fate of this biomass removed from the forest, and the occurrence and intensity of a future wildfire in this stand. In this study we investigate the carbon balance of a forest treatment with varying fates of harvested biomass, including use for bioenergy electricity production, and under varying scenarios of future disturbance and regeneration. Bioenergy is a carbon intensive energy source; in our study we find that carbon emissions from bioenergy electricity production are nearly twice that of coal for the same amount of electricity. However, some emissions from bioenergy electricity production are offset by avoided fossil fuel electricity emissions. The carbon benefit achieved by using harvested biomass for bioenergy electricity production may be increased through avoided pyrogenic emissions if the forest treatment can effectively reduce severity. Forest treatments with the use of harvested biomass for electricity generation can reduce carbon emissions to the atmosphere by offsetting fossil fuel electricity generation emissions, and potentially by avoided pyrogenic emissions due to reduced intensity and severity of a future wildfire in the treated stand. However, changes in future wildfire and regeneration regimes may affect forest carbon balance and these climate-induced changes may influence forest carbon balance as much, or more, than bioenergy production.

  16. Time-varying Crash Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    We estimate a continuous-time model with stochastic volatility and dynamic crash probability for the S&P 500 index and find that market illiquidity dominates other factors in explaining the stock market crash risk. While the crash probability is time-varying, its dynamic depends only weakly on re...

  17. Testing of Commercial Milk Production Technology Using A Combination of High Temperature Short Time and Pulsed Electric Field

    OpenAIRE

    Hadi A; Widjanarko SB; Kusnadi J

    2016-01-01

    The development of milk processing technology has grown excessively, and it contains advantage and disadvantage. This study used mixed between PEF (Pulsed Electric Field) and High Temperature Short Time (HTST) to produce milk processed product which is effective and efficient in killing milk microorganism without changing its color, scent, and nutrient content of processed product, therefore producing commercial sterile milk product in accord with milk Indonesian National Standard (SNI). The ...

  18. Electricity price modeling with stochastic time change

    International Nuclear Information System (INIS)

    Borovkova, Svetlana; Schmeck, Maren Diane

    2017-01-01

    In this paper, we develop a novel approach to electricity price modeling, based on the powerful technique of stochastic time change. This technique allows us to incorporate the characteristic features of electricity prices (such as seasonal volatility, time varying mean reversion and seasonally occurring price spikes) into the model in an elegant and economically justifiable way. The stochastic time change introduces stochastic as well as deterministic (e.g., seasonal) features in the price process' volatility and in the jump component. We specify the base process as a mean reverting jump diffusion and the time change as an absolutely continuous stochastic process with seasonal component. The activity rate of the stochastic time change can be related to the factors that influence supply and demand. Here we use the temperature as a proxy for the demand and hence, as the driving factor of the stochastic time change, and show that this choice leads to realistic price paths. We derive properties of the resulting price process and develop the model calibration procedure. We calibrate the model to the historical EEX power prices and apply it to generating realistic price paths by Monte Carlo simulations. We show that the simulated price process matches the distributional characteristics of the observed electricity prices in periods of both high and low demand. - Highlights: • We develop a novel approach to electricity price modeling, based on the powerful technique of stochastic time change. • We incorporate the characteristic features of electricity prices, such as seasonal volatility and spikes into the model. • We use the temperature as a proxy for the demand and hence, as the driving factor of the stochastic time change • We derive properties of the resulting price process and develop the model calibration procedure. • We calibrate the model to the historical EEX power prices and apply it to generating realistic price paths.

  19. A varying-α brane world cosmology

    International Nuclear Information System (INIS)

    Youm, Donam

    2001-08-01

    We study the brane world cosmology in the RS2 model where the electric charge varies with time in the manner described by the varying fine-structure constant theory of Bekenstein. We map such varying electric charge cosmology to the dual variable-speed-of-light cosmology by changing system of units. We comment on cosmological implications for such cosmological models. (author)

  20. Emergence of synchronization and regularity in firing patterns in time-varying neural hypernetworks

    Science.gov (United States)

    Rakshit, Sarbendu; Bera, Bidesh K.; Ghosh, Dibakar; Sinha, Sudeshna

    2018-05-01

    We study synchronization of dynamical systems coupled in time-varying network architectures, composed of two or more network topologies, corresponding to different interaction schemes. As a representative example of this class of time-varying hypernetworks, we consider coupled Hindmarsh-Rose neurons, involving two distinct types of networks, mimicking interactions that occur through the electrical gap junctions and the chemical synapses. Specifically, we consider the connections corresponding to the electrical gap junctions to form a small-world network, while the chemical synaptic interactions form a unidirectional random network. Further, all the connections in the hypernetwork are allowed to change in time, modeling a more realistic neurobiological scenario. We model this time variation by rewiring the links stochastically with a characteristic rewiring frequency f . We find that the coupling strength necessary to achieve complete neuronal synchrony is lower when the links are switched rapidly. Further, the average time required to reach the synchronized state decreases as synaptic coupling strength and/or rewiring frequency increases. To quantify the local stability of complete synchronous state we use the Master Stability Function approach, and for global stability we employ the concept of basin stability. The analytically derived necessary condition for synchrony is in excellent agreement with numerical results. Further we investigate the resilience of the synchronous states with respect to increasing network size, and we find that synchrony can be maintained up to larger network sizes by increasing either synaptic strength or rewiring frequency. Last, we find that time-varying links not only promote complete synchronization, but also have the capacity to change the local dynamics of each single neuron. Specifically, in a window of rewiring frequency and synaptic coupling strength, we observe that the spiking behavior becomes more regular.

  1. Time Domain Partitioning of Electricity Production Cost Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Barrows, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hummon, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jones, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hale, E. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-01-01

    Production cost models are often used for planning by simulating power system operations over long time horizons. The simulation of a day-ahead energy market can take several weeks to compute. Tractability improvements are often made through model simplifications, such as: reductions in transmission modeling detail, relaxation of commitment variable integrality, reductions in cost modeling detail, etc. One common simplification is to partition the simulation horizon so that weekly or monthly horizons can be simulated in parallel. However, horizon partitions are often executed with overlap periods of arbitrary and sometimes zero length. We calculate the time domain persistence of historical unit commitment decisions to inform time domain partitioning of production cost models. The results are implemented using PLEXOS production cost modeling software in an HPC environment to improve the computation time of simulations while maintaining solution integrity.

  2. Sensible production processes with electricity

    Energy Technology Data Exchange (ETDEWEB)

    Eerola, P.; Annala, T.; Wickstroem, T. [ed.

    1997-11-01

    Small and medium-sized industrial enterprises use electricity increasingly for both heating and production, as electricity offers easy adjustability and has little need for maintenance. In production processes, the advantages of electricity also include uniform quality, automation and cleanness

  3. Biodigester economic viability for electrical power production using biogas from swine waste

    Energy Technology Data Exchange (ETDEWEB)

    Cervi, Ricardo Ghantous; Esperancini, Maura Seiko Tsutsui; Bueno, Osmar de Carvalho [Universidade Estadual Paulista (FCA/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas], E-mail: ricardogc@fca.unesp.br; Souza, Samuel Nelson Melegari de [Universidade Estadual do Oeste do Parana (CCET/UNIOESTE), Cascavel, PR (Brazil). Centro de Ciencias Exatas e Tecnologicas

    2008-07-01

    The increase of energy use in agriculture and the raising prices of electricity demand studies on alternate sources of energy and improvement on biogas use efficiency so that agricultural activities become more competitive. Biogas production through anaerobic biodigestion represents an important breakthrough for the problem of swine waste and energy availability for rural areas. This work aimed to analyze the economy on biodigester investment for electrical power production using biogas from anaerobic biodigestion of swine waste. Two factors were used for this evaluation: the cost of electrical power production through biogas and time for equipment investment return. Results show that investment return time can be only 2.45 years for electrical power at peak time. (author)

  4. Hybrid systems to address seasonal mismatches between electricity production and demand in nuclear renewable electrical grids

    International Nuclear Information System (INIS)

    Forsberg, Charles

    2013-01-01

    A strategy to enable zero-carbon variable electricity production with full utilization of renewable and nuclear energy sources has been developed. Wind and solar systems send electricity to the grid. Nuclear plants operate at full capacity with variable steam to turbines to match electricity demand with production (renewables and nuclear). Excess steam at times of low electricity prices and electricity demand go to hybrid fuel production and storage systems. The characteristic of these hybrid technologies is that the economic penalties for variable nuclear steam inputs are small. Three hybrid systems were identified that could be deployed at the required scale. The first option is the gigawatt-year hourly-to-seasonal heat storage system where excess steam from the nuclear plant is used to heat rock a kilometer underground to create an artificial geothermal heat source. The heat source produces electricity on demand using geothermal technology. The second option uses steam from the nuclear plant and electricity from the grid with high-temperature electrolysis (HTR) cells to produce hydrogen and oxygen. Hydrogen is primarily for industrial applications; however, the HTE can be operated in reverse using hydrogen for peak electricity production. The third option uses variable steam and electricity for shale oil production. -- Highlights: •A system is proposed to meet variable hourly to seasonal electricity demand. •Variable solar and wind electricity sent to the grid. •Base-load nuclear plants send variable steam for electricity and hybrid systems. •Hybrid energy systems can economically absorb gigawatts of variable steam. •Hybrid systems include geothermal heat storage, hydrogen, and shale-oil production

  5. Design of 2D time-varying vector fields.

    Science.gov (United States)

    Chen, Guoning; Kwatra, Vivek; Wei, Li-Yi; Hansen, Charles D; Zhang, Eugene

    2012-10-01

    Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects.

  6. Schwinger pair production in space- and time-dependent electric fields: Relating the Wigner formalism to quantum kinetic theory

    International Nuclear Information System (INIS)

    Hebenstreit, F.; Alkofer, R.; Gies, H.

    2010-01-01

    The nonperturbative electron-positron pair production (Schwinger effect) is considered for space- and time-dependent electric fields E-vector(x-vector,t). Based on the Dirac-Heisenberg-Wigner formalism, we derive a system of partial differential equations of infinite order for the 16 irreducible components of the Wigner function. In the limit of spatially homogeneous fields the Vlasov equation of quantum kinetic theory is rediscovered. It is shown that the quantum kinetic formalism can be exactly solved in the case of a constant electric field E(t)=E 0 and the Sauter-type electric field E(t)=E 0 sech 2 (t/τ). These analytic solutions translate into corresponding expressions within the Dirac-Heisenberg-Wigner formalism and allow to discuss the effect of higher derivatives. We observe that spatial field variations typically exert a strong influence on the components of the Wigner function for large momenta or for late times.

  7. Design of 2D Time-Varying Vector Fields

    KAUST Repository

    Chen, Guoning

    2012-10-01

    Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects. © 1995-2012 IEEE.

  8. Design of 2D Time-Varying Vector Fields

    KAUST Repository

    Chen, Guoning; Kwatra, Vivek; Wei, Li-Yi; Hansen, Charles D.; Zhang, Eugene

    2012-01-01

    Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects. © 1995-2012 IEEE.

  9. Global Stability of Polytopic Linear Time-Varying Dynamic Systems under Time-Varying Point Delays and Impulsive Controls

    Directory of Open Access Journals (Sweden)

    M. de la Sen

    2010-01-01

    Full Text Available This paper investigates the stability properties of a class of dynamic linear systems possessing several linear time-invariant parameterizations (or configurations which conform a linear time-varying polytopic dynamic system with a finite number of time-varying time-differentiable point delays. The parameterizations may be timevarying and with bounded discontinuities and they can be subject to mixed regular plus impulsive controls within a sequence of time instants of zero measure. The polytopic parameterization for the dynamics associated with each delay is specific, so that (q+1 polytopic parameterizations are considered for a system with q delays being also subject to delay-free dynamics. The considered general dynamic system includes, as particular cases, a wide class of switched linear systems whose individual parameterizations are timeinvariant which are governed by a switching rule. However, the dynamic system under consideration is viewed as much more general since it is time-varying with timevarying delays and the bounded discontinuous changes of active parameterizations are generated by impulsive controls in the dynamics and, at the same time, there is not a prescribed set of candidate potential parameterizations.

  10. Hydrogen from nuclear plus wind using real-time electricity prices

    International Nuclear Information System (INIS)

    Miller, A.I.; Duffey, R.B.; Fairlie, M.; Anders, P.

    2004-01-01

    During the early years of hydrogen's use as a vehicle fuel, penetration of the market will be small. This favours distributed production by electrolysis, which avoids the scale-dependent costs of distribution from centralized plants. For electrolysis actually to be the preferred option, capital equipment for electrolysis must be reasonably cheap but the dominant cost component is the electricity price. By about 2006, advanced designs of nuclear reactors should be available to produce electricity at around 30 US$/MW.h at the plant gate. The best approach to producing low-cost electrolytic hydrogen is shown to be use of such reactors to supply electricity to the grid at times of peak price and demand and to make hydrogen at other times In this paper, this model has been used to calculate the production costs for electrolytic hydrogen at the location where the electricity is generated, using the actual prices of electricity paid by the Alberta Power Pool in 2002 and 2003 and by the Ontario Grid for 2003. The analysis shows clearly that by optimizing the co-production of hydrogen and electricity (referred to as the H 2 /e process) the cost for hydrogen produced can comfortably meet the US Department of Energy's target of 2000 US$/tonne. Because of its lower availability factor, wind-produced electricity cannot meet this cost target. However, if wind power availability can reach 35%, an intermittent supplementary current of wind-generated electricity may economically be fed to an electrolytic plant primarily supplied by nuclear power. Additional current raises the voltage for electrolysis but there would be only small additional capital costs. The two non-CO 2 -emitting sources, nuclear and wind could become complementary, providing an affordable way of storing wind-generated electricity when the supply exceeds demand in electricity markets The analyses presented in this paper looks at the case of bulk production of H 2 /e in a 'wholesale' energy market and does not

  11. Time-varying metamaterials based on graphene-wrapped microwires: Modeling and potential applications

    Science.gov (United States)

    Salary, Mohammad Mahdi; Jafar-Zanjani, Samad; Mosallaei, Hossein

    2018-03-01

    The successful realization of metamaterials and metasurfaces requires the judicious choice of constituent elements. In this paper, we demonstrate the implementation of time-varying metamaterials in the terahertz frequency regime by utilizing graphene-wrapped microwires as building blocks and modulation of graphene conductivity through exterior electrical gating. These elements enable enhancement of light-graphene interaction by utilizing optical resonances associated with Mie scattering, yielding a large tunability and modulation depth. We develop a semianalytical framework based on transition-matrix formulation for modeling and analysis of periodic and aperiodic arrays of such time-varying building blocks. The proposed method is validated against full-wave numerical results obtained using the finite-difference time-domain method. It provides an ideal tool for mathematical synthesis and analysis of space-time gradient metamaterials, eliminating the need for computationally expensive numerical models. Moreover, it allows for a wider exploration of exotic space-time scattering phenomena in time-modulated metamaterials. We apply the method to explore the role of modulation parameters in the generation of frequency harmonics and their emerging wavefronts. Several potential applications of such platforms are demonstrated, including frequency conversion, holographic generation of frequency harmonics, and spatiotemporal manipulation of light. The presented results provide key physical insights to design time-modulated functional metadevices using various building blocks and open up new directions in the emerging paradigm of time-modulated metamaterials.

  12. Validation of Micro-Meso Electrical Relations for Laminates with Varying Anisotropy

    KAUST Repository

    Selvakumaran, Lakshmi

    2015-08-01

    For electrical impedance tomography (EIT) to be useful in monitoring transverse cracks in composites, it is imperative to establish the relation between conductivity and cracking density. Micro to meso scale homogenization has been developed for classical carbon fiber reinforced polymer (CFRP) laminate which provides such a relationship. However, we have shown in previous studies that the detectability of transverse cracks in such CFRP, which are characterized by very anisotropic electrical properties, is poor. Then, it is better to lower the electrical anisotropy, which can be achieved by various technologies including doping the polymeric resin by conductive nanoparticles. However, the validity of mesoscale homogenization for laminates with such low anisotropy has not been tested before. Here, we show that the mesoscale damage indicator is intrinsic for composites with varying anisotropy.

  13. Vacuum radiation induced by time dependent electric field

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2017-04-01

    Full Text Available Many predictions of new phenomena given by strong field quantum electrodynamics (SFQED will be tested on next generation multi-petawatt laser facilities in the near future. These new phenomena are basis to understand physics in extremely strong electromagnetic fields therefore have attracted wide research interest. Here we discuss a new SFQED phenomenon that is named as vacuum radiation. In vacuum radiation, a virtual electron loop obtain energy from time dependent external electric field and radiate an entangled photon pair. Features of vacuum radiation in a locally time dependent electric field including spectrum, characteristic temperature, production rate and power are given.

  14. Vacuum radiation induced by time dependent electric field

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bo, E-mail: zhangbolfrc@caep.cn [Department of High Energy Density Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Laboratory of Science and Technology on Plasma Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Zhang, Zhi-meng; Hong, Wei; He, Shu-Kai; Teng, Jian [Department of High Energy Density Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Laboratory of Science and Technology on Plasma Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Gu, Yu-qiu, E-mail: yqgu@caep.cn [Department of High Energy Density Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Laboratory of Science and Technology on Plasma Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China)

    2017-04-10

    Many predictions of new phenomena given by strong field quantum electrodynamics (SFQED) will be tested on next generation multi-petawatt laser facilities in the near future. These new phenomena are basis to understand physics in extremely strong electromagnetic fields therefore have attracted wide research interest. Here we discuss a new SFQED phenomenon that is named as vacuum radiation. In vacuum radiation, a virtual electron loop obtain energy from time dependent external electric field and radiate an entangled photon pair. Features of vacuum radiation in a locally time dependent electric field including spectrum, characteristic temperature, production rate and power are given.

  15. Timed arrays wideband and time varying antenna arrays

    CERN Document Server

    Haupt, Randy L

    2015-01-01

    Introduces timed arrays and design approaches to meet the new high performance standards The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The auth

  16. Time-of-use based electricity demand response for sustainable manufacturing systems

    International Nuclear Information System (INIS)

    Wang, Yong; Li, Lin

    2013-01-01

    As required by the Energy Policy Act of 2005, utility companies across the U.S. are offering TOU (time-of-use) based electricity demand response programs. The TOU rate gives consumers opportunities to manage their electricity bill by shifting use from on-peak periods to mid-peak and off-peak periods. Reducing the amount of electricity needed during the peak load times makes it possible for the power grid to meet consumers' needs without building more costly backup infrastructures and help reduce GHG (greenhouse gas) emissions. Previous research on the applications of TOU and other electricity demand response programs has been mainly focused on residential and commercial buildings while largely neglected industrial manufacturing systems. This paper proposes a systems approach for TOU based electricity demand response for sustainable manufacturing systems under the production target constraint. Key features of this approach include: (i) the electricity related costs including both consumption and demand are integrated into production system modeling; (ii) energy-efficient and demand-responsive production scheduling problems are formulated and the solution technique is provided; and (iii) the effects of various factors on the near-optimal scheduling solutions are examined. The research outcome is expected to enhance the energy efficiency, electricity demand responsiveness, and cost effectiveness of modern manufacturing systems. - Highlights: • We propose a TOU based demand response approach for manufacturing systems. • Both electricity consumption and demand are integrated into the system modeling. • Energy-efficient and demand-responsive production scheduling problems are formulated. • The meta-heuristic solution technique is provided. • The effects of various factors on the scheduling solutions are examined

  17. Mediation analysis with time varying exposures and mediators.

    Science.gov (United States)

    VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J

    2017-06-01

    In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the "mediational g-formula." When there is no mediation, the mediational g-formula reduces to Robins' regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl's mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators.

  18. Time-varying properties of renal autoregulatory mechanisms

    DEFF Research Database (Denmark)

    Zou, Rui; Cupples, Will A; Yip, K P

    2002-01-01

    In order to assess the possible time-varying properties of renal autoregulation, time-frequency and time-scaling methods were applied to renal blood flow under broad-band forced arterial blood pressure fluctuations and single-nephron renal blood flow with spontaneous oscillations obtained from...... normotensive (Sprague-Dawley, Wistar, and Long-Evans) rats, and spontaneously hypertensive rats. Time-frequency analyses of normotensive and hypertensive blood flow data obtained from either the whole kidney or the single-nephron show that indeed both the myogenic and tubuloglomerular feedback (TGF) mechanisms...... have time-varying characteristics. Furthermore, we utilized the Renyi entropy to measure the complexity of blood-flow dynamics in the time-frequency plane in an effort to discern differences between normotensive and hypertensive recordings. We found a clear difference in Renyi entropy between...

  19. Time-Varying Transition Probability Matrix Estimation and Its Application to Brand Share Analysis.

    Directory of Open Access Journals (Sweden)

    Tomoaki Chiba

    Full Text Available In a product market or stock market, different products or stocks compete for the same consumers or purchasers. We propose a method to estimate the time-varying transition matrix of the product share using a multivariate time series of the product share. The method is based on the assumption that each of the observed time series of shares is a stationary distribution of the underlying Markov processes characterized by transition probability matrices. We estimate transition probability matrices for every observation under natural assumptions. We demonstrate, on a real-world dataset of the share of automobiles, that the proposed method can find intrinsic transition of shares. The resulting transition matrices reveal interesting phenomena, for example, the change in flows between TOYOTA group and GM group for the fiscal year where TOYOTA group's sales beat GM's sales, which is a reasonable scenario.

  20. Time-Varying Transition Probability Matrix Estimation and Its Application to Brand Share Analysis.

    Science.gov (United States)

    Chiba, Tomoaki; Hino, Hideitsu; Akaho, Shotaro; Murata, Noboru

    2017-01-01

    In a product market or stock market, different products or stocks compete for the same consumers or purchasers. We propose a method to estimate the time-varying transition matrix of the product share using a multivariate time series of the product share. The method is based on the assumption that each of the observed time series of shares is a stationary distribution of the underlying Markov processes characterized by transition probability matrices. We estimate transition probability matrices for every observation under natural assumptions. We demonstrate, on a real-world dataset of the share of automobiles, that the proposed method can find intrinsic transition of shares. The resulting transition matrices reveal interesting phenomena, for example, the change in flows between TOYOTA group and GM group for the fiscal year where TOYOTA group's sales beat GM's sales, which is a reasonable scenario.

  1. Space-time modeling of electricity spot prices

    DEFF Research Database (Denmark)

    Abate, Girum Dagnachew; Haldrup, Niels

    In this paper we derive a space-time model for electricity spot prices. A general spatial Durbin model that incorporates the temporal as well as spatial lags of spot prices is presented. Joint modeling of space-time effects is necessarily important when prices and loads are determined in a network...... in the spot price dynamics. Estimation of the spatial Durbin model show that the spatial lag variable is as important as the temporal lag variable in describing the spot price dynamics. We use the partial derivatives impact approach to decompose the price impacts into direct and indirect effects and we show...... that price effects transmit to neighboring markets and decline with distance. In order to examine the evolution of the spatial correlation over time, a time varying parameters spot price spatial Durbin model is estimated using recursive estimation. It is found that the spatial correlation within the Nord...

  2. Herbivore effects on productivity vary by guild: cattle increase mean productivity while wildlife reduce variability.

    Science.gov (United States)

    Charles, Grace K; Porensky, Lauren M; Riginos, Corinna; Veblen, Kari E; Young, Truman P

    2017-01-01

    Wild herbivores and livestock share the majority of rangelands worldwide, yet few controlled experiments have addressed their individual, additive, and interactive impacts on ecosystem function. While ungulate herbivores generally reduce standing biomass, their effects on aboveground net primary production (ANPP) can vary by spatial and temporal context, intensity of herbivory, and herbivore identity and species richness. Some evidence indicates that moderate levels of herbivory can stimulate aboveground productivity, but few studies have explicitly tested the relationships among herbivore identity, grazing intensity, and ANPP. We used a long-term exclosure experiment to examine the effects of three groups of wild and domestic ungulate herbivores (megaherbivores, mesoherbivore wildlife, and cattle) on herbaceous productivity in an African savanna. Using both field measurements (productivity cages) and satellite imagery, we measured the effects of different herbivore guilds, separately and in different combinations, on herbaceous productivity across both space and time. Results from both productivity cage measurements and satellite normalized difference vegetation index (NDVI) demonstrated a positive relationship between mean productivity and total ungulate herbivore pressure, driven in particular by the presence of cattle. In contrast, we found that variation in herbaceous productivity across space and time was driven by the presence of wild herbivores (primarily mesoherbivore wildlife), which significantly reduced heterogeneity in ANPP and NDVI across both space and time. Our results indicate that replacing wildlife with cattle (at moderate densities) could lead to similarly productive but more heterogeneous herbaceous plant communities in rangelands. © 2016 by the Ecological Society of America.

  3. Reference costs of the electric power production

    International Nuclear Information System (INIS)

    2003-06-01

    This study periodically realized by the DGEMP aims to compare the competitiveness of the different channels of electric power production, for different utilization conditions. The first part ''reference costs of the 2003 electric power production'' examines the prices of the electric power produced by different channels in particular in the framework of the industrial implementing in 2015. The nuclear and thermal power plants are concerned. The second part is devoted to the decentralized production channels (wind energy, photovoltaic, cogeneration heat-electricity) is under construction and will be presented next year. (A.L.B.)

  4. Wealth Transfers from Implementing Real-Time Retail Electricity Pricing

    OpenAIRE

    Borenstein, Severin

    2005-01-01

    Adoption of real-time electricity pricing %u2014 retail prices that vary hourly to reflect changing wholesale prices %u2014 removes existing cross-subsidies to those customers that consume disproportionately more when wholesale prices are highest. If their losses are substantial, these customers are likely to oppose RTP initiatives unless there is a supplemental program to offset their loss. Using data on a random sample of 636 industrial and commercial customers in southern California, I sho...

  5. Pemodelan Markov Switching Dengan Time-varying Transition Probability

    OpenAIRE

    Savitri, Anggita Puri; Warsito, Budi; Rahmawati, Rita

    2016-01-01

    Exchange rate or currency is an economic variable which reflects country's state of economy. It fluctuates over time because of its ability to switch the condition or regime caused by economic and political factors. The changes in the exchange rate are depreciation and appreciation. Therefore, it could be modeled using Markov Switching with Time-Varying Transition Probability which observe the conditional changes and use information variable. From this model, time-varying transition probabili...

  6. Experimental evidence for amplitude death induced by a time-varying interaction

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, K. [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India); Shrimali, M.D. [Department of Physics, Central University of Rajasthan, NH-8, Bandar Sindri, Ajmer 305 801 (India); Prasad, Awadhesh [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Thamilmaran, K., E-mail: maran.cnld@gmail.com [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India)

    2014-08-01

    In this paper, we study the time-varying interaction in coupled oscillatory systems. For this purpose, we have designed a novel time-varying resistive network using an analog switch and inverter circuits. We have applied this time-varying resistive network to mutually coupled identical Chua's oscillators. When the resistances are varied in time, we find that amplitude death arises in coupled identical oscillators. This has been observed numerically as well as verified through hardware experiments. - Highlights: • We have implemented the time-varying interaction in coupled oscillatory systems. • We have designed a novel time-varying resistive network using an analog switch and inverter circuits. • When the resistances are varied in time, we find that amplitude death arises in coupled identical oscillators.

  7. Analysis of time-varying psoriasis lesion image patterns

    DEFF Research Database (Denmark)

    Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær; Nielsen, Allan Aasbjerg

    2004-01-01

    The multivariate alteration detection transform is applied to pairs of within and between time varying registered psoriasis image patterns. Color band contribution to the variates explaining maximal change is analyzed.......The multivariate alteration detection transform is applied to pairs of within and between time varying registered psoriasis image patterns. Color band contribution to the variates explaining maximal change is analyzed....

  8. Three aspects of the Germany-France comparison on electricity. Electricity production and consumption in Germany

    International Nuclear Information System (INIS)

    Laponche, Bernard

    2014-01-01

    As a comparative overview of the French and German situation regarding electric power, a first article proposes tables and graphs illustrating data evolution, and brief comments about these evolutions. Comparison focuses on household electricity consumption, on electricity exchanges, and on the production of electricity based on renewable energies. An appendix proposes a presentation of the German policy for energy transition: principles and objectives, phasing out nuclear, implementation. Then, an article, illustrated by data tables and graphs, discusses the evolution of electric power production and consumption in Germany between 2000 and 2013. The author addresses power final consumption, power total production and exchanges, the components of electric power production, and greenhouse gas emissions (by fossil fuel, by sector, and by electricity and heat production)

  9. Electricity consumption, industrial production, and entrepreneurship in Singapore

    International Nuclear Information System (INIS)

    Sun, Sizhong; Anwar, Sajid

    2015-01-01

    Within the context of a tri-variate vector autoregressive framework that includes entrepreneurship, this paper examines the link between electricity consumption and industrial production in Singapore's manufacturing sector. Unlike the existing studies, this paper focuses on one sector of the economy and utilises a unique monthly dataset. Empirical analysis based on Johansen's cointegration approach shows that the three variables are cointegrated – i.e., a stable long-run relationship exists among electricity consumption, output and entrepreneurship in Singapore's manufacturing sector. Empirical analysis based on data from January 1983 to February 2014 reveals that electricity consumption adjusts very slowly to shocks to industrial production and entrepreneurship. Furthermore, entrepreneurship Granger causes electricity consumption, which causes industrial production. As electricity consumption causes industrial output, the growth hypothesis concerning energy consumption and economic growth holds in Singapore's manufacturing sector and policies that restrict electricity production, without electricity imports, are likely to lead to a decline in the manufacturing output. - Highlights: • Using a unique monthly dataset, we focus on Singapore's manufacturing sector. • Electricity consumption, output and entrepreneurship are cointegrated. • Electricity consumption adjusts very slowly to shocks to the other variables. • Entrepreneurship causes electricity consumption which causes industrial production. • We find that growth hypothesis governs the electricity consumption and real output

  10. Finite-time stability of neutral-type neural networks with random time-varying delays

    Science.gov (United States)

    Ali, M. Syed; Saravanan, S.; Zhu, Quanxin

    2017-11-01

    This paper is devoted to the finite-time stability analysis of neutral-type neural networks with random time-varying delays. The randomly time-varying delays are characterised by Bernoulli stochastic variable. This result can be extended to analysis and design for neutral-type neural networks with random time-varying delays. On the basis of this paper, we constructed suitable Lyapunov-Krasovskii functional together and established a set of sufficient linear matrix inequalities approach to guarantee the finite-time stability of the system concerned. By employing the Jensen's inequality, free-weighting matrix method and Wirtinger's double integral inequality, the proposed conditions are derived and two numerical examples are addressed for the effectiveness of the developed techniques.

  11. Hydrogen or Fossil Combustion Nuclear Combined Cycle Systems for Baseload and Peak Load Electricity Production. Annex X

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-12-15

    A combined cycle power plant is described that uses: (i) heat from a high temperature nuclear reactor to meet baseload electrical demands; and (ii) heat from the same high temperature reactor and burning natural gas, jet fuel or hydrogen to meet peak load electrical demands. For baseload electricity production, fresh air is compressed, then flows through a heat exchanger, where it is heated to between 700 and 900{sup o}C by using heat provided by a high temperature nuclear reactor via an intermediate heat transport loop, and finally exits through a high temperature gas turbine to produce electricity. The hot exhaust from the Brayton cycle gas turbine is then fed to a heat recovery steam generator that provides steam to a steam turbine for added electrical power production. To meet peak electricity demand, the air is first compressed and then heated with the heat from a high temperature reactor. Natural gas, jet fuel or hydrogen is then injected into the hot air in a combustion chamber, combusts and heats the air to 1300{sup o}C - the operating conditions for a standard natural gas fired combined cycle plant. The hot gas then flows through a gas turbine and a heat recovery steam generator before being sent to the exhaust stack. The higher temperatures increase the plant efficiency and power output. If hydrogen is used, it can be produced at night using energy from the nuclear reactor and stored until required. With hydrogen serving as the auxiliary fuel for peak power production, the electricity output to the electrical grid can vary from zero (i.e. when hydrogen is being produced) to the maximum peak power while the nuclear reactor operates at constant load. As nuclear heat raises air temperatures above the auto-ignition temperatures of the various fuels and powers the air compressor, the power output can be varied rapidly (compared with the capabilities of fossil fired turbines) to meet spinning reserve requirements and stabilize the electrical grid. This combined

  12. Macroeconomic aspects of decentralized electricity production

    International Nuclear Information System (INIS)

    Percebois, J.

    1991-01-01

    The development of decentralized electricity production should be viewed first and foremost as a means of adapting production resources to meet the needs of the users between 1995 and 1997. Consumer production and cogeneration are not, however, simply stopgap solutions operating on the fringe of electricity production. These methods serve to highlight a problem that has already been raised in the past: the real advantages and disadvantages of centralized systems managed by companies that exercise a virtual monopoly in either the public or private sector

  13. Entropy Rate of Time-Varying Wireless Networks

    DEFF Research Database (Denmark)

    Cika, Arta; Badiu, Mihai Alin; Coon, Justin P.

    2018-01-01

    In this paper, we present a detailed framework to analyze the evolution of the random topology of a time-varying wireless network via the information theoretic notion of entropy rate. We consider a propagation channel varying over time with random node positions in a closed space and Rayleigh...... fading affecting the connections between nodes. The existence of an edge between two nodes at given locations is modeled by a Markov chain, enabling memory effects in network dynamics. We then derive a lower and an upper bound on the entropy rate of the spatiotemporal network. The entropy rate measures...

  14. Nano-powder production by electrical explosion of wires

    International Nuclear Information System (INIS)

    Mao Zhiguo; Zou Xiaobing; Wang Xinxin; Jiang Weihua

    2010-01-01

    A device for nano-powder production by electrical explosion of wires was designed and built. Eight wires housed in the discharge chamber are exploded one by one before opening the chamber for the collection of the produced nano-powder. To increase the rate of energy deposition into a wire, the electrical behavior of the discharge circuit including the exploding wire was simulated. The results showed that both reducing the circuit inductance and reducing the capacitance of the energy-storage capacitor (keeping the storage energy constant) can increase the energy deposition rate. To better understand the physical processes of the nano-powder formation by the wire vapor, a Mach-Zehnder interferometer was used to record the time evolution of the wire vapor as well as the plasma. A thermal expansion lag of the dense vapor core as well as more than one times of the vapor burst was observed for the first time. Finally, nano-powders of titanium nitride, titanium dioxide, copper oxides and zinc oxide were produced by electrical explosion of wires. (authors)

  15. Multivariate time-varying volatility modeling using probabilistic fuzzy systems

    NARCIS (Netherlands)

    Basturk, N.; Almeida, R.J.; Golan, R.; Kaymak, U.

    2016-01-01

    Methods to accurately analyze financial risk have drawn considerable attention in financial institutions. One difficulty in financial risk analysis is the fact that banks and other financial institutions invest in several assets which show time-varying volatilities and hence time-varying financial

  16. Long memory of financial time series and hidden Markov models with time-varying parameters

    DEFF Research Database (Denmark)

    Nystrup, Peter; Madsen, Henrik; Lindström, Erik

    Hidden Markov models are often used to capture stylized facts of daily returns and to infer the hidden state of financial markets. Previous studies have found that the estimated models change over time, but the implications of the time-varying behavior for the ability to reproduce the stylized...... facts have not been thoroughly examined. This paper presents an adaptive estimation approach that allows for the parameters of the estimated models to be time-varying. It is shown that a two-state Gaussian hidden Markov model with time-varying parameters is able to reproduce the long memory of squared...... daily returns that was previously believed to be the most difficult fact to reproduce with a hidden Markov model. Capturing the time-varying behavior of the parameters also leads to improved one-step predictions....

  17. Ethanol from sugar cane with simultaneous production of electrical energy and biofertilizer

    Energy Technology Data Exchange (ETDEWEB)

    Filgueiras, G.

    1981-08-04

    A flexible nonpolluting industrial scheme is described for converting sugar cane into fuel-grade ethanol, fertilizer, and electric power. The cleaned cane is treated in a diffuser to separate the juice, which is enzymically hydrolyze d to ethanol, and bagasse containing 65-85% moisture, which is mechanically ground with the rest of the cane plant (leaves and buds) and biochemically digested to provide liquid and solid fertilizers as well as a methane-containing gas, which is burned in a gas turbine to generate electricity. The vinasse from the ethanol fermentation is also cycled to the digestion step. The process conditions can be varied depending upon the desired product ratio; if fuel is preferred, each ton of cane (dry weight) can produce 135 L ethanol, 50 kW electric power, and 150 kg fertilizer; if electric energy is preferred, each ton can give 75 L ethanol, 115 kW power, and 220 kg fertilizer.

  18. Overcoming Spurious Regression Using time-Varying Fourier ...

    African Journals Online (AJOL)

    Non-stationary time series data have been traditionally analyzed in the frequency domain by assuming constant amplitudes regardless of the timelag. A new approach called time-varying amplitude method (TVAM) is presented here. Oscillations are analyzed for changes in the magnitude of Fourier Coefficients which are ...

  19. Export of electric power through industrial products

    International Nuclear Information System (INIS)

    Azevedo, J.B.L. de; David, J.M.S.; Campos, J.M.; Perecmanis, J.; Carneiro, N.S.

    1990-01-01

    We forecast the electrical energy incorporated to the exports of products of the industrial sectors of steel, aluminium, ferro-alloys, chlorine and caustic soda, pulp and paper and petrochemistry, accordingly to scenarios for these sectors consistent with a macro economic reference scenario, for the period 1990/2000. We also compare the electrical energy exported through those industrial products with the forecasted industrial and total markets of electrical energy. (author)

  20. IEA Statistics 1993: electricity information

    International Nuclear Information System (INIS)

    1994-01-01

    Gross electricity production in 1993 in the OECD (including generation from pumped storage plants) was 7 466 TWh, a rise of 1.2 per cent from the level of gross production in 1992 (Tables 1 and 3). Nuclear plants accounted for 24.2 per cent of total gross electricity production in 1993, hydroelectric plants 16.7 per cent, total thermal plants 58.7 per cent and geothermal and other renewables 0.4 per cent. In 1992 total OECD heat production that is sold to third parties by public producers was 25 Mtoe (Table 6). About 86 per cent of this heat (21.6 Mtoe) was produced in CHP plants, about 12 per cent (3.1 Mtoe) in heat plants, and the remainder (0.3 Mtoe) in nuclear power plants (in Canada and Switzerland only). Based on preliminary data, apparent consumption of electricity (gross production plus imports less exports) in 1993 in OECD was 7 474 TWh. The corresponding figure for 1992 was 7 379 TWh, indicating a rise of 1.3 per cent in apparent electricity consumption in OECD countries in 1993. OECD countries imported a total of 219 TWh of electricity in 1993 (including from other OECD countries) and exported 211 TWh (including to other OECD countries). Accordingly, net imports of electricity in 1993 amounted to 7.7 TWh. Real electricity prices (as measured by the indices of real energy prices) in the OECD fell slightly in 1993 from 1992 levels for both industry and household end-users (Table 20). Electricity prices for industrial consumers vary widely across OECD countries. Based on data that are available for 1993, prices varied from 3.3 US cents per kWh in New Zealand to 12.1 US cents per kWh in Portugal. Electricity prices for industry are reported in Tables 24 and 25. Electricity prices for domestic consumers also vary widely across OECD countries. Based on data that are available for 1993, prices varied from 5.8 US cents per kWh in New Zealand to 18.0 US cents per kWh in Denmark (Tables 26 and 27)

  1. Production of electricity from the wind: a preliminary feasibility study for Greece

    Energy Technology Data Exchange (ETDEWEB)

    Galanis, N

    1977-01-01

    Wind statistics for Greece show that the conditions prevailing on the Aegean islands--i.e. considerable amounts of wind energy, small electrical loads and high generation costs--are especially favorable for the installation of wind turbine generators (WTGs). This study gives preliminary design parameters for WTGs at six locations and evaluates their performance. The duration of operation varies from 5000 to 7400 hours annually and the specific production is between 2300 and 3600 kwh/kw. The installation of the WTGs would result in diesel fuel savings corresponding to a month's consumption. Finally, the cost of wind generated electricity will be lower than that from diesel engines one to three years after the installation of the WTGs.

  2. Modelling Time-Varying Volatility in Financial Returns

    DEFF Research Database (Denmark)

    Amado, Cristina; Laakkonen, Helinä

    2014-01-01

    The “unusually uncertain” phase in the global financial markets has inspired many researchers to study the effects of ambiguity (or “Knightian uncertainty”) on the decisions made by investors and their implications for the capital markets. We contribute to this literature by using a modified...... version of the time-varying GARCH model of Amado and Teräsvirta (2013) to analyze whether the increasing uncertainty has caused excess volatility in the US and European government bond markets. In our model, volatility is multiplicatively decomposed into two time-varying conditional components: the first...... being captured by a stable GARCH(1,1) process and the second driven by the level of uncertainty in the financial market....

  3. Identification of time-varying nonlinear systems using differential evolution algorithm

    DEFF Research Database (Denmark)

    Perisic, Nevena; Green, Peter L; Worden, Keith

    2013-01-01

    (DE) algorithm for the identification of time-varying systems. DE is an evolutionary optimisation method developed to perform direct search in a continuous space without requiring any derivative estimation. DE is modified so that the objective function changes with time to account for the continuing......, thus identification of time-varying systems with nonlinearities can be a very challenging task. In order to avoid conventional least squares and gradient identification methods which require uni-modal and double differentiable objective functions, this work proposes a modified differential evolution...... inclusion of new data within an error metric. This paper presents results of identification of a time-varying SDOF system with Coulomb friction using simulated noise-free and noisy data for the case of time-varying friction coefficient, stiffness and damping. The obtained results are promising and the focus...

  4. The ''reference costs'' of the electrical production

    International Nuclear Information System (INIS)

    1997-05-01

    This study objective is to give an aid for the investments choice in the field of electricity production and for national choices in the field of long-dated production. Important evolutions appeared since the last exercise ''reference costs'' of 1993. Electricity production costs, presented in this study, are actualized economic costs. They consider the following production facilities: nuclear, pulverized coal with fumes processing, circulating fluidized bed, combustion turbines, cogeneration and wind turbines. (A.L.B.)

  5. A novel technique to measure interface trap density in a GaAs MOS capacitor using time-varying magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, Aditya N. Roy, E-mail: aditya@physics.iisc.ernet.in; Venkataraman, V. [Dept. of Physics, Indian Institute of Science, Bangalore – 560012 (India)

    2016-05-23

    Interface trap density (D{sub it}) in a GaAs metal-oxide-semiconductor (MOS) capacitor can be measured electrically by measuring its impedance, i.e. by exciting it with a small signal voltage source and measuring the resulting current through the circuit. We propose a new method of measuring D{sub it} where the MOS capacitor is subjected to a (time-varying) magnetic field instead, which produces an effect equivalent to a (time-varying) voltage drop across the sample. This happens because the electron chemical potential of GaAs changes with a change in an externally applied magnetic field (unlike that of the gate metal); this is not the voltage induced by Faraday’s law of electromagnetic induction. So, by measuring the current through the MOS, D{sub it} can be found similarly. Energy band diagrams and equivalent circuits of a MOS capacitor are drawn in the presence of a magnetic field, and analyzed. The way in which a magnetic field affects a MOS structure is shown to be fundamentally different compared to an electrical voltage source.

  6. Electrical production for domestic and industrial applications using hybrid PV-wind system

    International Nuclear Information System (INIS)

    Essalaimeh, S.; Al-Salaymeh, A.; Abdullat, Y.

    2013-01-01

    Highlights: ► Modeling and building hybrid system of PV and wind turbine. ► Investigation of the electrical generation under Amman–Jordan’s climate. ► Configuration of theoretical and actual characteristics of the hybrid system. ► Testing effects of dust, inclination and load on the electrical generation. ► Financial analysis for various applications. - Abstract: The present work shows an experimental investigation of using a combination of solar and wind energies as hybrid system for electrical generation under the Jordanian climate conditions. The generated electricity has been utilized for different types of applications and mainly for space heating and cooling. The system has also integration with grid connection to have more reliable system. Measurements included the solar radiation intensity, the ambient temperature, the wind speed and the output power from the solar PV panels and wind turbine. The performance characteristic of the PV panels has been obtained by varying the load value through a variable resistance. Some major factors have been studied and practically measured; one of them is the dust effect on electrical production efficiency for photovoltaic panels. Another factor is the inclination of the PV panels, where varying the angle of inclination has a seasonal importance for gathering the maximum solar intensity. Through mathematical calculation and the collected and measured data, a simple payback period has been calculated of the hybrid system in order to study the economical aspects of installing such a system under Jordanian climate conditions and for different usages and local tariffs including domestic, industrial and commercial applications. It was found through this work that the generated electricity of hybrid system and under Jordanian climate conditions can be utilized for electrical heating and cooling through split units and resistive heaters.

  7. Monopoly models with time-varying demand function

    Science.gov (United States)

    Cavalli, Fausto; Naimzada, Ahmad

    2018-05-01

    We study a family of monopoly models for markets characterized by time-varying demand functions, in which a boundedly rational agent chooses output levels on the basis of a gradient adjustment mechanism. After presenting the model for a generic framework, we analytically study the case of cyclically alternating demand functions. We show that both the perturbation size and the agent's reactivity to profitability variation signals can have counterintuitive roles on the resulting period-2 cycles and on their stability. In particular, increasing the perturbation size can have both a destabilizing and a stabilizing effect on the resulting dynamics. Moreover, in contrast with the case of time-constant demand functions, the agent's reactivity is not just destabilizing, but can improve stability, too. This means that a less cautious behavior can provide better performance, both with respect to stability and to achieved profits. We show that, even if the decision mechanism is very simple and is not able to always provide the optimal production decisions, achieved profits are very close to those optimal. Finally, we show that in agreement with the existing empirical literature, the price series obtained simulating the proposed model exhibit a significant deviation from normality and large volatility, in particular when underlying deterministic dynamics become unstable and complex.

  8. Innovation diffusion on time-varying activity driven networks

    Science.gov (United States)

    Rizzo, Alessandro; Porfiri, Maurizio

    2016-01-01

    Since its introduction in the 1960s, the theory of innovation diffusion has contributed to the advancement of several research fields, such as marketing management and consumer behavior. The 1969 seminal paper by Bass [F.M. Bass, Manag. Sci. 15, 215 (1969)] introduced a model of product growth for consumer durables, which has been extensively used to predict innovation diffusion across a range of applications. Here, we propose a novel approach to study innovation diffusion, where interactions among individuals are mediated by the dynamics of a time-varying network. Our approach is based on the Bass' model, and overcomes key limitations of previous studies, which assumed timescale separation between the individual dynamics and the evolution of the connectivity patterns. Thus, we do not hypothesize homogeneous mixing among individuals or the existence of a fixed interaction network. We formulate our approach in the framework of activity driven networks to enable the analysis of the concurrent evolution of the interaction and individual dynamics. Numerical simulations offer a systematic analysis of the model behavior and highlight the role of individual activity on market penetration when targeted advertisement campaigns are designed, or a competition between two different products takes place.

  9. Transition countries in the light of electricity production

    International Nuclear Information System (INIS)

    Kolin, I.

    2000-01-01

    The fall of the Berlin Wall in 1989 could be closely considered as the beginning of transition in many countries. during this period, lasting for about ten years, unavoidable fluctuations and stoppages caused degradation of electricity production and economic decline as well. This can be mathematically evaluated by means of equation for electricity production, valid before the fall of the Berlin Wall. However, electricity decrease has not been the same in all the countries. Therefore, in order to investigate and evaluate the transition process in the light of electricity production, eight transition states, including croatia, are analysed and mutually compared. (author)

  10. The time-dependent development of electric double-layers in saline solutions

    International Nuclear Information System (INIS)

    Morrow, R; McKenzie, D R; Bilek, M M M

    2006-01-01

    We have studied the time-dependent development of electric double-layers (ionic sheaths) in saline solutions by simultaneously solving the sodium and chlorine ion continuity equations coupled with Poisson's equation in one dimension. The study of the effects of time-varying electric fields in solution is relevant to the possible health effect of radio-frequency electric fields on cells in the human body and to assessing the potential of using external electric fields to orient proteins for attachment to surfaces for biosensing applications. Our calculations, for applied voltages of 10-175 mV between the electrode and the solution, predict time scales of ∼0.1-110 μs for the formation of double-layers in solutions of concentration between 0.001 and 1.0 M. We develop an empirical equation that can predict the double-layer formation time to within 10% over this wide parameter range. The method has been validated by comparing the solutions obtained, once the program has run to a steady state, with the standard non-linear Poisson-Boltzmann equations. Excellent agreement is found with the Gouy-Chapman solution of the non-linear Poisson-Boltzmann equation. Thus the method is not restricted in accuracy and applicability as is the case for the linear Poisson-Boltzmann equation. The method can also provide solutions for cases where there are orders of magnitude changes in the ion densities; this has not been the case for previous studies where small perturbation analysis has been employed. The method developed here can readily be extended to two and three dimensions using time-splitting methods

  11. Velocity distribution of electrons in time-varying low-temperature plasmas: progress in theoretical procedures over the past 70 years

    Science.gov (United States)

    Makabe, Toshiaki

    2018-03-01

    A time-varying low-temperature plasma sustained by electrical powers with various kinds of fRequencies has played a key role in the historical development of new technologies, such as gas lasers, ozonizers, micro display panels, dry processing of materials, medical care, and so on, since World War II. Electrons in a time-modulated low-temperature plasma have a proper velocity spectrum, i.e. velocity distribution dependent on the microscopic quantum characteristics of the feed gas molecule and on the external field strength and the frequency. In order to solve and evaluate the time-varying velocity distribution, we have mostly two types of theoretical methods based on the classical and linear Boltzmann equations, namely, the expansion method using the orthogonal function and the procedure of non-expansional temporal evolution. Both methods have been developed discontinuously and progressively in synchronization with those technological developments. In this review, we will explore the historical development of the theoretical procedure to evaluate the electron velocity distribution in a time-varying low-temperature plasma over the past 70 years.

  12. 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

  13. Multi-Step Time Series Forecasting with an Ensemble of Varied Length Mixture Models.

    Science.gov (United States)

    Ouyang, Yicun; Yin, Hujun

    2018-05-01

    Many real-world problems require modeling and forecasting of time series, such as weather temperature, electricity demand, stock prices and foreign exchange (FX) rates. Often, the tasks involve predicting over a long-term period, e.g. several weeks or months. Most existing time series models are inheritably for one-step prediction, that is, predicting one time point ahead. Multi-step or long-term prediction is difficult and challenging due to the lack of information and uncertainty or error accumulation. The main existing approaches, iterative and independent, either use one-step model recursively or treat the multi-step task as an independent model. They generally perform poorly in practical applications. In this paper, as an extension of the self-organizing mixture autoregressive (AR) model, the varied length mixture (VLM) models are proposed to model and forecast time series over multi-steps. The key idea is to preserve the dependencies between the time points within the prediction horizon. Training data are segmented to various lengths corresponding to various forecasting horizons, and the VLM models are trained in a self-organizing fashion on these segments to capture these dependencies in its component AR models of various predicting horizons. The VLM models form a probabilistic mixture of these varied length models. A combination of short and long VLM models and an ensemble of them are proposed to further enhance the prediction performance. The effectiveness of the proposed methods and their marked improvements over the existing methods are demonstrated through a number of experiments on synthetic data, real-world FX rates and weather temperatures.

  14. Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

    Science.gov (United States)

    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.

  15. New Balancing Equipment for Mass Production of Small and Medium-Sized Electrical Machines

    DEFF Research Database (Denmark)

    Argeseanu, Alin; Ritchie, Ewen; Leban, Krisztina Monika

    2010-01-01

    The level of vibration and noise is an important feature. It is good practice to explain the significance of the indicators of the quality of electrical machines. The mass production of small and medium-sized electrical machines demands speed (short typical measurement time), reliability...

  16. Scaling properties in time-varying networks with memory

    Science.gov (United States)

    Kim, Hyewon; Ha, Meesoon; Jeong, Hawoong

    2015-12-01

    The formation of network structure is mainly influenced by an individual node's activity and its memory, where activity can usually be interpreted as the individual inherent property and memory can be represented by the interaction strength between nodes. In our study, we define the activity through the appearance pattern in the time-aggregated network representation, and quantify the memory through the contact pattern of empirical temporal networks. To address the role of activity and memory in epidemics on time-varying networks, we propose temporal-pattern coarsening of activity-driven growing networks with memory. In particular, we focus on the relation between time-scale coarsening and spreading dynamics in the context of dynamic scaling and finite-size scaling. Finally, we discuss the universality issue of spreading dynamics on time-varying networks for various memory-causality tests.

  17. Carbon emission intensity in electricity production: A global analysis

    International Nuclear Information System (INIS)

    Ang, B.W.; Su, Bin

    2016-01-01

    We study changes in the aggregate carbon intensity (ACI) for electricity at the global and country levels. The ACI is defined as the energy-related CO_2 emissions in electricity production divided by the electricity produced. It is a performance indicator since a decrease in its value is a desirable outcome from the environmental and climate change viewpoints. From 1990 to 2013, the ACI computed at the global level decreased only marginally. However, fairly substantial decreases were observed in many countries. This apparent anomaly arises from a geographical shift in global electricity production with countries having a high ACI increasingly taking up a larger electricity production share. It is found that globally and in most major electricity producing countries, reduction in their ACI was due mainly to improvements in the thermal efficiency of electricity generation rather than to fuel switching. Estimates of the above-mentioned effects are made using LMDI decomposition analysis. Our study reveals several challenges in reducing global CO_2 emissions from the electricity production sector although technically the reduction potential for the sector is known to be great. - Highlights: •Variations of aggregate carbon intensity (ACI) for electricity of world countries are analysed. •Main drivers of changes in ACI of major electricity producing countries are studied using index decomposition analysis. •Geographical shift in electricity production had a significant impact on global ACI. •Improvements in the thermal efficiency of generation were the main driver of reduction in ACI.

  18. Testing for time-varying loadings in dynamic factor models

    DEFF Research Database (Denmark)

    Mikkelsen, Jakob Guldbæk

    Abstract: In this paper we develop a test for time-varying factor loadings in factor models. The test is simple to compute and is constructed from estimated factors and residuals using the principal components estimator. The hypothesis is tested by regressing the squared residuals on the squared...... there is evidence of time-varying loadings on the risk factors underlying portfolio returns for around 80% of the portfolios....

  19. Nuclear energy products except the electric power

    International Nuclear Information System (INIS)

    2004-01-01

    Technically the fission reactors, on service or under construction, can produce other products than the electric power. Meanwhile, these applications are known since the beginning of the reactors exploitation, they never have been developed industrially. This report examines the necessary technical characteristics for using the nuclear systems on non electric power applications with an economical efficiency. What are the markets for these products? What are the strategical challenges to favor the development of non electric power applications of the nuclear energy? (A.L.B.)

  20. Precision measurement of electric organ discharge timing from freely moving weakly electric fish.

    Science.gov (United States)

    Jun, James J; Longtin, André; Maler, Leonard

    2012-04-01

    Physiological measurements from an unrestrained, untethered, and freely moving animal permit analyses of neural states correlated to naturalistic behaviors of interest. Precise and reliable remote measurements remain technically challenging due to animal movement, which perturbs the relative geometries between the animal and sensors. Pulse-type electric fish generate a train of discrete and stereotyped electric organ discharges (EOD) to sense their surroundings actively, and rapid modulation of the discharge rate occurs while free swimming in Gymnotus sp. The modulation of EOD rates is a useful indicator of the fish's central state such as resting, alertness, and learning associated with exploration. However, the EOD pulse waveforms remotely observed at a pair of dipole electrodes continuously vary as the fish swims relative to the electrodes, which biases the judgment of the actual pulse timing. To measure the EOD pulse timing more accurately, reliably, and noninvasively from a free-swimming fish, we propose a novel method based on the principles of waveform reshaping and spatial averaging. Our method is implemented using envelope extraction and multichannel summation, which is more precise and reliable compared with other widely used threshold- or peak-based methods according to the tests performed under various source-detector geometries. Using the same method, we constructed a real-time electronic pulse detector performing an additional online pulse discrimination routine to enhance further the detection reliability. Our stand-alone pulse detector performed with high temporal precision (<10 μs) and reliability (error <1 per 10(6) pulses) and permits longer recording duration by storing only event time stamps (4 bytes/pulse).

  1. Time-Varying Periodicity in Intraday Volatility

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Thyrsgaard, Martin; Todorov, Viktor

    We develop a nonparametric test for deciding whether return volatility exhibits time-varying intraday periodicity using a long time-series of high-frequency data. Our null hypothesis, commonly adopted in work on volatility modeling, is that volatility follows a stationary process combined...... with a constant time-of-day periodic component. We first construct time-of-day volatility estimates and studentize the high-frequency returns with these periodic components. If the intraday volatility periodicity is invariant over time, then the distribution of the studentized returns should be identical across...... with estimating volatility moments through their sample counterparts. Critical values are computed via easy-to-implement simulation. In an empirical application to S&P 500 index returns, we find strong evidence for variation in the intraday volatility pattern driven in part by the current level of volatility...

  2. Electricity derivative markets: Investment valuation, production planning and hedging

    International Nuclear Information System (INIS)

    Naesaekkaelae, E.

    2005-01-01

    This thesis studies electricity derivative markets from a view point of an electricity producer. The traditionally used asset pricing methods, based on the no arbitrage principle, are extended to take into account electricity specific features: the non storability of electricity and the variability in the load process. The sources of uncertainty include electricity forward curve, prices of resources used to generate electricity, and the size of the future production. Also the effects of competitors' actions are considered. The thesis illustrates how the information in the derivative prices can be used in investment and production planning. In addition, the use of derivatives as a tool to stabilize electricity dependent cash flows is considered. The results indicate that the information about future electricity prices and their uncertainty, obtained from derivative markets, is important in investment analysis and production planning. (orig.)

  3. Electricity derivative markets: Investment valuation, production planning and hedging

    Energy Technology Data Exchange (ETDEWEB)

    Naesaekkaelae, E.

    2005-07-01

    This thesis studies electricity derivative markets from a view point of an electricity producer. The traditionally used asset pricing methods, based on the no arbitrage principle, are extended to take into account electricity specific features: the non storability of electricity and the variability in the load process. The sources of uncertainty include electricity forward curve, prices of resources used to generate electricity, and the size of the future production. Also the effects of competitors' actions are considered. The thesis illustrates how the information in the derivative prices can be used in investment and production planning. In addition, the use of derivatives as a tool to stabilize electricity dependent cash flows is considered. The results indicate that the information about future electricity prices and their uncertainty, obtained from derivative markets, is important in investment analysis and production planning. (orig.)

  4. Is Power Production Flexibility a Substitute for Storability? Evidence from Electricity Futures Prices

    NARCIS (Netherlands)

    M. Kilic (Mehtap); R. Huisman (Ronald)

    2010-01-01

    textabstractElectricity is not storable. As a consequence, electricity demand and supply need to be in balance at any moment in time as a shortage in production volume cannot be compensated with supply from inventories. However, if the installed power supply capacity is very flexible, variation in

  5. Finite-Time Stability of Large-Scale Systems with Interval Time-Varying Delay in Interconnection

    Directory of Open Access Journals (Sweden)

    T. La-inchua

    2017-01-01

    Full Text Available We investigate finite-time stability of a class of nonlinear large-scale systems with interval time-varying delays in interconnection. Time-delay functions are continuous but not necessarily differentiable. Based on Lyapunov stability theory and new integral bounding technique, finite-time stability of large-scale systems with interval time-varying delays in interconnection is derived. The finite-time stability criteria are delays-dependent and are given in terms of linear matrix inequalities which can be solved by various available algorithms. Numerical examples are given to illustrate effectiveness of the proposed method.

  6. Productivity growth and deregulation of Japanese electricity distribution

    International Nuclear Information System (INIS)

    Goto, Mika; Sueyoshi, Toshiyuki

    2009-01-01

    Deregulation of Japanese electric power industry began in 1995. After the amendment of Electricity Utility Industry Law in 1995, competition was partially introduced in a generation sector and retail competition started from 2000. Eligibility to choose suppliers was gradually extended from larger to smaller customers. As of 2008, almost all customers except households can choose their electricity suppliers. Based upon both previous implementation result of competition policy and review on their achievement, Japanese government will begin new policy debate in 2013 to assess further retail competition which includes household customers. To prepare for policy suggestion on the future electric power industry, this study examines the cost structure of Japanese electricity distribution. For the purpose, we estimate a multi-product translog cost function of Japanese electricity distribution from 1983 to 2003. Using the estimated cost function, we calculate several economic measures such as productivity growth, technical change and economies of scale and scope. The empirical results of this study indicate the improvement in productivity growth after deregulation.

  7. Green certificates will lead to increased electric power production

    International Nuclear Information System (INIS)

    Lind, Oddvar

    2004-01-01

    The implementation of green certificates will lead to increased electricity production from renewable energy sources and less risk of price crises. For the time being, a common market for green certificates will be established with Sweden from January 1, 2006. It is possible to realise a ''compulsory total quota'' of 20 TWh by 2016. Green certificates will imply a premium on the electricity bill. However, the quota system will imply increased power generation, which in turn tends to lower the price. Norway should in principle follow Sweden's definition of renewable energy: all new hydroelectric power, wind power, solar energy, wave and tidal power, biomass energy, and energy recovery. The certificate regime will apply to new investments in renewable power production. However, it would be natural to include the established renewable power production that is currently receiving support. Some critics fear that the consumers rather than the authorities will subsidize the production of green power. The point is being made that central EU countries may save great sums by investing in renewable energy in Norway

  8. Modeling information diffusion in time-varying community networks

    Science.gov (United States)

    Cui, Xuelian; Zhao, Narisa

    2017-12-01

    Social networks are rarely static, and they typically have time-varying network topologies. A great number of studies have modeled temporal networks and explored social contagion processes within these models; however, few of these studies have considered community structure variations. In this paper, we present a study of how the time-varying property of a modular structure influences the information dissemination. First, we propose a continuous-time Markov model of information diffusion where two parameters, mobility rate and community attractiveness, are introduced to address the time-varying nature of the community structure. The basic reproduction number is derived, and the accuracy of this model is evaluated by comparing the simulation and theoretical results. Furthermore, numerical results illustrate that generally both the mobility rate and community attractiveness significantly promote the information diffusion process, especially in the initial outbreak stage. Moreover, the strength of this promotion effect is much stronger when the modularity is higher. Counterintuitively, it is found that when all communities have the same attractiveness, social mobility no longer accelerates the diffusion process. In addition, we show that the local spreading in the advantage group has been greatly enhanced due to the agglomeration effect caused by the social mobility and community attractiveness difference, which thus increases the global spreading.

  9. Do Time-Varying Covariances, Volatility Comovement and Spillover Matter?

    OpenAIRE

    Lakshmi Balasubramanyan

    2005-01-01

    Financial markets and their respective assets are so intertwined; analyzing any single market in isolation ignores important information. We investigate whether time varying volatility comovement and spillover impact the true variance-covariance matrix under a time-varying correlation set up. Statistically significant volatility spillover and comovement between US, UK and Japan is found. To demonstrate the importance of modelling volatility comovement and spillover, we look at a simple portfo...

  10. Newtonian cosmology with a time-varying constant of gravitation

    International Nuclear Information System (INIS)

    McVittie, G.C.

    1978-01-01

    Newtonian cosmology is based on the Eulerian equations of fluid mechanics combined with Poisson's equation modified by the introduction of a time-varying G. Spherically symmetric model universes are worked out with instantaneously uniform densities. They are indeterminate unless instantaneous uniformity of the pressure is imposed. When G varies as an inverse power of the time, the models can in some cases be shown to depend on the solution of a second-order differential equation which also occurs in the Friedmann models of general relativity. In Section 3, a method for 'passing through' a singularity of this equation is proposed which entails making four arbitrary mathematical assumptions. When G varies as (time) -1 , models with initially cycloidal motion are possible, each cycle becoming longer as time progresses. Finally, gravitation becomes so weak that the model expands to infinity. Kinetic and potential energies for the whole model are derived from the basic equations; their sum is not constant. (author)

  11. The impact of Production Tax Credits on the profitable production of electricity from wind in the U.S

    International Nuclear Information System (INIS)

    Xi Lu; Tchou, Jeremy; McElroy, Michael B.; Nielsen, Chris P.

    2011-01-01

    A spatial financial model using wind data derived from assimilated meteorological condition was developed to investigate the profitability and competitiveness of onshore wind power in the contiguous U.S. It considers not only the resulting estimated capacity factors for hypothetical wind farms but also the geographically differentiated costs of local grid connection. The levelized cost of wind-generated electricity for the contiguous U.S. is evaluated assuming subsidy levels from the Production Tax Credit (PTC) varying from 0 to 4 cents /kWh under three cost scenarios: a reference case, a high cost case, and a low cost case. The analysis indicates that in the reference scenario, current PTC subsidies of 2.1 cents /kWh are at a critical level in determining the competitiveness of wind-generated electricity compared to conventional power generation in local power market. Results from this study suggest that the potential for profitable wind power with the current PTC subsidy amounts to more than seven times existing demand for electricity in the entire U.S. Understanding the challenges involved in scaling up wind energy requires further study of the external costs associated with improvement of the backbone transmission network and integration into the power grid of the variable electricity generated from wind. - Highlights: → Wind power competitiveness is driven by meteorology and proximity to the grid. → We spatially model U.S. onshore wind under ranges of subsidies and costs. → Wind power is competitive at a PTC subsidy of 2.1 cents/kWh. → Under current PTC levels, profitable wind potential far exceeds U.S. power demand.

  12. Hydrogen from nuclear plus wind using real-time electricity prices. Abstract 154

    International Nuclear Information System (INIS)

    Miller, A.I.; Duffey, R.B.; Fairlie, M.

    2004-01-01

    'Full text:' During the early years of hydrogen's use as a vehicle fuel, penetration of the market will be small. This favours distributed production by electrolysis, which avoids the scale-dependent costs of distribution from centralized plants. For electrolysis actually to be the preferred option, capital equipment for electrolysis must be reasonably cheap but the dominant cost component is the electricity price. By about 2006, advanced designs of nuclear reactors should be available to produce electricity at around 30 US$/MW.h. The best approach to producing low-cost electrolytic hydrogen is shown to be use of such reactors to supply electricity to the grid at times of peak price and demand and to make hydrogen at other times. This model has been analysed using the actual prices of electricity paid by the Alberta Power Pool in 2002 and 2003 and by the Ontario Grid for 2003. The analysis shows clearly that this route electrolytic hydrogen can comfortably meet the US Department of Energy's hydrogen production-cost target of 2000$/t. Because of its low availability wind-produced electricity cannot meet this cost target. However, if wind availability can reach 35% availability, an intermittent supplementary current of wind-generated electricity may economically be fed to an electrolytic plant primarily supplied by nuclear power. Additional current raises the voltage for electrolysis but there would be only small additional capital costs. The two non-CO 2 -emitting sources, nuclear and wind (or other intermittent renewables with costs comparable to advanced nuclear) could become complementary, providing an affordable way of storing wind-generated electricity. (author)

  13. Electric plant cost and power production expenses 1991

    International Nuclear Information System (INIS)

    1993-01-01

    Electric Plant Cost and Power Production Expenses is prepared by the Survey Management Division; Office of Coal, Nuclear, Electric and Alternate Fuels (CNEAF); Energy Information Administration (EIA); US Department of Energy. This publication presents electric utility statistics on power production expenses and construction costs of electric generating plants. Data presented here are intended to provide information to the electric utility industry, educational institutions, Federal, State, and local governments, and the general public. These data are collected and published to fulfill data collection and dissemination responsibilities of the Energy Information Administration (EIA), as specified in the Federal Energy Administration Act (Public Law 93-275), as amended

  14. Electric plant cost and power production expenses 1990

    International Nuclear Information System (INIS)

    1992-06-01

    Electric Plant Cost and Power Production Expenses is prepared by the Survey Management Division; Office of Coal, Nuclear, Electric and Alternate Fuels, Energy Information Administration (EIA); US Department of Energy. This publication presents electric utility statistics on power production expenses and construction costs of electric generating plants. Data presented here are intended to provide information to the electric utility industry, educational institutions, Federal, State, and local governments, and the general public. These data are collected and published to fulfill data collection and dissemination responsibilities of the Energy Information Administration (EIA), as specified in the Federal Energy Administration Act (Public Law 93-275), as amended

  15. Visualization of conduit-matrix conductivity differences in a karst aquifer using time-lapse electrical resistivity

    Science.gov (United States)

    Meyerhoff, Steven B.; Karaoulis, Marios; Fiebig, Florian; Maxwell, Reed M.; Revil, André; Martin, Jonathan B.; Graham, Wendy D.

    2012-12-01

    In the karstic upper Floridan aquifer, surface water flows into conduits of the groundwater system and may exchange with water in the aquifer matrix. This exchange has been hypothesized to occur based on differences in discharge at the Santa Fe River Sink-Rise system, north central Florida, but has yet to be visualized using any geophysical techniques. Using electrical resistivity tomography, we conducted a time-lapse study at two locations with mapped conduits connecting the Santa Fe River Sink to the Santa Fe River Rise to study changes of electrical conductivity during times of varying discharge over a six-week period. Our results show conductivity differences between matrix, conduit changes in resistivity occurring through time at the locations of mapped karst conduits, and changes in electrical conductivity during rainfall infiltration. These observations provide insight into time scales and matrix conduit conductivity differences, illustrating how surface water flow recharged to conduits may flow in a groundwater system in a karst aquifer.

  16. Time-varying correlation and common structures in volatility

    NARCIS (Netherlands)

    Liu, Yang

    2016-01-01

    This thesis studies time series properties of the covariance structure of multivariate asset returns. First, the time-varying feature of correlation is investigated at the intraday level with a new correlation model incorporating the intraday correlation dynamics. Second, the thesis develops a

  17. Centralized or decentralized electricity production

    International Nuclear Information System (INIS)

    Boer, H.A. de.

    1975-01-01

    Because of low overall efficiency in electric power generation, it is argued that energy provision based on gas, combined with locally decentralized electricity production, saves for the Netherlands slightly more fossile fuel than nuclear technologies and makes the country independent of uranium resources. The reason the Netherlands persues this approach is that a big part of the energy is finally used for heating in the normal or moderate temperatures

  18. Procurement model for copper and polymer electrical products

    Directory of Open Access Journals (Sweden)

    S. Sremac

    2013-10-01

    Full Text Available Procurement model for copper and polymer electrical products. Electrical cable structure (wire, insulation, filling and mantle is in accordance with the technical specifications of individual cable components in terms of the incorporated materials. Materials used in cable manufacture are copper, aluminum, rubber and polyvinyl chloride. One of the key issues in managing the flow of goods pertains to the timing of procurement. The combination of the two concepts can take advantage of individual strengths of fuzzy logic and neural networks in hybrid systems of homogeneous structure. The model has high practical significance, as, with minor modifications, it can be applied in any enterprise responsible for managing the goods flows.

  19. Effects of Temporal Wind Patterns on the Value of Wind-Generated Electricity in California and the Northwest

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ryan H; Wiser, Ryan H; Fripp, Matthias

    2008-05-01

    Wind power production is variable, but also has diurnal and seasonal patterns. These patterns differ between sites, potentially making electric power from some wind sites more valuable for meeting customer loads or selling in wholesale power markets. This paper investigates whether the timing of wind significantly affects the value of electricity from sites in California and the Northwestern United States. We use both measured and modeled wind data and estimate the time-varying value of wind power with both financial and load-based metrics. We find that the potential difference in wholesale market value between better-correlated and poorly correlated wind sites is modest, on the order of 5-10 percent. A load-based metric, power production during the top 10 percent of peak load hours, varies more strongly between sites, suggesting that the capacity value of different wind projects could vary by as much as 50 percent based on the timing of wind alone.

  20. Reference costs of the electric power production; Couts de reference de la production electrique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-01

    This study periodically realized by the DGEMP aims to compare the competitiveness of the different channels of electric power production, for different utilization conditions. The first part ''reference costs of the 2003 electric power production'' examines the prices of the electric power produced by different channels in particular in the framework of the industrial implementing in 2015. The nuclear and thermal power plants are concerned. The second part is devoted to the decentralized production channels (wind energy, photovoltaic, cogeneration heat-electricity) is under construction and will be presented next year. (A.L.B.)

  1. Note: Possibilities of detecting the trace-level erosion products from an electric propulsion hollow cathode plasma source by the method of time-of-flight mass spectrometry

    Science.gov (United States)

    Ning, Zhong-Xi; Zhang, Hai-Guang; Zhu, Xi-Ming; Jiang, Bin-Hao; Zhou, Zhong-Yue; Yu, Da-Ren; An, Bing-Jian; Wang, Yan-Fei

    2018-02-01

    A hollow cathode produces electrons which neutralize ions from electric propulsion thrusters. After hundreds to thousands of hours of operation in space, the cathode materials can be significantly eroded due to ion bombardment. As a result, the electric propulsion system performance will be obviously changed or even fail. In this work, the erosion products from a LaB6 hollow cathode (widely used presently in electric propulsion systems) are studied by using a specific detection system, which consists of a molecular beam sampler and a time-of-flight mass spectrometer. This system measures trace-level-concentration (10-6-10-3) products. Boron (B), tantalum (Ta), and tungsten (W)—originating from the emitter, keeper, and orifice of the hollow cathode—are measured. It is found that the erosion rate is significantly influenced by the gas flow rate to the cathode.

  2. Air pollution restrictions in electrical production system

    International Nuclear Information System (INIS)

    Gallizioli, G.

    1993-01-01

    A description of the principal characteristics regarding the Italian electrical power system and the evolution of standardization in air pollution control is given. Afterwards, ENEL (the Italian National Electricity Board) actions in the environmental protection field (with particular respect to thermo-electrical production) are presented. Finally, principal ENEL research programs on new air pollution control technologies are discussed

  3. Stabilization of the Wave Equation with Boundary Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Hao Li

    2014-01-01

    Full Text Available We study the stabilization of the wave equation with variable coefficients in a bounded domain and a time-varying delay term in the time-varying, weakly nonlinear boundary feedbacks. By the Riemannian geometry methods and a suitable assumption of nonlinearity, we obtain the uniform decay of the energy of the closed loop system.

  4. Fusion-product ash buildup in tokamak with radial electric field

    International Nuclear Information System (INIS)

    Downum, W.B.; Choi, C.K.; Miley, G.H.

    1979-01-01

    The buildup of thermalized fusion products (ash) in a tokamak can seriously limit burn times. Prior studies have concentrated on deposition profile effects on alpha particle transport in tokamaks but have not considered the effect on ash of radial electric fields (either created internally, e.g. due to high-energy alpha leakage, or generated externally). The present study focuses on this issue since it appears that electric fields might offer one approach to control of the ash. Approximate field and source profiles are used, based on prior calculations

  5. Investigating Time-Varying Drivers of Grid Project Emissions Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Emily L.; Thayer, Brandon L.; Pal, Seemita; Studarus, Karen E.

    2017-11-15

    The emissions consequences of smart grid technologies depend heavily on their context and vary not only by geographical location, but by time of year. The same technology operated to meet the same objective may increase the emissions associated with energy generation for part of the year and decrease emissions during other times. The Grid Project Impact Quantification (GridPIQ) tool provides the ability to estimate these seasonal variations and garner insight into the time-varying drivers of grid project emissions impacts. This work leverages GridPIQ to examine the emissions implications across years and seasons of adding energy storage technology to reduce daily peak demand in California and New York.

  6. Electricity production from biogas in Serbia: Assessment of emissions reduction

    Directory of Open Access Journals (Sweden)

    Cvetković Slobodan M.

    2016-01-01

    Full Text Available Biogas represents a promising source for the production of clean energy. The objective of this paper was to quantify the potential for the reduction of emissions to the environment during the production of electricity from biogas in comparison with environmental effects of the production of the same amount of electricity from fossil resources (coal from Kolubara basin and natural gas. Basis for comparison of environmental impacts in this work was the annual production of electricity in biogas plants of the total capacity of 80 MW. This study has shown that the annual production of electricity from biogas power plants of 80 MW results in: substitution of up to 840 kt of coal from Kolubara basin and 123.2 million m3 of natural gas; reduction in emissions of greenhouse gases in the range of 491.16 kt - 604.97 kt CO2-eq, depending on the energy efficiency of the process of electricity production from biogas; reduction in emissions of greenhouse gases up to 92.37 kt CO2-eq compared to the use of natural gas for electricity generation.

  7. Nonlinear recurrent neural networks for finite-time solution of general time-varying linear matrix equations.

    Science.gov (United States)

    Xiao, Lin; Liao, Bolin; Li, Shuai; Chen, Ke

    2018-02-01

    In order to solve general time-varying linear matrix equations (LMEs) more efficiently, this paper proposes two nonlinear recurrent neural networks based on two nonlinear activation functions. According to Lyapunov theory, such two nonlinear recurrent neural networks are proved to be convergent within finite-time. Besides, by solving differential equation, the upper bounds of the finite convergence time are determined analytically. Compared with existing recurrent neural networks, the proposed two nonlinear recurrent neural networks have a better convergence property (i.e., the upper bound is lower), and thus the accurate solutions of general time-varying LMEs can be obtained with less time. At last, various different situations have been considered by setting different coefficient matrices of general time-varying LMEs and a great variety of computer simulations (including the application to robot manipulators) have been conducted to validate the better finite-time convergence of the proposed two nonlinear recurrent neural networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Long Memory of Financial Time Series and Hidden Markov Models with Time-Varying Parameters

    DEFF Research Database (Denmark)

    Nystrup, Peter; Madsen, Henrik; Lindström, Erik

    2016-01-01

    Hidden Markov models are often used to model daily returns and to infer the hidden state of financial markets. Previous studies have found that the estimated models change over time, but the implications of the time-varying behavior have not been thoroughly examined. This paper presents an adaptive...... to reproduce with a hidden Markov model. Capturing the time-varying behavior of the parameters also leads to improved one-step density forecasts. Finally, it is shown that the forecasting performance of the estimated models can be further improved using local smoothing to forecast the parameter variations....

  9. Wealth Transfers Among Large Customers from Implementing Real-Time Retail Electricity Pricing

    OpenAIRE

    Borenstein, Severin

    2007-01-01

    Adoption of real-time electricity pricing — retail prices that vary hourly to reflect changing wholesale prices — removes existing cross-subsidies to those customers that consume disproportionately more when wholesale prices are highest. If their losses are substantial, these customers are likely to oppose RTP initiatives unless there is a supplemental program to offset their loss. Using data on a sample of 1142 large industrial and commercial customers in northern California, I show that RTP...

  10. Potential of brown algae for sustainable electricity production through anaerobic digestion

    International Nuclear Information System (INIS)

    Fasahati, Peyman; Saffron, Christopher M.; Woo, Hee Chul; Liu, J. Jay

    2017-01-01

    Highlights: • Electricity production through anaerobic digestion of brown algae was assessed. • Breakeven electricity selling price of 18.81 ¢/kWh was calculated. • AD unit has highest energy consumption of 14% of generated electricity. • Seaweed cost has largest cost contribution of 11.95 ¢/kWh to the calculated BESP. • Impact of economic and process parameters on BESP was assessed. - Abstract: This paper assesses the economics of heat and power production from the anaerobic digestion (AD) of brown algae (Laminaria japonica) at a plant scale of 400,000 dry tons/year. The conversion process was simulated in Aspen Plus v.8.6 to obtain rigorous heat and material balance for energy assessments and the development of a techno-economic model. The breakeven electricity selling price (BESP) was found to be 18.81 ¢/kWh assuming 30 years of plant life and a 10% internal rate of return. The results show that the AD unit has the highest energy demand in the entire process and consumes approximately 14% of all electricity produced. In addition, the seaweed cost of 11.95 ¢/kWh is the largest cost component that contributes to the calculated BESP, which means that a reduction in the cost of seaweed cultivation can significantly decrease the electricity production cost. A sensitivity analysis was performed on the economic and process parameters in order to assess the impact of possible variations and uncertainties in these parameters. Results showed that solids loading, anaerobic digestion yield, and time, respectively, have the highest impact on BESP.

  11. Continuous time modelling with individually varying time intervals for oscillating and non-oscillating processes.

    Science.gov (United States)

    Voelkle, Manuel C; Oud, Johan H L

    2013-02-01

    When designing longitudinal studies, researchers often aim at equal intervals. In practice, however, this goal is hardly ever met, with different time intervals between assessment waves and different time intervals between individuals being more the rule than the exception. One of the reasons for the introduction of continuous time models by means of structural equation modelling has been to deal with irregularly spaced assessment waves (e.g., Oud & Delsing, 2010). In the present paper we extend the approach to individually varying time intervals for oscillating and non-oscillating processes. In addition, we show not only that equal intervals are unnecessary but also that it can be advantageous to use unequal sampling intervals, in particular when the sampling rate is low. Two examples are provided to support our arguments. In the first example we compare a continuous time model of a bivariate coupled process with varying time intervals to a standard discrete time model to illustrate the importance of accounting for the exact time intervals. In the second example the effect of different sampling intervals on estimating a damped linear oscillator is investigated by means of a Monte Carlo simulation. We conclude that it is important to account for individually varying time intervals, and encourage researchers to conceive of longitudinal studies with different time intervals within and between individuals as an opportunity rather than a problem. © 2012 The British Psychological Society.

  12. Decentralized electricity production. v. 1 and 2

    International Nuclear Information System (INIS)

    1991-01-01

    The first part of the symposium is concerned with market analysis, case studies and prospectives for the decentralized production of electricity in France: cogeneration, heat networks, municipal waste incineration, etc. Financing systems and microeconomical analysis are presented. The second part is devoted to macroeconomical outlooks (France and Europe mainly) on decentralized electricity production (cogeneration, small-scale hydroelectric power plants), to other countries experience (PV systems connected to the grid, cogeneration, etc.) and to price contracts and regulations

  13. Lyapunov Functions to Caputo Fractional Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Ravi Agarwal

    2018-05-01

    Full Text Available One of the main properties of solutions of nonlinear Caputo fractional neural networks is stability and often the direct Lyapunov method is used to study stability properties (usually these Lyapunov functions do not depend on the time variable. In connection with the Lyapunov fractional method we present a brief overview of the most popular fractional order derivatives of Lyapunov functions among Caputo fractional delay differential equations. These derivatives are applied to various types of neural networks with variable coefficients and time-varying delays. We show that quadratic Lyapunov functions and their Caputo fractional derivatives are not applicable in some cases when one studies stability properties. Some sufficient conditions for stability of equilibrium of nonlinear Caputo fractional neural networks with time dependent transmission delays, time varying self-regulating parameters of all units and time varying functions of the connection between two neurons in the network are obtained. The cases of time varying Lipschitz coefficients as well as nonLipschitz activation functions are studied. We illustrate our theory on particular nonlinear Caputo fractional neural networks.

  14. The necessity for a time local dimension in systems with time-varying attractors

    DEFF Research Database (Denmark)

    Særmark, Knud H; Ashkenazy, Y; Levitan, J

    1997-01-01

    We show that a simple non-linear system for ordinary differential equations may possess a time-varying attractor dimension. This indicates that it is infeasible to characterize EEG and MEG time series with a single time global dimension. We suggest another measure for the description of non...

  15. Managing price risk in emerging electricity markets : OTC products and applications

    International Nuclear Information System (INIS)

    Weiss, P.

    1998-01-01

    The evolution of power markets in the United States from traditional cost based rates to mature markets, characterized by significant specialization, high volume financial market and multiple futures/indices, is described. The meaning and characteristic features of the commodity market in electricity, OTC/futures products for the electricity markets, physical delivery vs. financial settlement, models for producer trading positions and consumer trading positions, long producer position, long spread option position, short consumer position, and long producer time spread position were explained

  16. Multiscale response of ionic systems to a spatially varying electric field

    Directory of Open Access Journals (Sweden)

    Jesper Schmidt Hansen

    2017-05-01

    Full Text Available In this paper the response of ionic systems subjected to a spatially varying electric field is studied. Following the Nernst-Planck equation, two forces driving the mass flux are present, namely, the concentration gradient and the electric potential gradient. The mass flux due to the concentration gradient is modelled through Fick's law, and a new constitutive relation for the mass flux due to the potential gradient is proposed. In the regime of low screening the response function due to the potential gradient is closely related to the ionic conductivity. In the large screening regime, on the other hand, the response function is governed by the charge-charge structure. Molecular dynamics simulations are conducted and the two wave vector dependent response functions are evaluated for models of a molten salt and an ionic liquid. In the low screening regime the response functions show same wave vector dependency, indicating that it is the same underlying physical processes that govern the response. In the screening regime the wave vector dependency is very different and, thus, the overall response is determined by different processes. This is in agreement with the observed failure of the Nernst-Einstein relation.

  17. Products cooked in preheated versus non-preheated ovens. Baking times, calculated energy consumption, and product quality compared.

    Science.gov (United States)

    Odland, D; Davis, C

    1982-08-01

    Plain muffins, yellow cake, baked custard, apple pie, tuna casserole, frozen tuna casserole, cheese soufflé, and meat loaf were baked in preheated and non-preheated standard gas, continuous-clean gas, standard electric, and self-cleaning electric ovens. Products generally required 5 min. or less extra baking time when cooked in non-preheated rather than in preheated ovens. The variability in baking times often was less between preheated and non-preheated ovens than among oven types. Calculated energy consumption values showed that usually less energy was required to bake products in non-preheated than in preheated ovens; savings averaged about 10 percent. Few significant differences were found in physical measurements or eating quality either between preheated and non-preheated ovens or among oven types. Overall, for the products tested, findings confirmed that preheating the oven is not essential for good product quality and, therefore, is an unnecessary use of energy.

  18. Statistical analysis of the electric energy production from photovoltaic conversion using mobile and fixed constructions

    Science.gov (United States)

    Bugała, Artur; Bednarek, Karol; Kasprzyk, Leszek; Tomczewski, Andrzej

    2017-10-01

    The paper presents the most representative - from the three-year measurement time period - characteristics of daily and monthly electricity production from a photovoltaic conversion using modules installed in a fixed and 2-axis tracking construction. Results are presented for selected summer, autumn, spring and winter days. Analyzed measuring stand is located on the roof of the Faculty of Electrical Engineering Poznan University of Technology building. The basic parameters of the statistical analysis like mean value, standard deviation, skewness, kurtosis, median, range, or coefficient of variation were used. It was found that the asymmetry factor can be useful in the analysis of the daily electricity production from a photovoltaic conversion. In order to determine the repeatability of monthly electricity production, occurring between the summer, and summer and winter months, a non-parametric Mann-Whitney U test was used as a statistical solution. In order to analyze the repeatability of daily peak hours, describing the largest value of the hourly electricity production, a non-parametric Kruskal-Wallis test was applied as an extension of the Mann-Whitney U test. Based on the analysis of the electric energy distribution from a prepared monitoring system it was found that traditional forecasting methods of the electricity production from a photovoltaic conversion, like multiple regression models, should not be the preferred methods of the analysis.

  19. Electrical stimulation in white oyster mushroom (Pleurotus florida) production

    Science.gov (United States)

    Roshita, I.; Nurfazira, K. M. P.; Fern, C. Shi; Ain, M. S. Nur

    2017-09-01

    White oyster mushroom (Pleurotus florida) is an edible mushroom that gained popularity due to its nutritional values, low production cost and ease of cultivation. There are several research reported on the mushroom fruiting bodies which were actively developed when applying electrical shock treatment. This study was aimed to investigate the effects of different electrical voltages on the growth and yield of white oyster mushroom (Pleurotus florida). Five different electrical voltages had been applied during spawning period which were 6V, 9V, 12V, 15V and mushroom bags without any treatment served as control. Treatment at 6V showed the highest rate for mycelium growth while 15V took the shortest time for fruiting body formation. However, no significant different (P>0.05) among all the treatments was observed for the time taken for the mycelium to fill-up the bag and pinhead emergence. The total fresh weight and percentage of biological efficiency for treatment at 9V showed higher values compared to control. Treatment at 9V also showed the largest pileus diameter and the most firm in the pileus texture. Meanwhile, treatment at 6V showed the highest a* value (redness). In addition, different electrical voltage treatments applied did not show any significant effect on substrate utilization efficiency, colour L* and b* values. In conclusion, among all the electrical treatments applied, 9V could be considered as the best treatment to enhance the yield of white oyster mushroom.

  20. Analysis of relationships between hourly electricity price and load in deregulated real-time power markets

    International Nuclear Information System (INIS)

    Lo, K.L.; Wu, Y.K.

    2004-01-01

    Risk management in the electric power industry involves measuring the risk for all instruments owned by a company. The value of many of these instruments depends directly on electricity prices. In theory, the wholesale price in a real-time market should reflect the short-run marginal cost. However, most markets are not perfectly competitive, therefore by understanding the degree of correlation between price and physical drivers, electric traders and consumers can manage their risk more effectively and efficiently. Market data from two power-pool architectures, both pre-2003 ISO-NE and Australia's NEM, have been studied. The dynamic character of electricity price is mean-reverting, and consists of intra-day and weekly variations, seasonal fluctuations, and instant jumps. Parts of them are affected by load demands. Hourly signals on both price and load are divided into deterministic and random components with a discrete Fourier transform algorithm. Next, the real-time price-load relationship for periodic and random signals is examined. In addition, time-varying volatility models are constructed on random price and random load with the GARCH model, and the correlation between them analysed. Volatility plays a critical role on evaluating option pricing and risk management. (author)

  1. Surplus electricity production in sugarcane mills using residual bagasse and straw as fuel

    International Nuclear Information System (INIS)

    Alves, Moises; Ponce, Gustavo H.S.F.; Silva, Maria Aparecida; Ensinas, Adriano V.

    2015-01-01

    The cogeneration system is one of the most important parts of sugarcane mills which use the bagasse as fuel. In the recent years, modern equipments and energy efficiency measures made possible to the sugarcane industry, the production of surplus electricity which become, besides the sugar and ethanol, a third product from the same renewable source, the sugarcane. This work analyses the surplus electric power systems for three different schemes of cogeneration system in the sugarcane industry through the simulator Thermoflow"®. The analysis is made considering both the available bagasse and sugarcane straw recovery as fuel in three different scenarios for the industrial process energy requirements. The results show that the CEST (Condensing Extraction Steam Turbine) system can have a surplus of electricity of up to four times higher than the BPST (Backpressure Steam Turbine) system. The system CEST can have an increase in surplus power above 23% and 102% for the rate of 10% and 50% of cane straw recovery in the field respectively. The BPST-C (Backpressure and Condensing Turbines) system can produce similar values of surplus electricity when compared with the system CEST, but may represent an opportunity of flexible operation of the cogeneration systems in harvest and off-seasons. - Highlights: • At least three cogeneration system options are available in sugarcane mills. • Nowadays, only steam-based cycle cogeneration systems are used in sugarcane mills. • BPST system is limited to 70 e kWh/t cane of surplus electricity production. • CEST system increases the surplus electricity up to four times than the BPST. • Operation during off-season of the BPST-C system is an advantage for this option.

  2. Flexible time-varying filter banks

    Science.gov (United States)

    Tuncer, Temel E.; Nguyen, Truong Q.

    1993-09-01

    Linear phase maximally flat FIR Butterworth filter approximations are discussed and a new filter design method is introduced. This variable cutoff filter design method uses the cosine modulated versions of a prototype filter. The design procedure is simple and different variants of this procedure can be used to obtain close to optimum linear phase filters. Using this method, flexible time-varying filter banks with good reconstruction error are introduced. These types of oversampled filter banks have small magnitude error which can be easily controlled by the appropriate choice of modulation frequency. This error can be further decreased by magnitude equalization without increasing the computational complexity considerably. Two dimensional design examples are also given.

  3. A New Time-varying Concept of Risk in a Changing Climate

    Science.gov (United States)

    Sarhadi, Ali; Ausín, María Concepción; Wiper, Michael P.

    2016-10-01

    In a changing climate arising from anthropogenic global warming, the nature of extreme climatic events is changing over time. Existing analytical stationary-based risk methods, however, assume multi-dimensional extreme climate phenomena will not significantly vary over time. To strengthen the reliability of infrastructure designs and the management of water systems in the changing environment, multidimensional stationary risk studies should be replaced with a new adaptive perspective. The results of a comparison indicate that current multi-dimensional stationary risk frameworks are no longer applicable to projecting the changing behaviour of multi-dimensional extreme climate processes. Using static stationary-based multivariate risk methods may lead to undesirable consequences in designing water system infrastructures. The static stationary concept should be replaced with a flexible multi-dimensional time-varying risk framework. The present study introduces a new multi-dimensional time-varying risk concept to be incorporated in updating infrastructure design strategies under changing environments arising from human-induced climate change. The proposed generalized time-varying risk concept can be applied for all stochastic multi-dimensional systems that are under the influence of changing environments.

  4. A New Time-varying Concept of Risk in a Changing Climate.

    Science.gov (United States)

    Sarhadi, Ali; Ausín, María Concepción; Wiper, Michael P

    2016-10-20

    In a changing climate arising from anthropogenic global warming, the nature of extreme climatic events is changing over time. Existing analytical stationary-based risk methods, however, assume multi-dimensional extreme climate phenomena will not significantly vary over time. To strengthen the reliability of infrastructure designs and the management of water systems in the changing environment, multidimensional stationary risk studies should be replaced with a new adaptive perspective. The results of a comparison indicate that current multi-dimensional stationary risk frameworks are no longer applicable to projecting the changing behaviour of multi-dimensional extreme climate processes. Using static stationary-based multivariate risk methods may lead to undesirable consequences in designing water system infrastructures. The static stationary concept should be replaced with a flexible multi-dimensional time-varying risk framework. The present study introduces a new multi-dimensional time-varying risk concept to be incorporated in updating infrastructure design strategies under changing environments arising from human-induced climate change. The proposed generalized time-varying risk concept can be applied for all stochastic multi-dimensional systems that are under the influence of changing environments.

  5. Time-Varying Networks of Inter-Ictal Discharging Reveal Epileptogenic Zone.

    Science.gov (United States)

    Zhang, Luyan; Liang, Yi; Li, Fali; Sun, Hongbin; Peng, Wenjing; Du, Peishan; Si, Yajing; Song, Limeng; Yu, Liang; Xu, Peng

    2017-01-01

    The neuronal synchronous discharging may cause an epileptic seizure. Currently, most of the studies conducted to investigate the mechanism of epilepsy are based on EEGs or functional magnetic resonance imaging (fMRI) recorded during the ictal discharging or the resting-state, and few studies have probed into the dynamic patterns during the inter-ictal discharging that are much easier to record in clinical applications. Here, we propose a time-varying network analysis based on adaptive directed transfer function to uncover the dynamic brain network patterns during the inter-ictal discharging. In addition, an algorithm based on the time-varying outflow of information derived from the network analysis is developed to detect the epileptogenic zone. The analysis performed revealed the time-varying network patterns during different stages of inter-ictal discharging; the epileptogenic zone was activated prior to the discharge onset then worked as the source to propagate the activity to other brain regions. Consistence between the epileptogenic zones detected by our proposed approach and the actual epileptogenic zones proved that time-varying network analysis could not only reveal the underlying neural mechanism of epilepsy, but also function as a useful tool in detecting the epileptogenic zone based on the EEGs in the inter-ictal discharging.

  6. The Study for Shortening the Process Time at Soy Food Production by using the Pulsed Electric Field

    Science.gov (United States)

    Saito, Tsukasa; Jinushi, Makoto; Minamitani, Yasushi

    We investigated method to osmose water and seasoner to dried soybeans fast by pulsed electric field, in order to make soybeans a processed food fast. By applying the pulsed electric field to the dried soybeans in water, osmosis time of water to the soybean became approximately half. Then the emission of the discharge was observed on dried soybean. The color of coffee permeated more into the soybean treated than no-treated by the pulsed electric field.

  7. Frequency variations of gravity waves interacting with a time-varying tide

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.M.; Zhang, S.D.; Yi, F.; Huang, K.M.; Gan, Q.; Gong, Y. [Wuhan Univ., Hubei (China). School of Electronic Information; Ministry of Education, Wuhan, Hubei (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan, Hubei (China); Zhang, Y.H. [Nanjing Univ. of Information Science and Technology (China). College of Hydrometeorolgy

    2013-11-01

    Using a nonlinear, 2-D time-dependent numerical model, we simulate the propagation of gravity waves (GWs) in a time-varying tide. Our simulations show that when aGW packet propagates in a time-varying tidal-wind environment, not only its intrinsic frequency but also its ground-based frequency would change significantly. The tidal horizontal-wind acceleration dominates the GW frequency variation. Positive (negative) accelerations induce frequency increases (decreases) with time. More interestingly, tidal-wind acceleration near the critical layers always causes the GW frequency to increase, which may partially explain the observations that high-frequency GW components are more dominant in the middle and upper atmosphere than in the lower atmosphere. The combination of the increased ground-based frequency of propagating GWs in a time-varying tidal-wind field and the transient nature of the critical layer induced by a time-varying tidal zonal wind creates favorable conditions for GWs to penetrate their originally expected critical layers. Consequently, GWs have an impact on the background atmosphere at much higher altitudes than expected, which indicates that the dynamical effects of tidal-GW interactions are more complicated than usually taken into account by GW parameterizations in global models.

  8. 78 FR 20176 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

    Science.gov (United States)

    2013-04-03

    ..., Refined Coal Production, and Indian Coal Production, and Publication of Inflation Adjustment Factors and... renewable electricity production, refined coal production, and Indian coal production under section 45... resources, and to 2013 sales of refined coal and Indian coal produced in the United States or a possession...

  9. 77 FR 21835 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

    Science.gov (United States)

    2012-04-11

    ..., Refined Coal Production, and Indian Coal Production, and Publication of Inflation Adjustment Factors and... electricity production, refined coal production, and Indian coal production under section 45. DATES: The 2012... sales of refined coal and Indian coal produced in the United States or a possession thereof. Inflation...

  10. Computing Conditional VaR using Time-varying CopulasComputing Conditional VaR using Time-varying Copulas

    Directory of Open Access Journals (Sweden)

    Beatriz Vaz de Melo Mendes

    2005-12-01

    Full Text Available It is now widespread the use of Value-at-Risk (VaR as a canonical measure at risk. Most accurate VaR measures make use of some volatility model such as GARCH-type models. However, the pattern of volatility dynamic of a portfolio follows from the (univariate behavior of the risk assets, as well as from the type and strength of the associations among them. Moreover, the dependence structure among the components may change conditionally t past observations. Some papers have attempted to model this characteristic by assuming a multivariate GARCH model, or by considering the conditional correlation coefficient, or by incorporating some possibility for switches in regimes. In this paper we address this problem using time-varying copulas. Our modeling strategy allows for the margins to follow some FIGARCH type model while the copula dependence structure changes over time.

  11. The history of Korea electric times for four decades

    International Nuclear Information System (INIS)

    2004-11-01

    This book reports the history of Korea electric times for four decades, which is comprised of six parts, it deals with establishment of electric times and organizational systems and an editorial policy, status and pains for rebirth, open up new future, foundation of growth for the electric times, stability of organization extension of organization, establishing independent corporation, carrying out a radical reform, changing reading newspaper into seeing newspaper, ensuring internal stability, for the daily newspaper, development of contents on power industry technology, strategy for specialization, plan for campaign for patriotism, major business for four decades, today's electric times newspaper and future, and electric times years through the paper.

  12. Productivity incentives in the electricity sector

    International Nuclear Information System (INIS)

    Brunekreeft, G.

    2000-01-01

    July 19, 1999, the Netherlands Electricity Regulatory Service ('Dienst uitvoering en toezicht elektriciteitswet Dte) issued the consultation document 'Price-cap regulation in the electric power sector'. The document is strongly based on a modern, UK inspired method of regulation. The methods, as proposed in the document, will have an impact on the final electricity tariffs, and thus of great importance for the consumers and the businesses involved. In this article the most striking element in the consultation document is discussed: how to determine the X (i.e. the expected growth of the productivity) in the price-cap regulation

  13. String pair production in non homogeneous backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Bolognesi, S. [Department of Physics “E. Fermi” University of Pisa, and INFN - Sezione di Pisa,Largo Pontecorvo, 3, Ed. C, 56127 Pisa (Italy); Rabinovici, E. [Racah Institute of Physics, The Hebrew University of Jerusalem,91904 Jerusalem (Israel); Tallarita, G. [Departamento de Ciencias, Facultad de Artes Liberales,Universidad Adolfo Ibáñez, Santiago 7941169 (Chile)

    2016-04-28

    We consider string pair production in non homogeneous electric backgrounds. We study several particular configurations which can be addressed with the Euclidean world-sheet instanton technique, the analogue of the world-line instanton for particles. In the first case the string is suspended between two D-branes in flat space-time, in the second case the string lives in AdS and terminates on one D-brane (this realizes the holographic Schwinger effect). In some regions of parameter space the result is well approximated by the known analytical formulas, either the particle pair production in non-homogeneous background or the string pair production in homogeneous background. In other cases we see effects which are intrinsically stringy and related to the non-homogeneity of the background. The pair production is enhanced already for particles in time dependent electric field backgrounds. The string nature enhances this even further. For spacial varying electrical background fields the string pair production is less suppressed than the rate of particle pair production. We discuss in some detail how the critical field is affected by the non-homogeneity, for both time and space dependent electric field backgrouds. We also comment on what could be an interesting new prediction for the small field limit. The third case we consider is pair production in holographic confining backgrounds with homogeneous and non-homogeneous fields.

  14. String pair production in non homogeneous backgrounds

    International Nuclear Information System (INIS)

    Bolognesi, S.; Rabinovici, E.; Tallarita, G.

    2016-01-01

    We consider string pair production in non homogeneous electric backgrounds. We study several particular configurations which can be addressed with the Euclidean world-sheet instanton technique, the analogue of the world-line instanton for particles. In the first case the string is suspended between two D-branes in flat space-time, in the second case the string lives in AdS and terminates on one D-brane (this realizes the holographic Schwinger effect). In some regions of parameter space the result is well approximated by the known analytical formulas, either the particle pair production in non-homogeneous background or the string pair production in homogeneous background. In other cases we see effects which are intrinsically stringy and related to the non-homogeneity of the background. The pair production is enhanced already for particles in time dependent electric field backgrounds. The string nature enhances this even further. For spacial varying electrical background fields the string pair production is less suppressed than the rate of particle pair production. We discuss in some detail how the critical field is affected by the non-homogeneity, for both time and space dependent electric field backgrouds. We also comment on what could be an interesting new prediction for the small field limit. The third case we consider is pair production in holographic confining backgrounds with homogeneous and non-homogeneous fields.

  15. Electromagnetic radiation in a time-varying background medium

    NARCIS (Netherlands)

    Budko, N.V.

    2009-01-01

    Analytical solutions are presented for the electromagnetic radiation by an arbitrary pulsed source into a homogeneous time-varying background medium. In the constant-impedance case an explicit radiation formula is obtained for the synchronous permittivity and permeability described by any positive

  16. Housing Cycles in Switzerland - A Time-Varying Approach

    OpenAIRE

    Drechsel, Dirk

    2015-01-01

    In light of the strong increase of house prices in Switzerland, we analyze the effects of mortgage rate shocks, changes in the interplay between housing demand and supply and GDP growth on house prices for the time period 1981- 2014. We employ Bayesian time-varying coefficients vector autoregressions to allow different monetary and immigration regimes over time. A number of structural changes, such as regulatory changes in the aftermath of the 1990s real estate crisis, the introduction of fre...

  17. Swiss electricity production into the future

    International Nuclear Information System (INIS)

    Steinmann, Walter

    2008-01-01

    In January 2007 the Swiss Federal Office of Energy's work on energy perspectives up until 2035 were concluded and presented. The results form the basis for political debate on the future direction of Switzerland's energy and climate policies. The energy perspectives point to an increase in demand for electricity in Switzerland by 2035 of around 20% and a deficit of roughly 17 billion kWh if no extra measures are taken. This corresponds to twice the annual production of a Swiss nuclear power station. This development and the unharnessed potential in the areas of efficiency and renewable energies prompted Switzerland's Federal Council to decide on a reorientation of its energy policy in 2007. This is based on four pillars: 1. Improved energy efficiency; 2. Promotion of renewable energy; 3. Targeted extension and construction of large-scale power stations; 4. Intensification of foreign energy policy, particularly in terms of cooperation with the EU. 2008 has got off to a strong start in terms of energy policy - the CO 2 tax on fuels has been introduced and the first package of the new Energy Supply Act (StromVG) has entered into force. The new Electricity Supply Act creates the necessary conditions for a progressive opening of Switzerland's electricity market. From 2009 some 50,000 large customers with an annual electricity consumption of over 100 megawatt hours will be able to benefit from this partial opening and be free to choose their power suppliers. But all other power consumers will benefit right from the start too because their electricity suppliers will also be able to buy in their electricity from the free market and pass on any price savings to their customers. Furthermore, the Electricity Supply Act delivers a clear legal framework for cross-border trade in electricity. In actual fact the opening of the electricity market is already well advanced around Switzerland. Liberalisation also results in cost transparency: As the opening of the electricity market

  18. Time varying, multivariate volume data reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, James P [Los Alamos National Laboratory; Fout, Nathaniel [UC DAVIS; Ma, Kwan - Liu [UC DAVIS

    2010-01-01

    Large-scale supercomputing is revolutionizing the way science is conducted. A growing challenge, however, is understanding the massive quantities of data produced by large-scale simulations. The data, typically time-varying, multivariate, and volumetric, can occupy from hundreds of gigabytes to several terabytes of storage space. Transferring and processing volume data of such sizes is prohibitively expensive and resource intensive. Although it may not be possible to entirely alleviate these problems, data compression should be considered as part of a viable solution, especially when the primary means of data analysis is volume rendering. In this paper we present our study of multivariate compression, which exploits correlations among related variables, for volume rendering. Two configurations for multidimensional compression based on vector quantization are examined. We emphasize quality reconstruction and interactive rendering, which leads us to a solution using graphics hardware to perform on-the-fly decompression during rendering. In this paper we present a solution which addresses the need for data reduction in large supercomputing environments where data resulting from simulations occupies tremendous amounts of storage. Our solution employs a lossy encoding scheme to acrueve data reduction with several options in terms of rate-distortion behavior. We focus on encoding of multiple variables together, with optional compression in space and time. The compressed volumes can be rendered directly with commodity graphics cards at interactive frame rates and rendering quality similar to that of static volume renderers. Compression results using a multivariate time-varying data set indicate that encoding multiple variables results in acceptable performance in the case of spatial and temporal encoding as compared to independent compression of variables. The relative performance of spatial vs. temporal compression is data dependent, although temporal compression has the

  19. Fuel Cell Electric Vehicle Composite Data Products | Hydrogen and Fuel

    Science.gov (United States)

    Cells | NREL Vehicle Composite Data Products Fuel Cell Electric Vehicle Composite Data Products The following composite data products (CDPs) focus on current fuel cell electric vehicle evaluations Cell Operation Hour Groups CDP FCEV 39, 2/19/16 Comparison of Fuel Cell Stack Operation Hours and Miles

  20. A Tentative Application Of Morphological Filters To Time-Varying Images

    Science.gov (United States)

    Billard, D.; Poquillon, B.

    1989-03-01

    In this paper, morphological filters, which are commonly used to process either 2D or multidimensional static images, are generalized to the analysis of time-varying image sequence. The introduction of the time dimension induces then interesting prop-erties when designing such spatio-temporal morphological filters. In particular, the specification of spatio-temporal structuring ele-ments (equivalent to time-varying spatial structuring elements) can be adjusted according to the temporal variations of the image sequences to be processed : this allows to derive specific morphological transforms to perform noise filtering or moving objects discrimination on dynamic images viewed by a non-stationary sensor. First, a brief introduction to the basic principles underlying morphological filters will be given. Then, a straightforward gener-alization of these principles to time-varying images will be pro-posed. This will lead us to define spatio-temporal opening and closing and to introduce some of their possible applications to process dynamic images. At last, preliminary results obtained us-ing a natural forward looking infrared (FUR) image sequence are presented.

  1. A study on the implementation of the performance of electrical products standards

    Energy Technology Data Exchange (ETDEWEB)

    Berkowitz, M A

    1984-03-01

    The Steering Committee on Electrical Products (SCOPEP) has developed a number of performance standards for selected electrical products and product attributes, under the direction of the Canadian Standards Association. Although the development of these standards shows that a successful standards writing process is in place, the initiation and implementation has been achieved by one or more stakeholder groups spearheading the requirement for the standard. As a result, SCOPEP has been unable to achieve its full potential in its role of developing peformance standards for electrical products. A study was undertaken with the aim of developing a strategic plan for SCOPEP which would be supported by marketing and other strategies. The major elements of the strategy include: selecting those products for which the benefits of a standards program significantly outweigh the costs; agreeing on the use of a framework which rigorously evaluates the cost-benefits of developing performance standards; producing a critical mass of products through the selection process so that revenues from label fees will ultimately balance program costs and support a full time SCOPEP secretariat; aggressively marketing the standards in all sectors, using a balanced push-and-pull strategy; and developing a protagonist attitude so that standards programs implemented are credible to all SCOPEP stakeholders. Detailed cost-benefit tables are appended. 11 figs., 18 tabs.

  2. Productivity in Swedish electricity retail distribution

    International Nuclear Information System (INIS)

    Hjalmarsson, L.; Veiderpass, A.

    1992-01-01

    This paper examines productivity growth in electricity retail distribution in Sweden in a multiple output-multiple input framework. The approach used is nonparametric Data Envelopment Analysis (DEA). Productivity is measured by means of the Malmquist index. Productivity comparisons are made between different types of ownership and between different service areas. The study indicates a high rate of productivity growth, due to economics of density, when measured over a period of 17 years. The results show no significant differences in productivity growth between different types of ownership or economic organization. (20 refs., 1 fig., 4 tabs.)

  3. Projected space-time and varying speed of light

    International Nuclear Information System (INIS)

    Iovane, G.; Bellucci, S.; Benedetto, E.

    2008-01-01

    In this paper starting from El Naschie's Cantorian space-time and our model of projected Universe, we consider its properties in connection with varying speed of light. A possible way-out of the related problem is provided by the Fantappie group approach

  4. Epidemic spreading in time-varying community networks.

    Science.gov (United States)

    Ren, Guangming; Wang, Xingyuan

    2014-06-01

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold qc. The epidemic will survive when q > qc and die when q epidemic spreading in complex networks with community structure.

  5. Time-varying Concurrent Risk of Extreme Droughts and Heatwaves in California

    Science.gov (United States)

    Sarhadi, A.; Diffenbaugh, N. S.; Ausin, M. C.

    2016-12-01

    Anthropogenic global warming has changed the nature and the risk of extreme climate phenomena such as droughts and heatwaves. The concurrent of these nature-changing climatic extremes may result in intensifying undesirable consequences in terms of human health and destructive effects in water resources. The present study assesses the risk of concurrent extreme droughts and heatwaves under dynamic nonstationary conditions arising from climate change in California. For doing so, a generalized fully Bayesian time-varying multivariate risk framework is proposed evolving through time under dynamic human-induced environment. In this methodology, an extreme, Bayesian, dynamic copula (Gumbel) is developed to model the time-varying dependence structure between the two different climate extremes. The time-varying extreme marginals are previously modeled using a Generalized Extreme Value (GEV) distribution. Bayesian Markov Chain Monte Carlo (MCMC) inference is integrated to estimate parameters of the nonstationary marginals and copula using a Gibbs sampling method. Modelled marginals and copula are then used to develop a fully Bayesian, time-varying joint return period concept for the estimation of concurrent risk. Here we argue that climate change has increased the chance of concurrent droughts and heatwaves over decades in California. It is also demonstrated that a time-varying multivariate perspective should be incorporated to assess realistic concurrent risk of the extremes for water resources planning and management in a changing climate in this area. The proposed generalized methodology can be applied for other stochastic nature-changing compound climate extremes that are under the influence of climate change.

  6. Time-varying wing-twist improves aerodynamic efficiency of forward flight in butterflies.

    Science.gov (United States)

    Zheng, Lingxiao; Hedrick, Tyson L; Mittal, Rajat

    2013-01-01

    Insect wings can undergo significant chordwise (camber) as well as spanwise (twist) deformation during flapping flight but the effect of these deformations is not well understood. The shape and size of butterfly wings leads to particularly large wing deformations, making them an ideal test case for investigation of these effects. Here we use computational models derived from experiments on free-flying butterflies to understand the effect of time-varying twist and camber on the aerodynamic performance of these insects. High-speed videogrammetry is used to capture the wing kinematics, including deformation, of a Painted Lady butterfly (Vanessa cardui) in untethered, forward flight. These experimental results are then analyzed computationally using a high-fidelity, three-dimensional, unsteady Navier-Stokes flow solver. For comparison to this case, a set of non-deforming, flat-plate wing (FPW) models of wing motion are synthesized and subjected to the same analysis along with a wing model that matches the time-varying wing-twist observed for the butterfly, but has no deformation in camber. The simulations show that the observed butterfly wing (OBW) outperforms all the flat-plate wings in terms of usable force production as well as the ratio of lift to power by at least 29% and 46%, respectively. This increase in efficiency of lift production is at least three-fold greater than reported for other insects. Interestingly, we also find that the twist-only-wing (TOW) model recovers much of the performance of the OBW, demonstrating that wing-twist, and not camber is key to forward flight in these insects. The implications of this on the design of flapping wing micro-aerial vehicles are discussed.

  7. Time-varying wing-twist improves aerodynamic efficiency of forward flight in butterflies.

    Directory of Open Access Journals (Sweden)

    Lingxiao Zheng

    Full Text Available Insect wings can undergo significant chordwise (camber as well as spanwise (twist deformation during flapping flight but the effect of these deformations is not well understood. The shape and size of butterfly wings leads to particularly large wing deformations, making them an ideal test case for investigation of these effects. Here we use computational models derived from experiments on free-flying butterflies to understand the effect of time-varying twist and camber on the aerodynamic performance of these insects. High-speed videogrammetry is used to capture the wing kinematics, including deformation, of a Painted Lady butterfly (Vanessa cardui in untethered, forward flight. These experimental results are then analyzed computationally using a high-fidelity, three-dimensional, unsteady Navier-Stokes flow solver. For comparison to this case, a set of non-deforming, flat-plate wing (FPW models of wing motion are synthesized and subjected to the same analysis along with a wing model that matches the time-varying wing-twist observed for the butterfly, but has no deformation in camber. The simulations show that the observed butterfly wing (OBW outperforms all the flat-plate wings in terms of usable force production as well as the ratio of lift to power by at least 29% and 46%, respectively. This increase in efficiency of lift production is at least three-fold greater than reported for other insects. Interestingly, we also find that the twist-only-wing (TOW model recovers much of the performance of the OBW, demonstrating that wing-twist, and not camber is key to forward flight in these insects. The implications of this on the design of flapping wing micro-aerial vehicles are discussed.

  8. AN APPLICATION FOR ELECTRICAL PRODUCTION WITH SOLAR TOWER SYSTEM

    Directory of Open Access Journals (Sweden)

    Reşat SELBAŞ

    2003-02-01

    Full Text Available The requirement of electric energy rises with increasing of the population and faster improvement demands. Energy necessity generally is provided by using fossil based fuel sources. In order to supply energy requirements, today, using alternative sources became necessary because of the problems such as decreasing of available fossil fuel sources and environment pollution from this fuel. The solar energy which has a wide range of application potential is the most hopeful and unlimited energy source without environment pollution in electric energy production. In this paper, the electric production methods from solar energy are studied and the most suitable method for solar energy plant is tried to find out. The selected method, known as Solar Tower in literature is an electric production method. In this study, technical and cost analysis of an application using this method are carried out.

  9. Management of surplus electricity-production from a fluctuating renewable-energy source

    International Nuclear Information System (INIS)

    Lund, H.

    2003-01-01

    Renewable-energy sources and energy efficiency are important elements in Danish Energy Policy. The implementation of wind power and combined heat- and power-production (CHP) have already led to substantial fuel savings, and both technologies are intended for further expansion in the coming decade. Today, approximately 50% of both Danish electricity and heat demand are produced via CHP, and more than 15% of the electricity demands are produced by wind turbines. However, the electricity production from these technologies is linked to fluctuations either in wind or in heat demands rather than fluctuations in demand for electricity. Consequently, the electricity production exceeds the demand during certain periods and creates a problem of ''surplus production''. This paper discusses and analyses different national strategies for solving this problem. (author)

  10. Wood pellets, what else? Greenhouse gas parity times of European electricity from wood pellets produced in the south-eastern United States using different softwood feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Hanssen, Steef V. [Radboud Univ., Nijmegen (Netherlands). Dept. of Environmental Science, Faculty of Science; Utrecht Univ., Utrecht (The Netherlands). Copernicus Inst. of Sustainable Development, Faculty of Geosciences; Duden, Anna S. [Utrecht Univ., Utrecht (The Netherlands). Copernicus Inst. of Sustainable Development, Faculty of Geosciences; Junginger, Martin [Utrecht Univ., Utrecht (The Netherlands). Copernicus Inst. of Sustainable Development, Faculty of Geosciences; Dale, Virginia H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division, Center for BioEnergy Sustainability; van der Hilst, Floor [Utrecht Univ., Utrecht (The Netherlands). Copernicus Inst. of Sustainable Development, Faculty of Geosciences

    2016-12-29

    Several EU countries import wood pellets from the south-eastern United States. The imported wood pellets are (co-)fired in power plants with the aim of reducing overall greenhouse gas (GHG) emissions from electricity and meeting EU renewable energy targets. To assess whether GHG emissions are reduced and on what timescale, we construct the GHG balance of wood-pellet electricity. This GHG balance consists of supply chain and combustion GHG emissions, carbon sequestration during biomass growth, and avoided GHG emissions through replacing fossil electricity. We investigate wood pellets from four softwood feedstock types: small roundwood, commercial thinnings, harvest residues, and mill residues. Per feedstock, the GHG balance of wood-pellet electricity is compared against those of alternative scenarios. Alternative scenarios are combinations of alternative fates of the feedstock material, such as in-forest decomposition, or the production of paper or wood panels like oriented strand board (OSB). Alternative scenario composition depends on feedstock type and local demand for this feedstock. Results indicate that the GHG balance of wood-pellet electricity equals that of alternative scenarios within 0 to 21 years (the GHG parity time), after which wood-pellet electricity has sustained climate benefits. Parity times increase by a maximum of twelve years when varying key variables (emissions associated with paper and panels, soil carbon increase via feedstock decomposition, wood-pellet electricity supply chain emissions) within maximum plausible ranges. Using commercial thinnings, harvest residues or mill residues as feedstock leads to the shortest GHG parity times (0-6 years) and fastest GHG benefits from wood-pellet electricity. Here, we find shorter GHG parity times than previous studies, for we use a novel approach that differentiates feedstocks and considers alternative scenarios based on (combinations of) alternative feedstock fates, rather than on alternative land

  11. Discrete-Time Sliding-Mode Control of Uncertain Systems with Time-Varying Delays via Descriptor Approach

    Directory of Open Access Journals (Sweden)

    Maode Yan

    2008-01-01

    Full Text Available This paper considers the problem of robust discrete-time sliding-mode control (DT-SMC design for a class of uncertain linear systems with time-varying delays. By applying a descriptor model transformation and Moon's inequality for bounding cross terms, a delay-dependent sufficient condition for the existence of stable sliding surface is given in terms of linear matrix inequalities (LMIs. Based on this existence condition, the synthesized sliding mode controller can guarantee the sliding-mode reaching condition of the specified discrete-time sliding surface for all admissible uncertainties and time-varying delays. An illustrative example verifies the effectiveness of the proposed method.

  12. Natural gas and production of electricity

    International Nuclear Information System (INIS)

    Defago, E.

    2005-01-01

    The forthcoming power supply shortage in Switzerland due to increasing consumption is discussed, as are the possibilities for securing the future supply. Today, the main sources are hydroelectric (roughly 55 %) and nuclear (40 %) power. The share of electricity from natural gas amounts to only 1.4 %. The possibilities of further economic production of hydropower are practically exhausted. Therefore, further electric power has to be either imported or generated from other energy sources (renewable, nuclear, fossil) in the country itself. Due to the low acceptance of nuclear energy and the limited potential of renewable energy sources, natural gas is the most favoured candidate. The advantages of distributed production in cogeneration plants are compared with the centralized production in larger plants using combined cycles. Finally, a project currently under development is presented: an existing thermal power plant fueled with heavy fuel oil shall be refurbished and converted to natural gas as the new fuel

  13. An overall assessment of the responsiveness of households to time-of-use electricity rates: The Ontario experiment

    International Nuclear Information System (INIS)

    Mountain, D.C.

    1993-01-01

    From 1982 to 1988, Ontario Hydro conducted an experiment in residential time-of-use pricing. A selection of households was offered one of 14 time-of-use treatments and each was monitored for electricity consumption on a 15-minute basis. The different rate structures were designed to reflect time variations in future system and distribution costs, both at the bulk and at the municipal level. Results were analyzed in terms of econometric models which to date have yielded information on the experimental changes in residential load shapes resulting from the time-of-use rates. The results are presented in the form of economic elasticities, percentage impacts, load changes at the household level, and simulated province-wide load changes. Also included are comparisons of results with other jurisdictions, comparisons of impacts on households with and without electric heating and with and without air conditioning, and comparisons across rate treatments with varying lengths of peak periods and relative prices. A fundamental conclusion is that time-of-use electricity rates do make a difference in residential load shapes. 17 refs., 8 tabs

  14. Time-varying spatial data integration and visualization: 4 Dimensions Environmental Observations Platform (4-DEOS)

    Science.gov (United States)

    Paciello, Rossana; Coviello, Irina; Filizzola, Carolina; Genzano, Nicola; Lisi, Mariano; Mazzeo, Giuseppe; Pergola, Nicola; Sileo, Giancanio; Tramutoli, Valerio

    2014-05-01

    In environmental studies the integration of heterogeneous and time-varying data, is a very common requirement for investigating and possibly visualize correlations among physical parameters underlying the dynamics of complex phenomena. Datasets used in such kind of applications has often different spatial and temporal resolutions. In some case superimposition of asynchronous layers is required. Traditionally the platforms used to perform spatio-temporal visual data analyses allow to overlay spatial data, managing the time using 'snapshot' data model, each stack of layers being labeled with different time. But this kind of architecture does not incorporate the temporal indexing neither the third spatial dimension which is usually given as an independent additional layer. Conversely, the full representation of a generic environmental parameter P(x,y,z,t) in the 4D space-time domain could allow to handle asynchronous datasets as well as less traditional data-products (e.g. vertical sections, punctual time-series, etc.) . In this paper we present the 4 Dimensions Environmental Observation Platform (4-DEOS), a system based on a web services architecture Client-Broker-Server. This platform is a new open source solution for both a timely access and an easy integration and visualization of heterogeneous (maps, vertical profiles or sections, punctual time series, etc.) asynchronous, geospatial products. The innovative aspect of the 4-DEOS system is that users can analyze data/products individually moving through time, having also the possibility to stop the display of some data/products and focus on other parameters for better studying their temporal evolution. This platform gives the opportunity to choose between two distinct display modes for time interval or for single instant. Users can choose to visualize data/products in two ways: i) showing each parameter in a dedicated window or ii) visualize all parameters overlapped in a single window. A sliding time bar, allows

  15. Synchronization of uncertain time-varying network based on sliding mode control technique

    Science.gov (United States)

    Lü, Ling; Li, Chengren; Bai, Suyuan; Li, Gang; Rong, Tingting; Gao, Yan; Yan, Zhe

    2017-09-01

    We research synchronization of uncertain time-varying network based on sliding mode control technique. The sliding mode control technique is first modified so that it can be applied to network synchronization. Further, by choosing the appropriate sliding surface, the identification law of uncertain parameter, the adaptive law of the time-varying coupling matrix element and the control input of network are designed, it is sure that the uncertain time-varying network can synchronize effectively the synchronization target. At last, we perform some numerical simulations to demonstrate the effectiveness of the proposed results.

  16. Conceptual Modeling of Time-Varying Information

    DEFF Research Database (Denmark)

    Gregersen, Heidi; Jensen, Christian S.

    2004-01-01

    A wide range of database applications manage information that varies over time. Many of the underlying database schemas of these were designed using the Entity-Relationship (ER) model. In the research community as well as in industry, it is common knowledge that the temporal aspects of the mini......-world are important, but difficult to capture using the ER model. Several enhancements to the ER model have been proposed in an attempt to support the modeling of temporal aspects of information. Common to the existing temporally extended ER models, few or no specific requirements to the models were given...

  17. Electricity production from microbial fuel cell by using yeast

    International Nuclear Information System (INIS)

    Vorasingha, A.; Souvakon, C.; Boonchom, K.

    2006-01-01

    The continuous search for methods to generate electricity from renewable sources such as water, solar energy, wind, nuclear or chemicals was discussed with particular focus on attaining the full power of the microbial fuel cell (MFC). Under ideal environmental conditions, the only byproducts of a biofuel cell would be water and carbon dioxide (CO 2 ). The production of energy from renewables such as biomass is important for sustainable development and reducing global emissions of CO 2 . Hydrogen can also be an important component of an energy infrastructure that reduces CO 2 emissions if the hydrogen is produced from renewable sources and used in fuel cells. Hydrogen gas can be biologically produced at high concentration from the fermentation of high sugar substrates such as glucose and sucrose. Some of the issues of MFC design were addressed, including the use of cheap substrates to derive microbial electricity. In the MFC, yeast donates electrons to a chemical electron mediator, which in turn transfers the electrons to an electrode, producing electricity. Experimental results showed that glucose yielded the highest peak voltage, but a semi-processed sugar and molasses were similar to glucose in the electricity production pattern. It was noted that this technology is only at the research stages, and more research is needed before household microbial fuel cells can be made available for producing power for prolonged periods of time. Future research efforts will focus on increasing the efficiency, finding alternatives to hazardous electron mediators and finding new microbes. 12 refs., 6 figs

  18. Environmental aspects of decentralized electricity production

    International Nuclear Information System (INIS)

    Henry, J.P.

    1991-01-01

    Renewable energy sources are the focus of considerable interest because they do not place future generations at risk; the development of cogeneration has been favorably received on the whole because it uses energy that would otherwise be lost. Difficulties are sometimes encountered in the development of small-scale hydroelectric facilities (older facilities negative aspects, over production impression in France, etc.). Environmental protection regulations do not distinguish between centralized and decentralized electricity production, but between large and small production facilities

  19. Time varying determinants of bond flows to emerging markets

    Directory of Open Access Journals (Sweden)

    Yasemin Erduman

    2016-06-01

    Full Text Available This paper investigates the time varying nature of the determinants of bond flows with a focus on the global financial crisis period. We estimate a time varying regression model using Bayesian estimation methods, where the posterior distribution is approximated by Gibbs sampling algorithm. Our findings suggest that the interest rate differential is the most significant pull factor of portfolio bond flows, along with the inflation rate, while the growth rate does not play a significant role. Among the push factors, global liquidity is the most important driver of bond flows. It matters the most, when unconventional monetary easing policies were first announced; and its importance as a determinant of portfolio bond flows decreases over time, starting with the Eurozone crisis, and diminishes with the tapering talk. Global risk appetite and the risk perception towards the emerging countries also have relatively small and stable significant effects on bond flows.

  20. Economic competitiveness of electricity production means inside smart grids: application to nuclear energy and variable renewable energies

    International Nuclear Information System (INIS)

    Keppler, J.H.; Baritaud, M.; Berthelemy, M.

    2017-01-01

    For a long time the comparison of the production costs of electricity from various primary sources were made on the basis of levelised costs of electricity (LCOE). LCOE is in fact the cost of the technology used for the production. In recent years solar and wind energies have seen their LCOE drop sharply (-60 % for solar power in 5 years) while nuclear energy's LCOE is now stabilized. In order to assess the cost of renewable energies, LCOE are not sufficient because variable energies like solar or wind power require other means of production to compensate their variability. Another point is that renewable energies are decentralized and as a consequence require investments to develop the power distribution system. This analysis presents a new methodology to compare the costs of electricity production means. This methodology takes into account LCOE and a system cost that represents the cost of the effects of the technology on the rest of the electricity production system. (A.C.)

  1. What kind of liberalization of electricity production in Italy?

    International Nuclear Information System (INIS)

    De Paoli, L.

    1993-01-01

    Critical analysis of the implications of the deregulation of electric power generation and distribution in Italy evidences severe problems regarding the definition of future regional and national regulatory frameworks and constraints regarding future expansion strategies of independent producers. In particular, local administrative bodies will faced with the difficult task of having to develop optimum pricing strategies so as to encourage production and healthy competition amongst private firms while at the same time safeguarding the rights and wishes of consumers

  2. Global stabilization of linear continuous time-varying systems with bounded controls

    International Nuclear Information System (INIS)

    Phat, V.N.

    2004-08-01

    This paper deals with the problem of global stabilization of a class of linear continuous time-varying systems with bounded controls. Based on the controllability of the nominal system, a sufficient condition for the global stabilizability is proposed without solving any Riccati differential equation. Moreover, we give sufficient conditions for the robust stabilizability of perturbation/uncertain linear time-varying systems with bounded controls. (author)

  3. An integrative time-varying frequency detection and channel sounding method for dynamic plasma sheath

    Science.gov (United States)

    Shi, Lei; Yao, Bo; Zhao, Lei; Liu, Xiaotong; Yang, Min; Liu, Yanming

    2018-01-01

    The plasma sheath-surrounded hypersonic vehicle is a dynamic and time-varying medium and it is almost impossible to calculate time-varying physical parameters directly. The in-fight detection of the time-varying degree is important to understand the dynamic nature of the physical parameters and their effect on re-entry communication. In this paper, a constant envelope zero autocorrelation (CAZAC) sequence based on time-varying frequency detection and channel sounding method is proposed to detect the plasma sheath electronic density time-varying property and wireless channel characteristic. The proposed method utilizes the CAZAC sequence, which has excellent autocorrelation and spread gain characteristics, to realize dynamic time-varying detection/channel sounding under low signal-to-noise ratio in the plasma sheath environment. Theoretical simulation under a typical time-varying radio channel shows that the proposed method is capable of detecting time-variation frequency up to 200 kHz and can trace the channel amplitude and phase in the time domain well under -10 dB. Experimental results conducted in the RF modulation discharge plasma device verified the time variation detection ability in practical dynamic plasma sheath. Meanwhile, nonlinear phenomenon of dynamic plasma sheath on communication signal is observed thorough channel sounding result.

  4. 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.

  5. Management of surplus electricity-production from a fluctuating renewable-energy source

    DEFF Research Database (Denmark)

    Lund, Henrik; Münster, E.

    2003-01-01

    The paper discusses and analyses different national strategies for solving a surplus production problem in Denmark, caused by electricity production from turbines and CHP.......The paper discusses and analyses different national strategies for solving a surplus production problem in Denmark, caused by electricity production from turbines and CHP....

  6. Loss Aversion and Time-Differentiated Electricity Pricing

    Energy Technology Data Exchange (ETDEWEB)

    Spurlock, C. Anna [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-06-01

    I develop a model of loss aversion over electricity expenditure, from which I derive testable predictions for household electricity consumption while on combination time-of-use (TOU) and critical peak pricing (CPP) plans. Testing these predictions results in evidence consistent with loss aversion: (1) spillover effects - positive expenditure shocks resulted in significantly more peak consumption reduction for several weeks thereafter; and (2) clustering - disproportionate probability of consuming such that expenditure would be equal between the TOUCPP or standard flat-rate pricing structures. This behavior is inconsistent with a purely neoclassical utility model, and has important implications for application of time-differentiated electricity pricing.

  7. Finite-time and fixed-time synchronization analysis of inertial memristive neural networks with time-varying delays.

    Science.gov (United States)

    Wei, Ruoyu; Cao, Jinde; Alsaedi, Ahmed

    2018-02-01

    This paper investigates the finite-time synchronization and fixed-time synchronization problems of inertial memristive neural networks with time-varying delays. By utilizing the Filippov discontinuous theory and Lyapunov stability theory, several sufficient conditions are derived to ensure finite-time synchronization of inertial memristive neural networks. Then, for the purpose of making the setting time independent of initial condition, we consider the fixed-time synchronization. A novel criterion guaranteeing the fixed-time synchronization of inertial memristive neural networks is derived. Finally, three examples are provided to demonstrate the effectiveness of our main results.

  8. THE MAIN DIRECTIONS OF IMPROVING THE EFFICIENCY OF PRODUCTION, TRANSMISSION AND DISTRIBUTION OF ELECTRICAL ENERGY

    Directory of Open Access Journals (Sweden)

    I. V. Zhezhelenko

    2018-01-01

    Full Text Available The main directions of increase of efficiency of production, transmission and distribution of electric energy have been formulated. The relation between the values of electricity losses during transmission via power grids of different countries and the level of the economies of these countries characterized by the value of gross domestic product at purchasing power parity per capita has been established. In the countries with a gross domestic product at purchasing power parity per capita less than 20 thousand US dollars electricity losses during its transmission via power grids are 1.5–2.5 times more than the ones transmitted via power grids of the industrialized countries where the specified purchasing power parity is in the range of 30.4–54.5 thousand US dollars. In the countries with more developed economies the technical culture of production, transmission and distribution of electricity is higher; the modern control systems of operation modes of electrical networks are used as well as of monitoring and accounting of electricity; also there are solvent and disciplined consumers in such countries as well as clear regulatory framework and tariff regulation system. However, the process of transmission and distribution of electricity is effective if not only low relative losses take place, but the normal (contractual requirements for carrying capacity, quality and reliability of electricity supply are provided. The possibility of analytical determination of the optimum value of reserve capacity of power plants providing the required level of reliability of the power system has been considered.

  9. Stratum Electricity Markets: Toward Multi-temporal Distributed Risk Management for Sustainable Electricity Provision

    Science.gov (United States)

    Wu, Zhiyong (Richard)

    values for the same amount of energy during different time and at different location can vary dramatically. Moreover, for the same hour, the values for the same amount of power at base load level or at peak load level are different due to the different generation technologies and other non-convex constraints like unit commitment. The multiple market products at zonal/nodal levels with different time horizon and time of use categories are designed to reflect more realistic demand and supply conditions at various temporal and spatial granularities. Detailed market rules, rights and regulations (3Rs) concerning the sub-markets interactions, product hierarchy and financial settlements are also examined.

  10. Fiscal planning of private electricity production projects

    International Nuclear Information System (INIS)

    Gauthier, R.

    2002-01-01

    Various fiscal considerations frequently encountered in the context of the planning of private electricity production projects were described. Two major themes were discussed: 1) the different jurisdictional vehicles that can be used during the planning of private electricity production projects and the associated fiscal considerations, and 2) the two main fiscal incentives of the Income Tax Act (Canada) which could impact on the financing and operation costs of such a project, namely the accelerated amortization and the possibility of deducting the costs associated to renewable energies and energy savings in Canada. This was a general presentation that did not go into specific details and did not represent a legal opinion. refs

  11. Modelling of coupled heat and electric field distribution during ohmic heating of solid foods with varying sizes

    DEFF Research Database (Denmark)

    Feyissa, Aberham Hailu; Bøknæs, Niels; Nielsen, P.L.

    factors leading to variations and uncertainties in prediction of the right process parameters. The current work is focused on modelling of OH of solid food pieces of varying sizes cooked in one batch. A 3D mathematical model of coupled heat transfer and electric field during OH of shrimps has been...

  12. Vector-field statistics for the analysis of time varying clinical gait data.

    Science.gov (United States)

    Donnelly, C J; Alexander, C; Pataky, T C; Stannage, K; Reid, S; Robinson, M A

    2017-01-01

    In clinical settings, the time varying analysis of gait data relies heavily on the experience of the individual(s) assessing these biological signals. Though three dimensional kinematics are recognised as time varying waveforms (1D), exploratory statistical analysis of these data are commonly carried out with multiple discrete or 0D dependent variables. In the absence of an a priori 0D hypothesis, clinicians are at risk of making type I and II errors in their analyis of time varying gait signatures in the event statistics are used in concert with prefered subjective clinical assesment methods. The aim of this communication was to determine if vector field waveform statistics were capable of providing quantitative corroboration to practically significant differences in time varying gait signatures as determined by two clinically trained gait experts. The case study was a left hemiplegic Cerebral Palsy (GMFCS I) gait patient following a botulinum toxin (BoNT-A) injection to their left gastrocnemius muscle. When comparing subjective clinical gait assessments between two testers, they were in agreement with each other for 61% of the joint degrees of freedom and phases of motion analysed. For tester 1 and tester 2, they were in agreement with the vector-field analysis for 78% and 53% of the kinematic variables analysed. When the subjective analyses of tester 1 and tester 2 were pooled together and then compared to the vector-field analysis, they were in agreement for 83% of the time varying kinematic variables analysed. These outcomes demonstrate that in principle, vector-field statistics corroborates with what a team of clinical gait experts would classify as practically meaningful pre- versus post time varying kinematic differences. The potential for vector-field statistics to be used as a useful clinical tool for the objective analysis of time varying clinical gait data is established. Future research is recommended to assess the usefulness of vector-field analyses

  13. Time-varying economic dominance in financial markets: A bistable dynamics approach

    Science.gov (United States)

    He, Xue-Zhong; Li, Kai; Wang, Chuncheng

    2018-05-01

    By developing a continuous-time heterogeneous agent financial market model of multi-assets traded by fundamental and momentum investors, we provide a potential mechanism for generating time-varying dominance between fundamental and non-fundamental in financial markets. We show that investment constraints lead to the coexistence of a locally stable fundamental steady state and a locally stable limit cycle around the fundamental, characterized by a Bautin bifurcation. This provides a mechanism for market prices to switch stochastically between the two persistent but very different market states, leading to the coexistence and time-varying dominance of seemingly controversial efficient market and price momentum over different time periods. The model also generates other financial market stylized facts, such as spillover effects in both momentum and volatility, market booms, crashes, and correlation reduction due to cross-sectional momentum trading. Empirical evidence based on the U.S. market supports the main findings. The mechanism developed in this paper can be used to characterize time-varying economic dominance in economics and finance in general.

  14. Optimal critic learning for robot control in time-varying environments.

    Science.gov (United States)

    Wang, Chen; Li, Yanan; Ge, Shuzhi Sam; Lee, Tong Heng

    2015-10-01

    In this paper, optimal critic learning is developed for robot control in a time-varying environment. The unknown environment is described as a linear system with time-varying parameters, and impedance control is employed for the interaction control. Desired impedance parameters are obtained in the sense of an optimal realization of the composite of trajectory tracking and force regulation. Q -function-based critic learning is developed to determine the optimal impedance parameters without the knowledge of the system dynamics. The simulation results are presented and compared with existing methods, and the efficacy of the proposed method is verified.

  15. Electric Car Users’ Time of Charging Problem under Peak Load Pricing When Delay in Charging Time Involves Uncertain Cost

    DEFF Research Database (Denmark)

    Fetene, Gebeyehu Manie

    The problem of peak load arises when demand fluctuates over time while the pro- duction technology is not flexible (or making it flexible is economically inefficient) and/or when a product is non-storable (or storage cost is huge). Peak load is a com- mon problem in consumption of public utilities......, on the one hand, observed cost saving benefit of postponing the time of charging to off-peak lower fee of charging and, on the other hand, the cost of delay in departure time for planned trips and uncertain cost of late charging associated with likelihood occur- rence of unanticipated trip before the car...... of electricity. The electric vehicle (EV) users choice of time of charging problem under PLP is different from that of general households using energy for house appliances since there is uncertain cost to the former as- sociated with likelihood occurrence of unanticipated trips such as visiting hospital...

  16. Epidemic spreading in time-varying community networks

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Guangming, E-mail: wangxy@dlut.edu.cn, E-mail: ren-guang-ming@163.com [School of Electronic and Information, Guangdong Polytechnic Normal University, Guangzhou 510665 (China); Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Xingyuan, E-mail: wangxy@dlut.edu.cn, E-mail: ren-guang-ming@163.com [Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China)

    2014-06-15

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold q{sub c}. The epidemic will survive when q > q{sub c} and die when q < q{sub c}. These results can help understanding the impacts of human travel on the epidemic spreading in complex networks with community structure.

  17. Epidemic spreading in time-varying community networks

    International Nuclear Information System (INIS)

    Ren, Guangming; Wang, Xingyuan

    2014-01-01

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold q c . The epidemic will survive when q > q c and die when q  c . These results can help understanding the impacts of human travel on the epidemic spreading in complex networks with community structure

  18. ENVIRONMENTAL MONITORING OF LEAKS USING TIME LAPSED LONG ELECTRODE ELECTRICAL RESISTIVITY

    International Nuclear Information System (INIS)

    Myers, D.A.; Rucker, D.F.; Fink, J.B.; Loke, M.H.

    2009-01-01

    Highly industrialized areas pose challenges for surface electrical resistivity characterization due to metallic infrastructure. The infrastructure is typically more conductive than the desired targets and will mask the deeper subsurface information. These challenges may be minimized if steel-cased wells are used as long electrodes in the area near the target. We demonstrate a method of using long electrodes to electrically monitor a simulated leak from an underground storage tank with both synthetic examples and a field demonstration. The synthetic examples place a simple target of varying electrical properties beneath a very low resistivity layer. The layer is meant to replicate the effects of infrastructure. Both surface and long electrodes are tested on the synthetic domain. The leak demonstration for the field experiment is simulated by injecting a high conductivity fluid in a perforated well within the S tank farm at Hanford, and the resistivity measurements are made before and after the leak test. All data are processed in four dimensions, where a regularization procedure is applied in both the time and space domains. The synthetic test case shows that the long electrode ERM could detect relative changes in resistivity that are commensurate with the differing target properties. The surface electrodes, on the other hand, had a more difficult time matching the original target's footprint. The field results shows a lowered resistivity feature develop south of the injection site after cessation of the injections. The time lapsed regularization parameter has a strong influence on the differences in inverted resistivity between the pre and post injection datasets, but the interpretation of the target is consistent across all values of the parameter. The long electrode ERM method may provide a tool for near real-time monitoring of leaking underground storage tanks.

  19. Methodology for Time-Domain Estimation of Storm-Time Electric Fields Using the 3D Earth Impedance

    Science.gov (United States)

    Kelbert, A.; Balch, C. C.; Pulkkinen, A. A.; Egbert, G. D.; Love, J. J.; Rigler, E. J.; Fujii, I.

    2016-12-01

    Magnetic storms can induce geoelectric fields in the Earth's electrically conducting interior, interfering with the operations of electric-power grid industry. The ability to estimate these electric fields at Earth's surface in close to real-time and to provide local short-term predictions would improve the ability of the industry to protect their operations. At any given time, the electric field at the Earth's surface is a function of the time-variant magnetic activity (driven by the solar wind), and the local electrical conductivity structure of the Earth's crust and mantle. For this reason, implementation of an operational electric field estimation service requires an interdisciplinary, collaborative effort between space science, real-time space weather operations, and solid Earth geophysics. We highlight in this talk an ongoing collaboration between USGS, NOAA, NASA, Oregon State University, and the Japan Meteorological Agency, to develop algorithms that can be used for scenario analyses and which might be implemented in a real-time, operational setting. We discuss the development of a time domain algorithm that employs discrete time domain representation of the impedance tensor for a realistic 3D Earth, known as the discrete time impulse response (DTIR), convolved with the local magnetic field time series, to estimate the local electric field disturbances. The algorithm is validated against measured storm-time electric field data collected in the United States and Japan. We also discuss our plans for operational real-time electric field estimation using 3D Earth impedances.

  20. Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

    Science.gov (United States)

    Zhang, Ruobing; Liang, Dapeng; Zheng, Nanchen; Xiao, Jianfu; Mo, Mengbin; Li, Jing

    2013-03-01

    Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

  1. Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

    International Nuclear Information System (INIS)

    Zhang, Ruobing; Liang, Dapeng; Xiao, Jianfu; Mo, Mengbin; Li, Jing; Zheng, Nanchen

    2013-01-01

    Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

  2. A Study of Digging Productivity of an Electric Rope Shovel for Different Operators

    Directory of Open Access Journals (Sweden)

    Mohammad Babaei Khorzoughi

    2016-05-01

    Full Text Available A performance monitoring study of an electric rope shovel operating in an open pit coal mine was conducted. As the mining industry moves toward higher productivity, profitability and predictability, the need for more reliable, productive and efficient mining shovels increases. Consequently, it is critical to study the productivity of these machines and to understand the effect of different operational parameters on that. In this paper a clustering analysis is performed to classify shovel digging effort and behaviour based on digging energy, dig time and payload per pass. Then the influence of the operator on the digging efficiency and productivity of the machine is analyzed with a focus on operator technique during digging. A statistical analysis is conducted on different cycle time components (dig time, swing time, return time for different operators. In addition to time components, swing and return angles as well as loading rate and mucking rate are observed and analyzed. The results of this study help to understand the effect of different operators on the digging productivity of the shovel and then to set the best operator practice.

  3. TIME-VARYING DYNAMICAL STAR FORMATION RATE

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eve J.; Chang, Philip; Murray, Norman, E-mail: evelee@berkeley.edu [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto, ON M5S 3H8 (Canada)

    2015-02-10

    We present numerical evidence of dynamic star formation in which the accreted stellar mass grows superlinearly with time, roughly as t {sup 2}. We perform simulations of star formation in self-gravitating hydrodynamic and magnetohydrodynamic turbulence that is continuously driven. By turning the self-gravity of the gas in the simulations on or off, we demonstrate that self-gravity is the dominant physical effect setting the mass accretion rate at early times before feedback effects take over, contrary to theories of turbulence-regulated star formation. We find that gravitational collapse steepens the density profile around stars, generating the power-law tail on what is otherwise a lognormal density probability distribution function. Furthermore, we find turbulent velocity profiles to flatten inside collapsing regions, altering the size-line width relation. This local flattening reflects enhancements of turbulent velocity on small scales, as verified by changes to the velocity power spectra. Our results indicate that gas self-gravity dynamically alters both density and velocity structures in clouds, giving rise to a time-varying star formation rate. We find that a substantial fraction of the gas that forms stars arrives via low-density flows, as opposed to accreting through high-density filaments.

  4. Time-varying and time-invariant dimensions of depression in children and adolescents: Implications for cross-informant agreement.

    Science.gov (United States)

    Cole, David A; Martin, Joan M; Jacquez, Farrah M; Tram, Jane M; Zelkowitz, Rachel; Nick, Elizabeth A; Rights, Jason D

    2017-07-01

    The longitudinal structure of depression in children and adolescents was examined by applying a Trait-State-Occasion structural equation model to 4 waves of self, teacher, peer, and parent reports in 2 age groups (9 to 13 and 13 to 16 years old). Analyses revealed that the depression latent variable consisted of 2 longitudinal factors: a time-invariant dimension that was completely stable over time and a time-varying dimension that was not perfectly stable over time. Different sources of information were differentially sensitive to these 2 dimensions. Among adolescents, self- and parent reports better reflected the time-invariant aspects. For children and adolescents, peer and teacher reports better reflected the time-varying aspects. Relatively high cross-informant agreement emerged for the time-invariant dimension in both children and adolescents. Cross-informant agreement for the time-varying dimension was high for adolescents but very low for children. Implications emerge for theoretical models of depression and for its measurement, especially when attempting to predict changes in depression in the context of longitudinal studies. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. Real-time electricity pricing mechanism in China based on system dynamics

    International Nuclear Information System (INIS)

    He, Yongxiu; Zhang, Jixiang

    2015-01-01

    Highlights: • The system dynamics is used to research the real-time electricity pricing mechanism. • Four kinds of the real-time electricity pricing models are carried out and simulated. • It analysed the electricity price, the user satisfaction and the social benefits under the different models. • Market pricing is the trend of the real-time electricity pricing mechanism. • Initial development path of the real-time price mechanism for China is designed between 2015 and 2030. - Abstract: As an important means of demand-side response, the reasonable formulation of the electricity price mechanism will have an important impact on the balance between the supply and demand of electric power. With the introduction of Chinese intelligence apparatus and the rapid development of smart grids, real-time electricity pricing, as the frontier electricity pricing mechanism in the smart grid, will have great significance on the promotion of energy conservation and the improvement of the total social surplus. From the perspective of system dynamics, this paper studies different real-time electricity pricing mechanisms based on load structure, cost structure and bidding and analyses the situation of user satisfaction and the total social surplus under different pricing mechanisms. Finally, through the comparative analysis of examples under different real-time pricing scenarios, this paper aims to explore and design the future dynamic real-time electricity pricing mechanism in China, predicts the dynamic real-time pricing level and provides a reference for real-time electricity price promotion in the future

  6. The bright side of snow cover effects on PV production - How to lower the seasonal mismatch between electricity supply and demand in a fully renewable Switzerland

    Science.gov (United States)

    Kahl, Annelen; Dujardin, Jérôme; Dupuis, Sonia; Lehning, Michael

    2017-04-01

    One of the major problems with solar PV in the context of a fully renewable electricity production at mid-latitudes is the trend of higher production in summer and lower production in winter. This trend is most often exactly opposite to demand patterns, causing a seasonal mismatch that requires extensive balancing power from other production sources or large storage capacities. Which possibilities do we have to bring PV production into closer correlation with demand? This question motivated our research and in response we investigated the effects of placing PV panels at different tilt angles in regions with extensive snow cover to increase winter production from ground reflected short wave radiation. The aim of this project is therefore to quantify the effect of varying snow cover duration (SCD) and of panel tilt angle on the annual total production and on production during winter months when electricity is most needed. We chose Switzerland as ideal test site, because it has a wide range of snow cover conditions and a high potential for renewable electricity production. But methods can be applied to other regions of comparable conditions for snow cover and irradiance. Our analysis can be separated into two steps: 1. A systematic, GIS and satellite-based analysis for all of Switzerland: We use time series of satellite-derived irradiance, and snow cover characteristics together with land surface cover types and elevation information to quantify the environmental conditions and to estimate potential production and ideal tilt angles. 2. A scenario-based analysis that contrasts the production patterns of different placement scenarios for PV panels in urban, rural and mountainous areas. We invoke a model of a fully renewable electricity system (including Switzerland's large hydropower system) at national level to compute the electricity import and storage capacity that will be required to balance the remaining mismatch between production and demand to further illuminate

  7. PCA-based detection of damage in time-varying systems

    Science.gov (United States)

    Bellino, A.; Fasana, A.; Garibaldi, L.; Marchesiello, S.

    2010-10-01

    When performing Structural Health Monitoring, it is well known that the natural frequencies do not depend only on the damage but also on environmental conditions, such as temperature and humidity. The Principal Component Analysis is used to take this problem into account, because it allows eliminating the effect of external factors. The purpose of the present work is to show that this technique can be successfully used not only for time-invariant systems, but also for time-varying ones. Referring to the latter, one of the most studied systems which shows these characteristics is the bridge with crossing loads, such as the case of the railway bridge studied in present paper; in this case, the mass and the velocity of the train can be considered as "environmental" factors.This paper, after a brief description of the PCA method and one example of its application on time-invariant systems, presents the great potentialities of the methodology when applied to time-varying systems. The results show that this method is able to better detect the presence of damage and also to properly distinguish among different levels of crack depths.

  8. Modelling Conditional and Unconditional Heteroskedasticity with Smoothly Time-Varying Structure

    DEFF Research Database (Denmark)

    Amado, Christina; Teräsvirta, Timo

    multiplier type misspecification tests. Finite-sample properties of these procedures and tests are examined by simulation. An empirical application to daily stock returns and another one to daily exchange rate returns illustrate the functioning and properties of our modelling strategy in practice......In this paper, we propose two parametric alternatives to the standard GARCH model. They allow the conditional variance to have a smooth time-varying structure of either ad- ditive or multiplicative type. The suggested parameterizations describe both nonlinearity and structural change...... in the conditional and unconditional variances where the transition between regimes over time is smooth. A modelling strategy for these new time-varying parameter GARCH models is developed. It relies on a sequence of Lagrange multiplier tests, and the adequacy of the estimated models is investigated by Lagrange...

  9. On the synchronization of neural networks containing time-varying delays and sector nonlinearity

    International Nuclear Information System (INIS)

    Yan, J.-J.; Lin, J.-S.; Hung, M.-L.; Liao, T.-L.

    2007-01-01

    We present a systematic design procedure for synchronization of neural networks subject to time-varying delays and sector nonlinearity in the control input. Based on the drive-response concept and the Lyapunov stability theorem, a memoryless decentralized control law is proposed which guarantees exponential synchronization even when input nonlinearity is present. The supplementary requirement that the time-derivative of time-varying delays must be smaller than one is released for the proposed control scheme. A four-dimensional Hopfield neural network with time-varying delays is presented as the illustrative example to demonstrate the effectiveness of the proposed synchronization scheme

  10. A Greenhouse Gas Balance of Electricity Production from Co-firing Palm Oil Products from Malaysia

    International Nuclear Information System (INIS)

    Wicke, B.; Dornburg, V.; Faaij, A.; Junginger, M.

    2007-05-01

    The Netherlands imports significant quantities of biomass for energy production, among which palm oil has been used increasingly for co-firing in existing gas-fired power plants for renewable electricity production. Imported biomass, however, can not simply be considered a sustainable energy source. The production and removal of biomass in other places in the world result in ecological, land-use and socio-economic impacts and in GHG emissions (e.g. for transportation). As a result of the sustainability discussions, the Cramer Commission in the Netherlands has formulated (draft) criteria and indicators for sustainable biomass production. This study develops a detailed methodology for determining the GHG balance of co-firing palm oil products in the Netherlands based on the Cramer Commission methodology. The methodology is applied to a specific bio-electricity chain: the production of palm oil and a palm oil derivative, palm fatty acid distillate (PFAD), in Northeast Borneo in Malaysia, their transport to the Netherlands and co-firing with natural gas for electricity production at the Essent Claus power plant

  11. Short time ahead wind power production forecast

    International Nuclear Information System (INIS)

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-01-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast. (paper)

  12. Short time ahead wind power production forecast

    Science.gov (United States)

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-09-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast.

  13. Asymptotic stability of discrete-time systems with time-varying delay subject to saturation nonlinearities

    International Nuclear Information System (INIS)

    Chen, S.-F.

    2009-01-01

    The asymptotic stability problem for discrete-time systems with time-varying delay subject to saturation nonlinearities is addressed in this paper. In terms of linear matrix inequalities (LMIs), a delay-dependent sufficient condition is derived to ensure the asymptotic stability. A numerical example is given to demonstrate the theoretical results.

  14. Parallel time domain solvers for electrically large transient scattering problems

    KAUST Repository

    Liu, Yang; Yucel, Abdulkadir; Bagcý , Hakan; Michielssen, Eric

    2014-01-01

    scattering from perfect electrically conducting objects are obtained by enforcing electric field boundary conditions and implicitly time advance electric surface current densities by iteratively solving sparse systems of equations at all time steps. Contrary

  15. Electrical conductivity of the screening residuals of coke production in context of ferrochromium production in a submerged arc furnace

    Energy Technology Data Exchange (ETDEWEB)

    Rousu, Arto; Mattila, Olli [Lab. of Process Metallurgy, Univ. of Oulu (Finland)

    2009-11-15

    Coke is used as a reducing agent in the production of ferrochromium in a submerged arc furnace (SAF). Its good electrical conductivity compared to other input materials makes it a dominant current conductivity substance in the burden. The resistance of the coke has to be high enough to ensure the proper functionality of the furnace. Used cokes for submerged arc furnace production are relatively small in size compared to e.g. blast furnace (BF) cokes. A common practice is to use screening residual coke, which is too small for the BF, in SAF. The goal of this study was to show differences in the electrical properties of screening residual cokes compared to coke formed in different parts of the coke battery, in dependence of particle size. The resistances of different cokes were measured and XRD measurements were performed to define the crystallographic structure of the selected cokes. The results indicate that small coke particles have higher overall resistance, which is due to their internal properties. This small weakly carbonized coke is formed in the middle of the coking battery and is subject to changes in varying coking practices. Continuous quality control of screening residual coke is needed to use it in the SAF. (orig.)

  16. Report on renewable electricity self-consumption and self-production

    International Nuclear Information System (INIS)

    2014-12-01

    After having indicated the main conclusions of this study in terms of observations, of objectives of a support arrangement, and of recommendations for the photovoltaic sector, this report first presents the legal context and some definitions for energy self-production and self-consumption: foreign experiments, legal framework of photovoltaic electricity sales, definition of self-production and self-consumption. It proposes an overview of opportunities and stakes for self-production and self-consumption: potential benefits, impact on the electric grid, supply safety, grid control, supply-demand equilibrium, safety of persons and goods, flexibility of the electric system. It presents the different types of self-consumers and self-producers in the individual housing sector, in collective building and urban blocks, and in industrial and office buildings. It addresses the case of non-interconnected areas: context, opportunity, principles. It discusses the impact of self-production/self-consumption on the economic fundamentals of the electric system and on the financing of renewable energies. The remuneration and financing issues are then discussed (examples, net-metering system, additional premium system, other arrangements) as well as the architecture of a support system. Several contributions of an association of individual producers and of different professional bodies of the energy, photovoltaic, and building sectors are proposed in appendix

  17. The impact of a carbon tax on Greek electricity production

    Energy Technology Data Exchange (ETDEWEB)

    Vassos, S [Strategy and Planning Dept., Public Power Corp., Athens (Greece); Vlachou, A [Department of Economics, Athens Univ. of Economics and Business, Athens (Greece)

    1997-09-01

    The impact of proposed carbon taxes on the electric power industry, using the Greek power system as a case study, is investigated in this paper. It uses the WASP model for electric generation capacity expansion to explore the optimal expansion path under alternative carbon tax scenarios and to estimate their impact on CO{sub 2} and other types of emissions and on electricity production costs. The findings suggest that low carbon taxes would lead to a considerable reduction of the use of conventional lignite fired power plants counterbalanced predominantly by natural gas fired plants. High carbon taxes (100-200 US dollars per ton of carbon) would lead to a drastic reduction of the use of conventional lignite fired power plants which would be mainly replaced by coal or lignite fired technologies with CO{sub 2} removal capabilities, which are not available today but might become available within the time horizon of the present study. Hydropower and renewable sources would be the second least-cost alternatives to lignite under both low and high tax scenarios. The study provides evidence that carbon taxes also result in significant increases in the cost of producing electricity, implying adverse economic effects on electricity consumers and the Greek economy in general. (author). 35 refs, 1 fig., 7 tabs.

  18. The impact of a carbon tax on Greek electricity production

    International Nuclear Information System (INIS)

    Vassos, S.; Vlachou, A.

    1997-01-01

    The impact of proposed carbon taxes on the electric power industry, using the Greek power system as a case study, is investigated in this paper. It uses the WASP model for electric generation capacity expansion to explore the optimal expansion path under alternative carbon tax scenarios and to estimate their impact on CO 2 and other types of emissions and on electricity production costs. The findings suggest that low carbon taxes would lead to a considerable reduction of the use of conventional lignite fired power plants counterbalanced predominantly by natural gas fired plants. High carbon taxes (100-200 US dollars per ton of carbon) would lead to a drastic reduction of the use of conventional lignite fired power plants which would be mainly replaced by coal or lignite fired technologies with CO 2 removal capabilities, which are not available today but might become available within the time horizon of the present study. Hydropower and renewable sources would be the second least-cost alternatives to lignite under both low and high tax scenarios. The study provides evidence that carbon taxes also result in significant increases in the cost of producing electricity, implying adverse economic effects on electricity consumers and the Greek economy in general. (author). 35 refs, 1 fig., 7 tabs

  19. Testing and estimating time-varying elasticities of Swiss gasoline demand

    International Nuclear Information System (INIS)

    Neto, David

    2012-01-01

    This paper is intended to test and estimate time-varying elasticities for gasoline demand in Switzerland. For this purpose, a smooth time-varying cointegrating parameters model is investigated in order to describe smooth mutations of the Swiss gasoline demand. The methodology, based on Chebyshev polynomials, is rigorously outlined. Our empirical finding states that the time-invariance assumption does not hold for long-run price and income elasticities. Furthermore they highlight that gasoline demand passed through some periods of sensitivity and non sensitivity with respect to the price. Our empirical statements are of great importance to assess the performance of a gasoline tax as an instrument for CO 2 reduction policy. Indeed, such an instrument can contribute to reduce emissions of greenhouse gases only if the demand is not fully inelastic with respect to the price. Our results suggest that such a carbon-tax would not be always suitable since the price elasticity is found not stable over time and not always significant.

  20. Dashboard: biogas for electricity production - Forth quarter 2015

    International Nuclear Information System (INIS)

    Cavaud, Denis; Reynaud, Didier

    2016-02-01

    This publication describes the situation of biogas-based electricity production in France and its evolution over the first quarters of 2015. A map indicates the level of connected power per district. Graphs illustrate the evolution of the number of new connections per quarter since 2009, the evolution of electricity quarterly production since 2011. Tables indicate the number of installations per power level (less than 0.5 MW, between 0.5 and 1.0 MW, more than 1 MW) and per installation type. Regional data are given in terms of number of installations, installed power in December 2015, regional share and evolution

  1. DISTRIBUTED ELECTRICAL POWER PRODUCTION SYSTEM AND METHOD OF CONTROL THEREOF

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention relates to a distributed electrical power production system wherein two or more electrical power units comprise respective sets of power supply attributes. Each set of power supply attributes is associated with a dynamic operating state of a particular electrical power unit....

  2. Time-Varying Biased Proportional Guidance with Seeker’s Field-of-View Limit

    OpenAIRE

    Yang, Zhe; Wang, Hui; Lin, Defu

    2016-01-01

    Traditional guidance laws with range-to-go information or time-to-go estimation may not be implemented in passive homing missiles since passive seekers cannot measure relative range directly. A time-varying biased proportional guidance law, which only uses line-of-sight (LOS) rate and look angle information, is proposed to satisfy both impact angle constraint and seeker’s field-of-view (FOV) limit. In the proposed guidance law, two time-varying bias terms are applied to divide the trajectory ...

  3. Whatever the customer wants, the customer gets? Exploring the gap between consumer preferences and default electricity products in Germany

    International Nuclear Information System (INIS)

    Kaenzig, Josef; Heinzle, Stefanie Lena; Wüstenhagen, Rolf

    2013-01-01

    In liberalized electricity markets, residential customers can choose their preferred provider and select among a variety of different electricity products, including green power options. Successful product design and marketing strategies for green electricity may provide electricity providers with a competitive advantage, while at the same time contributing to energy policy objectives. This requires, however, a thorough understanding of customer preferences. We investigate the relative importance of different product attributes in creating customer value, and find that price and electricity mix are the two most important attributes. The German electricity customers we surveyed in 2009 expressed an implicit willingness to pay a premium of about 16% for electricity from renewable sources. We conclude that consumers are willing to pay a significant price premium for an upgrade from the current default electricity mix in Germany to a more environmentally friendly default electricity mix, and discuss implications for marketing strategy and energy policy. Our findings are based on a dataset of 4968 experimental choices made by 414 German residential consumers, collected in a stated preference survey. - Highlights: ► Study is based on 4968 experimental choices made by 414 German retail consumers. ► Apart from price, the electricity mix is the most important product attribute. ► Majority of consumers prefer nuclear-free electricity. ► Respondents are willing to pay a premium for green electricity. ► German default electricity mix does not correspond to current customer preferences.

  4. Study of solar electric production potential in the Herault district

    International Nuclear Information System (INIS)

    Dubois, Anthony; Baldini, Florent; Bruant, Marc; Bouchet, Jean-Alain; Bouzige, Romain

    2010-06-01

    The first part of this report presents various contextual issues: general context (commitments in production with renewable energies, aspects related to the national electric production, electric production and consumption in the Languedoc-Roussillon region), analysis of techniques and sectors of solar electric production (inventory of available or being developed technical and industrial sectors, potential environmental impacts), economic analysis of photovoltaic techniques (purchase tariffs, other financing sources, grid parity, installation costs, application to case study), and regulatory and administrative procedures. The second part reports a regional approach of this study: characterisation of the raw solar resource, territorial sensitivity analysis (influence of various factors: technical, geological, hydro-geological, urban, environmental, related to landscape, heritage and natural environment), definition of a territorial sensitivity grid. The third part reports the definition of the solar production potential: on buildings, in man-made locations (mines, landfills, industrial wastelands), and in ordinary non-built spaces. Appendices propose detailed economic data for case studies, presentations of purchase tariffs in 2010, and presentations of existing installations

  5. Energy, Environmental and Economic Performance of a Micro-trigeneration System upon Varying the Electric Vehicle Charging Profiles

    Directory of Open Access Journals (Sweden)

    Sergio Sibilio

    2017-09-01

    Full Text Available The widespread adoption of electric vehicles and electric heat pumps would result in radically different household electrical demand characteristics, while also possibly posing a threat to the stability of the electrical grid. In this paper, a micro-trigeneration system (composed of a 6.0 kWel cogeneration device feeding a 4.5 kWcool electric air-cooled vapor compression water chiller serving an Italian residential multi-family house was investigated by using the dynamic simulation software TRNSYS. The charging of an electric vehicle was considered by analyzing a set of seven electric vehicle charging profiles representing different scenarios. The simulations were performed in order to evaluate the capability of micro-cogeneration technology in: alleviating the impact on the electric infrastructure (a; saving primary energy (b; reducing the carbon dioxide equivalent emissions (c and determining the operating costs in comparison to a conventional supply system based on separate energy production (d.

  6. The relationship between global oil price shocks and China's output: A time-varying analysis

    International Nuclear Information System (INIS)

    Cross, Jamie; Nguyen, Bao H.

    2017-01-01

    We employ a class of time-varying Bayesian vector autoregressive (VAR) models on new standard dataset of China's GDP constructed by to examine the relationship between China's economic growth and global oil market fluctuations between 1992Q1 and 2015Q3. We find that: (1) the time varying parameter VAR with stochastic volatility provides a better fit as compared to it's constant counterparts; (2) the impacts of intertemporal global oil price shocks on China's output are often small and temporary in nature; (3) oil supply and specific oil demand shocks generally produce negative movements in China's GDP growth whilst oil demand shocks tend to have positive effects; (4) domestic output shocks have no significant impact on price or quantity movements within the global oil market. The results are generally robust to three commonly employed indicators of global economic activity: Kilian's global real economic activity index, the metal price index and the global industrial production index, and two alternative oil price metrics: the US refiners' acquisition cost for imported crude oil and the West Texas Intermediate price of crude oil. - Highlights: • A class of time-varying BVARs is used to examine the relationship between China's economic growth and global oil market fluctuations. • The impacts of intertemporal global oil price shocks on China's output are often small and temporary in nature. • Oil supply and specific oil demand shocks generally produce negative movements in China's GDP growth while oil demand shocks tend to have positive effects. • Domestic output shocks have no significant impact on price or quantity movements within the global oil market.

  7. Linear electric field time-of-flight ion mass spectrometer

    Science.gov (United States)

    Funsten, Herbert O [Los Alamos, NM; Feldman, William C [Los Alamos, NM

    2008-06-10

    A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

  8. Scattering of a TEM wave from a time varying surface

    Science.gov (United States)

    Elcrat, Alan R.; Harder, T. Mark; Stonebraker, John T.

    1990-03-01

    A solution is given for reflection of a plane wave with TEM polarization from a planar surface with time varying properties. These properties are given in terms of the currents on the surface. The solution is obtained by numerically solving a system of differential-delay equations in the time domain.

  9. Examination of Electrical Resistance of Carburizers Used for Cast Iron Production

    Directory of Open Access Journals (Sweden)

    Książek D.

    2016-12-01

    Full Text Available The publication presents the results of examination of selected carburizers used for cast iron production with respect to their electric resistance. Both the synthetic graphite carburizers and petroleum coke (petcoke carburizers of various chemical composition were compared. The relationships between electrical resistance of tested carburizers and their quality were found. The graphite carburizers exhibited much better conductivity than the petcoke ones. Resistance characteristics were different for the different types of carburizers. The measurements were performed according to the authors’ own method based on recording the electric current flow through the compressed samples. The samples of the specified diameter were put under pressure of the gradually increased value (10, 20, 50, 60, and finally 70 bar, each time the corresponding value of electric resistance being measured with a gauge of high accuracy, equal to 0.1μΩ. The higher pressure values resulted in the lower values of resistance. The relation between both the thermal conductance and the electrical conductance (or the resistance is well known and mentioned in the professional literature. The results were analysed and presented both in tabular and, additionally, in graphic form.

  10. Time-resolved electrical measurements of a pulsed-dc methane discharge used in diamond-like carbon films production

    International Nuclear Information System (INIS)

    Corbella, C.; Polo, M.C.; Oncins, G.; Pascual, E.; Andujar, J.L.; Bertran, E.

    2005-01-01

    Amorphous hydrogenated carbon (a-C:H) thin films were obtained at room temperature via asymmetric bipolar pulsed-dc methane glow discharge. The power frequency values were varied from 100 to 200 kHz and the maximum amplitude voltage from -600 to -1400 V. Such films present diamond-like carbon (DLC) properties [J.L. Andujar, M. Vives, C. Corbella, E. Bertran, Diamond Relat. Mater. 12 (2003) 98]. The plasma, powered by a pulse frequency of 100 kHz, was electrically studied by a Langmuir probe. The next parameters were calculated within the pulse cycle from I-V measurements with 1 μs resolution: plasma and floating potentials, electron temperature, and electron and ion densities. The presence of a population of hot electrons (10 eV) was detected at high bias voltage region. The density of cold electrons grows one order of magnitude after each negative pulse, whereas the ion density suffers a prompt increase during each positive pulse. The surface topography of DLC films was scanned by atomic force microscopy (AFM). A smoothly varying friction coefficient (between 0.2 and 0.3) was measured by AFM in contact mode. X-ray reflectivity (XRR) analysis provided a wide characterization of the films, involving density, thickness and roughness. The C/H ratio, as directly obtained by elemental analysis (EA), shows an increase at higher bias voltages. All these features are discussed in terms of process parameters varied in film growth

  11. Contact Dynamics of EHL Contacts under Time Varying Conditions

    NARCIS (Netherlands)

    Venner, Cornelis H.; Popovici, G.; Wijnant, Ysbrand H.; Dalmaz, G.; Lubrecht, A.A.; Priest, M

    2004-01-01

    By means of numerical simulations of two situations with time varying operating conditions it is shown that the dynamic behaviour of Elasto-Hydrodynamically Lubricated contacts in terms of vibrations can be characterized as: Changes in the mutual approach lead to film thickness changes in the inlet

  12. The extinction probability in systems randomly varying in time

    Directory of Open Access Journals (Sweden)

    Imre Pázsit

    2017-09-01

    Full Text Available The extinction probability of a branching process (a neutron chain in a multiplying medium is calculated for a system randomly varying in time. The evolution of the first two moments of such a process was calculated previously by the authors in a system randomly shifting between two states of different multiplication properties. The same model is used here for the investigation of the extinction probability. It is seen that the determination of the extinction probability is significantly more complicated than that of the moments, and it can only be achieved by pure numerical methods. The numerical results indicate that for systems fluctuating between two subcritical or two supercritical states, the extinction probability behaves as expected, but for systems fluctuating between a supercritical and a subcritical state, there is a crucial and unexpected deviation from the predicted behaviour. The results bear some significance not only for neutron chains in a multiplying medium, but also for the evolution of biological populations in a time-varying environment.

  13. The magnetohydrodynamic flow near a time-varying accelerated porous plate

    International Nuclear Information System (INIS)

    Roy, A.; Das, A.K.

    1985-01-01

    This paper confines to the study of the flow of an electrically conducting incompressible viscous liquid due to the varying motion of an infinite nonconducting porous flat pjate in the presence of a transverse magnetic field under the following assumptions: (1) the fluid flows subject to uniform section, (2) the magnetic Reynold number is equai to the viscous Reynold number, (3) the plate moves in its own plane with the velocity of esup(at)tsup(n) (n is an integer and α > a), (4) the Alfven velocity is less than the suction velocity. The induced magnetic field produced by the motion is taken into account. General expressions of the velocity and skinfriction have been obtained when the plate moves with the velocity esup(at)tsup(n). Several particular cases have been studied. (authors)

  14. Varying constants, black holes, and quantum gravity

    International Nuclear Information System (INIS)

    Carlip, S.

    2003-01-01

    Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain 'constants' vary in time. Assuming fixed black hole mass and the standard form of the Bekenstein-Hawking entropy, Davies, Davis and Lineweaver have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that with these assumptions, similar considerations severely constrain 'varying speed of light' models, unless we are prepared to abandon cherished assumptions about quantum gravity. Relaxation of these assumptions permits sensible theories of quantum gravity with ''varying constants,'' but also eliminates the thermodynamic constraints, though the black hole mass spectrum may still provide some restrictions on the range of allowable models

  15. Electrical power system integrated thermal/electrical system simulation

    International Nuclear Information System (INIS)

    Freeman, W.E.

    1992-01-01

    This paper adds thermal properties to previously developed electrical Saber templates and incorporates these templates into a functional Electrical Power Subsystem (EPS) simulation. These combined electrical and thermal templates enable the complete and realistic simulation of a vehicle EPS on-orbit. Applications include on-orbit energy balance determinations for system load changes, initial array and battery EPS sizing for new EPS development, and array and battery technology trade studies. This effort proves the versatility of the Saber simulation program in handling varied and complex simulations accurately and in a reasonable amount of computer time. 9 refs

  16. A combined hydro-nuclear-solar project for electric power production

    International Nuclear Information System (INIS)

    Yiftah, S.

    1985-01-01

    Some of the main, general-perspective themes of Dr. Alvin Weinberg's leadership and long and varied work are: the effect of present and future nuclear energy projects on society, not only in the United States but throughout the world; analysis, comparison, and combination of various sources of energy; extensive multiple use of nuclear energy complexes (so-called NUPLEX, for nuclear complex) for various areas of the world; and use of ''Big Technology'' and ''Big Science'' for solving, or helping to solve, political problems. A combined hydro-nuclear-solar project for electric power production is discussed, as well as two other energy-related engineering projects. Some of the projects originated or were inspired by work done at the Oak Ridge National Laboratory under the leadership of Dr. Alvin Weinberg. Also reported are the technical characteristics and interrelationships of the three components of the envisaged hydronuclear-solar project

  17. Tolerable Time-Varying Overflow on Grass-Covered Slopes

    Directory of Open Access Journals (Sweden)

    Steven A. Hughes

    2015-03-01

    Full Text Available Engineers require estimates of tolerable overtopping limits for grass-covered levees, dikes, and embankments that might experience steady overflow. Realistic tolerance estimates can be used for both resilient design and risk assessment. A simple framework is developed for estimating tolerable overtopping on grass-covered slopes caused by slowly-varying (in time overtopping discharge (e.g., events like storm surges or river flood waves. The framework adapts the well-known Hewlett curves of tolerable limiting velocity as a function of overflow duration. It has been hypothesized that the form of the Hewlett curves suggests that the grass erosion process is governed by the flow work on the slope above a critical threshold velocity (referred to as excess work, and the tolerable erosional limit is reached when the cumulative excess work exceeds a given value determined from the time-dependent Hewlett curves. The cumulative excess work is expressed in terms of overflow discharge above a critical discharge that slowly varies in time, similar to a discharge hydrograph. The methodology is easily applied using forecast storm surge hydrographs at specific locations where wave action is minimal. For preliminary planning purposes, when storm surge hydrographs are unavailable, hypothetical equations for the water level and overflow discharge hydrographs are proposed in terms of the values at maximum overflow and the total duration of overflow. An example application is given to illustrate use of the methodology.

  18. Finite-Time H∞ Filtering for Linear Continuous Time-Varying Systems with Uncertain Observations

    Directory of Open Access Journals (Sweden)

    Huihong Zhao

    2012-01-01

    Full Text Available This paper is concerned with the finite-time H∞ filtering problem for linear continuous time-varying systems with uncertain observations and ℒ2-norm bounded noise. The design of finite-time H∞ filter is equivalent to the problem that a certain indefinite quadratic form has a minimum and the filter is such that the minimum is positive. The quadratic form is related to a Krein state-space model according to the Krein space linear estimation theory. By using the projection theory in Krein space, the finite-time H∞ filtering problem is solved. A numerical example is given to illustrate the performance of the H∞ filter.

  19. Internalising external costs of electricity and heat production in a municipal energy system

    International Nuclear Information System (INIS)

    Holmgren, Kristina; Amiri, Shahnaz

    2007-01-01

    Both energy supply and waste treatment give rise to negative effects on the environment, so-called external effects. In this study, monetary values on external costs collected from the EU's ExternE project are used to evaluate inclusion of these costs in comparison with an energy utility perspective including present policy instruments. The studied object is a municipal district heating system with a waste incineration plant as the base supplier of heat. The evaluation concerns fuels used for heat production and total electricity production, for scenarios with external costs included and for a scenario using the present policy instrument. Impacts of assumptions on marginal power producers (coal or natural gas power plants) are investigated, since locally produced electricity is assumed to replace marginal power and thus is credited for the avoided burden. Varying levels of external costs for carbon dioxide emissions are analysed. The method used is an economic optimisation model, MODEST. The conclusion is that present policy instruments are strong incentives for cogeneration, even when external costs are included. Waste is fully utilised in all scenarios. In cases where coal is the marginal power producer, more electricity is produced; when natural gas is the marginal power producer, less is produced. There are several uncertainties in the data for external costs, both methodological and ethical. In the ExternE data, not all environmental impacts are included. For waste incineration, ashes are not included, and another difficulty is how to treat the avoided burden of other waste treatment methods

  20. Two-dimensional phononic crystals with time-varying properties: a multiple scattering analysis

    International Nuclear Information System (INIS)

    Wright, D W; Cobbold, R S C

    2010-01-01

    Multiple scattering theory is a versatile two- and three-dimensional method for characterizing the acoustic wave transmission through many scatterers. It provides analytical solutions to wave propagation in scattering structures, and its computational complexity grows logarithmically with the number of scatterers. In this paper we show how the 2D method can be adapted to include the effects of time-varying material parameters. Specifically, a new T-matrix is defined to include the effects of frequency modulation that occurs in time-varying phononic crystals. Solutions were verified against finite difference time domain (FDTD) simulations and showed excellent agreement. This new method enables fast characterization of time-varying phononic crystals without the need to resort to lengthy FDTD simulations. Also, the method of combining T-matrices to form the T-supermatrix remains unchanged provided that the new matrix definitions are used. The method is quite compatible with existing implementations of multiple scattering theory and could be readily extended to three-dimensional multiple scattering theory

  1. Production inefficiency of electricity markets with hydro generation

    International Nuclear Information System (INIS)

    Philpott, Andy; Guan, Ziming; Khazaei, Javad; Zakeri, Golbon

    2010-01-01

    Electricity market designs that decentralize decision making for participants can lead to inefficiencies in the presence of nonconvexity or missing markets. This has been shown in the case of unit-commitment problems that can make a decentralized market equilibrium less efficient than a centrally planned solution. Less attention has been focused on systems with large amounts of hydro-electric generation. We describe the results of an empirical study of the New Zealand wholesale electricity market that attempts to quantify production efficiency losses by comparing market outcomes with a counterfactual central plan. (author)

  2. Near real-time imaging of molasses injections using time-lapse electrical geophysics at the Brandywine DRMO, Brandywine, Maryland

    Science.gov (United States)

    Versteeg, R. J.; Johnson, T.; Major, B.; Day-Lewis, F. D.; Lane, J. W.

    2010-12-01

    Enhanced bioremediation, which involves introduction of amendments to promote biodegradation, increasingly is used to accelerate cleanup of recalcitrant compounds and has been identified as the preferred remedial treatment at many contaminated sites. Although blind introduction of amendments can lead to sub-optimal or ineffective remediation, the distribution of amendment throughout the treatment zone is difficult to measure using conventional sampling. Because amendments and their degradation products commonly have electrical properties that differ from those of ambient soil, time-lapse electrical geophysical monitoring has the potential to verify amendment emplacement and distribution. In order for geophysical monitoring to be useful, however, results of the injection ideally should be accessible in near real time. In August 2010, we demonstrated the feasibility of near real-time, autonomous electrical geophysical monitoring of amendment injections at the former Defense Reutilization and Marketing Office (DRMO) in Brandywine, Maryland. Two injections of about 1000 gallons each of molasses, a widely used amendment for enhanced bioremediation, were monitored using measurements taken with borehole and surface electrodes. During the injections, multi-channel resistance data were recorded; data were transmitted to a server and processed using a parallel resistivity inversion code; and results in the form of time-lapse imagery subsequently were posted to a website. This process occurred automatically without human intervention. The resulting time-lapse imagery clearly showed the evolution of the molasses plume. The delay between measurements and online delivery of images was between 45 and 60 minutes, thus providing actionable information that could support decisions about field procedures and a check on whether amendment reached target zones. This experiment demonstrates the feasibility of using electrical imaging as a monitoring tool both during amendment emplacement

  3. Time-varying effect moderation using the structural nested mean model: estimation using inverse-weighted regression with residuals

    Science.gov (United States)

    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

  4. Commercial green electricity products; Zakelijke groenestroomproducten

    Energy Technology Data Exchange (ETDEWEB)

    Wielders, L.M.L.; Afman, M.R.

    2012-12-15

    The Dutch 100% Sustainable Energy: Green ICT campaign initiated by Hivos targets data centres, appealing to these companies to consider the environmental footprint of the electricity they use. Hivos is keen for a debate on greener alternatives and wanted a review of the sustainability of the various options available for buying 'green power' on the commercial market in the Netherlands, with a reasoned discussion of each. That review, laid down in this report, examines and discusses the various 'green power products' for the commercial market, providing a springboard for data centres to switch to a 'greener' product. To that end 'green power products' were categorized to highlight the differences between them. The highest score was given to renewable energy produced without any operating subsidy (the so-called SDE+ scheme), or with the higher price being paid for entirely by customers. Supply in these two categories is still fairly negligible, as this essentially represents an energy market in which renewables are cost-competitive with 'grey' electricity, or one in which customers are willing to pay (far) more for their electricity. The lowest scores were assigned to renewable power sourced in other countries and to 'grey' electricity [Dutch] De Hivos-bedrijvencampagne 100% Sustainable Energy: Green ICT richt zich op de datacenterbedrijven. De datacenterbedrijven worden aangesproken op de duurzaamheid van hun keuze voor de ingekochte elektriciteit. Hivos wil het gesprek aangaan over meer duurzame alternatieven. Hiervoor heeft Hivos behoefte aan een overzicht van de duurzaamheid van de verschillende opties voor de afname van duurzame elektriciteit (groene stroom) zoals die op de zakelijke markt in Nederland worden aangeboden, inclusief een onderbouwing. Dit rapport geeft een overzicht en inzicht in de verschillende groenestroomproducten voor de zakelijke markt zodat de datacenters kunnen overstappen op een

  5. Identification of Time Varying Civil Engineering Structures using Multivariate Recursive Time Domain Models

    DEFF Research Database (Denmark)

    Andersen, P.; Skjærbæk, P. S.; Kirkegaard, Poul Henning

    with the smoothed quanties which have been obtained from SARCOF. The results show the usefulness of the technique for identification of a time varying civil engineering structure. It is found that all the techniques give reliable estiates of the frequencies of the two lowest modes and the first mode shape. Only...

  6. Dashboard: biogas for electricity production - Third quarter 2015

    International Nuclear Information System (INIS)

    Cavaud, Denis

    2015-12-01

    This publication describes the situation of biogas-based electricity production in France and its evolution over the first quarters of 2015. A map indicates the level of connected power per district. Graphs illustrate the evolution of the number of new connections per quarter since 2009, the evolution of electricity quarterly production since 2011. Tables indicate the number of installations per power level (less than 0.5 MW, between 0.5 and 1.0 MW, more than 1 MW) and per installation type. Regional data are given in terms of number of installations, installed power in September 2015 and in December 2015, regional share and evolution

  7. Stochastic analysis of epidemics on adaptive time varying networks

    Science.gov (United States)

    Kotnis, Bhushan; Kuri, Joy

    2013-06-01

    Many studies investigating the effect of human social connectivity structures (networks) and human behavioral adaptations on the spread of infectious diseases have assumed either a static connectivity structure or a network which adapts itself in response to the epidemic (adaptive networks). However, human social connections are inherently dynamic or time varying. Furthermore, the spread of many infectious diseases occur on a time scale comparable to the time scale of the evolving network structure. Here we aim to quantify the effect of human behavioral adaptations on the spread of asymptomatic infectious diseases on time varying networks. We perform a full stochastic analysis using a continuous time Markov chain approach for calculating the outbreak probability, mean epidemic duration, epidemic reemergence probability, etc. Additionally, we use mean-field theory for calculating epidemic thresholds. Theoretical predictions are verified using extensive simulations. Our studies have uncovered the existence of an “adaptive threshold,” i.e., when the ratio of susceptibility (or infectivity) rate to recovery rate is below the threshold value, adaptive behavior can prevent the epidemic. However, if it is above the threshold, no amount of behavioral adaptations can prevent the epidemic. Our analyses suggest that the interaction patterns of the infected population play a major role in sustaining the epidemic. Our results have implications on epidemic containment policies, as awareness campaigns and human behavioral responses can be effective only if the interaction levels of the infected populace are kept in check.

  8. Time-varying long term memory in the European Union stock markets

    Science.gov (United States)

    Sensoy, Ahmet; Tabak, Benjamin M.

    2015-10-01

    This paper proposes a new efficiency index to model time-varying inefficiency in stock markets. We focus on European stock markets and show that they have different degrees of time-varying efficiency. We observe that the 2008 global financial crisis has an adverse effect on almost all EU stock markets. However, the Eurozone sovereign debt crisis has a significant adverse effect only on the markets in France, Spain and Greece. For the late members, joining EU does not have a uniform effect on stock market efficiency. Our results have important implications for policy makers, investors, risk managers and academics.

  9. Real-time pricing when some consumers resist in saving electricity

    International Nuclear Information System (INIS)

    Salies, Evens

    2013-01-01

    Successful real-time electricity pricing depends firstly upon consumers' willingness to subscribe to such terms and, secondly, on their ability to curb consumption levels. The present paper addresses both issues by considering consumers differentiated by their electricity saving costs, half of whom resist saving electricity. We demonstrate that when consumers are free to adopt real-time prices, producers prefer charging inefficient prices and, in so doing, discriminate against that portion of the consumer population which faces no saving costs. We also find that efficient marginal cost pricing is feasible, but is incompatible with mass adoption of real-time prices. - Highlights: • We model consumers switching from uniform to real-time electricity pricing (RTP). • Half the consumer population is pro-RTP and half resists saving electricity. • Efficient RTP is feasible but is incompatible with mass adoption

  10. Adaptive Neural Network Control for Nonlinear Hydraulic Servo-System with Time-Varying State Constraints

    Directory of Open Access Journals (Sweden)

    Shu-Min Lu

    2017-01-01

    Full Text Available An adaptive neural network control problem is addressed for a class of nonlinear hydraulic servo-systems with time-varying state constraints. In view of the low precision problem of the traditional hydraulic servo-system which is caused by the tracking errors surpassing appropriate bound, the previous works have shown that the constraint for the system is a good way to solve the low precision problem. Meanwhile, compared with constant constraints, the time-varying state constraints are more general in the actual systems. Therefore, when the states of the system are forced to obey bounded time-varying constraint conditions, the high precision tracking performance of the system can be easily realized. In order to achieve this goal, the time-varying barrier Lyapunov function (TVBLF is used to prevent the states from violating time-varying constraints. By the backstepping design, the adaptive controller will be obtained. A radial basis function neural network (RBFNN is used to estimate the uncertainties. Based on analyzing the stability of the hydraulic servo-system, we show that the error signals are bounded in the compacts sets; the time-varying state constrains are never violated and all singles of the hydraulic servo-system are bounded. The simulation and experimental results show that the tracking accuracy of system is improved and the controller has fast tracking ability and strong robustness.

  11. An ultrafast programmable electrical tester for enabling time-resolved, sub-nanosecond switching dynamics and programming of nanoscale memory devices

    Science.gov (United States)

    Shukla, Krishna Dayal; Saxena, Nishant; Manivannan, Anbarasu

    2017-12-01

    Recent advancements in commercialization of high-speed non-volatile electronic memories including phase change memory (PCM) have shown potential not only for advanced data storage but also for novel computing concepts. However, an in-depth understanding on ultrafast electrical switching dynamics is a key challenge for defining the ultimate speed of nanoscale memory devices that demands for an unconventional electrical setup, specifically capable of handling extremely fast electrical pulses. In the present work, an ultrafast programmable electrical tester (PET) setup has been developed exceptionally for unravelling time-resolved electrical switching dynamics and programming characteristics of nanoscale memory devices at the picosecond (ps) time scale. This setup consists of novel high-frequency contact-boards carefully designed to capture extremely fast switching transient characteristics within 200 ± 25 ps using time-resolved current-voltage measurements. All the instruments in the system are synchronized using LabVIEW, which helps to achieve various programming characteristics such as voltage-dependent transient parameters, read/write operations, and endurance test of memory devices systematically using short voltage pulses having pulse parameters varied from 1 ns rise/fall time and 1.5 ns pulse width (full width half maximum). Furthermore, the setup has successfully demonstrated strikingly one order faster switching characteristics of Ag5In5Sb60Te30 (AIST) PCM devices within 250 ps. Hence, this novel electrical setup would be immensely helpful for realizing the ultimate speed limits of various high-speed memory technologies for future computing.

  12. Endogenous time-varying risk aversion and asset returns.

    Science.gov (United States)

    Berardi, Michele

    2016-01-01

    Stylized facts about statistical properties for short horizon returns in financial markets have been identified in the literature, but a satisfactory understanding for their manifestation is yet to be achieved. In this work, we show that a simple asset pricing model with representative agent is able to generate time series of returns that replicate such stylized facts if the risk aversion coefficient is allowed to change endogenously over time in response to unexpected excess returns under evolutionary forces. The same model, under constant risk aversion, would instead generate returns that are essentially Gaussian. We conclude that an endogenous time-varying risk aversion represents a very parsimonious way to make the model match real data on key statistical properties, and therefore deserves careful consideration from economists and practitioners alike.

  13. Estimating time-varying exposure-outcome associations using case-control data: logistic and case-cohort analyses.

    Science.gov (United States)

    Keogh, Ruth H; Mangtani, Punam; Rodrigues, Laura; Nguipdop Djomo, Patrick

    2016-01-05

    Traditional analyses of standard case-control studies using logistic regression do not allow estimation of time-varying associations between exposures and the outcome. We present two approaches which allow this. The motivation is a study of vaccine efficacy as a function of time since vaccination. Our first approach is to estimate time-varying exposure-outcome associations by fitting a series of logistic regressions within successive time periods, reusing controls across periods. Our second approach treats the case-control sample as a case-cohort study, with the controls forming the subcohort. In the case-cohort analysis, controls contribute information at all times they are at risk. Extensions allow left truncation, frequency matching and, using the case-cohort analysis, time-varying exposures. Simulations are used to investigate the methods. The simulation results show that both methods give correct estimates of time-varying effects of exposures using standard case-control data. Using the logistic approach there are efficiency gains by reusing controls over time and care should be taken over the definition of controls within time periods. However, using the case-cohort analysis there is no ambiguity over the definition of controls. The performance of the two analyses is very similar when controls are used most efficiently under the logistic approach. Using our methods, case-control studies can be used to estimate time-varying exposure-outcome associations where they may not previously have been considered. The case-cohort analysis has several advantages, including that it allows estimation of time-varying associations as a continuous function of time, while the logistic regression approach is restricted to assuming a step function form for the time-varying association.

  14. Structural nested mean models for assessing time-varying effect moderation.

    Science.gov (United States)

    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.

  15. The real-time price elasticity of electricity

    NARCIS (Netherlands)

    Lijesen, M.G.

    2007-01-01

    The real-time price elasticity of electricity contains important information on the demand response of consumers to the volatility of peak prices. Despite the importance, empirical estimates of the real-time elasticity are hardly available. This paper provides a quantification of the real-time

  16. Managing time-substitutable electricity usage using dynamic controls

    Science.gov (United States)

    Ghosh, Soumyadip; Hosking, Jonathan R.; Natarajan, Ramesh; Subramaniam, Shivaram; Zhang, Xiaoxuan

    2017-02-21

    A predictive-control approach allows an electricity provider to monitor and proactively manage peak and off-peak residential intra-day electricity usage in an emerging smart energy grid using time-dependent dynamic pricing incentives. The daily load is modeled as time-shifted, but cost-differentiated and substitutable, copies of the continuously-consumed electricity resource, and a consumer-choice prediction model is constructed to forecast the corresponding intra-day shares of total daily load according to this model. This is embedded within an optimization framework for managing the daily electricity usage. A series of transformations are employed, including the reformulation-linearization technique (RLT) to obtain a Mixed-Integer Programming (MIP) model representation of the resulting nonlinear optimization problem. In addition, various regulatory and pricing constraints are incorporated in conjunction with the specified profit and capacity utilization objectives.

  17. Managing time-substitutable electricity usage using dynamic controls

    Science.gov (United States)

    Ghosh, Soumyadip; Hosking, Jonathan R.; Natarajan, Ramesh; Subramaniam, Shivaram; Zhang, Xiaoxuan

    2017-02-07

    A predictive-control approach allows an electricity provider to monitor and proactively manage peak and off-peak residential intra-day electricity usage in an emerging smart energy grid using time-dependent dynamic pricing incentives. The daily load is modeled as time-shifted, but cost-differentiated and substitutable, copies of the continuously-consumed electricity resource, and a consumer-choice prediction model is constructed to forecast the corresponding intra-day shares of total daily load according to this model. This is embedded within an optimization framework for managing the daily electricity usage. A series of transformations are employed, including the reformulation-linearization technique (RLT) to obtain a Mixed-Integer Programming (MIP) model representation of the resulting nonlinear optimization problem. In addition, various regulatory and pricing constraints are incorporated in conjunction with the specified profit and capacity utilization objectives.

  18. Potential for reducing global carbon emissions from electricity production-A benchmarking analysis

    International Nuclear Information System (INIS)

    Ang, B.W.; Zhou, P.; Tay, L.P.

    2011-01-01

    We present five performance indicators for electricity generation for 129 countries using the 2005 data. These indicators, measured at the national level, are the aggregate CO 2 intensity of electricity production, the efficiencies of coal, oil and gas generation and the share of electricity produced from non-fossil fuels. We conduct a study on the potential for reducing global energy-related CO 2 emissions from electricity production through simple benchmarking. This is performed based on the last four performance indicators and the construction of a cumulative curve for each of these indicators. It is found that global CO 2 emissions from electricity production would be reduced by 19% if all these indicators are benchmarked at the 50th percentile. Not surprisingly, the emission reduction potential measured in absolute terms is the highest for large countries such as China, India, Russia and the United States. When the potential is expressed as a percentage of a country's own emissions, few of these countries appear in the top-five list. - Research highlights: → We study variations in emissions per kWh of electricity generated among countries. → We analyze emissions from electricity production through benchmarking. → Estimates of reduction in emissions are made based on different assumptions.

  19. Impact of variable renewable production on electricity prices in Germany: a Markov switching model

    International Nuclear Information System (INIS)

    Martin de Lagarde, Cyril; Lantz, Frederic

    2016-01-01

    transition between the two regimes to vary over time, following a binomial logistic link with the relative share of RES production. This analysis shows that both wind and solar productions have a significant impact on the switching mechanism, especially on the probability of switching from the high-price regime to the low-price one, and consequently on the expected duration of each regime. However, the effect of wind production on the probabilities is much higher than the effect of solar production, whereas they have a rather similar marginal effect on the price. Finally, although the regimes are sometimes highly correlated with some hours of the day, their endogenous determination (opposed to a semi-deterministic approach with dummy variables, for example) gives flexibility and keeps the model parsimonious. (authors)

  20. Safety policy in the production of electricity

    International Nuclear Information System (INIS)

    Siddall, E.

    1982-01-01

    When safety is properly understood, defined and quantified, it can be seen that the development of our present industrial civilization has resulted in a progressive improvement in human safety. Increased safety has come with increased wealth in such close association that a high degree of cause-and-effect relationship must be considered. The quantitative relationship between wealth production and safety improvement is derived from different sources of evidence. When this is applied to the wealth production from electricity generation in a standard module of population in an advanced society, a safety benefit is indicated which exceeds the assessed direct risk associated with the electricity generation by orders of magnitude. It appears that a goal or policy intended to confer the greatest safety benefit to the population would result in attitudes and actions diametrically opposite to those which are conventional at the moment

  1. Internalization of external cost for the production and distribution of electricity in Flanders, Belgium

    International Nuclear Information System (INIS)

    Torfs, R.; De Nocker, L.; Schrooten, L.; Aernouts, K.; Liekens, I.

    2005-04-01

    This report elaborates the external costs of electricity production and distribution in Flanders, Belgium, and tests them against prices and taxes for electricity use. The authors examined whether these external costs decrease in time and whether such a decrease leads to internalization in the price for the users through taxes, levies or other economic instruments. The external costs mainly include external environmental costs caused by air pollution and greenhouse gases, but also damage caused by accidents, hindrance and radioactive substances that may be released. [nl

  2. Local inertial oscillations in the surface ocean generated by time-varying winds

    Science.gov (United States)

    Chen, Shengli; Polton, Jeff A.; Hu, Jianyu; Xing, Jiuxing

    2015-12-01

    A new relationship is presented to give a review study on the evolution of inertial oscillations in the surface ocean locally generated by time-varying wind stress. The inertial oscillation is expressed as the superposition of a previous oscillation and a newly generated oscillation, which depends upon the time-varying wind stress. This relationship is employed to investigate some idealized wind change events. For a wind series varying temporally with different rates, the induced inertial oscillation is dominated by the wind with the greatest variation. The resonant wind, which rotates anti-cyclonically at the local inertial frequency with time, produces maximal amplitude of inertial oscillations, which grows monotonically. For the wind rotating at non-inertial frequencies, the responses vary periodically, with wind injecting inertial energy when it is in phase with the currents, but removing inertial energy when it is out of phase. The wind rotating anti-cyclonically with time is much more favorable to generate inertial oscillations than the cyclonic rotating wind. The wind with a frequency closer to the inertial frequency generates stronger inertial oscillations. For a diurnal wind, the induced inertial oscillation is dependent on latitude and is most significant at 30 °. This relationship is also applied to examine idealized moving cyclones. The inertial oscillation is much stronger on the right-hand side of the cyclone path than on the left-hand side (in the northern hemisphere). This is due to the wind being anti-cyclonic with time on the right-hand side, but cyclonic on the other side. The inertial oscillation varies with the cyclone translation speed. The optimal translation speed generating the greatest inertial oscillations is 2 m/s at the latitude of 10 ° and gradually increases to 6 m/s at the latitude of 30 °.

  3. The Electric Traveling Salesman Problem with Time Windows

    DEFF Research Database (Denmark)

    Roberti, Roberto; Wen, Min

    2016-01-01

    To minimize greenhouse gas emissions, the logistic field has seen an increasing usage of electric vehicles. The resulting distribution planning problems present new computational challenges.We address a problem, called Electric Traveling Salesman Problem with Time Windows. We propose a mixed...

  4. Network Coded Cooperation Over Time-Varying Channels

    DEFF Research Database (Denmark)

    Khamfroush, Hana; Roetter, Daniel Enrique Lucani; Barros, João

    2014-01-01

    transmissions, e.g., in terms of the rate of packet transmission or the energy consumption. A comprehensive analysis of the MDP solution is carried out under different network conditions to extract optimal rules of packet transmission. Inspired by the extracted rules, we propose two near-optimal heuristics......In this paper, we investigate the optimal design of cooperative network-coded strategies for a three-node wireless network with time-varying, half-duplex erasure channels. To this end, we formulate the problem of minimizing the total cost of transmitting M packets from source to two receivers...... as a Markov Decision Process (MDP). The actions of the MDP model include the source and the type of transmission to be used in a given time slot given perfect knowledge of the system state. The cost of packet transmission is defined such that it can incorporate the difference between broadcast and unicast...

  5. Quite time convection electric field properties derived from keV electron measurements at the inner edge of the plasma sheet by means of GEOS 2

    International Nuclear Information System (INIS)

    Reme, H.; Kremser, G.; Bahnsen, A.; Jespersen, M.; Hultqvist, B.; Borg, H.; Holmgren, L.Aa.

    1981-04-01

    From an analysis of the local time distribution of the electron upper energy limit reached by the geostationary satellite GEOS 2 in cutting through the innermost part of the electron plasma sheet during fairly quite condition the following results have been obtained, among others: An electric field model given by E = -grad(AR 4 sinphi), with the dusk singular point of the forbidden region boundary at 1500, instead of at 1800 MLT, is in quite good agreement with the observations. This means that effects due to the shielding by the hot plasma of the inner magnetosphere from the convection electric field are quite strong in situations of low disturbance level. The quiet time convection electric field strength at 2100 MLT in the geostationary orbit obtained from this analysis varies in the range 0.15 - 0.3 keV/Rsub(e). Six hours earlier or later in the satellite orbit the convection field is 4 times stronger. Also when the convection field varies, some information about its magnitude can be obtained from the keV electron measurements. (author)

  6. Time dependent charging of layer clouds in the global electric circuit

    Science.gov (United States)

    Zhou, Limin; Tinsley, Brian A.

    2012-09-01

    clean air being about a minute. The charging timescale is also a strong function of droplet size, with the rate for 15 μm radii droplets being about 70% longer than that for 10 μm droplets, and the rate for 5 μm radii droplets being about 50% smaller. The equilibrium charges accumulated on droplets ranged from tens to hundreds of elementary charges, which is comparable to observed values, and to vary approximately directly with Jz and inversely with the ion production rate q, which is due to the Galactic Cosmic Ray (GCR) flux and depends strongly on altitude.For the case of Jz varying directly with q, which to some extent is the case during Forbush decreases of the GCR flux, the effects on the equilibrium charge tend to cancel. In one run with the model, both q and Jz were decreased by 30%. There was little change in equilibrium charge, but the timescale for charging increased by about 40%, or equivalently, the rate of charging decreased by about 40%. Thus, for exploring the hypothesis that space charge provides a link between GCR (and other inputs that modulate Jz) and changes in clouds and atmospheric dynamics, it is necessary to consider variations in the rate of charging. The present work is intended to provide illustrative examples of time dependent charging for several different types of layer clouds.

  7. Optimum Design of Multi-Function Robot Arm Gripper for Varying Shape Green Product

    Directory of Open Access Journals (Sweden)

    Razali Zol Bahri

    2016-01-01

    Full Text Available The project focuses on thorough experimentally studies of the optimum design of Multi-function Robot Arm Gripper for varying shape green product. The purpose of this project is to design a few of robot arm gripper for multi-functionally grip a green product with varying shape. The main character of the gripper is that it can automated adjust its finger to suit with the shape of the product. An optimum design of multi-function robot arm gripper is verified through experimental study. The expected result is a series of analytical results on the proposal of gripper design and material that will be selected for the gripper. The analysis of the gripper design proposal by using ANSYS and CATIA software is described in detail in this paper.

  8. Frequency-scanning interferometry using a time-varying Kalman filter for dynamic tracking measurements.

    Science.gov (United States)

    Jia, Xingyu; Liu, Zhigang; Tao, Long; Deng, Zhongwen

    2017-10-16

    Frequency scanning interferometry (FSI) with a single external cavity diode laser (ECDL) and time-invariant Kalman filtering is an effective technique for measuring the distance of a dynamic target. However, due to the hysteresis of the piezoelectric ceramic transducer (PZT) actuator in the ECDL, the optical frequency sweeps of the ECDL exhibit different behaviors, depending on whether the frequency is increasing or decreasing. Consequently, the model parameters of Kalman filter appear time varying in each iteration, which produces state estimation errors with time-invariant filtering. To address this, in this paper, a time-varying Kalman filter is proposed to model the instantaneous movement of a target relative to the different optical frequency tuning durations of the ECDL. The combination of the FSI method with the time-varying Kalman filter was theoretically analyzed, and the simulation and experimental results show the proposed method greatly improves the performance of dynamic FSI measurements.

  9. A behavioral asset pricing model with a time-varying second moment

    International Nuclear Information System (INIS)

    Chiarella, Carl; He Xuezhong; Wang, Duo

    2006-01-01

    We develop a simple behavioral asset pricing model with fundamentalists and chartists in order to study price behavior in financial markets when chartists estimate both conditional mean and variance by using a weighted averaging process. Through a stability, bifurcation, and normal form analysis, the market impact of the weighting process and time-varying second moment are examined. It is found that the fundamental price becomes stable (unstable) when the activities from both types of traders are balanced (unbalanced). When the fundamental price becomes unstable, the weighting process leads to different price dynamics, depending on whether the chartists act as either trend followers or contrarians. It is also found that a time-varying second moment of the chartists does not change the stability of the fundamental price, but it does influence the stability of the bifurcations. The bifurcation becomes stable (unstable) when the chartists are more (less) concerned about the market risk characterized by the time-varying second moment. Different routes to complicated price dynamics are also observed. The analysis provides an analytical foundation for the statistical analysis of the corresponding stochastic version of this type of behavioral model

  10. Historical plant cost and annual production expenses for selected electric plants, 1982

    International Nuclear Information System (INIS)

    1984-01-01

    This publication is a composite of the two prior publications, Hydroelectric Plant Construction Cost and Annual Production Expenses and Thermal-Electric Plant Construction Cost and Annual Production Expenses. Beginning in 1979, Thermal-Electric Plant Construction Cost and Annual Production Expenses contained information on both steam-electric and gas-turbine electric plant construction cost and annual production expenses. The summarized historical plant cost described under Historical Plant Cost in this report is the net cumulative-to-date actual outlays or expenditures for land, structures, and equipment to the utility. Historical plant cost is the initial investment in plant (cumulative to the date of initial commercial operation) plus the costs of all additions to the plant, less the value of retirements. Thus, historical plant cost includes expenditures made over several years, as modifications are made to the plant. Power Production Expenses is the reporting year's plant operation and maintenance expenses, including fuel expenses. These expenses do not include annual fixed charges on plant cost (capital costs) such as interest on debt, depreciation or amortization expenses, and taxes. Consequently, total production expenses and the derived unit costs are not the total cost of producing electric power at the various plants. This publication contains data on installed generating capacity, net generation, net capability, historical plant cost, production expenses, fuel consumption, physical and operating plant characteristics, and other relevant statistical information for selected plants

  11. Estimating time-varying exposure-outcome associations using case-control data: logistic and case-cohort analyses

    Directory of Open Access Journals (Sweden)

    Ruth H. Keogh

    2016-01-01

    Full Text Available Abstract Background Traditional analyses of standard case-control studies using logistic regression do not allow estimation of time-varying associations between exposures and the outcome. We present two approaches which allow this. The motivation is a study of vaccine efficacy as a function of time since vaccination. Methods Our first approach is to estimate time-varying exposure-outcome associations by fitting a series of logistic regressions within successive time periods, reusing controls across periods. Our second approach treats the case-control sample as a case-cohort study, with the controls forming the subcohort. In the case-cohort analysis, controls contribute information at all times they are at risk. Extensions allow left truncation, frequency matching and, using the case-cohort analysis, time-varying exposures. Simulations are used to investigate the methods. Results The simulation results show that both methods give correct estimates of time-varying effects of exposures using standard case-control data. Using the logistic approach there are efficiency gains by reusing controls over time and care should be taken over the definition of controls within time periods. However, using the case-cohort analysis there is no ambiguity over the definition of controls. The performance of the two analyses is very similar when controls are used most efficiently under the logistic approach. Conclusions Using our methods, case-control studies can be used to estimate time-varying exposure-outcome associations where they may not previously have been considered. The case-cohort analysis has several advantages, including that it allows estimation of time-varying associations as a continuous function of time, while the logistic regression approach is restricted to assuming a step function form for the time-varying association.

  12. Time-dependent correlations in electricity markets

    International Nuclear Information System (INIS)

    Alvarez-Ramirez, Jose; Escarela-Perez, Rafael

    2010-01-01

    In the last years, many electricity markets were subjected to deregulated operation where prices are set by the action of market participants. In this form, producers and consumers rely on demand and price forecasts to decide their bidding strategies, allocate assets, negotiate bilateral contracts, hedge risks, and plan facility investments. A basic feature of efficient market hypothesis is the absence of correlations between price increments over any time scale leading to random walk-type behavior of prices, so arbitrage is not possible. However, recent studies have suggested that this is not the case and correlations are present in the behavior of diverse electricity markets. In this paper, a temporal quantification of electricity market correlations is made by means of detrended fluctuation and Allan analyses. The approach is applied to two Canadian electricity markets, Ontario and Alberta. The results show the existence of correlations in both demand and prices, exhibiting complex time-dependent behavior with lower correlations in winter while higher in summer. Relatively steady annual cycles in demand but unstable cycles in prices are detected. On the other hand, the more significant nonlinear effects (measured in terms of a multifractality index) are found for winter months, while the converse behavior is displayed during the summer period. In terms of forecasting models, our results suggest that nonlinear recursive models (e.g., feedback NNs) should be used for accurate day-ahead price estimation. In contrast, linear models can suffice for demand forecasting purposes. (author)

  13. Robust stabilisation of time-varying delay systems with probabilistic uncertainties

    Science.gov (United States)

    Jiang, Ning; Xiong, Junlin; Lam, James

    2016-09-01

    For robust stabilisation of time-varying delay systems, only sufficient conditions are available to date. A natural question is as follows: if the existing sufficient conditions are not satisfied, and hence no controllers can be found, what can one do to improve the stability performance of time-varying delay systems? This question is addressed in this paper when there is a probabilistic structure on the parameter uncertainty set. A randomised algorithm is proposed to design a state-feedback controller, which stabilises the system over the uncertainty domain in a probabilistic sense. The capability of the designed controller is quantified by the probability of stability of the resulting closed-loop system. The accuracy of the solution obtained from the randomised algorithm is also analysed. Finally, numerical examples are used to illustrate the effectiveness and advantages of the developed controller design approach.

  14. Robust Stabilization of Discrete-Time Systems with Time-Varying Delay: An LMI Approach

    Directory of Open Access Journals (Sweden)

    Valter J. S. Leite

    2008-01-01

    Full Text Available Sufficient linear matrix inequality (LMI conditions to verify the robust stability and to design robust state feedback gains for the class of linear discrete-time systems with time-varying delay and polytopic uncertainties are presented. The conditions are obtained through parameter-dependent Lyapunov-Krasovskii functionals and use some extra variables, which yield less conservative LMI conditions. Both problems, robust stability analysis and robust synthesis, are formulated as convex problems where all system matrices can be affected by uncertainty. Some numerical examples are presented to illustrate the advantages of the proposed LMI conditions.

  15. Industry evolution, rational agents and the transition to sustainable electricity production

    Energy Technology Data Exchange (ETDEWEB)

    Safarzynska, Karolina, E-mail: ksafarzy@wu.ac.at [Institute for the Environment and Regional Development, WU Vienna University of Economics and Business, Nordbergstrasse 15 (UZA4, 4B), A-1090 Vienna (Austria); Bergh, Jeroen C.J.M. van den, E-mail: jeroen.bergh@uab.es [ICREA, Barcelona (Spain); Institute for Environmental Science and Technology and Department of Economics and Economic History, Universitat Autonoma de Barcelona, Edifici Cn-Campus UAB, 08193 Bellaterra (Spain); Faculty of Economics and Business Administration, and the Institute for Environmental Studies, VU University Amsterdam (Netherlands); Fellow of Tinbergen Institute and NAKE (Netherlands)

    2011-10-15

    Guiding a transition to low carbon electricity requires a good understanding of the substitution of old by new technologies in the electricity industry. With the aim of explaining historical change from coal to gas in the British electricity industry, we develop a formal model of technological change, where energy technologies diffuse through the construction of new power plants. We considered two model versions: with rational and boundedly rational investors. In each model version, we look at the causal relations between price and output setting mechanisms, fuel and labour use, and investment decisions for different institutional arrangements. We quantify model parameters on data for the United Kingdom. We find that the version of the model with rational investors is capable of replicating well core features of UK electricity history. This includes a rapid diffusion of gas in electricity production, the evolution of the average size of newly installed plants, and a high percentage of electricity sales covered by (forward) contracts-for-difference. In this model setting, nuclear and renewable energies have no chance to diffuse on the market. In the version of the model with boundedly rational investors, nuclear power typically dominates electricity production. We discuss implications of our modelling results for making a transition to low carbon electricity in the future. - Highlights: > We propose a model of a transition from coal to gas in electricity production. > Energy technologies diffuse through the construction of new power plants. > We considered two model versions: with rational and boundedly rational investors. > We quantify model parameters on data for the UK for the period 1990-2002. > We draw policy conclusions for guiding a transition to low carbon electricity.

  16. Industry evolution, rational agents and the transition to sustainable electricity production

    International Nuclear Information System (INIS)

    Safarzynska, Karolina; Bergh, Jeroen C.J.M. van den

    2011-01-01

    Guiding a transition to low carbon electricity requires a good understanding of the substitution of old by new technologies in the electricity industry. With the aim of explaining historical change from coal to gas in the British electricity industry, we develop a formal model of technological change, where energy technologies diffuse through the construction of new power plants. We considered two model versions: with rational and boundedly rational investors. In each model version, we look at the causal relations between price and output setting mechanisms, fuel and labour use, and investment decisions for different institutional arrangements. We quantify model parameters on data for the United Kingdom. We find that the version of the model with rational investors is capable of replicating well core features of UK electricity history. This includes a rapid diffusion of gas in electricity production, the evolution of the average size of newly installed plants, and a high percentage of electricity sales covered by (forward) contracts-for-difference. In this model setting, nuclear and renewable energies have no chance to diffuse on the market. In the version of the model with boundedly rational investors, nuclear power typically dominates electricity production. We discuss implications of our modelling results for making a transition to low carbon electricity in the future. - Highlights: → We propose a model of a transition from coal to gas in electricity production. → Energy technologies diffuse through the construction of new power plants. → We considered two model versions: with rational and boundedly rational investors. → We quantify model parameters on data for the UK for the period 1990-2002. → We draw policy conclusions for guiding a transition to low carbon electricity.

  17. Robust stability analysis of uncertain stochastic neural networks with interval time-varying delay

    International Nuclear Information System (INIS)

    Feng Wei; Yang, Simon X.; Fu Wei; Wu Haixia

    2009-01-01

    This paper addresses the stability analysis problem for uncertain stochastic neural networks with interval time-varying delays. The parameter uncertainties are assumed to be norm bounded, and the delay factor is assumed to be time-varying and belong to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. A sufficient condition is derived such that for all admissible uncertainties, the considered neural network is robustly, globally, asymptotically stable in the mean square. Some stability criteria are formulated by means of the feasibility of a linear matrix inequality (LMI), which can be effectively solved by some standard numerical packages. Finally, numerical examples are provided to demonstrate the usefulness of the proposed criteria.

  18. Nonlinearly Activated Neural Network for Solving Time-Varying Complex Sylvester Equation.

    Science.gov (United States)

    Li, Shuai; Li, Yangming

    2013-10-28

    The Sylvester equation is often encountered in mathematics and control theory. For the general time-invariant Sylvester equation problem, which is defined in the domain of complex numbers, the Bartels-Stewart algorithm and its extensions are effective and widely used with an O(n³) time complexity. When applied to solving the time-varying Sylvester equation, the computation burden increases intensively with the decrease of sampling period and cannot satisfy continuous realtime calculation requirements. For the special case of the general Sylvester equation problem defined in the domain of real numbers, gradient-based recurrent neural networks are able to solve the time-varying Sylvester equation in real time, but there always exists an estimation error while a recently proposed recurrent neural network by Zhang et al [this type of neural network is called Zhang neural network (ZNN)] converges to the solution ideally. The advancements in complex-valued neural networks cast light to extend the existing real-valued ZNN for solving the time-varying real-valued Sylvester equation to its counterpart in the domain of complex numbers. In this paper, a complex-valued ZNN for solving the complex-valued Sylvester equation problem is investigated and the global convergence of the neural network is proven with the proposed nonlinear complex-valued activation functions. Moreover, a special type of activation function with a core function, called sign-bi-power function, is proven to enable the ZNN to converge in finite time, which further enhances its advantage in online processing. In this case, the upper bound of the convergence time is also derived analytically. Simulations are performed to evaluate and compare the performance of the neural network with different parameters and activation functions. Both theoretical analysis and numerical simulations validate the effectiveness of the proposed method.

  19. Forecasting of energy and diesel consumption and the cost of energy production in isolated electrical systems in the Amazon using a fuzzification process in time series models

    Energy Technology Data Exchange (ETDEWEB)

    Neto, Joao C. do L, E-mail: jcaldas@ufam.edu.br [Group of Optimization and Fuzzy Systems, Federal University of Amazonas, General Rodrigo Octavio Jordao Ramos Avenue, 3000, Academic Campus, 69077-000 Manaus, Amazonas (Brazil); Costa Junior, Carlos T. da [Postgraduate Program in Electrical Engineering, Institute of Technology, Federal University of Para, Augusto Correa Street, 1, Guama, 66075-900 Belem, Para (Brazil); Bitar, Sandro D.B. [Group of Optimization and Fuzzy Systems, Federal University of Amazonas, General Rodrigo Octavio Jordao Ramos Avenue, 3000, Academic Campus, 69077-000 Manaus, Amazonas (Brazil); Junior, Walter B. [Postgraduate Program in Electrical Engineering, Institute of Technology, Federal University of Para, Augusto Correa Street, 1, Guama, 66075-900 Belem, Para (Brazil)

    2011-09-15

    Understanding the uncertainty inherent in the analysis of diesel fuel consumption and its impact on the generation of electricity is an important topic for planning the expansion of isolated thermoelectric systems in the state of Amazonas. In light of this, a decision support system has been developed to forecast the cost of electricity production using non-stationary data by integrating the methodology of time series models with fuzzy systems and optimization tools. The method presented herein combines the potential of the Autoregressive Integrated Moving Average (ARIMA) and the Seasonal ARIMA (SARIMA) models, such as the forecasting tool, with the advantages of fuzzy set theory to compensate for the uncertainties and errors encountered in the observed data, which would degrade the validity of forecasted values. The results show that incorporation of the {alpha}-cut concept facilitated the evaluation of risks while allowing simultaneous consideration of intervals for the unitary cost of energy production. This provides the analyst with the ability to make decisions using various predicted intervals with different membership values instead of the common practice of simply using the specific costs. - Highlights: > A decision support system has been developed using SARIMA with fuzzy systems and optimizations tools. > It assists the decision-making process for planning the expansion in isolated thermoelectric systems. > The {alpha}-cut concept facilitated the evaluation of risks for the cost of electricity production. > Provides decisions using various forecasted interval for this cost with different membership values.

  20. Forecasting of energy and diesel consumption and the cost of energy production in isolated electrical systems in the Amazon using a fuzzification process in time series models

    International Nuclear Information System (INIS)

    Neto, Joao C. do L; Costa Junior, Carlos T. da; Bitar, Sandro D.B.; Junior, Walter B.

    2011-01-01

    Understanding the uncertainty inherent in the analysis of diesel fuel consumption and its impact on the generation of electricity is an important topic for planning the expansion of isolated thermoelectric systems in the state of Amazonas. In light of this, a decision support system has been developed to forecast the cost of electricity production using non-stationary data by integrating the methodology of time series models with fuzzy systems and optimization tools. The method presented herein combines the potential of the Autoregressive Integrated Moving Average (ARIMA) and the Seasonal ARIMA (SARIMA) models, such as the forecasting tool, with the advantages of fuzzy set theory to compensate for the uncertainties and errors encountered in the observed data, which would degrade the validity of forecasted values. The results show that incorporation of the α-cut concept facilitated the evaluation of risks while allowing simultaneous consideration of intervals for the unitary cost of energy production. This provides the analyst with the ability to make decisions using various predicted intervals with different membership values instead of the common practice of simply using the specific costs. - Highlights: → A decision support system has been developed using SARIMA with fuzzy systems and optimizations tools. → It assists the decision-making process for planning the expansion in isolated thermoelectric systems. → The α-cut concept facilitated the evaluation of risks for the cost of electricity production. → Provides decisions using various forecasted interval for this cost with different membership values.

  1. Delay-Dependent Exponential Stability for Discrete-Time BAM Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Yonggang Chen

    2008-01-01

    Full Text Available This paper considers the delay-dependent exponential stability for discrete-time BAM neural networks with time-varying delays. By constructing the new Lyapunov functional, the improved delay-dependent exponential stability criterion is derived in terms of linear matrix inequality (LMI. Moreover, in order to reduce the conservativeness, some slack matrices are introduced in this paper. Two numerical examples are presented to show the effectiveness and less conservativeness of the proposed method.

  2. Effects of Variable Production Rate and Time-Dependent Holding Cost for Complementary Products in Supply Chain Model

    Directory of Open Access Journals (Sweden)

    Mitali Sarkar

    2017-01-01

    Full Text Available Recently, a major trend is going to redesign a production system by controlling or making variable the production rate within some fixed interval to maintain the optimal level. This strategy is more effective when the holding cost is time-dependent as it is interrelated with holding duration of products and rate of production. An effort is made to make a supply chain model (SCM to show the joint effect of variable production rate and time-varying holding cost for specific type of complementary products, where those products are made by two different manufacturers and a common retailer makes them bundle and sells bundles to end customers. Demand of each product is specified by stochastic reservation prices with a known potential market size. Those players of the SCM are considered with unequal power. Stackelberg game approach is employed to obtain global optimum solution of the model. An illustrative numerical example, graphical representation, and managerial insights are given to illustrate the model. Results prove that variable production rate and time-dependent holding cost save more than existing literature.

  3. Sojourn time asymptotics in Processor Sharing queues with varying service rate

    NARCIS (Netherlands)

    Egorova, R.; Mandjes, M.R.H.; Zwart, B.

    2007-01-01

    Abstract This paper addresses the sojourn time asymptotics for a GI/GI/⋅ queue operating under the Processor Sharing (PS) discipline with stochastically varying service rate. Our focus is on the logarithmic estimates of the tail of sojourn-time distribution, under the assumption that the job-size

  4. Safety policy in the production of electricity

    International Nuclear Information System (INIS)

    Siddall, E.

    1983-01-01

    When safety is properly understood, defined and quantified, it can be seen that the development of our present industrial civilization has resulted in a progressive and great improvement in human safety which is still continuing. Increased safety has come with increased wealth in such close association that a high degree of cause-and-effect relationship must be considered. The quantitative relationship between wealth production and safety improvement is derived from different sources of evidence. When this is applied to the wealth production from electricity generation in a standard module of population in an advanced society, a safety benefit is indicated which exceeds the assessed direct risk associated with the electricity generation by orders of magnitude. It appears that a goal or policy intended to confer the greatest safety benefit to the population would result in attitudes and actions diametrically opposite to those which are conventional at the moment

  5. Time development of electric fields and currents in space plasmas

    Directory of Open Access Journals (Sweden)

    A. T. Y. Lui

    2006-05-01

    Full Text Available Two different approaches, referred to as Bu and Ej, can be used to examine the time development of electric fields and currents in space plasmas based on the fundamental laws of physics. From the Bu approach, the required equation involves the generalized Ohm's law with some simplifying assumptions. From the Ej approach, the required equation can be derived from the equation of particle motion, coupled self-consistently with Maxwell's equation, and the definition of electric current density. Recently, some strong statements against the Ej approach have been made. In this paper, we evaluate these statements by discussing (1 some limitations of the Bu approach in solving the time development of electric fields and currents, (2 the procedure in calculating self-consistently the time development of the electric current in space plasmas without taking the curl of the magnetic field in some cases, and (3 the dependency of the time development of magnetic field on electric current. It is concluded that the Ej approach can be useful to understand some magnetospheric problems. In particular, statements about the change of electric current are valid theoretical explanations of change in magnetic field during substorms.

  6. A Method of Time-Varying Rayleigh Channel Tracking in MIMO Radio System

    Institute of Scientific and Technical Information of China (English)

    GONG Yan-fei; HE Zi-shu; HAN Chun-lin

    2005-01-01

    A method of MIMO channel tracking based on Kalman filter and MMSE-DFE is proposed. The Kalman filter tracks the time-varying channel by using the MMSE-DFE decision and the MMSE-DFE conducts the next decision by using the channel estimates produced by the Kalman filter. Polynomial fitting is used to bridge the gap between the channel estimates produced by the Kalman filter and those needed for the DFE decision. Computer simulation demonstrates that this method can track the MIMO time-varying channel effectively.

  7. Adopting small-scale production of electricity

    Energy Technology Data Exchange (ETDEWEB)

    Tengvard, Maria; Palm, Jenny (Linkoeping Univ., Dept. of Technology and Social Change, Linkoeping (Sweden)). e-mail: maria.tengvard@liu.se

    2009-07-01

    In Sweden in 2008, a 'new' concept for small-scale electricity production attracted massive media attention. This was mainly due to the efforts of Swedish company Egen El, which is marketing small-scale photovoltaics (PVs) and wind turbines to households, both homeowners and tenants. Their main selling point is simplicity: their products are so easy to install that everyone can do it. Autumn 2008 also saw IKEA announce that within three years it would market solar panels. How, then, do households perceive these products? Why would households choose to buy them? How do households think about producing their own electricity? Analysis of material based on in-depth interviews with members of 20 households reveals that environmental concerns supply the main motive for adopting PVs or micro wind power generation. In some cases, the adopting households have an extensively ecological lifestyle and such adoption represents a way to take action in the energy area. For some, this investment is symbolic: a way of displaying environmental consciousness or setting an example to others. For still others, the adoption is a protest against 'the system' with its large dominant actors or is a way to become self-sufficient. These microgeneration installations are rejected mainly on economic grounds; other motives are respect for neighbours and difficulties finding a place to install a wind turbine.

  8. Comparison of control systems for the optimisation of ice storage in a dynamic real time electricity pricing environment

    International Nuclear Information System (INIS)

    Murphy, M.D.; O’Mahony, M.J.; Upton, J.

    2015-01-01

    Highlights: • A cold thermal energy storage system model was created and validated. • Pseudo real time electricity pricing was derived to represent the smart grid. • A demand side management optimisation algorithm was developed. • Demand side management algorithm performance was compared to a standard controller. • Overall the demand side management algorithm produced modest cost savings. - Abstract: The objective of this study was to assess the benefits of introducing a demand side management optimisation controller to a cold thermal storage ice bank. This controller consisted of an ice bank model, an air temperature forecast model and an optimisation algorithm. The financial and grid utilisation benefits produced by implementation of this controller over the current state of the art in ice bank load shifting control was tested in a day ahead real time electricity pricing forecast environment. This hypothetical real time electricity price was based on the cost of electricity in the Irish wholesale market. Multiple ice bank charge levels were simulated in order to quantify the performance of two control methods for varying operating conditions. First, the “standard controller” was based on the current modus operandi for ice bank systems where ice was generated for food cooling at night when the off-peak electricity tariff is available (00:00–08:00 h). Second, the “upgraded controller” was developed as a bespoke Demand Side Management control system for food refrigeration in a future electricity pricing environment. It consisted of a dual function load shifting optimisation algorithm, an ice bank model, and a predictive air temperature model. A preliminary study was also carried out to test the robustness of the controller’s performance in an uncertain real time electricity pricing forecast scenario. Both economic and grid management benefits were found by simulating the operation of the cold thermal storage load shifting controller in a

  9. Electric power production contra electricity savings

    International Nuclear Information System (INIS)

    Schleisner, L.; Grohnheit, P.E.; Soerensen, H.

    1991-01-01

    The expansion of electricity-producing plants has, in Denmark until now, taken place in accordance with the demand for electricity. Recently, it has been suggested that the cost of the further development of such systems is greater than the cost of instigating and carrying out energy conservation efforts. The aim of the project was to evaluate the consequences for power producing plants of a reduction of the electricity consumption of end-users. A method for the analysis of the costs involved in the system and operation of power plants contra the costs that are involved in saving electricity is presented. In developing a model of this kind, consideration is given to the interplay of the individual saving project and the existing or future electricity supply. Thus it can be evaluated to what extent it would be advisable to substitute investments in the development of the capacity of the power plants with investments in the reduction of electricity consumption by the end users. This model is described in considerable detail. It will be tested in representative situations and locations throughout the Nordic countries. (AB) 17 refs

  10. Models of quality-adjusted life years when health varies over time

    DEFF Research Database (Denmark)

    Hansen, Kristian Schultz; Østerdal, Lars Peter Raahave

    2006-01-01

    Qualityadjusted life year (QALY) models are widely used for economic evaluation in the health care sector. In the first part of the paper, we establish an overview of QALY models where health varies over time and provide a theoretical analysis of model identification and parameter estimation from...... time tradeoff (TTO) and standard gamble (SG) scores. We investigate deterministic and probabilistic models and consider five different families of discounting functions in all. The second part of the paper discusses four issues recurrently debated in the literature. This discussion includes questioning...... of these two can be used to disentangle risk aversion from discounting. We find that caution must be taken when drawing conclusions from models with chronic health states to situations where health varies over time. One notable difference is that in the former case, risk aversion may be indistinguishable from...

  11. Dispatchable Hydrogen Production at the Forecourt for Electricity Demand Shaping

    Directory of Open Access Journals (Sweden)

    Abdulla Rahil

    2017-10-01

    Full Text Available Environmental issues and concerns about depletion of fossil fuels have driven rapid growth in the generation of renewable energy (RE and its use in electricity grids. Similarly, the need for an alternative to hydrocarbon fuels means that the number of fuel cell vehicles is also expected to increase. The ability of electricity networks to balance supply and demand is greatly affected by the variable, intermittent output of RE generators; however, this could be relieved using energy storage and demand-side response (DSR techniques. One option would be production of hydrogen by electrolysis powered from wind and solar sources. The use of tariff structures would provide an incentive to operate electrolysers as dispatchable loads. The aim of this paper is to compare the cost of hydrogen production by electrolysis at garage forecourts in Libya, for both dispatchable and continuous operation, without interruption of fuel supply to vehicles. The coastal city of Derna was chosen as a case study, with the renewable energy being produced via a wind turbine farm. Wind speed was analysed in order to determine a suitable turbine, then the capacity was calculated to estimate how many turbines would be needed to meet demand. Finally, the excess power was calculated, based on the discrepancy between supply and demand. The study looked at a hydrogen refueling station in both dispatchable and continuous operation, using an optimisation algorithm. The following three scenarios were considered to determine whether the cost of electrolytic hydrogen could be reduced by a lower off-peak electricity price. These scenarios are: Standard Continuous, in which the electrolyser operates continuously on a standard tariff of 12 p/kWh; Off-peak Only, in which the electrolyser operates only during off-peak periods at the lower price of 5 p/kWh; and 2-Tier Continuous, in which the electrolyser operates continuously on a low tariff at off-peak times and a high tariff at other

  12. A Regional Time-of-Use Electricity Price Based Optimal Charging Strategy for Electrical Vehicles

    Directory of Open Access Journals (Sweden)

    Jun Yang

    2016-08-01

    Full Text Available With the popularization of electric vehicles (EVs, the out-of-order charging behaviors of large numbers of EVs will bring new challenges to the safe and economic operation of power systems. This paper studies an optimal charging strategy for EVs. For that a typical urban zone is divided into four regions, a regional time-of-use (RTOU electricity price model is proposed to guide EVs when and where to charge considering spatial and temporal characteristics. In light of the elastic coefficient, the user response to the RTOU electricity price is analyzed, and also a bilayer optimization charging strategy including regional-layer and node-layer models is suggested to schedule the EVs. On the one hand, the regional layer model is designed to coordinate the EVs located in different time and space. On the other hand, the node layer model is built to schedule the EVs to charge in certain nodes. According to the simulations of an IEEE 33-bus distribution network, the performance of the proposed optimal charging strategy is verified. The results demonstrate that the proposed bilayer optimization strategy can effectively decrease the charging cost of users, mitigate the peak-valley load difference and the network loss. Besides, the RTOU electricity price shows better performance than the time-of-use (TOU electricity price.

  13. Anistropically varying conductivity in irreversible electroporation simulations.

    Science.gov (United States)

    Labarbera, Nicholas; Drapaca, Corina

    2017-11-01

    One recent area of cancer research is irreversible electroporation (IRE). Irreversible electroporation is a minimally invasive procedure where needle electrodes are inserted into the body to ablate tumor cells with electricity. The aim of this paper is to propose a mathematical model that incorporates a tissue's conductivity increasing more in the direction of the electrical field as this has been shown to occur in experiments. It was necessary to mathematically derive a valid form of the conductivity tensor such that it is dependent on the electrical field direction and can be easily implemented into numerical software. The derivation of a conductivity tensor that can take arbitrary functions for the conductivity in the directions tangent and normal to the electrical field is the main contribution of this paper. Numerical simulations were performed for isotropic-varying and anisotropic-varying conductivities to evaluate the importance of including the electrical field's direction in the formulation for conductivity. By starting from previously published experimental results, this paper derived a general formulation for an anistropic-varying tensor for implementation into irreversible electroporation modeling software. The anistropic-varying tensor formulation allows the conductivity to take into consideration both electrical field direction and magnitude, as opposed to previous published works that only took into account electrical field magnitude. The anisotropic formulation predicts roughly a five percent decrease in ablation size for the monopolar simulation and approximately a ten percent decrease in ablation size for the bipolar simulations. This is a positive result as previously reported results found the isotropic formulation to overpredict ablation size for both monopolar and bipolar simulations. Furthermore, it was also reported that the isotropic formulation overpredicts the ablation size more for the bipolar case than the monopolar case. Thus, our

  14. Time-varying causality between energy consumption, CO2 emissions, and economic growth: evidence from US states.

    Science.gov (United States)

    Tzeremes, Panayiotis

    2018-02-01

    This study is the first attempt to investigate the relationship between CO 2 emissions, energy consumption, and economic growth at a state level, for the 50 US states, through a time-varying causality approach using annual data over the periods 1960-2010. The time-varying causality test facilitates the better understanding of the causal relationship between the covariates owing to the fact that it might identify causalities when the time-constant hypothesis is rejected. Our findings indicate the existence of a time-varying causality at the state level. Specifically, the results probe eight bidirectional time-varying causalities between energy consumption and CO 2 emission, six cases of two-way time-varying causalities between economic growth and energy consumption, and five bidirectional time-varying causalities between economic growth and CO 2 emission. Moreover, we examine the traditional environmental Kuznets curve hypothesis for the states. Notably, our results do not endorse the validity of the EKC, albeit the majority of states support an inverted N-shaped relationship. Lastly, we can identify multiple policy implications based on the empirical results.

  15. Pulsed electric fields (PEF applications on wine production: A review

    Directory of Open Access Journals (Sweden)

    Ozturk Burcu

    2017-01-01

    Full Text Available Novel techniques have been searched in the last decades as a result of increasing demand for high quality food products. Non-thermal processing technologies, such as pulsed electric fields (PEF have been improved to achieve inhibition of deleterious effects on quality-related compounds. The working principle of PEF is based on the application of pulses of high voltage (typically above 20 kV/cm up to 70 kV/cm to liquid foods placed between two electrodes. Pulsed electric fields technique has also been studied in winemaking process. Certain positive influences of PEF on vinification have been reported as elimination of pathogenic microorganisms, reduction of maceration time, increase in phenolic compounds extraction , acceleration of wine aging and inactivation of oxidative enzymes. The aim of this review is to summarize the potential applications of PEF in winemaking and to express its effects on quality of wine.

  16. Multi-disciplinary techniques for understanding time-varying space-based imagery

    Science.gov (United States)

    Casasent, D.; Sanderson, A.; Kanade, T.

    1984-06-01

    A multidisciplinary program for space-based image processing is reported. This project combines optical and digital processing techniques and pattern recognition, image understanding and artificial intelligence methodologies. Time change image processing was recognized as the key issue to be addressed. Three time change scenarios were defined based on the frame rate of the data change. This report details the recent research on: various statistical and deterministic image features, recognition of sub-pixel targets in time varying imagery, and 3-D object modeling and recognition.

  17. External costs of electricity production: case study Croatia

    International Nuclear Information System (INIS)

    Bozicevic Vrhovcak, Maja; Tomsic, Zeljko; Debrecin, Nenad

    2005-01-01

    Because electricity production is one of the major sources of pollution, and at the same time is the most centralised one, environmental issues in power system operation and planning are gaining ever-increasing attention. It is very difficult to compare environmental impacts of various electricity generation technologies and fuel types because they are extremely divergent. The most widely accepted common denominator today is the so-called external cost by which a monetary value is associated with environmental damage. In this paper, damages to human health resulting from Croatian thermal power plants annual operation are presented. Stack emissions have been translated into ambient concentrations by atmospheric dispersion modelling. Existing data on relations between human health degradation and ground concentrations of the analysed pollutants have been used. Geographic information software has been used in order to account for spatially dependent data. Monetary values have been assigned to the estimated human health damage. External costs resulting from impact of Croatian thermal power plants airborne emissions on human health have been calculated. The total Croatian thermal power system external costs, resulting from impacts on human health, are presented and discussed

  18. Robustness analysis of the Zhang neural network for online time-varying quadratic optimization

    International Nuclear Information System (INIS)

    Zhang Yunong; Ruan Gongqin; Li Kene; Yang Yiwen

    2010-01-01

    A general type of recurrent neural network (termed as Zhang neural network, ZNN) has recently been proposed by Zhang et al for the online solution of time-varying quadratic-minimization (QM) and quadratic-programming (QP) problems. Global exponential convergence of the ZNN could be achieved theoretically in an ideal error-free situation. In this paper, with the normal differentiation and dynamics-implementation errors considered, the robustness properties of the ZNN model are investigated for solving these time-varying problems. In addition, linear activation functions and power-sigmoid activation functions could be applied to such a perturbed ZNN model. Both theoretical-analysis and computer-simulation results demonstrate the good ZNN robustness and superior performance for online time-varying QM and QP problem solving, especially when using power-sigmoid activation functions.

  19. Time-dependent electric field in Al/CdTe/Pt detectors

    Energy Technology Data Exchange (ETDEWEB)

    Turturici, A.A. [Dipartimento di Fisica e Chimica,Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Abbene, L., E-mail: leonardo.abbene@unipa.it [Dipartimento di Fisica e Chimica,Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); Franc, J.; Grill, R.; Dědič, V. [Institute of Physics of Charles University, MFF, Ke Karlovu 5, Prague 2 (Czech Republic); Principato, F. [Dipartimento di Fisica e Chimica,Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128 (Italy)

    2015-09-21

    Al/CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopy, even though they suffer from bias-induced time instability (polarization). Polarization phenomena cause a progressive time-degradation of the spectroscopic performance of the detectors, due to hole trapping and detrapping from deep acceptor levels that directly control the electric field distribution. In this work we present experimental investigations on the electric field profile of planar Al/CdTe/Pt detectors by means of Pockels effect measurements. The time/temperature dependence of the electric field was investigated in a long time window (up to 10 h) and the correlation with the reverse current transients was also studied. Two energy levels (0.62 eV and 1.16 eV) of the deep hole traps were measured, in agreement with our previous results obtained through electrical and spectroscopic approaches.

  20. Time dependent convection electric fields and plasma injection

    International Nuclear Information System (INIS)

    Kaye, S.M.; Kivelson, M.G.

    1979-01-01

    Large-scale electric fields associated with storms or substorms are responsible for inward convection and energization of plasma sheet plasma. Calculations based on steady state convection theory show that the response to such electric fields qualitatively accounts for many features of the injected particle distribution, but quantitative agreement with the theory has not yet been obtained. It is known that the predictions can be improved by introducing the concept of convection in response to a time dependent electric field. On the other hand, time dependent calculations are sensitive to the choice of initial conditions, and most models have failed to incorporate these conditions in a realistic and self-consistent manner. In this paper we present a more complete model consisting of realisic initial conditions and time dependent convection to explain a typical substorm-associated electron injection event. We find very good agreement between the observed electron flux changes and those predicted by our model

  1. Is Power Production Flexibility a Substitute for Storability? Evidence from Electricity Futures Prices

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, M.; Huisman, R. [Erasmus School of Economics, Erasmus University Rotterdam, Rotterdam (Netherlands)

    2010-07-15

    Electricity is not storable. As a consequence, electricity demand and supply need to be in balance at any moment in time as a shortage in production volume cannot be compensated with supply from inventories. However, if the installed power supply capacity is very flexible, variation in demand can be counterbalanced with flexible adjustment of production volumes. Therefore, supply flexibility can replace the role of inventory. In this paper, we question whether power production flexibility is a substitute for storability. To do so, we examine power futures prices from countries that differ in their power supply and test whether power futures prices contain information about expected future spot prices and risk premiums and examine whether futures prices from a market in which power supply is more flexible would lead to futures prices that are more in line with the theory of storage. We find the opposite; futures prices from markets with flexible power supply behave according to the expectations theory. The implicit view from futures prices is that flexibility is not a substitute for storability.

  2. Is Power Production Flexibility a Substitute for Storability? Evidence from Electricity Futures Prices

    International Nuclear Information System (INIS)

    Kilic, M.; Huisman, R.

    2010-07-01

    Electricity is not storable. As a consequence, electricity demand and supply need to be in balance at any moment in time as a shortage in production volume cannot be compensated with supply from inventories. However, if the installed power supply capacity is very flexible, variation in demand can be counterbalanced with flexible adjustment of production volumes. Therefore, supply flexibility can replace the role of inventory. In this paper, we question whether power production flexibility is a substitute for storability. To do so, we examine power futures prices from countries that differ in their power supply and test whether power futures prices contain information about expected future spot prices and risk premiums and examine whether futures prices from a market in which power supply is more flexible would lead to futures prices that are more in line with the theory of storage. We find the opposite; futures prices from markets with flexible power supply behave according to the expectations theory. The implicit view from futures prices is that flexibility is not a substitute for storability.

  3. Exponential stability of fuzzy cellular neural networks with constant and time-varying delays

    International Nuclear Information System (INIS)

    Liu Yanqing; Tang Wansheng

    2004-01-01

    In this Letter, the global stability of delayed fuzzy cellular neural networks (FCNN) with either constant delays or time varying delays is proposed. Firstly, we give the existence and uniqueness of the equilibrium point by using the theory of topological degree and the properties of nonsingular M-matrix and the sufficient conditions for ascertaining the global exponential stability by constructing a suitable Lyapunov functional. Secondly, the criteria for guaranteeing the global exponential stability of FCNN with time varying delays are given and the estimation of exponential convergence rate with regard to speed of vary of delays is presented by constructing a suitable Lyapunov functional

  4. Tracking control of time-varying knee exoskeleton disturbed by interaction torque.

    Science.gov (United States)

    Li, Zhan; Ma, Wenhao; Yin, Ziguang; Guo, Hongliang

    2017-11-01

    Knee exoskeletons have been increasingly applied as assistive devices to help lower-extremity impaired people to make their knee joints move through providing external movement compensation. Tracking control of knee exoskeletons guided by human intentions often encounters time-varying (time-dependent) issues and the disturbance interaction torque, which may dramatically put an influence up on their dynamic behaviors. Inertial and viscous parameters of knee exoskeletons can be estimated to be time-varying due to unexpected mechanical vibrations and contact interactions. Moreover, the interaction torque produced from knee joint of wearers has an evident disturbance effect on regular motions of knee exoskeleton. All of these points can increase difficultly of accurate control of knee exoskeletons to follow desired joint angle trajectories. This paper proposes a novel control strategy for controlling knee exoskeleton with time-varying inertial and viscous coefficients disturbed by interaction torque. Such designed controller is able to make the tracking error of joint angle of knee exoskeletons exponentially converge to zero. Meanwhile, the proposed approach is robust to guarantee the tracking error bounded when the interaction torque exists. Illustrative simulation and experiment results are presented to show efficiency of the proposed controller. Additionally, comparisons with gradient dynamic (GD) approach and other methods are also presented to demonstrate efficiency and superiority of the proposed control strategy for tracking joint angle of knee exoskeleton. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Forced solitary Rossby waves under the influence of slowly varying topography with time

    International Nuclear Information System (INIS)

    Yang Hong-Wei; Yin Bao-Shu; Yang De-Zhou; Xu Zhen-Hua

    2011-01-01

    By using a weakly nonlinear and perturbation method, the generalized inhomogeneous Korteweg—de Vries (KdV)—Burgers equation is derived, which governs the evolution of the amplitude of Rossby waves under the influence of dissipation and slowly varying topography with time. The analysis indicates that dissipation and slowly varying topography with time are important factors in causing variation in the mass and energy of solitary waves. (general)

  6. Technology for Intensive Poultry Production as a Source of Odour Emissions with Time-Varying Intensity

    Directory of Open Access Journals (Sweden)

    Kuneš Radim

    2017-12-01

    Full Text Available The technology for intensive broiler breeding using deep litter method provides convenient conditions for production of odour substances inside the barn. As a consequence, there are relatively high odour emissions in the breeding area and its surrounding, which has significant impacts on the life quality of both people and animals. The amount of produced emissions increases in time because it is closely related to the amount of poultry droppings accumulated in litter inside the barn. This paper deals with changes in odour intensity depending on time measured since the beginning of broiler fattening. Odour intensity was measured by methods of dynamic olfactometry. The estimated values gradually increased from 45 ouE·m-3 to the highest value of 259 ouE·m-3, which was determined in the final fattening phase (broilers’ age 33 days. The calculated odour substances emission values were in range from 0.02 ouE·s-1·bird-1 at the beginning of fattening up to 0.10 ouE·s-1·bird-1 in the final fattening phase. Odour emissions increased five times during the fattening period.

  7. Stability of Nonlinear Systems with Unknown Time-varying Feedback Delay

    Science.gov (United States)

    Chunodkar, Apurva A.; Akella, Maruthi R.

    2013-12-01

    This paper considers the problem of stabilizing a class of nonlinear systems with unknown bounded delayed feedback wherein the time-varying delay is 1) piecewise constant 2) continuous with a bounded rate. We also consider application of these results to the stabilization of rigid-body attitude dynamics. In the first case, the time-delay in feedback is modeled specifically as a switch among an arbitrarily large set of unknown constant values with a known strict upper bound. The feedback is a linear function of the delayed states. In the case of linear systems with switched delay feedback, a new sufficiency condition for average dwell time result is presented using a complete type Lyapunov-Krasovskii (L-K) functional approach. Further, the corresponding switched system with nonlinear perturbations is proven to be exponentially stable inside a well characterized region of attraction for an appropriately chosen average dwell time. In the second case, the concept of the complete type L-K functional is extended to a class of nonlinear time-delay systems with unknown time-varying time-delay. This extension ensures stability robustness to time-delay in the control design for all values of time-delay less than the known upper bound. Model-transformation is used in order to partition the nonlinear system into a nominal linear part that is exponentially stable with a bounded perturbation. We obtain sufficient conditions which ensure exponential stability inside a region of attraction estimate. A constructive method to evaluate the sufficient conditions is presented together with comparison with the corresponding constant and piecewise constant delay. Numerical simulations are performed to illustrate the theoretical results of this paper.

  8. Robustness Analysis of Hybrid Stochastic Neural Networks with Neutral Terms and Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Chunmei Wu

    2015-01-01

    Full Text Available We analyze the robustness of global exponential stability of hybrid stochastic neural networks subject to neutral terms and time-varying delays simultaneously. Given globally exponentially stable hybrid stochastic neural networks, we characterize the upper bounds of contraction coefficients of neutral terms and time-varying delays by using the transcendental equation. Moreover, we prove theoretically that, for any globally exponentially stable hybrid stochastic neural networks, if additive neutral terms and time-varying delays are smaller than the upper bounds arrived, then the perturbed neural networks are guaranteed to also be globally exponentially stable. Finally, a numerical simulation example is given to illustrate the presented criteria.

  9. Production-distribution of electric power in France: 1997-98 statistical data

    International Nuclear Information System (INIS)

    1999-01-01

    This document has been realized using the annual inquiry carried out by the French direction of gas, electricity and coal (Digec). It brings together the main statistical data about the production, transport and consumption of electric power in France: 1997 and 1998 balance sheets, foreign exchanges, long-term evolutions, production with respect to the different energy sources, consumption in the different departments and regions.. (J.S.)

  10. Potential benefits from improved energy efficiency of key electrical products: The case of India

    International Nuclear Information System (INIS)

    McNeil, Michael A.; Iyer, Maithili; Meyers, Stephen; Letschert, Virginie E.; McMahon, James E.

    2008-01-01

    The economy of the world's second most populous country continues to grow rapidly, bringing prosperity to a growing middle class while further straining an energy infrastructure already stretched beyond capacity. At the same time, efficiency policy initiatives have gained a foothold in India, and promise to grow in number over the coming years. This paper considers the maximum cost-effective potential of efficiency improvement for key energy-consuming products in the Indian context. The products considered are: household refrigerators, window air conditioners, motors and distribution transformers. Together, these products account for about 27% of delivered electricity consumption in India. The analysis estimates the minimum Life-Cycle Cost option for each product class, according to use patterns and prevailing customer marginal rates in each sector. This option represents an efficiency improvement ranging between 12% and 60%, depending on product class. If this level of efficiency was achieved starting in 2010, we estimate that total electricity consumption in India could be reduced by 4.7% by 2020, saving over 74 million tons of oil equivalent and over 246 million tons of carbon dioxide emissions. Net present financial savings of this efficiency improvement totals 8.1 billion dollars

  11. Time dependent response of equatorial ionospheric electric fieldsto magnetospheric disturbances

    OpenAIRE

    Fejer, Bela G.; Scherliess, L.

    1995-01-01

    We use extensive radar measurements of F region vertical plasma drifts and auroral electrojet indices to determine the storm time dependence of equatorial zonal electric fields. These disturbance drifts result from the prompt penetration of high latitude electric fields and from the dynamo action of storm time winds which produce largest perturbations a few hours after the onset of magnetic activity. The signatures of the equatorial disturbance electric fields change significantly depending o...

  12. Estimating time-varying conditional correlations between stock and foreign exchange markets

    Science.gov (United States)

    Tastan, Hüseyin

    2006-02-01

    This study explores the dynamic interaction between stock market returns and changes in nominal exchange rates. Many financial variables are known to exhibit fat tails and autoregressive variance structure. It is well-known that unconditional covariance and correlation coefficients also vary significantly over time and multivariate generalized autoregressive model (MGARCH) is able to capture the time-varying variance-covariance matrix for stock market returns and changes in exchange rates. The model is applied to daily Euro-Dollar exchange rates and two stock market indexes from the US economy: Dow-Jones Industrial Average Index and S&P500 Index. The news impact surfaces are also drawn based on the model estimates to see the effects of idiosyncratic shocks in respective markets.

  13. Computer-aided production in the chemical industry

    International Nuclear Information System (INIS)

    Perez Castellanos, J.L.

    1993-01-01

    In these centres, chlorine is produced by means of electrochemical reactions which, moreover, originate other products such as soda and potash. Both the chlorine and the soda and potash are sold on demand in markets associated to the production centres and at prices which vary depending on the period of sale and the centre. Production surpluses of any one of the centres may be transported to any other so as to optimize the overall supply-demand combination of all the plants. The relevant transport and storage costs may also vary depending on the centre and on the time of year. The main problem lies in controlling the multiple combinations which permit a determined overall annual production of chlorine at the lowest possible cost. What is important is not only the quantity manufactured per month (for sale and self-consumption, or storage), but also how much is manufactured at each production centre. The monthly production of a plant could be obtained in different ways (modulations) giving rise to different production power costs (due to the electrolysis process itself, or because of the structure of electricity rates). In the first step towards solving the problem, for each plant and each month, a range of chlorine productions was selected -per plant and per month- with their corresponding electricity bills for the entire plant (once again, the rating structure makes it difficult to distinguish which part of the bill refers to electrolysis and which does not). These electric bills can be considered to be optimum in that they are minimal for a determined production of chlorine. Otherwise, in view of the targeted monthly production of chlorine, the current in the electrolysis is modulated so that the electricity bill shows the lowest possible amount, while minimum technical conditions are respected and the rest of the plant remains constant. In the assumptions described, the essence of the problem consists in deciding how much to produce every month and where to

  14. Dynamics of productivity change in the Australian electricity industry: Assessing the impacts of electricity reform

    Energy Technology Data Exchange (ETDEWEB)

    Aghdam, Reza Fathollahzadeh, E-mail: reza_f_a@yahoo.com [Department of Finance and Economics, College of Industrial Management, King Fahd University of Petroleum and Minerals, PO Box 257, Dhahran 31261 (Saudi Arabia)

    2011-06-15

    The Australian electricity industry has undergone a significant reform, since the mid-1990s. Key changes comprised functional unbundling, market restructuring, regulatory reform, public corporatisation and privatisation. Technological development has been another indisputable constituent of these changes, in the wake of ICT revolution. The principle rationale behind these changes has been that they would improve productivity of the industry and social well-being of people. This paper examines the dynamics of productivity changes in the Australian electricity industry and conducts several hypotheses-testings to identify whether industry's efficiency measures are truly improved as a result of the reform-driven changes. Malmquist Total Factor Productivity Index approach and ANOVA are used for this purpose. The results reveal that the productivity gains in the industry have been largely driven by technological improvements and, to a lesser extent, by reform-induced comparative efficiency gains. On average at national level and for the entire industry, there are efficiency gains that, to large extents, can be attributed to functional unbundling and public corporatisation and, to a lesser extent, to market restructuring and privatisation. The results, however, reveal that the reform-driven changes have made insignificant contribution to comparative efficiency, at the level of thermal generation. - Highlights: > Dynamics of productivity changes in Australian electricity industry are examined. > Several hypotheses are also tested against reform-driven changes. > Technology impact is proved to be far larger than reform-induced impacts. > Unbundling and corporatisation had larger impacts than market restructuring and privatisation. > At thermal generation level, no reform-induced impact is encountered.

  15. Dynamics of productivity change in the Australian electricity industry: Assessing the impacts of electricity reform

    International Nuclear Information System (INIS)

    Aghdam, Reza Fathollahzadeh

    2011-01-01

    The Australian electricity industry has undergone a significant reform, since the mid-1990s. Key changes comprised functional unbundling, market restructuring, regulatory reform, public corporatisation and privatisation. Technological development has been another indisputable constituent of these changes, in the wake of ICT revolution. The principle rationale behind these changes has been that they would improve productivity of the industry and social well-being of people. This paper examines the dynamics of productivity changes in the Australian electricity industry and conducts several hypotheses-testings to identify whether industry's efficiency measures are truly improved as a result of the reform-driven changes. Malmquist Total Factor Productivity Index approach and ANOVA are used for this purpose. The results reveal that the productivity gains in the industry have been largely driven by technological improvements and, to a lesser extent, by reform-induced comparative efficiency gains. On average at national level and for the entire industry, there are efficiency gains that, to large extents, can be attributed to functional unbundling and public corporatisation and, to a lesser extent, to market restructuring and privatisation. The results, however, reveal that the reform-driven changes have made insignificant contribution to comparative efficiency, at the level of thermal generation. - Highlights: → Dynamics of productivity changes in Australian electricity industry are examined. → Several hypotheses are also tested against reform-driven changes. → Technology impact is proved to be far larger than reform-induced impacts. → Unbundling and corporatisation had larger impacts than market restructuring and privatisation. → At thermal generation level, no reform-induced impact is encountered.

  16. Wind farm electrical power production model for load flow analysis

    International Nuclear Information System (INIS)

    Segura-Heras, Isidoro; Escriva-Escriva, Guillermo; Alcazar-Ortega, Manuel

    2011-01-01

    The importance of renewable energy increases in activities relating to new forms of managing and operating electrical power: especially wind power. Wind generation is increasing its share in the electricity generation portfolios of many countries. Wind power production in Spain has doubled over the past four years and has reached 20 GW. One of the greatest problems facing wind farms is that the electrical power generated depends on the variable characteristics of the wind. To become competitive in a liberalized market, the reliability of wind energy must be guaranteed. Good local wind forecasts are therefore essential for the accurate prediction of generation levels for each moment of the day. This paper proposes an electrical power production model for wind farms based on a new method that produces correlated wind speeds for various wind farms. This method enables a reliable evaluation of the impact of new wind farms on the high-voltage distribution grid. (author)

  17. Global exponential stability of BAM neural networks with time-varying delays: The discrete-time case

    Science.gov (United States)

    Raja, R.; Marshal Anthoni, S.

    2011-02-01

    This paper deals with the problem of stability analysis for a class of discrete-time bidirectional associative memory (BAM) neural networks with time-varying delays. By employing the Lyapunov functional and linear matrix inequality (LMI) approach, a new sufficient conditions is proposed for the global exponential stability of discrete-time BAM neural networks. The proposed LMI based results can be easily checked by LMI control toolbox. Moreover, an example is also provided to demonstrate the effectiveness of the proposed method.

  18. Free movement of the electricity product in Europe

    International Nuclear Information System (INIS)

    Kupiec, M.

    1992-06-01

    In the eyes of the Commission of the European Communities, electricity is an industrial product as an other; it must therefore, as stated in the Rome Treaty, be characterized and must benefit from free movement within the European Community. The purpose of this note is to set out the ideas and objectives of Brussels and authorities as regards the large European electricity market. Consequently, the proposals or objectives presented in this note do not necessarily reflect Electricite de France's position

  19. Electrifying white biotechnology: engineering and economic potential of electricity-driven bio-production.

    Science.gov (United States)

    Harnisch, Falk; Rosa, Luis F M; Kracke, Frauke; Virdis, Bernardino; Krömer, Jens O

    2015-03-01

    The production of fuels and chemicals by electricity-driven bio-production (i.e., using electric energy to drive biosynthesis) holds great promises. However, this electrification of white biotechnology is particularly challenging to achieve because of the different optimal operating conditions of electrochemical and biochemical reactions. In this article, we address the technical parameters and obstacles to be taken into account when engineering microbial bioelectrochemical systems (BES) for bio-production. In addition, BES-based bio-production processes reported in the literature are compared against industrial needs showing that a still large gap has to be closed. Finally, the feasibility of BES bio-production is analysed based on bulk electricity prices. Using the example of lysine production from sucrose, we demonstrate that there is a realistic market potential as cost savings of 8.4 % (in EU) and 18.0 % (in US) could be anticipated, if the necessary yields can be obtained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. 76 FR 21947 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

    Science.gov (United States)

    2011-04-19

    ..., open-loop biomass, geothermal energy, solar energy, small irrigation power, municipal solid waste, qualified hydropower production, marine and hydrokinetic renewable energy have not been determined for... electricity produced from closed-loop biomass, open-loop biomass, geothermal energy, solar energy, small...

  1. 75 FR 16576 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

    Science.gov (United States)

    2010-04-01

    ..., open-loop biomass, geothermal energy, solar energy, small irrigation power, municipal solid waste, qualified hydropower production, marine and hydrokinetic renewable energy have not been determined for... electricity produced from closed-loop biomass, open-loop biomass, geothermal energy, solar energy, small...

  2. Overlapping quadratic optimal control of linear time-varying commutative systems

    Czech Academy of Sciences Publication Activity Database

    Bakule, Lubomír; Rodellar, J.; Rossell, J. M.

    2002-01-01

    Roč. 40, č. 5 (2002), s. 1611-1627 ISSN 0363-0129 R&D Projects: GA AV ČR IAA2075802 Institutional research plan: CEZ:AV0Z1075907 Keywords : overlapping * optimal control * linear time-varying systems Subject RIV: BC - Control Systems Theory Impact factor: 1.441, year: 2002

  3. Parallel time domain solvers for electrically large transient scattering problems

    KAUST Repository

    Liu, Yang

    2014-09-26

    Marching on in time (MOT)-based integral equation solvers represent an increasingly appealing avenue for analyzing transient electromagnetic interactions with large and complex structures. MOT integral equation solvers for analyzing electromagnetic scattering from perfect electrically conducting objects are obtained by enforcing electric field boundary conditions and implicitly time advance electric surface current densities by iteratively solving sparse systems of equations at all time steps. Contrary to finite difference and element competitors, these solvers apply to nonlinear and multi-scale structures comprising geometrically intricate and deep sub-wavelength features residing atop electrically large platforms. Moreover, they are high-order accurate, stable in the low- and high-frequency limits, and applicable to conducting and penetrable structures represented by highly irregular meshes. This presentation reviews some recent advances in the parallel implementations of time domain integral equation solvers, specifically those that leverage multilevel plane-wave time-domain algorithm (PWTD) on modern manycore computer architectures including graphics processing units (GPUs) and distributed memory supercomputers. The GPU-based implementation achieves at least one order of magnitude speedups compared to serial implementations while the distributed parallel implementation are highly scalable to thousands of compute-nodes. A distributed parallel PWTD kernel has been adopted to solve time domain surface/volume integral equations (TDSIE/TDVIE) for analyzing transient scattering from large and complex-shaped perfectly electrically conducting (PEC)/dielectric objects involving ten million/tens of millions of spatial unknowns.

  4. Towards nuclear energy applications other than electricity production

    International Nuclear Information System (INIS)

    Lecomte, M.

    2007-01-01

    Use of nuclear energy relies on operation of a boiler, involving practically no greenhouse gas emission. Whereas production of electricity is, nowadays, virtually its sole purpose, demand for heat production could equally arise, particularly with the emergence of high-temperature, or even very-high-temperature reactors. With the abilities this involves, as regards the recovery of heavy crude oils from tar sands, seawater desalination, or, most importantly, production of hydrogen by electrolysis, or thermochemistry, this being the energy carrier of tomorrow. (authors)

  5. Time-varying Capital Requirements and Disclosure Rules

    DEFF Research Database (Denmark)

    Kragh, Jonas; Rangvid, Jesper

    , implying that resilience in the banking system is also increased. The increase in capital ratios is partly due to a modest reduction in lending. Using a policy changes, we show that banks react stronger to changes in capital requirements when these are public. Our results further suggest that the impact......Unique and confidential Danish data allow us to identify how changes in disclosure requirements and bank-specific time-varying capital requirements affect banks' lending and capital accumu-lation decisions. We find that banks increase their capital ratios after capital requirements are increased...... of capital requirements differ for small and large banks. Large banks raise their capital ratios more, reduce lending less, and accumulate more new capital compared to small banks....

  6. Time-varying vector fields and their flows

    CERN Document Server

    Jafarpour, Saber

    2014-01-01

    This short book provides a comprehensive and unified treatment of time-varying vector fields under a variety of regularity hypotheses, namely finitely differentiable, Lipschitz, smooth, holomorphic, and real analytic. The presentation of this material in the real analytic setting is new, as is the manner in which the various hypotheses are unified using functional analysis. Indeed, a major contribution of the book is the coherent development of locally convex topologies for the space of real analytic sections of a vector bundle, and the development of this in a manner that relates easily to classically known topologies in, for example, the finitely differentiable and smooth cases. The tools used in this development will be of use to researchers in the area of geometric functional analysis.

  7. Body size and the timing of egg production in parasitoid wasps.

    NARCIS (Netherlands)

    Ellers, J.; Jervis, M.

    2003-01-01

    In insects several key fitness-related variables are positively correlated with intraspecific variation in body size, but little is known about size-related variation in the timing of egg production within species. Female insects are known to vary in the degree to which they concentrate egg

  8. Delay-Dependent Guaranteed Cost Control of an Interval System with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Xiao Min

    2009-01-01

    Full Text Available This paper concerns the problem of the delay-dependent robust stability and guaranteed cost control for an interval system with time-varying delay. The interval system with matrix factorization is provided and leads to less conservative conclusions than solving a square root. The time-varying delay is assumed to belong to an interval and the derivative of the interval time-varying delay is not a restriction, which allows a fast time-varying delay; also its applicability is broad. Based on the Lyapunov-Ktasovskii approach, a delay-dependent criterion for the existence of a state feedback controller, which guarantees the closed-loop system stability, the upper bound of cost function, and disturbance attenuation lever for all admissible uncertainties as well as out perturbation, is proposed in terms of linear matrix inequalities (LMIs. The criterion is derived by free weighting matrices that can reduce the conservatism. The effectiveness has been verified in a number example and the compute results are presented to validate the proposed design method.

  9. Future electricity production methods. Part 1: Nuclear energy

    International Nuclear Information System (INIS)

    Nifenecker, Herve

    2011-01-01

    The global warming challenge aims at stabilizing the concentrations of Green House Gas (GHG) in the atmosphere. Carbon dioxide is the most effective of the anthropogenic GHG and is essentially produced by consumption of fossil fuels. Electricity production is the dominant cause of CO 2 emissions. It is, therefore, crucial that the share of 'carbon less' electricity production techniques increases at a fast pace. This is the more so, that 'clean' electricity would be useful to displace 'dirty' techniques in other fields such as heat production and transportation. Here we examine the extent to which nuclear energy could be operational in providing 'clean' electricity. A nuclear intensive scenario is shown to give the possibility to divide CO 2 emissions by a factor of 2 worldwide, within 50 years. However, the corresponding sharp increase in nuclear power will put a heavy burden on uranium reserves and will necessitate the development of breeding reactors as soon as possible. A review of present and future reactors is given with special attention to the safety issues. The delicate question of nuclear fuel cycle is discussed concerning uranium reserves and management of used fuels. It is shown that dealing with nuclear wastes is more a socio-political problem than a technical one. The third difficult question associated with the development of nuclear energy is the proliferation risk. It is advocated that, while this is, indeed, a very important question, it is only weakly related to nuclear power development. Finally, the possibilities of nuclear fusion are discussed and it is asserted that, under no circumstances, could nuclear fusion give a significant contribution to the solution of the energy problem before 50 years, too late for dealing with the global warming challenge.

  10. Aligning PEV Charging Times with Electricity Supply and Demand

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, Cabell [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-06-05

    Plug-in electric vehicles (PEVs) are a growing source of electricity consumption that could either exacerbate supply shortages or smooth electricity demand curves. Extensive research has explored how vehicle-grid integration (VGI) can be optimized by controlling PEV charging timing or providing vehicle-to-grid (V2G) services, such as storing energy in vehicle batteries and returning it to the grid at peak times. While much of this research has modeled charging, implementation in the real world requires a cost-effective solution that accounts for consumer behavior. To function across different contexts, several types of charging administrators and methods of control are necessary to minimize costs in the VGI context.

  11. The effects of rate of return and environmental regulations on the productivity performance in the US electric utility industry

    International Nuclear Information System (INIS)

    Durongkaveroj, P.

    1991-01-01

    Productivity growth in the US electric power industry has been declining since the late 1960's. Rate of return regulation and environmental regulations are hypothesized to adversely affect the productivity performance. Employing a Divisa index of the total factor productivity (TEP) an electric utility's performance is measured based on a profit maximization framework subject to both regulatory constraints. The empirical analysis attempts to analyze the effects of these regulations on the productivity growth employing data from privately-owned, fossil-fueled electric utilities. Results show a consistent decline in productivity growth over time averaging at 2% annually during 1977 and 1982, as well as the existence of regional differences in TFP growth among utilities. It shows positive and significant relationships between TFP growth and the rate of return, regulatory lag, the use of future test year, and deferred tax credit in the rate-making process. In the environmental case, results show that a stringent emission standard, using scrubbers for sulfur reduction and the utilization of aging power plants all contribute to the decline in productivity growth

  12. A Canadian case study : the value of real time electricity monitoring : a real-time cost utility management solution

    International Nuclear Information System (INIS)

    Rouse, S.; Dittburner, D.

    2006-01-01

    Energy prices can vary significantly over the course of a single day in response to changing levels in energy demand and availability of supply. The impacts of varying energy prices on business and industry means that hourly electricity costs can fluctuate widely over the course of a day even though energy use remains stable. This presentation gave details of an energy efficiency initiative at Unilever's Rexdale site which has resulted in $4 million saved through reductions in energy consumption and equipment retrofits. The Rexdale plant won an energy efficiency award in 2005, and the success of the initiative was attributed to the use of Utility 3 + , an energy management software tool. A turn key system with integrated software and hardware, Utility 3 + is capable of measuring how much energy is being used and can provide details of costs using a combination of historical and forecast prices. The tool is equipped with alarms with pre-set thresholds to match real-time rises in energy prices. Real-time prices are relayed from the Internet along with a 2 way data communication system. It was concluded that use of the tool has resulted in improved cash flow management and greater control of energy costs. A system description of the tool was provided, as well as details of various equipment retrofits. refs.., tabs., figs

  13. A Canadian case study : the value of real time electricity monitoring : a real-time cost utility management solution

    Energy Technology Data Exchange (ETDEWEB)

    Rouse, S. [Energy at Work, Toronto, ON (Canada); Dittburner, D. [Unilever Canada, Toronto, ON (Canada)

    2006-07-01

    Energy prices can vary significantly over the course of a single day in response to changing levels in energy demand and availability of supply. The impacts of varying energy prices on business and industry means that hourly electricity costs can fluctuate widely over the course of a day even though energy use remains stable. This presentation gave details of an energy efficiency initiative at Unilever's Rexdale site which has resulted in $4 million saved through reductions in energy consumption and equipment retrofits. The Rexdale plant won an energy efficiency award in 2005, and the success of the initiative was attributed to the use of Utility 3{sup +}, an energy management software tool. A turn key system with integrated software and hardware, Utility 3{sup +} is capable of measuring how much energy is being used and can provide details of costs using a combination of historical and forecast prices. The tool is equipped with alarms with pre-set thresholds to match real-time rises in energy prices. Real-time prices are relayed from the Internet along with a 2 way data communication system. It was concluded that use of the tool has resulted in improved cash flow management and greater control of energy costs. A system description of the tool was provided, as well as details of various equipment retrofits. refs.., tabs., figs.

  14. Discrete-time recurrent neural networks with time-varying delays: Exponential stability analysis

    International Nuclear Information System (INIS)

    Liu, Yurong; Wang, Zidong; Serrano, Alan; Liu, Xiaohui

    2007-01-01

    This Letter is concerned with the analysis problem of exponential stability for a class of discrete-time recurrent neural networks (DRNNs) with time delays. The delay is of the time-varying nature, and the activation functions are assumed to be neither differentiable nor strict monotonic. Furthermore, the description of the activation functions is more general than the recently commonly used Lipschitz conditions. Under such mild conditions, we first prove the existence of the equilibrium point. Then, by employing a Lyapunov-Krasovskii functional, a unified linear matrix inequality (LMI) approach is developed to establish sufficient conditions for the DRNNs to be globally exponentially stable. It is shown that the delayed DRNNs are globally exponentially stable if a certain LMI is solvable, where the feasibility of such an LMI can be easily checked by using the numerically efficient Matlab LMI Toolbox. A simulation example is presented to show the usefulness of the derived LMI-based stability condition

  15. Global exponential stability of uncertain fuzzy BAM neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Syed Ali, M.; Balasubramaniam, P.

    2009-01-01

    In this paper, the Takagi-Sugeno (TS) fuzzy model representation is extended to the stability analysis for uncertain Bidirectional Associative Memory (BAM) neural networks with time-varying delays using linear matrix inequality (LMI) theory. A novel LMI-based stability criterion is obtained by LMI optimization algorithms to guarantee the exponential stability of uncertain BAM neural networks with time-varying delays which are represented by TS fuzzy models. Finally, the proposed stability conditions are demonstrated with numerical examples.

  16. Wind blows where (and when) it wants: an analysis of the French electricity production, September-December 2010 - preliminary analysis

    International Nuclear Information System (INIS)

    2011-01-01

    This document analyses the set of data published on the RTE web site and concerning the electricity production and consumption in France from September to December 2010. Having a closer look to the wind energy production, it notably shows that, as expected, all steerable means of production play a coordinated role in covering the required power needs. The analysis of the wind energy power shows a 23 pc average efficiency which is associated to the strong fluctuations which are typical for this type of intermittent production. It notices that time and energy distributions of wind energy power supplied to the network are not related to increased electricity needs during this autumn period which is marked by several cold waves

  17. External costs of electricity production under scrutiny

    International Nuclear Information System (INIS)

    Wagner, H.J.; Melchert, A.

    1993-01-01

    After a short introduction into the problems and questions surrounding the issue of external costs Chapter 2 presents the most important results of the studies under review and analysis in this work. Occasionally, minor discrepancies were found between the results given in the summary of a study and the data reported in the relevant chapters. Chapter 3 identifies and discusses differences in perspective between the studies under consideration. Chapter 4 analyses the most important premises and parameters adopted in the studies for the calculation of overall costs and net benefits of the different modes of electricity production. This serves to probe the reliability of the data, plausibility of the premises, and nature of the presupposed relationships. Chapter 5 examines the relationships of time assumed in the studies and gives a first comment on the more advanced Prognos study. Chapter 6, finally, offers a summarizing evaluation. (orig./UA) [de

  18. Time-varying market integration and expected returns in emerging mrkets

    NARCIS (Netherlands)

    de Jong, F.C.J.M.; de Roon, F.

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematicrisk as measured by their beta relative to the world portfolio as well as on the level ofintegration in that market. The level of integration is a time-varying variable that depends on themarket value

  19. 77 FR 25538 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

    Science.gov (United States)

    2012-04-30

    ... DEPARTMENT OF THE TREASURY Internal Revenue Service Credit for Renewable Electricity Production... Reference Prices for Calendar Year 2012; Correction AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Correction to a publication of inflation adjustment factors and reference prices for calendar year 2012 as...

  20. Optimal the tilt angles for photovoltaic modules using PSO method with nonlinear time-varying evolution

    International Nuclear Information System (INIS)

    Chang, Ying-Pin

    2010-01-01

    A particle-swarm optimization method with nonlinear time-varying evolution (PSO-NTVE) is employed in determining the tilt angle of photovoltaic (PV) modules in Taiwan. The objective is to maximize the output electrical energy of the modules. In this study, seven Taiwanese cities were selected for analysis. First, the sun's position at any time and location was predicted by the mathematical procedure of Julian dating, and then the solar irradiation was obtained at each site under a clear sky. By combining the temperature effect, the PSO-NTVE method is adopted to calculate the optimal tilt angles for fixed south-facing PV modules. In this method, the parameters are determined by using matrix experiments with an orthogonal array, in which a minimal number of experiments have an effect that approximates the full factorial experiments. Statistical error analysis was performed to compare the results between the four PSO methods and experimental results. Hengchun city in which the minimum total error value of 6.12% the reasons for the weather more stability and less building shade. A comparison of the measurement results in electrical energy between the four PSO methods and the PV modules set a six tilt angles. Obviously four types of PSO methods simulation of electrical energy value from 231.12 kWh/m 2 for Taipei to 233.81 kWh/m 2 for Hengchun greater than the measurement values from 224.71 kWh/m 2 for Taichung to 228.47 kWh/m 2 for Hengchun by PV module which is due to instability caused by climate change. Finally, the results show that the annual optimal angle for the Taipei area is 18.16 o ; for Taichung, 17.3 o ; for Tainan, 16.15 o ; for Kaosiung, 15.79 o ; for Hengchung, 15.17 o ; for Hualian, 17.16 o ; and for Taitung, 15.94 o . It is evident that the authorized Industrial Technology Research Institute (ITRI) recommends that tilt angle of 23.5 o was not an appropriate use of Taiwan's seven cities. PV modules with the installation of the tilt angle should be

  1. Application Protocol, Initial Graphics Exchange Specification (IGES), Layered Electrical Product

    Energy Technology Data Exchange (ETDEWEB)

    O`Connell, L.J. [ed.

    1994-12-01

    An application protocol is an information systems engineering view of a specific product The view represents an agreement on the generic activities needed to design and fabricate the product the agreement on the information needed to support those activities, and the specific constructs of a product data standard for use in transferring some or all of the information required. This application protocol describes the data for electrical and electronic products in terms of a product description standard called the Initial Graphics Exchange Specification (IGES). More specifically, the Layered Electrical Product IGES Application Protocol (AP) specifies the mechanisms for defining and exchanging computer-models and their associated data for those products which have been designed in two dimensional geometry so as to be produced as a series of layers in IGES format The AP defines the appropriateness of the data items for describing the geometry of the various parts of a product (shape and location), the connectivity, and the processing and material characteristics. Excluded is the behavioral requirements which the product was intended to satisfy, except as those requirements have been recorded as design rules or product testing requirements.

  2. Estimation of time-varying reactivity by the H∞ optimal linear filter

    International Nuclear Information System (INIS)

    Suzuki, Katsuo; Shimazaki, Junya; Watanabe, Koiti

    1995-01-01

    The problem of estimating the time-varying net reactivity from flux measurements is solved for a point reactor kinetics model using a linear filtering technique in an H ∞ settings. In order to sue this technique, an appropriate dynamical model of the reactivity is constructed that can be embedded into the reactor model as one of its variables. A filter, which minimizes the H ∞ norm of the estimation error power spectrum, operates on neutron density measurements corrupted by noise and provides an estimate of the dynamic net reactivity. Computer simulations are performed to reveal the basic characteristics of the H ∞ optimal filter. The results of the simulation indicate that the filter can be used to determine the time-varying reactivity from neutron density measurements that have been corrupted by noise

  3. Gain-scheduled {{\\mathscr{H}}}_{\\infty } buckling control of a circular beam-column subject to time-varying axial loads

    Science.gov (United States)

    Schaeffner, Maximilian; Platz, Roland

    2018-06-01

    For slender beam-columns loaded by axial compressive forces, active buckling control provides a possibility to increase the maximum bearable axial load above that of a purely passive structure. In this paper, an approach for gain-scheduled {{\\mathscr{H}}}∞ buckling control of a slender beam-column with circular cross-section subject to time-varying axial loads is investigated experimentally. Piezo-elastic supports with integrated piezoelectric stack actuators at the beam-column ends allow an active stabilization in arbitrary lateral directions. The axial loads on the beam-column influence its lateral dynamic behavior and, eventually, cause the beam-column to buckle. A reduced modal model of the beam-column subject to axial loads including the dynamics of the electrical components is set up and calibrated with experimental data. Particularly, the linear parameter-varying open-loop plant is used to design a model-based gain-scheduled {{\\mathscr{H}}}∞ buckling control that is implemented in an experimental test setup. The beam-column is loaded by ramp- and step-shaped time-varying axial compressive loads that result in a lateral deformation of the beam-column due to imperfections, such as predeformation, eccentric loading or clamping moments. The lateral deformations and the maximum bearable loads of the beam-column are analyzed and compared for the beam-column with and without gain-scheduled {{\\mathscr{H}}}∞ buckling control or, respectively, active and passive configuration. With the proposed gain-scheduled {{\\mathscr{H}}}∞ buckling control it is possible to increase the maximum bearable load of the active beam-column by 19% for ramp-shaped axial loads and to significantly reduce the beam-column deformations for step-shaped axial loads compared to the passive structure.

  4. Globally Asymptotic Stability of Stochastic Nonlinear Systems with Time-Varying Delays via Output Feedback Control

    Directory of Open Access Journals (Sweden)

    Mingzhu Song

    2016-01-01

    Full Text Available We address the problem of globally asymptotic stability for a class of stochastic nonlinear systems with time-varying delays. By the backstepping method and Lyapunov theory, we design a linear output feedback controller recursively based on the observable linearization for a class of stochastic nonlinear systems with time-varying delays to guarantee that the closed-loop system is globally asymptotically stable in probability. In particular, we extend the deterministic nonlinear system to stochastic nonlinear systems with time-varying delays. Finally, an example and its simulations are given to illustrate the theoretical results.

  5. The plant for co-production of synfuel and electricity with reduced CO{sub 2} emissions

    Energy Technology Data Exchange (ETDEWEB)

    Kler, A.M.; Tyurina, E.A.; Mednikov, A.S. [Russian Academy of Sciences, Irkutsk (Russian Federation). Energy Systems Inst.

    2013-07-01

    Consideration is given to the prospective technologies for combined production of synthetic fuel (SF) and electricity. The mathematical models of plant for co-production of synfuel and electricity (PCSE) intended for combined production of electricity and synthesis of methanol and dimethyl ether or membrane-based hydrogen production from coal were developed. They were used in the optimization studies on the installations. As a result of the studies, the design characteristics for the plant elements, the relationships between the SF and electricity productions, etc. were determined. These data were used to identify the ranges of SF price for various prices of fuel, electricity and equipment, and estimate the profitability of SF production. Special attention is paid to modeling of CO{sub 2} removal system as part of PCSE and studies on PCSE optimization. The account is taken of additional capital investments and power consumption in the systems.

  6. Options for electricity production, the actual opportunities and regulatory framework

    International Nuclear Information System (INIS)

    Raphals, P.

    2006-01-01

    Thermal power and nuclear power represent the traditional methods of generating electricity. This paper presented opportunities for alternative centralized power production methods that include wind energy, biomass and solar energy. It also discussed decentralized alternatives for power generation, such as geothermal energy and cogeneration, including microturbines. The primary focus was on aspects of competitive market design for residential and small commercial applications as well as commercial and industrial applications. Law 116 of Quebec's Energy Board was reviewed in terms of energy policy and utility regulation. In particular, the framework agreement between Hydro-Quebec Production (HQP) and Hydro-Quebec Distribution (HQD) was discussed with reference to balancing electricity produced from renewable energy sources and energy security. The presentation also addressed issues regarding the role of competition, regulation and environmental implications of electricity trade. refs., tabs., figs

  7. Soil erosion under multiple time-varying rainfall events

    Science.gov (United States)

    Heng, B. C. Peter; Barry, D. Andrew; Jomaa, Seifeddine; Sander, Graham C.

    2010-05-01

    Soil erosion is a function of many factors and process interactions. An erosion event produces changes in surface soil properties such as texture and hydraulic conductivity. These changes in turn alter the erosion response to subsequent events. Laboratory-scale soil erosion studies have typically focused on single independent rainfall events with constant rainfall intensities. This study investigates the effect of multiple time-varying rainfall events on soil erosion using the EPFL erosion flume. The rainfall simulator comprises ten Veejet nozzles mounted on oscillating bars 3 m above a 6 m × 2 m flume. Spray from the nozzles is applied onto the soil surface in sweeps; rainfall intensity is thus controlled by varying the sweeping frequency. Freshly-prepared soil with a uniform slope was subjected to five rainfall events at daily intervals. In each 3-h event, rainfall intensity was ramped up linearly to a maximum of 60 mm/h and then stepped down to zero. Runoff samples were collected and analysed for particle size distribution (PSD) as well as total sediment concentration. We investigate whether there is a hysteretic relationship between sediment concentration and discharge within each event and how this relationship changes from event to event. Trends in the PSD of the eroded sediment are discussed and correlated with changes in sediment concentration. Close-up imagery of the soil surface following each event highlight changes in surface soil structure with time. This study enhances our understanding of erosion processes in the field, with corresponding implications for soil erosion modelling.

  8. Wireless Sensing System Using Open-circuit, Electrically-conductive Spiral-trace Sensor

    Science.gov (United States)

    Woodard, Stanley E. (Inventor); Taylor, Bryant D. (Inventor)

    2013-01-01

    A wireless sensing system includes a sensor made from an electrical conductor shaped to form an open-circuit, electrically-conductive spiral trace having inductance and capacitance. In the presence of a time-varying magnetic field, the sensor resonates to generate a harmonic response having a frequency, amplitude and bandwidth. A magnetic field response recorder wirelessly transmits the time-varying magnetic field to the sensor and wirelessly detects the sensor's response frequency, amplitude and bandwidth.

  9. Exponential stability of switched linear systems with time-varying delay

    Directory of Open Access Journals (Sweden)

    Satiracoo Pairote

    2007-11-01

    Full Text Available We use a Lyapunov-Krasovskii functional approach to establish the exponential stability of linear systems with time-varying delay. Our delay-dependent condition allows to compute simultaneously the two bounds that characterize the exponential stability rate of the solution. A simple procedure for constructing switching rule is also presented.

  10. Relay selection in cooperative communication systems over continuous time-varying fading channel

    Directory of Open Access Journals (Sweden)

    Ke Geng

    2017-02-01

    Full Text Available In this paper, we study relay selection under outdated channel state information (CSI in a decode-and-forward (DF cooperative system. Unlike previous researches on cooperative communication under outdated CSI, we consider that the channel varies continuously over time, i.e., the channel not only changes between relay selection and data transmission but also changes during data transmission. Thus the level of accuracy of the CSI used in relay selection degrades with data transmission. We first evaluate the packet error rate (PER of the cooperative system under continuous time-varying fading channel, and find that the PER performance deteriorates more seriously under continuous time-varying fading channel than when the channel is assumed to be constant during data transmission. Then, we propose a repeated relay selection (RRS strategy to improve the PER performance, in which the forwarded data is divided into multiple segments and relay is reselected before the transmission of each segment based on the updated CSI. Finally, we propose a combined relay selection (CRS strategy which takes advantage of three different relay selection strategies to further mitigate the impact of outdated CSI.

  11. Challenges and prospects of electricity production from renewable energy sources in Slovenia

    International Nuclear Information System (INIS)

    Al-Mansour, Fouad; Sucic, Boris; Pusnik, Matevz

    2014-01-01

    Development of the utilisation of renewable energy sources and energy efficiency represents the main policy for sustainable development. The overall target of the European Union Directive on the promotion of the use of energy from renewables (RES) is to achieve at least a 20% share of energy from renewables in the gross final energy consumption in 2020. The mandatory national target for Slovenia is a 25% share of energy from RES in the gross final consumption. The share of RES in the gross final energy consumption in Slovenia was 18.8% in 2011 and the share of electricity production from RES was 30.8% in the gross electricity consumption. Electricity production from photovoltaics (PV) and biogas plants in agriculture has been growing fast after the adoption of the new supportive decree for electricity from RES in 2009. The very fast growth of PV plants has caused a problem for financing electricity from RES. Similar effects have been also recorded in the biogas sector, which represents a threat to food production. The state of the art, targets and challenges of electricity production from RES in Slovenia are described in the paper. - Highlights: • Slovenia's RES policy, regulatory frameworks and incentives are described. • The most important development challenges of the RES-E sector are discussed. • RES-E policy priorities need to be reassessed in view of recent global trends. • Responsible policy making and implementation follow-up are necessary

  12. Summary of Market Opportunities for Electric Vehicles and Dispatchable Load in Electrolyzers

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, Paul [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Eichman, Joshua [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Markel, Tony [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ma, Ookie [U.S Department of Energy, Washington, DC (United States)

    2015-05-19

    Electric vehicles (EVs) and electrolyzers are potentially significant sources of new electric loads. Both are flexible in that the amount of electricity consumed can be varied in response to a variety of factors including the cost of electricity. Because both EVs and electrolyzers can control the timing of electricity purchases, they can minimize energy costs by timing the purchases of energy to periods of lowest costs.

  13. One-dimensional radionuclide transport under time-varying conditions

    International Nuclear Information System (INIS)

    Gelbard, F.; Olague, N.E.; Longsine, D.E.

    1990-01-01

    This paper discusses new analytical and numerical solutions presented for one-dimensional radionuclide transport under time-varying fluid-flow conditions including radioactive decay. The analytical solution assumes that all radionuclides have identical retardation factors, and is limited to instantaneous releases. The numerical solution does not have these limitations, but is tested against the limiting case given for the analytical solution. Reasonable agreement between the two solutions was found. Examples are given for the transport of a three-member radionuclide chain transported over distances and flow rates comparable to those reported for Yucca Mountain, the proposed disposal site for high-level nuclear waste

  14. Generalized Projective Synchronization between Two Complex Networks with Time-Varying Coupling Delay

    International Nuclear Information System (INIS)

    Mei, Sun; Chang-Yan, Zeng; Li-Xin, Tian

    2009-01-01

    Generalized projective synchronization (GPS) between two complex networks with time-varying coupling delay is investigated. Based on the Lyapunov stability theory, a nonlinear controller and adaptive updated laws are designed. Feasibility of the proposed scheme is proven in theory. Moreover, two numerical examples are presented, using the energy resource system and Lü's system [Physica A 382 (2007) 672] as the nodes of the networks. GPS between two energy resource complex networks with time-varying coupling delay is achieved. This study can widen the application range of the generalized synchronization methods and will be instructive for the demand–supply of energy resource in some regions of China

  15. Compensating Unknown Time-Varying Delay in Opto-Electronic Platform Tracking Servo System

    Directory of Open Access Journals (Sweden)

    Ruihong Xie

    2017-05-01

    Full Text Available This paper investigates the problem of compensating miss-distance delay in opto-electronic platform tracking servo system. According to the characteristic of LOS (light-of-sight motion, we setup the Markovian process model and compensate this unknown time-varying delay by feed-forward forecasting controller based on robust H∞ control. Finally, simulation based on double closed-loop PI (Proportion Integration control system indicates that the proposed method is effective for compensating unknown time-varying delay. Tracking experiments on the opto-electronic platform indicate that RMS (root-mean-square error is 1.253 mrad when tracking 10° 0.2 Hz signal.

  16. Generalized Projective Synchronization between Two Complex Networks with Time-Varying Coupling Delay

    Science.gov (United States)

    Sun, Mei; Zeng, Chang-Yan; Tian, Li-Xin

    2009-01-01

    Generalized projective synchronization (GPS) between two complex networks with time-varying coupling delay is investigated. Based on the Lyapunov stability theory, a nonlinear controller and adaptive updated laws are designed. Feasibility of the proposed scheme is proven in theory. Moreover, two numerical examples are presented, using the energy resource system and Lü's system [Physica A 382 (2007) 672] as the nodes of the networks. GPS between two energy resource complex networks with time-varying coupling delay is achieved. This study can widen the application range of the generalized synchronization methods and will be instructive for the demand-supply of energy resource in some regions of China.

  17. Time-lapse electrical resistivity anomalies due to contaminant transport around landfills

    Directory of Open Access Journals (Sweden)

    J. Yang

    2007-06-01

    Full Text Available The extent of landfill leachate can be delineated by geo-electrical imaging as a response to the varying electrical resistivity in the contaminated area. This research was based on a combination of hydrogeological numerical simulation followed by geophysical forward and inversion modeling performed to evaluate the migration of a contaminant plume from a landfill. As a first step, groundwater flow and contaminant transport was simulated using the finite elements numerical modeling software FEFLOW. The extent of the contaminant plume was acquired through a hydrogeological model depicting the distributions of leachate concentration in the system. Next, based on the empirical relationship between the concentration and electrical conductivity of the leachate in the porous media, the corresponding geo-electrical structure was derived from the hydrogeological model. Finally, forward and inversion computations of geo-electrical anomalies were performed using the finite difference numerical modeling software DCIP2D/DCIP3D. The image obtained by geophysical inversion of the electric data was expected to be consistent with the initial hydrogeological model, as described by the distribution of leachate concentration. Numerical case studies were conducted for various geological conditions, hydraulic parameters and electrode arrays, from which conclusions were drawn regarding the suitability of the methodology to assess simple to more complex geo-electrical models. Thus, optimal mapping and monitoring configurations were determined.

  18. Pricing electricity for sustainability : climate change and Canada's electricity sector

    International Nuclear Information System (INIS)

    2010-01-01

    The electricity sector is Canada's largest single source of greenhouse gas (GHG) emissions. This paper discussed electricity and carbon pricing approaches to reducing GHG emissions in the electricity sector. An overview of the links between electricity pricing and climate change was presented, and current and emerging trends in electricity pricing related to encouraging energy conservation were reviewed. Market prices and failures were discussed. Approaches to pricing electricity included an increase in block prices; time-of-use prices; demand-side management and energy efficiency; and carbon pricing in Canada and electricity pricing signals. The study showed that several provincial utilities in Canada are experimenting with market-based pricing approaches for electricity and carbon that may help to reduce GHG emissions over time. Concerns over electricity supply and the negative environmental impacts of electricity production may lead to the full social pricing of electricity in some regions of Canada. 46 refs., 3 tabs., 5 figs.

  19. Multi-pulse chaotic motions of a rotor-active magnetic bearing system with time-varying stiffness

    International Nuclear Information System (INIS)

    Zhang, W.; Yao, M.H.; Zhan, X.P.

    2006-01-01

    In this paper, we investigate the Shilnikov type multi-pulse chaotic dynamics for a rotor-active magnetic bearings (AMB) system with 8-pole legs and the time-varying stiffness. The stiffness in the AMB is considered as the time-varying in a periodic form. The dimensionless equation of motion for the rotor-AMB system with the time-varying stiffness in the horizontal and vertical directions is a two-degree-of-freedom nonlinear system with quadratic and cubic nonlinearities and parametric excitation. The asymptotic perturbation method is used to obtain the averaged equations in the case of primary parametric resonance and 1/2 subharmonic resonance. It is found from the numerical results that there are the phenomena of the Shilnikov type multi-pulse chaotic motions for the rotor-AMB system. A new jumping phenomenon is discovered in the rotor-AMB system with the time-varying stiffness

  20. Dual Extended Kalman Filter for the Identification of Time-Varying Human Manual Control Behavior

    Science.gov (United States)

    Popovici, Alexandru; Zaal, Peter M. T.; Pool, Daan M.

    2017-01-01

    A Dual Extended Kalman Filter was implemented for the identification of time-varying human manual control behavior. Two filters that run concurrently were used, a state filter that estimates the equalization dynamics, and a parameter filter that estimates the neuromuscular parameters and time delay. Time-varying parameters were modeled as a random walk. The filter successfully estimated time-varying human control behavior in both simulated and experimental data. Simple guidelines are proposed for the tuning of the process and measurement covariance matrices and the initial parameter estimates. The tuning was performed on simulation data, and when applied on experimental data, only an increase in measurement process noise power was required in order for the filter to converge and estimate all parameters. A sensitivity analysis to initial parameter estimates showed that the filter is more sensitive to poor initial choices of neuromuscular parameters than equalization parameters, and bad choices for initial parameters can result in divergence, slow convergence, or parameter estimates that do not have a real physical interpretation. The promising results when applied to experimental data, together with its simple tuning and low dimension of the state-space, make the use of the Dual Extended Kalman Filter a viable option for identifying time-varying human control parameters in manual tracking tasks, which could be used in real-time human state monitoring and adaptive human-vehicle haptic interfaces.

  1. Time Varying Market Integration and Expected Rteurns in Emerging Markets

    NARCIS (Netherlands)

    de Jong, F.C.J.M.; de Roon, F.A.

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market.The level of integration is a time-varying variable that depends on the market value

  2. A new time-varying harmonic decomposition structure based on recursive hanning window

    NARCIS (Netherlands)

    Martins, C.H.; Silva, L.R.M.; Duque, C.A.; Cerqueira, A.S.; Teixeira, E.C.; Ribeiro, P.F.

    2012-01-01

    Analysis of power quality phenomena under time-varying conditions has become an important subject as the complexity of the grid increases. As a consequence, several methods have been developed/applied also to study power quality parameters during transient conditions such as time-frequency methods.

  3. Uniform stability for time-varying infinite-dimensional discrete linear systems

    International Nuclear Information System (INIS)

    Kubrusly, C.S.

    1988-09-01

    Stability for time-varying discrete linear systems in a Banach space is investigated. On the one hand, it established a fairly complete collection of necessary and sufficient conditions for uniform asymptotic equistability for input-free systems. This includes uniform and strong power equistability, and uniform and strong l p -equistability, among other technical conditions which also play essential role in stability theory. On other hand, it is shown that uniform asymptotic equistability for input-free systems is equivalent to each of the following concepts of uniform stability for forced systems: l p -input l p -state, c o -input c o -state, bounded-input bounded-state, l p>1 -input bounded-state, c sub (o)-input bounded-state, and convergent-input bounded-state; which are also equivalent to their nonuniform counterparts. For time-varying convergent systems, the above is also equivalent to convergent-input convergent-state stability. The proofs presented here are all ''elementary'' in the sense that they are based essentially only on the Banach-Steinhaus theorem. (autor) [pt

  4. Neutron fluctuations in a medium randomly varying in time

    International Nuclear Information System (INIS)

    Lenard, Pal; Imre, Pazsit

    2005-01-01

    The master equation approach, which has traditionally been used for the calculation of neutron fluctuations in zero power systems with constant parameters, is extended to a case when the parameters of the system change randomly in time. We consider a forward type master equation for the probability distribution of the number of particles in a multiplying system whose properties jump randomly between two discrete states, both with and without an external source. The first two factorial moments are calculated, including the covariance. This model can be considered the unification of stochastic methods that were used either in a constant multiplying medium via the master equation technique, or in a fluctuating medium via the Langevin technique. In contrast to these methods, the one presented here can calculate the inherent noise in time-varying systems. The results obtained show a much richer characteristics of the zero power noise than that in constant systems. Even the concept of criticality has to be given a probabilistic interpretation. The asymptotic behaviour of the variance will be also qualitatively different from that in constant systems. The covariance of the neutron number in a subcritical system with a source, and the corresponding power spectrum, shows both the inherent and parametrically induced noise components. The results are relevant in medium power subcritical systems where the zero power noise is still significant, but they also have a bearing on all types of branching processes, such as evolution of biological systems, spreading of epidemics etc., which are set in a time-varying environment. (authors)

  5. Neutron fluctuations in a medium randomly varying in time

    Energy Technology Data Exchange (ETDEWEB)

    Lenard, Pal [KFKI Atomic Energy Research Institute, Budapest (Hungary); Imre, Pazsit [Chalmers Univ. of Technology, Dept. of Nuclear Engineering, SE, Goteborg (Sweden)

    2005-07-01

    The master equation approach, which has traditionally been used for the calculation of neutron fluctuations in zero power systems with constant parameters, is extended to a case when the parameters of the system change randomly in time. We consider a forward type master equation for the probability distribution of the number of particles in a multiplying system whose properties jump randomly between two discrete states, both with and without an external source. The first two factorial moments are calculated, including the covariance. This model can be considered the unification of stochastic methods that were used either in a constant multiplying medium via the master equation technique, or in a fluctuating medium via the Langevin technique. In contrast to these methods, the one presented here can calculate the inherent noise in time-varying systems. The results obtained show a much richer characteristics of the zero power noise than that in constant systems. Even the concept of criticality has to be given a probabilistic interpretation. The asymptotic behaviour of the variance will be also qualitatively different from that in constant systems. The covariance of the neutron number in a subcritical system with a source, and the corresponding power spectrum, shows both the inherent and parametrically induced noise components. The results are relevant in medium power subcritical systems where the zero power noise is still significant, but they also have a bearing on all types of branching processes, such as evolution of biological systems, spreading of epidemics etc., which are set in a time-varying environment. (authors)

  6. Abatement cost of GHG emissions for wood-based electricity and ethanol at production and consumption levels.

    Directory of Open Access Journals (Sweden)

    Puneet Dwivedi

    Full Text Available Woody feedstocks will play a critical role in meeting the demand for biomass-based energy products in the US. We developed an integrated model using comparable system boundaries and common set of assumptions to ascertain unit cost and greenhouse gas (GHG intensity of electricity and ethanol derived from slash pine (Pinus elliottii at the production and consumption levels by considering existing automobile technologies. We also calculated abatement cost of greenhouse gas (GHG emissions with respect to comparable energy products derived from fossil fuels. The production cost of electricity derived using wood chips was at least cheaper by 1 ¢ MJ-1 over electricity derived from wood pellets. The production cost of ethanol without any income from cogenerated electricity was costlier by about 0.7 ¢ MJ-1 than ethanol with income from cogenerated electricity. The production cost of electricity derived from wood chips was cheaper by at least 0.7 ¢ MJ-1 than the energy equivalent cost of ethanol produced in presence of cogenerated electricity. The cost of using ethanol as a fuel in a flex-fuel vehicle was at least higher by 6 ¢ km-1 than a comparable electric vehicle. The GHG intensity of per km distance traveled in a flex-fuel vehicle was greater or lower than an electric vehicle running on electricity derived from wood chips depending on presence and absence of GHG credits related with co-generated electricity. A carbon tax of at least $7 Mg CO2e-1 and $30 Mg CO2e-1 is needed to promote wood-based electricity and ethanol production in the US, respectively. The range of abatement cost of GHG emissions is significantly dependent on the harvest age and selected baseline especially for electricity generation.

  7. Customers' preferences with regard to attributes of electric power products; Kundenpraeferenzen fuer leistungsrelevante Attribute von Stromprodukten

    Energy Technology Data Exchange (ETDEWEB)

    Burkhalter, Andreas; Kaenzig, Josef; Wuestenhagen, Rolf [Univ. St. Gallen (Switzerland). Inst. fuer Wirtschaft und Oekologie

    2009-06-15

    This article addresses whether standard electricity products in Switzerland meet the preferences of private customers. To determine customers' preferred electricity product we conducted an online survey with choice experiments implying 9420 choice decisions by 628 respondents in Switzerland. Using hierarchical Bayes estimation we determined customer preferences and the importance of individual product attributes in product choice. This procedure makes it possible to calculate part worth utilities for product attributes and to derive customers' implicit willingness to pay. The ''electricity mix'' had the most important influence on choice decisions, followed by ''monthly electricity costs'' and the ''location of the electricity generation''. The current Swiss electricity mix which consists of mainly nuclear and hydro power was only rated second to last in a comparison of five alternative mixes. Customers clearly prefer electricity mixes containing green energy. Findings of this study reveal strategic options for product design, positioning, and marketing for a liberalized electricity market. (orig.)

  8. Optimal Consumption and Investment under Time-Varying Relative Risk Aversion

    DEFF Research Database (Denmark)

    Steffensen, Mogens

    2011-01-01

    We consider the continuous time consumption-investment problem originally formalized and solved by Merton in case of constant relative risk aversion. We present a complete solution for the case where relative risk aversion with respect to consumption varies with time, having in mind an investor...... with age-dependent risk aversion. This provides a new motivation for life-cycle investment rules. We study the optimal consumption and investment rules, in particular in the case where the relative risk aversion with respect to consumption is increasing with age....

  9. Detection of dynamically varying interaural time differences

    DEFF Research Database (Denmark)

    Kohlrausch, Armin; Le Goff, Nicolas; Breebaart, Jeroen

    2010-01-01

    of fringes surrounding the probe is equal to the addition of the effects of the individual fringes. In this contribution, we present behavioral data for the same experimental condition, called dynamically varying ITD detection, but for a wider range of probe and fringe durations. Probe durations varied...

  10. 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.

  11. Greengrid Electric

    International Nuclear Information System (INIS)

    Argue, D.

    1998-01-01

    This presentation focused on what customers want from a competitive electricity market and what motivates customers to choose a renewable energy product and service. Greengrid Electric, a subsidiary of Enershare Technology Corp., intends to provide the green electricity that they believe customers have wanted for some time. Enershare and Greengrid have been active participants in the electricity restructuring process in Ontario, and have provided input to the Market Design Committee. Once licensed as a retailer, Greengrid intends to be the major provider of green electricity in Ontario. The company will supply a 100 per cent renewable energy product to their wholesale and retail customers. The company is confident that there is a significant niche market in Ontario for selling a green product that has a blend of wind, small hydro (run-of-river or existing dam), solar, and for energy produced from capturing methane gas from municipal landfill sites. Company officials are confident that customers will be willing to pay a premium price for energy if their purchases will lead to environmental improvement

  12. Evaluation of electrical energy production patterns

    International Nuclear Information System (INIS)

    Conti, F.; Graziani, G.; Zanantoni, C.

    1975-06-01

    The main features and typical applications of the code TOTEM, developed by the CCR under request of DG XVII are described. The code is used to evaluate the physical and economical consequences of electrical power station installation policies. The input data are: the time-dependent electrical energy demand and its load duration curve, the physical and economical characteristics of the power stations, and the splitting of the energy between the various types of stations, apart from the energy produced by a plutonium burner and plutonium producer, which is calculated by the code. The output includes; costs, fuel consumption, separative work requirements

  13. H ∞ synchronization of the coronary artery system with input time-varying delay

    International Nuclear Information System (INIS)

    Li Xiao-Meng; Zhao Zhan-Shan; Sun Lian-Kun; Zhang Jing

    2016-01-01

    This paper investigates the H ∞ synchronization of the coronary artery system with input delay and disturbance. We focus on reducing the conservatism of existing synchronization strategies. Base on the triple integral forms of the Lyapunov–Krasovskii functional (LKF), we utilize single and double integral forms of Wirtinger-based inequality to guarantee that the synchronization feedback controller has good performance against time-varying delay and external disturbance. The effectiveness of our strategy can be exhibited by simulations under the different time-varying delays and different disturbances. (paper)

  14. Energy and environmental impacts of electric vehicle battery production and recycling

    International Nuclear Information System (INIS)

    Gaines, L.; Singh, M.

    1995-01-01

    Electric vehicle batteries use energy and generate environmental residuals when they are produced and recycled. This study estimates, for 4 selected battery types (advanced lead-acid, sodium-sulfur, nickel-cadmium, and nickel-metal hydride), the impacts of production and recycling of the materials used in electric vehicle batteries. These impacts are compared, with special attention to the locations of the emissions. It is found that the choice among batteries for electric vehicles involves tradeoffs among impacts. For example, although the nickel-cadmium and nickel-metal hydride batteries are similar, energy requirements for production of the cadmium electrodes may be higher than those for the metal hydride electrodes, but the latter may be more difficult to recycle

  15. Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process.

    Science.gov (United States)

    Lehtinen, Tapio; Efimova, Elena; Tremblay, Pier-Luc; Santala, Suvi; Zhang, Tian; Santala, Ville

    2017-11-01

    Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long chain alkyl esters. In the first stage, the carbon dioxide is reduced to organic compounds, mainly acetate, in a MES process by Sporomusa ovata. In the second stage, the liquid end-products of the MES process are converted to the final product by a second microorganism, Acinetobacter baylyi in an aerobic bioprocess. In this proof-of-principle study, we demonstrate for the first time the bacterial production of long alkyl esters (wax esters) from carbon dioxide and electricity as the sole sources of carbon and energy. The process holds potential for the efficient production of carbon-neutral chemicals or biofuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Waiting Endurance Time Estimation of Electric Two-Wheelers at Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Mei Huan

    2014-01-01

    Full Text Available The paper proposed a model for estimating waiting endurance times of electric two-wheelers at signalized intersections using survival analysis method. Waiting duration times were collected by video cameras and they were assigned as censored and uncensored data to distinguish between normal crossing and red-light running behavior. A Cox proportional hazard model was introduced, and variables revealing personal characteristics and traffic conditions were defined as covariates to describe the effects of internal and external factors. Empirical results show that riders do not want to wait too long to cross intersections. As signal waiting time increases, electric two-wheelers get impatient and violate the traffic signal. There are 12.8% of electric two-wheelers with negligible wait time. 25.0% of electric two-wheelers are generally nonrisk takers who can obey the traffic rules after waiting for 100 seconds. Half of electric two-wheelers cannot endure 49.0 seconds or longer at red-light phase. Red phase time, motor vehicle volume, and conformity behavior have important effects on riders’ waiting times. Waiting endurance times would decrease with the longer red-phase time, the lower traffic volume, or the bigger number of other riders who run against the red light. The proposed model may be applicable in the design, management and control of signalized intersections in other developing cities.

  17. Waiting endurance time estimation of electric two-wheelers at signalized intersections.

    Science.gov (United States)

    Huan, Mei; Yang, Xiao-bao

    2014-01-01

    The paper proposed a model for estimating waiting endurance times of electric two-wheelers at signalized intersections using survival analysis method. Waiting duration times were collected by video cameras and they were assigned as censored and uncensored data to distinguish between normal crossing and red-light running behavior. A Cox proportional hazard model was introduced, and variables revealing personal characteristics and traffic conditions were defined as covariates to describe the effects of internal and external factors. Empirical results show that riders do not want to wait too long to cross intersections. As signal waiting time increases, electric two-wheelers get impatient and violate the traffic signal. There are 12.8% of electric two-wheelers with negligible wait time. 25.0% of electric two-wheelers are generally nonrisk takers who can obey the traffic rules after waiting for 100 seconds. Half of electric two-wheelers cannot endure 49.0 seconds or longer at red-light phase. Red phase time, motor vehicle volume, and conformity behavior have important effects on riders' waiting times. Waiting endurance times would decrease with the longer red-phase time, the lower traffic volume, or the bigger number of other riders who run against the red light. The proposed model may be applicable in the design, management and control of signalized intersections in other developing cities.

  18. Tracking time-varying coefficient-functions

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.

    2000-01-01

    is a combination of recursive least squares with exponential forgetting and local polynomial regression. It is argued, that it is appropriate to let the forgetting factor vary with the value of the external signal which is the argument of the coefficient functions. Some of the key properties of the modified method...... are studied by simulation...

  19. Challenges of electricity production scenarios modelling for life cycle assessment of environmental impacts

    International Nuclear Information System (INIS)

    Blanc, Isabelle; Beloin-Saint-Pierre, Didier

    2013-01-01

    This communication presents a first attempt at making a life cycle assessment of prospective electricity production scenarios which were designed in the EnerGEO project. We start by a basic review of system (in this case, scenario) modelling expectations in today's LCA study. We then review some of the challenges of implementation due to the lack of detailed description of present and future electricity production systems. The importance of a detailed description is then shown with an evaluation of uncertainty of life cycle impact assessment results for three scenarios of German electricity production in 2030. The significant uncertainties we found, prevent us from detecting a relevant trend or making any comparison between the three chosen scenarios. We finally come to the conclusion that the LCA methodology will become relevant for the environmental assessment of electricity production scenarios when many more detailed information are accounted to describe future technologies, structures and sources of energy. (orig.)

  20. Challenges of electricity production scenarios modelling for life cycle assessment of environmental impacts

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, Isabelle; Beloin-Saint-Pierre, Didier [MINES ParisTech, Sophia Antipolis (France). Observation, Impacts, Energy Center

    2013-07-01

    This communication presents a first attempt at making a life cycle assessment of prospective electricity production scenarios which were designed in the EnerGEO project. We start by a basic review of system (in this case, scenario) modelling expectations in today's LCA study. We then review some of the challenges of implementation due to the lack of detailed description of present and future electricity production systems. The importance of a detailed description is then shown with an evaluation of uncertainty of life cycle impact assessment results for three scenarios of German electricity production in 2030. The significant uncertainties we found, prevent us from detecting a relevant trend or making any comparison between the three chosen scenarios. We finally come to the conclusion that the LCA methodology will become relevant for the environmental assessment of electricity production scenarios when many more detailed information are accounted to describe future technologies, structures and sources of energy. (orig.)

  1. Measuring efficiency and productivity change (PTF) in the Peruvian electricity distribution companies after reforms

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Reyes, Raul [Organismo Supervisor de la Inversion en Energia y Mineria, Osinergmin (Peru); Tovar, Beatriz [Infrastructure and Transport Research Group (EIT), Department of Applied Economics, University of Palmas de Gran Canaria (Spain)

    2009-06-15

    This paper analyzes the evolution of productivity of the electricity distribution companies in Peru, to assess whether reforms have improved the efficiency in this sector. The paper also identifies potential sources of productivity changes, based on market restructuring the electricity sector and changes in property. To do this, we rely on a set of data for 14 distribution companies, for the period 1996-2006. Our analysis suggests that improvements in the efficiency and productivity of electricity distribution in Peru have occurred, and that there is a relationship between the restructuring of distribution sector and the enhancement of productivity. (author)

  2. Measuring efficiency and productivity change (PTF) in the Peruvian electricity distribution companies after reforms

    International Nuclear Information System (INIS)

    Perez-Reyes, Raul; Tovar, Beatriz

    2009-01-01

    This paper analyzes the evolution of productivity of the electricity distribution companies in Peru, to assess whether reforms have improved the efficiency in this sector. The paper also identifies potential sources of productivity changes, based on market restructuring the electricity sector and changes in property. To do this, we rely on a set of data for 14 distribution companies, for the period 1996-2006. Our analysis suggests that improvements in the efficiency and productivity of electricity distribution in Peru have occurred, and that there is a relationship between the restructuring of distribution sector and the enhancement of productivity. (author)

  3. Time-varying coefficient estimation in SURE models. Application to portfolio management

    DEFF Research Database (Denmark)

    Casas, Isabel; Ferreira, Eva; Orbe, Susan

    This paper provides a detailed analysis of the asymptotic properties of a kernel estimator for a Seemingly Unrelated Regression Equations model with time-varying coefficients (tv-SURE) under very general conditions. Theoretical results together with a simulation study differentiates the cases...

  4. Effects of varying feeding times on fertility and hatchability of broiler ...

    African Journals Online (AJOL)

    Effects of varying feeding times on fertility and hatchability of broiler chicken breeders in a tropical environment. ... Journal Home > Vol 65, No 4 (2017) > ... Prior to the eighth week data collection, the birds were allowed to get accustomed to ...

  5. Non-conventional rule of making a periodically varying different-pole magnetic field in low-power alternating current electrical machines with using ring coils in multiphase armature winding

    Science.gov (United States)

    Plastun, A. T.; Tikhonova, O. V.; Malygin, I. V.

    2018-02-01

    The paper presents methods of making a periodically varying different-pole magnetic field in low-power electrical machines. Authors consider classical designs of electrical machines and machines with ring windings in armature, structural features and calculated parameters of magnetic circuit for these machines.

  6. Slovenske elektrarne has fulfilled the plan of electric power production at 101 %

    International Nuclear Information System (INIS)

    Anon

    2004-01-01

    Slovenske elektrarne, a. s., produced in 2003 year the electric power in capacity 26,047.6 GWh, whereby they fulfilled business plan at 101 %. In compare with the last year it is a reduction in production by 1,397.3 GWh. The biggest share of production - till 68.6 % of overall production of the Slovenske elektrarne, was provided by nuclear sources. Nuclear power plants fulfilled business plan at 104 %, when Jaslovske Bohunice NPP has produced 11,625 GWh and Mochovce NPP 6,238 GWh. The share of other power plants on the electricity production is presented

  7. Price dynamics among U.S. electricity spot markets

    International Nuclear Information System (INIS)

    Park, Haesun; Mjelde, James W.; Bessler, David A.

    2006-01-01

    Combining recent advances in causal flows with time series analysis, relationships among 11 U.S. spot market electricity prices are examined. Results suggest that the relationships among the markets vary by time frame. In contemporaneous time, the western markets are separated from the eastern markets and the Electricity Reliability Council of Texas. At longer time frames these separations disappear, even though electricity transmission between the regions is limited. It appears the relationships among markets are not only a function of physical assets (such as transmissions lines among markets), but by similar and dissimilar institutional arrangements among the markets. (Author)

  8. Synchronization of Hierarchical Time-Varying Neural Networks Based on Asynchronous and Intermittent Sampled-Data Control.

    Science.gov (United States)

    Xiong, Wenjun; Patel, Ragini; Cao, Jinde; Zheng, Wei Xing

    In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.

  9. Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor Blade Systems

    DEFF Research Database (Denmark)

    Christensen, Rene Hardam; Santos, Ilmar

    2004-01-01

    of active modal controllers. The main aim is to reduce vibrations in periodic time-varying structures. Special emphasis is given to vibration control of coupled bladed rotor systems. A state feedback modal control law is developed based on modal analysis in periodic time-varying structures. The first step...... in the procedure is a transformation of the model into a time-invariant modal form by applying the modal matrices, which are also periodic time-variant. Due to coupled rotor and blade motions complex vibration modes occur in the modal transformed state space model. This implies that the modal transformed model...

  10. Storm time electric field penetration observed at mid-latitude

    International Nuclear Information System (INIS)

    Yeh, H.C.; Foster, J.C.; Rich, F.J.; Swider, W.

    1991-01-01

    During the height of the February 8-9, 1986, magnetic storm the Millstone Hill radar was in the evening local time sector (1600-2200 MLT). Radar observations indicate that high speed (>1,000 m s -1 ) westward ion flow penetrated deeply below 50 degree invariant latitude (Λ) and persisted for 6 hours between 2100 UT on February 8 and 0300 UT on February 9. The double-peaked ion convection feature was pronounced throughout the period, and the separation in the dual maxima ranged from 4 degree to 10 degree. The latitude positions of the high-latitude ion drift peak and the convection reversal varied in unison. The low-latitude ion drift peak (∼49 degree Λ or L =2.3) did not show significant universal time/magnetic local time (UT/MLT) variation in its latitude location but showed a decrease in magnitude during the initial recovery phase of the storm. Using simultaneous particle (30 eV-30 keV) precipitation data from the DMSP F6 and F7 satellites, the authors find the high-latitude ion drift peak to coincide with the boundary plasma sheet/central plasma sheet transition in the high ionospheric conductivity (>15 mho) region. The low-latitude ion drift peak lay between the equatorward edges of the electron and soft ( + dominated ring current energy density in magnetic latitude. The low-latitude ion drift peak is the low-altitude signature of the electric field shielding effect associated with ring current penetration into the outer layer of the storm time plasmasphere

  11. Relaxation of the vibrational distribution function in N2 time varying discharges

    International Nuclear Information System (INIS)

    Capitelli, M.; Gorse, C.; Ricard, A.

    1981-01-01

    Relaxation of the electron and vibrational distribution functions have been calculated in function of residence time in nitrogen electrical discharges and post-discharges. In the discharge the vibrational temperature get bigger with the residence time for t -2 s. In the post-discharge the vibrational distribution is evolving in such a manner that the high levels are overpopulated as the low vibrational level population is dropping

  12. Varying rotation lengths in northern production forests: Implications for habitats provided by retention and production trees.

    Science.gov (United States)

    Felton, Adam; Sonesson, Johan; Nilsson, Urban; Lämås, Tomas; Lundmark, Tomas; Nordin, Annika; Ranius, Thomas; Roberge, Jean-Michel

    2017-04-01

    Because of the limited spatial extent and comprehensiveness of protected areas, an increasing emphasis is being placed on conserving habitats which promote biodiversity within production forest. For this reason, alternative silvicultural programs need to be evaluated with respect to their implications for forest biodiversity, especially if these programs are likely to be adopted. Here we simulated the effect of varied rotation length and associated thinning regimes on habitat availability in Scots pine and Norway spruce production forests, with high and low productivity. Shorter rotation lengths reduced the contribution made by production trees (trees grown for industrial use) to the availability of key habitat features, while concurrently increasing the contribution from retention trees. The contribution of production trees to habitat features was larger for high productivity sites, than for low productivity sites. We conclude that shortened rotation lengths result in losses of the availability of habitat features that are key for biodiversity conservation and that increased retention practices may only partially compensate for this. Ensuring that conservation efforts better reflect the inherent variation in stand rotation lengths would help improve the maintenance of key forest habitats in production forests.

  13. State space modeling of time-varying contemporaneous and lagged relations in connectivity maps.

    Science.gov (United States)

    Molenaar, Peter C M; Beltz, Adriene M; Gates, Kathleen M; Wilson, Stephen J

    2016-01-15

    Most connectivity mapping techniques for neuroimaging data assume stationarity (i.e., network parameters are constant across time), but this assumption does not always hold true. The authors provide a description of a new approach for simultaneously detecting time-varying (or dynamic) contemporaneous and lagged relations in brain connectivity maps. Specifically, they use a novel raw data likelihood estimation technique (involving a second-order extended Kalman filter/smoother embedded in a nonlinear optimizer) to determine the variances of the random walks associated with state space model parameters and their autoregressive components. The authors illustrate their approach with simulated and blood oxygen level-dependent functional magnetic resonance imaging data from 30 daily cigarette smokers performing a verbal working memory task, focusing on seven regions of interest (ROIs). Twelve participants had dynamic directed functional connectivity maps: Eleven had one or more time-varying contemporaneous ROI state loadings, and one had a time-varying autoregressive parameter. Compared to smokers without dynamic maps, smokers with dynamic maps performed the task with greater accuracy. Thus, accurate detection of dynamic brain processes is meaningfully related to behavior in a clinical sample. Published by Elsevier Inc.

  14. Effects of climate change on the production and consumption of electricity in Finland

    International Nuclear Information System (INIS)

    Kuivalainen, P.; Forsius, J.; Maekinen, P.

    1996-01-01

    The purpose of this study was to use the latest knowledge about the greenhouse effect and its impact on electricity production and consumption in Finland and so to update the former study of Aittoniemi made at IVO in 1990. This research used the new climate change scenarios which were drawn up in the Nordic research project entitled Climate Change and Energy Production, financed by the Nordic Council of Ministers, and in the Finnish Research Programme on Climate Change, SILMU. These scenarios have been specially made for Finland, and are thus more suitable than the former global models. The base scenario was chosen to be the year 2025 with no climate change, and the climate change-affected years studied were 2025 and 2100. The base scenario of electricity consumption and production took advantage of the scenario of Ministry of Trade and Industry made at the end of the 1980s. Some changes were essential, however, since the present development proves that some of the assumptions concerning power production forms will not be relevant in 2025. Based on the known dependencies between electricity consumption and temperature, impacts were calculated for each affected consumption sector: electric heating, household consumption and industrial consumption, process industry excluded. The total effect on the supply system was estimated with the KAPAS model, developed for capacity planning of Finland. According to the results, the effects of the projected climate change on the total consumption and production of electricity will be limited. The structure of both electricity consumption and production will remain rather similar, the most important changes applying to hydro power. (13 refs.)

  15. The Analysis of Electrical Energy Consumption of the Impact Screwdriver During Assembly of Fixed Threaded Joints

    Science.gov (United States)

    Grinevich, I.; Nikishin, Vl.; Mozga, N.; Laitans, M.

    2017-06-01

    The paper deals with the possibilities of reducing the consumption of electrical energy of the impact screwdriver during the assembly of fixed threaded joints. The recommendations related to a decrease in electrical energy consumption would allow reducing product costs but so far there have been no such recommendations from the producers of the tool as to the effective operating regimes of the impact screwdrivers in relation to electrical energy consumption and necessary tightening moment of the nut. The aim of the study is to find out the economical operating mode of the electrical impact screwdriver when assembling fixed threaded joints. By varying the set speed of the rotor head and working time of the impact mechanism, there is an opportunity to determine electrical energy consumption of the tool for the given tightening moment. The results of the experiment show that at the same tightening moment obtained the electrical energy consumption of the impact screwdriver is less at a higher starting set speed of the rotor head but shorter operating time of the impact mechanism than at a lower speed of the rotor head and longer operating time of the impact mechanism.

  16. Fluctuating interaction network and time-varying stability of a natural fish community

    Science.gov (United States)

    Ushio, Masayuki; Hsieh, Chih-Hao; Masuda, Reiji; Deyle, Ethan R.; Ye, Hao; Chang, Chun-Wei; Sugihara, George; Kondoh, Michio

    2018-02-01

    Ecological theory suggests that large-scale patterns such as community stability can be influenced by changes in interspecific interactions that arise from the behavioural and/or physiological responses of individual species varying over time. Although this theory has experimental support, evidence from natural ecosystems is lacking owing to the challenges of tracking rapid changes in interspecific interactions (known to occur on timescales much shorter than a generation time) and then identifying the effect of such changes on large-scale community dynamics. Here, using tools for analysing nonlinear time series and a 12-year-long dataset of fortnightly collected observations on a natural marine fish community in Maizuru Bay, Japan, we show that short-term changes in interaction networks influence overall community dynamics. Among the 15 dominant species, we identify 14 interspecific interactions to construct a dynamic interaction network. We show that the strengths, and even types, of interactions change with time; we also develop a time-varying stability measure based on local Lyapunov stability for attractor dynamics in non-equilibrium nonlinear systems. We use this dynamic stability measure to examine the link between the time-varying interaction network and community stability. We find seasonal patterns in dynamic stability for this fish community that broadly support expectations of current ecological theory. Specifically, the dominance of weak interactions and higher species diversity during summer months are associated with higher dynamic stability and smaller population fluctuations. We suggest that interspecific interactions, community network structure and community stability are dynamic properties, and that linking fluctuating interaction networks to community-level dynamic properties is key to understanding the maintenance of ecological communities in nature.

  17. Electric energy production and environmental licensing: citizenship in Brazil in time of ecological crisis; Producao de energia eletrica e licenciamento ambiental: cidadania no Brasil em tempo de crise ecologica

    Energy Technology Data Exchange (ETDEWEB)

    Bettencourt, Marcia Pires da Luz

    2017-11-01

    The choices of energy sources gain relevance in the face of the ecological crisis which has a central questioning on the modes of production and consumption and that stems from a system which changes everything into merchandise. On one hand, brazilian electricity generation has the advantage of using clean energy in great part of its composition, at least in discourse. On the other hand, though, there are high social and environmental costs, especially for communities living near the regions where projects for the electricity sector are built. This research aimed to identify and analyse different modes society takes part in the process of choosing energy sources for electricity generation in Brazil. It discusses the links between the ecological crisis and the production of electrical energy; how the institutional mechanisms for social participation on issues related to the production of electric power in Brazil work; and, how civil society participates in environmental licensing in the National Environment Council (CONAMA). A set of related approaches to the nature of the ecological crisis and the forms of social participation was adopted in the theoretical framework and an analysis of the electric sector panorama in Brazil has been drawn up. In order to investigate the forms society participates in issues related to the composition of the brazilian electricity matrix, the methodology comprised a documentary analysis and a case study. They included three categories of actors: (1) CONAMA's councilors, (2) experts from the Field; and (3) actors involved in the diagnosis study, planning and management of the electricity sector. The research identified inconsistencies, ambiguities and other relevant issues about the participation of society in the production of electrical energy. Such issues are related to: deficiencies in the mechanisms for information access; lack of transparency and patterns in internal documents; lack of social participation in the elaboration

  18. Time-dependent plug-in hybrid electric vehicle charging based on national driving patterns and demographics

    International Nuclear Information System (INIS)

    Kelly, Jarod C.; MacDonald, Jason S.; Keoleian, Gregory A.

    2012-01-01

    Highlights: ► Analyzed National Household Travel Survey to simulate driving and charging patterns. ► Average compact PHEVs used 49 kW h of electricity and 6.8 L of gasoline per week. ► Percent of electrically driven miles increased from 64.3 in 2001 to 66.7 in 2009. ► Investigated demographic effects of sex, age, income, and household location. ► Analysis shows higher utility factors for females versus males and high age variation. -- Abstract: Plug-in hybrid electric vehicles (PHEVs) are one promising technology for addressing concerns around petroleum consumption, energy security and greenhouse gas emissions. However, there is much uncertainty in the impact that PHEVs can have on energy consumption and related emissions, as they are dependent on vehicle technology, driving patterns, and charging behavior. A methodology is used to simulate PHEV charging and gasoline consumption based on driving pattern data in USDOT’s National Household Travel Survey. The method uses information from each trip taken by approximately 170,000 vehicles to track their battery state of charge throughout the day, and to determine the timing and quantity of electricity and gasoline consumption for a fleet of PHEVs. Scenarios were developed to examine the effects of charging location, charging rate, time of charging and battery size. Additionally, demographic information was examined to see how driver and household characteristics influence consumption patterns. Results showed that a compact vehicle with a 10.4 kW h useable battery (approximately a 42 mile [68 km] all electric range) travels between 62.5% and 75.7% on battery electricity, depending on charging scenario. The percent of travel driven electrically (Utility Factor, UF) in a baseline charging scenario increased from 64.3% using 2001 NHTS data to 66.7% using 2009 data. The average UF was 63.5% for males and 72.9% for females and in both cases they are highly sensitive to age. Vehicle charging load profiles across

  19. Exponential stability for stochastic delayed recurrent neural networks with mixed time-varying delays and impulses: the continuous-time case

    International Nuclear Information System (INIS)

    Karthik Raja, U; Leelamani, A; Raja, R; Samidurai, R

    2013-01-01

    In this paper, the exponential stability for a class of stochastic neural networks with time-varying delays and impulsive effects is considered. By constructing suitable Lyapunov functionals and by using the linear matrix inequality optimization approach, we obtain sufficient delay-dependent criteria to ensure the exponential stability of stochastic neural networks with time-varying delays and impulses. Two numerical examples with simulation results are provided to illustrate the effectiveness of the obtained results over those already existing in the literature. (paper)

  20. A discrete time-varying internal model-based approach for high precision tracking of a multi-axis servo gantry.

    Science.gov (United States)

    Zhang, Zhen; Yan, Peng; Jiang, Huan; Ye, Peiqing

    2014-09-01

    In this paper, we consider the discrete time-varying internal model-based control design for high precision tracking of complicated reference trajectories generated by time-varying systems. Based on a novel parallel time-varying internal model structure, asymptotic tracking conditions for the design of internal model units are developed, and a low order robust time-varying stabilizer is further synthesized. In a discrete time setting, the high precision tracking control architecture is deployed on a Voice Coil Motor (VCM) actuated servo gantry system, where numerical simulations and real time experimental results are provided, achieving the tracking errors around 3.5‰ for frequency-varying signals. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Electric system management through hydrogen production - A market driven approach in the French context

    International Nuclear Information System (INIS)

    Mansilla, C.; Dautremont, S.; Thais, F.; Louyrette, J.; Martin, J.; Albou, S.; Barbieri, G.; Collignon, N.; Bourasseau, C.; Salasc, B.; Valentin, S.

    2012-01-01

    Hydrogen is usually presented as a promising energy carrier that has a major role to play in low carbon transportation, through the use of fuel cells. However, such a development is not expected in the short term. In the meantime, hydrogen may also contribute to reduce carbon emissions in diverse sectors among which methanol production. Methanol can be produced by combining carbon dioxide and hydrogen, hence facilitating carbon dioxide emission mitigation while providing a beneficial tool to manage the electric system, if hydrogen is produced by alkaline electrolysis operated in a variable way driven by the spot and balancing electricity markets. Such a concept is promoted by the VItESSE project (Industrial and Energy value of CO 2 through Efficient use of CO 2 -free electricity - Electricity Network System Control and Electricity Storage). Through the proposed market driven approach, hydrogen production offers a possibility to help managing the electric system, together with an opportunity to reduce hydrogen production costs. (authors)

  2. Real-time Kalman filter implementation for active feedforward control of time-varying broadband noise and vibrations

    NARCIS (Netherlands)

    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

  3. ANALYSIS OF GROSS REGIONAL PRODUCT FLUCTUATIONS AND ELECTRIC POWER CONSUMPTION IN 2005- 2014. RESERVES FOR DECREASING ELECTRIC POWER PRICES

    Directory of Open Access Journals (Sweden)

    Suslov N. I.

    2016-09-01

    Full Text Available In this work we considered the trajectories of change in indicators characterizing the status of economics and power industry: gross regional product, electric power consumption, industrial production, energy prices and costs of delivering electric power to consumers in Russian regions for the last 10 years. Low global commodity prices and sanctions led to a sharp decrease of equipment import, which resulted in an acute problem of import substitution. The level of tariffs of natural monopolies is of great importance for industrial development. The goal of this work was to analyze possibilities for reducing electric power prices by changing the institutional and economic conditions of management. We analyzed not only the official information from Rosstat, but also government regulations, figures given in the official government publication «The Rossiyskaya Gazeta» as well as articles and interviews on economic problems of the electric power industry over the recent years published in «The Kommersant» newspaper. High tariffs of network marketing companies for electric energy transmission, state regulation of heating prices, financing the construction of new capacities by charging the payment in power provision contracts, high price of electric power of nuclear power plants lead to an annual increase in electric power prices for end users. In this work we considered possible solutions to limit the growth of electric power prices.

  4. Estimation of Time-Varying Coherence and Its Application in Understanding Brain Functional Connectivity

    Directory of Open Access Journals (Sweden)

    Cheng Liu

    2010-01-01

    Full Text Available Time-varying coherence is a powerful tool for revealing functional dynamics between different regions in the brain. In this paper, we address ways of estimating evolutionary spectrum and coherence using the general Cohen's class distributions. We show that the intimate connection between the Cohen's class-based spectra and the evolutionary spectra defined on the locally stationary time series can be linked by the kernel functions of the Cohen's class distributions. The time-varying spectra and coherence are further generalized with the Stockwell transform, a multiscale time-frequency representation. The Stockwell measures can be studied in the framework of the Cohen's class distributions with a generalized frequency-dependent kernel function. A magnetoencephalography study using the Stockwell coherence reveals an interesting temporal interaction between contralateral and ipsilateral motor cortices under the multisource interference task.

  5. Robust outer synchronization between two nonlinear complex networks with parametric disturbances and mixed time-varying delays

    Science.gov (United States)

    Zhang, Chuan; Wang, Xingyuan; Luo, Chao; Li, Junqiu; Wang, Chunpeng

    2018-03-01

    In this paper, we focus on the robust outer synchronization problem between two nonlinear complex networks with parametric disturbances and mixed time-varying delays. Firstly, a general complex network model is proposed. Besides the nonlinear couplings, the network model in this paper can possess parametric disturbances, internal time-varying delay, discrete time-varying delay and distributed time-varying delay. Then, according to the robust control strategy, linear matrix inequality and Lyapunov stability theory, several outer synchronization protocols are strictly derived. Simple linear matrix controllers are designed to driver the response network synchronize to the drive network. Additionally, our results can be applied on the complex networks without parametric disturbances. Finally, by utilizing the delayed Lorenz chaotic system as the dynamics of all nodes, simulation examples are given to demonstrate the effectiveness of our theoretical results.

  6. Improvement of and Parameter Identification for the Bimodal Time-Varying Modified Kanai-Tajimi Power Spectral Model

    Directory of Open Access Journals (Sweden)

    Huiguo Chen

    2017-01-01

    Full Text Available Based on the Kanai-Tajimi power spectrum filtering method proposed by Du Xiuli et al., a genetic algorithm and a quadratic optimization identification technique are employed to improve the bimodal time-varying modified Kanai-Tajimi power spectral model and the parameter identification method proposed by Vlachos et al. Additionally, a method for modeling time-varying power spectrum parameters for ground motion is proposed. The 8244 Orion and Chi-Chi earthquake accelerograms are selected as examples for time-varying power spectral model parameter identification and ground motion simulations to verify the feasibility and effectiveness of the improved bimodal time-varying modified Kanai-Tajimi power spectral model. The results of this study provide important references for designing ground motion inputs for seismic analyses of major engineering structures.

  7. Electricity demand and conservation potential in the Chinese nonmetallic mineral products industry

    International Nuclear Information System (INIS)

    Lin, Boqiang; Ouyang, Xiaoling

    2014-01-01

    As the high energy-consuming manufacturing industry, electricity consumption of nonmetallic mineral products in China accounted for 7.93% of industrial, 5.84% of national and 1.33% of global electricity consumption in 2010. This study attempts to specify the determinants of sectoral electricity demand, forecast future electricity consumption by creating a model using the Johansen cointegration methodology and estimate the sectoral electricity conservation potential. Results indicate that GDP per capita is the leading force explaining the sectoral electricity consumption increase, while value-added per worker, R and D intensity and electricity price are the main factors contributing to the sectoral electricity consumption decrease. Results demonstrate that sectoral electricity consumption in 2020 will be 369.79–464.83 billion kWh under the low-growth scenario and 530.14–666.39 billion kWh under the high-growth scenario. Moreover, under the low-growth scenario, the sectoral electricity conservation potential in 2020 will be 33.72–95.03 billion kWh, accounting for 0.45–1.26% of China's total electricity demand in 2020; under the high-growth scenario, the sectoral electricity conservation potential in 2020 will be 48.34–136.24 billion kWh, accounting for 0.26–0.74% of world's total electricity consumption in 2010 respectively. Finally, we provide some policy recommendations for encouraging energy conservation in China's nonmetallic mineral products industry. - Highlights: • A long-term relationship of electricity demand in nonmetallic minerals industry is established. • Determinants of the sectoral electricity consumption are specified. • The sectoral electricity demand and saving potential are analyzed using scenarios analysis. • Electricity saving potential will be 48.34–136.24 billion kWh under the high-growth scenario

  8. Turkey's High Temperature Geothermal Energy Resources and Electricity Production Potential

    Science.gov (United States)

    Bilgin, Ö.

    2012-04-01

    Turkey is in the first 7 countries in the world in terms of potential and applications. Geothermal energy which is an alternative energy resource has advantages such as low-cost, clean, safe and natural resource. Geothermal energy is defined as hot water and steam which is formed by heat that accumulated in various depths of the Earth's crust; with more than 20oC temperature and which contain more than fused minerals, various salts and gases than normal underground and ground water. It is divided into three groups as low, medium and high temperature. High-temperature fluid is used in electricity generation, low and medium temperature fluids are used in greenhouses, houses, airport runways, animal farms and places such as swimming pools heating. In this study high temperature geothermal fields in Turkey which is suitable for electricity production, properties and electricity production potential was investigated.

  9. Production in Italian industry: Electric power demand indicators

    International Nuclear Information System (INIS)

    Ajello, V.

    1993-01-01

    The effects of the recession in Italy were first evidenced during the period spanning 1990-1992 with a sharp drop in the international competitiveness of Italian products. This phase was then followed by a significant drop in internal demand, the devaluation of the Italian Lira and subsequent market uncertainty. This paper presents graphs of national and regional electric power production and consumption figures which reflect the downturn in the viability of the Italian economy, especially in the industrial sector

  10. Pair production of Dirac particles in a d + 1-dimensional noncommutative space-time

    Energy Technology Data Exchange (ETDEWEB)

    Ousmane Samary, Dine [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); University of Abomey-Calavi, International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), Cotonou (Benin); N' Dolo, Emanonfi Elias; Hounkonnou, Mahouton Norbert [University of Abomey-Calavi, International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), Cotonou (Benin)

    2014-11-15

    This work addresses the computation of the probability of fermionic particle pair production in d + 1-dimensional noncommutative Moyal space. Using Seiberg-Witten maps, which establish relations between noncommutative and commutative field variables, up to the first order in the noncommutative parameter θ, we derive the probability density of vacuum-vacuum pair production of Dirac particles. The cases of constant electromagnetic, alternating time-dependent, and space-dependent electric fields are considered and discussed. (orig.)

  11. Estimating time-varying RSA to examine psychophysiological linkage of marital dyads.

    Science.gov (United States)

    Gates, Kathleen M; Gatzke-Kopp, Lisa M; Sandsten, Maria; Blandon, Alysia Y

    2015-08-01

    One of the primary tenets of polyvagal theory dictates that parasympathetic influence on heart rate, often estimated by respiratory sinus arrhythmia (RSA), shifts rapidly in response to changing environmental demands. The current standard analytic approach of aggregating RSA estimates across time to arrive at one value fails to capture this dynamic property within individuals. By utilizing recent methodological developments that enable precise RSA estimates at smaller time intervals, we demonstrate the utility of computing time-varying RSA for assessing psychophysiological linkage (or synchrony) in husband-wife dyads using time-locked data collected in a naturalistic setting. © 2015 Society for Psychophysiological Research.

  12. Non-electrical uses of thermal energy generated in the production of fissile fuel in fusion--fission reactors: a comparative economic parametric analysis for a hybrid with or without synthetic fuel production

    International Nuclear Information System (INIS)

    Tai, A.S.; Krakowski, R.A.

    1979-01-01

    A parametric analysis has been carried out for testing the sensitivity of the synfuel production cost in relation to crucial economic and technologic quantities (investment costs of hybrid and synfuel plant, energy multiplication of the fission blanket, recirculating power fraction of the fusion driver, etc.). In addition, a minimum synfuel selling price has been evaluated, from which the fission--fusion--synfuel complex brings about a higher economic benefit than does the fusion--fission hybrid entirely devoted to fissile-fuel and electricity generation. Assuming an electricity cost of 2.7 cents/kWh, an annual investment cost per power unit of 4.2 to 6 $/GJ (132 to 189 k$/MWty) for the fission--fusion complex and 1.5 to 3 $/GJ (47 to 95 k$/MWty) for the synfuel plant, the synfuel production net cost (i.e., revenue = cost) varies between 6.5 and 8.6 $/GJ. These costs can compete with those obtained by other processes (natural gas reforming, resid partial oxidation, coal gasification, nuclear fission, solar electrolysis, etc.). This study points out a potential use of the fusion--fission hybrid other than fissile-fuel and electricity generation

  13. Multimodal Pilot Behavior in Multi-Axis Tracking Tasks with Time-Varying Motion Cueing Gains

    Science.gov (United States)

    Zaal, P. M. T; Pool, D. M.

    2014-01-01

    In a large number of motion-base simulators, adaptive motion filters are utilized to maximize the use of the available motion envelope of the motion system. However, not much is known about how the time-varying characteristics of such adaptive filters affect pilots when performing manual aircraft control. This paper presents the results of a study investigating the effects of time-varying motion filter gains on pilot control behavior and performance. An experiment was performed in a motion-base simulator where participants performed a simultaneous roll and pitch tracking task, while the roll and/or pitch motion filter gains changed over time. Results indicate that performance increases over time with increasing motion gains. This increase is a result of a time-varying adaptation of pilots' equalization dynamics, characterized by increased visual and motion response gains and decreased visual lead time constants. Opposite trends are found for decreasing motion filter gains. Even though the trends in both controlled axes are found to be largely the same, effects are less significant in roll. In addition, results indicate minor cross-coupling effects between pitch and roll, where a cueing variation in one axis affects the behavior adopted in the other axis.

  14. Firm size and productivity. Evidence from the electricity distribution industry in Brazil

    International Nuclear Information System (INIS)

    Tovar, Beatriz; Javier Ramos-Real, Francisco; De Almeida, Edmar Fagundes

    2011-01-01

    In this paper we apply Stochastic Frontier Analysis through a distance function to investigate the impact of firm size on productivity development in electricity distribution. We use a sample of seventeen Brazilian firms from 1998 to 2005 and decompose productivity into technical efficiency, scale efficiency and technical change. Moreover, a further step is to decompose the technical change measurement into several components. The results indicate that firm size is important for industry's productivity, and therefore a key aspect to consider when making decisions that affect the market structure in the electricity distribution industry. (author)

  15. Conditional CAPM: Time-varying Betas in the Brazilian Market

    Directory of Open Access Journals (Sweden)

    Frances Fischberg Blank

    2014-10-01

    Full Text Available The conditional CAPM is characterized by time-varying market beta. Based on state-space models approach, beta behavior can be modeled as a stochastic process dependent on conditioning variables related to business cycle and estimated using Kalman filter. This paper studies alternative models for portfolios sorted by size and book-to-market ratio in the Brazilian stock market and compares their adjustment to data. Asset pricing tests based on time-series and cross-sectional approaches are also implemented. A random walk process combined with conditioning variables is the preferred model, reducing pricing errors compared to unconditional CAPM, but the errors are still significant. Cross-sectional test show that book-to-market ratio becomes less relevant, but past returns still capture cross-section variation

  16. Wavelet ridge diagnosis of time-varying elliptical signals with application to an oceanic eddy

    OpenAIRE

    Lilly , J. M.; Gascard , Jean-Claude

    2006-01-01

    International audience; A method for diagnosing the physical properties of a time-varying ellipse is presented. This essentially involves extending the notion of instantaneous frequency to the bivariate case. New complications, and possibilities, arise from the fact that there are several meaningful forms in which a time-varying ellipse may be represented. A perturbation analysis valid for the near-circular case clarifies these issues. Diagnosis of the ellipse properties may then be performed...

  17. Industry sector analysis, Mexico: Electric power production and distribution equipment. Export Trade Information

    International Nuclear Information System (INIS)

    Wood, J.S.; Miller, R.W.

    1988-09-01

    The Industry Sector Analyses (I.S.A.) for electric power production and distribution equipment contains statistical and narrative information on projected market demand, end-users, receptivity of Mexican consumers to U.S. products, the competitive situation - Mexican production, total import market, U.S. market position, foreign competition, and competitive factors, and market access - Mexican tariffs, non-tariff barriers, standards, taxes and distribution channels. The I.S.A. provides the United States industry with meaningful information regarding the Mexican market for electric power production and distribution equipment

  18. Electricity mix and ecological assessments. Consequences of the choice of specific electricity mixes in analyses of the environmental performance of products and services

    International Nuclear Information System (INIS)

    Menard, M.; Dones, R.; Gantner, U.

    1998-12-01

    The study aims at analysing the methodological issues associated with the definition of electricity mixes and discussing the consequences of the choice of specific electricity mixes in analyses of the environmental performance of products and services, based on Life Cycle Assessment (LCA). This report has been designed as a guideline to support LCA practitioners in the systematic identification of the most appropriate electricity mixes for LCA applications. A detailed checklist has been developed for this purpose. It includes the following items: type of electricity supply (from the net, self production, direct contracts); voltage level; country/place of utilisation; year of utilisation; season/daytime of utilisation; import/export model; and, marginal vs. average approach. A few examples, utilising published LCA studies, illustrate the impacts of the insights gained in the present work. Although primarily aimed at applications in Switzerland, the main concepts, the modelling and parts of the information provided can also be applied to other European countries. In addition to the three models proposed earlier for the assessment of the Swiss yearly average electricity mix, a new model (M4) has been developed in the frame of the present task in order to take into account the conditions characteristic for Switzerland as a transit land for electricity trades between its neighbour countries. All existing electricity mix models as well as selected environmental inventories are described and compared in the report. As an example of results, the CO 2 emissions calculated for the Swiss yearly electricity supply mix are relatively small (48 g/kWh with model M4, as compared with 497 g/kWh for the average UCPTE mix). Key information on the structure of electricity generation and trade in Europe is provided. The modelling of the electricity supply for most of the European countries is less sensitive to the choice of an electricity model than for Switzerland. Considering that

  19. Applications, dosimetry and biological interactions of static and time-varying magnetic fields

    International Nuclear Information System (INIS)

    Tenforde, T.S.

    1988-08-01

    The primary topics of this presentation include: (1) the applications of magnetic fields in research, industry, and medical technologies; (2) mechanisms of interaction of static and time-varying magnetic fields with living systems; (3) human health effects of exposure to static and time-varying magnetic fields in occupational, medical, and residential settings; and (4) recent advances in the dosimetry of extremely-low-frequency electromagnetic fields. The discussion of these topics is centered about two issues of considerable contemporary interest: (1) potential health effects of the fields used in magnetic resonance imaging and in vivo spectroscopy, and (2) the controversial issue of whether exposure to extremely-low-frequency (ELF) electromagnetic fields in the home and workplace leads to an elevated risk of cancer. 11 refs

  20. A simple analytical model for dynamics of time-varying target leverage ratios

    Science.gov (United States)

    Lo, C. F.; Hui, C. H.

    2012-03-01

    In this paper we have formulated a simple theoretical model for the dynamics of the time-varying target leverage ratio of a firm under some assumptions based upon empirical observations. In our theoretical model the time evolution of the target leverage ratio of a firm can be derived self-consistently from a set of coupled Ito's stochastic differential equations governing the leverage ratios of an ensemble of firms by the nonlinear Fokker-Planck equation approach. The theoretically derived time paths of the target leverage ratio bear great resemblance to those used in the time-dependent stationary-leverage (TDSL) model [Hui et al., Int. Rev. Financ. Analy. 15, 220 (2006)]. Thus, our simple model is able to provide a theoretical foundation for the selected time paths of the target leverage ratio in the TDSL model. We also examine how the pace of the adjustment of a firm's target ratio, the volatility of the leverage ratio and the current leverage ratio affect the dynamics of the time-varying target leverage ratio. Hence, with the proposed dynamics of the time-dependent target leverage ratio, the TDSL model can be readily applied to generate the default probabilities of individual firms and to assess the default risk of the firms.

  1. Delay-Dependent Guaranteed Cost H∞ Control of an Interval System with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Zhongke Shi

    2009-01-01

    Full Text Available This paper concerns the problem of the delay-dependent robust stability and guaranteed cost H∞ control for an interval system with time-varying delay. The interval system with matrix factorization is provided and leads to less conservative conclusions than solving a square root. The time-varying delay is assumed to belong to an interval and the derivative of the interval time-varying delay is not a restriction, which allows a fast time-varying delay; also its applicability is broad. Based on the Lyapunov-Ktasovskii approach, a delay-dependent criterion for the existence of a state feedback controller, which guarantees the closed-loop system stability, the upper bound of cost function, and disturbance attenuation lever for all admissible uncertainties as well as out perturbation, is proposed in terms of linear matrix inequalities (LMIs. The criterion is derived by free weighting matrices that can reduce the conservatism. The effectiveness has been verified in a number example and the compute results are presented to validate the proposed design method.

  2. Observation of time-varying photoconductivity and persistent photoconductivity in porous silicon

    DEFF Research Database (Denmark)

    Frello, T.; Veje, E.; Leistiko, Otto

    1996-01-01

    We have observed time-varying photoconductivity and persistent photoconductivity in porous silicon, both with time-evolution scales of the order of several minutes or hours. The time evolutions depend on the wavelength and the intensity of the illuminating light. The data indicate the presence...... of at least two competing mechanisms, one is tentatively related to photoinduced creation of charge carriers in the silicon substrate followed by diffusion into the porous silicon layer, and the other is tentatively related to desorption of hydrogen from the porous silicon. ©1996 American Institute of Physics....

  3. A delay-dependent approach to robust control for neutral uncertain neural networks with mixed interval time-varying delays

    International Nuclear Information System (INIS)

    Lu, Chien-Yu

    2011-01-01

    This paper considers the problem of delay-dependent global robust stabilization for discrete, distributed and neutral interval time-varying delayed neural networks described by nonlinear delay differential equations of the neutral type. The parameter uncertainties are norm bounded. The activation functions are assumed to be bounded and globally Lipschitz continuous. Using a Lyapunov functional approach and linear matrix inequality (LMI) techniques, the stability criteria for the uncertain neutral neural networks with interval time-varying delays are established in the form of LMIs, which can be readily verified using the standard numerical software. An important feature of the result reported is that all the stability conditions are dependent on the upper and lower bounds of the delays. Another feature of the results lies in that it involves fewer free weighting matrix strategy, and upper bounds of the inner product between two vectors are not introduced to reduce the conservatism of the criteria. Two illustrative examples are provided to demonstrate the effectiveness and the reduced conservatism of the proposed method

  4. Potential for reducing global carbon emissions from electricity production-A bench marking analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ang, B.W.; Zhou, P.; Tay, L.P. [National University of Singapore (Singapore). Department of Industrial and Systems Engineering

    2011-05-15

    We present five performance indicators for electricity generation for 129 countries using the 2005 data. These indicators, measured at the national level, are the aggregate CO{sub 2} intensity of electricity production, the efficiencies of coal, oil and gas generation and the share of electricity produced from non-fossil fuels. We conduct a study on the potential for reducing global energy-related CO{sub 2} emissions from electricity production through simple bench marking. This is performed based on the last four performance indicators and the construction of a cumulative curve for each of these indicators. It is found that global CO{sub 2} emissions from electricity production would be reduced by 19% if all these indicators are benchmarked at the 50th percentile. Not surprisingly, the emission reduction potential measured in absolute terms is the highest for large countries such as China, India, Russia and the United States. When the potential is expressed as a percentage of a country's own emissions, few of these countries appear in the top-five list. 14 refs., 8 figs., 4 tabs.

  5. Data and code for the exploratory data analysis of the electrical energy demand in the time domain in Greece.

    Science.gov (United States)

    Tyralis, Hristos; Karakatsanis, Georgios; Tzouka, Katerina; Mamassis, Nikos

    2017-08-01

    We present data and code for visualizing the electrical energy data and weather-, climate-related and socioeconomic variables in the time domain in Greece. The electrical energy data include hourly demand, weekly-ahead forecasted values of the demand provided by the Greek Independent Power Transmission Operator and pricing values in Greece. We also present the daily temperature in Athens and the Gross Domestic Product of Greece. The code combines the data to a single report, which includes all visualizations with combinations of all variables in multiple time scales. The data and code were used in Tyralis et al. (2017) [1].

  6. Microbial surface displayed enzymes based biofuel cell utilizing degradation products of lignocellulosic biomass for direct electrical energy.

    Science.gov (United States)

    Fan, Shuqin; Hou, Chuantao; Liang, Bo; Feng, Ruirui; Liu, Aihua

    2015-09-01

    In this work, a bacterial surface displaying enzyme based two-compartment biofuel cell for the direct electrical energy conversion from degradation products of lignocellulosic biomass is reported. Considering that the main degradation products of the lignocellulose are glucose and xylose, xylose dehydrogenase (XDH) displayed bacteria (XDH-bacteria) and glucose dehydrogenase (GDH) displayed bacteria (GDH-bacteria) were used as anode catalysts in anode chamber with methylene blue as electron transfer mediator. While the cathode chamber was constructed with laccase/multi-walled-carbon nanotube/glassy-carbon-electrode. XDH-bacteria exhibited 1.75 times higher catalytic efficiency than GDH-bacteria. This assembled enzymatic fuel cell exhibited a high open-circuit potential of 0.80 V, acceptable stability and energy conversion efficiency. Moreover, the maximum power density of the cell could reach 53 μW cm(-2) when fueled with degradation products of corn stalk. Thus, this finding holds great potential to directly convert degradation products of biomass into electrical energy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Identification of time-varying structural dynamic systems - An artificial intelligence approach

    Science.gov (United States)

    Glass, B. J.; Hanagud, S.

    1992-01-01

    An application of the artificial intelligence-derived methodologies of heuristic search and object-oriented programming to the problem of identifying the form of the model and the associated parameters of a time-varying structural dynamic system is presented in this paper. Possible model variations due to changes in boundary conditions or configurations of a structure are organized into a taxonomy of models, and a variant of best-first search is used to identify the model whose simulated response best matches that of the current physical structure. Simulated model responses are verified experimentally. An output-error approach is used in a discontinuous model space, and an equation-error approach is used in the parameter space. The advantages of the AI methods used, compared with conventional programming techniques for implementing knowledge structuring and inheritance, are discussed. Convergence conditions and example problems have been discussed. In the example problem, both the time-varying model and its new parameters have been identified when changes occur.

  8. Time-varying parameter models for catchments with land use change: the importance of model structure

    Science.gov (United States)

    Pathiraja, Sahani; Anghileri, Daniela; Burlando, Paolo; Sharma, Ashish; Marshall, Lucy; Moradkhani, Hamid

    2018-05-01

    Rapid population and economic growth in Southeast Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modeling methodologies capable of handling changing land use conditions are therefore becoming ever more important and are receiving increasing attention from hydrologists. A recently developed data-assimilation-based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium-sized catchment (2880 km2) in northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen model structure in ensuring the success of a time-varying parameter method. The method was used with two lumped daily conceptual models (HBV and HyMOD) that gave good-quality streamflow predictions during pre-change conditions. Although both time-varying parameter models gave improved streamflow predictions under changed conditions compared to the time-invariant parameter model, persistent biases for low flows were apparent in the HyMOD case. It was found that HyMOD was not suited to representing the modified baseflow conditions, resulting in extreme and unrealistic time-varying parameter estimates. This work shows that the chosen model can be critical for ensuring the time-varying parameter framework successfully models streamflow under changing land cover conditions. It can also be used to determine whether land cover changes (and not just meteorological factors) contribute to the observed hydrologic changes in retrospective studies where the lack of a paired control catchment precludes such an assessment.

  9. Time-varying parameter models for catchments with land use change: the importance of model structure

    Directory of Open Access Journals (Sweden)

    S. Pathiraja

    2018-05-01

    Full Text Available Rapid population and economic growth in Southeast Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modeling methodologies capable of handling changing land use conditions are therefore becoming ever more important and are receiving increasing attention from hydrologists. A recently developed data-assimilation-based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium-sized catchment (2880 km2 in northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen model structure in ensuring the success of a time-varying parameter method. The method was used with two lumped daily conceptual models (HBV and HyMOD that gave good-quality streamflow predictions during pre-change conditions. Although both time-varying parameter models gave improved streamflow predictions under changed conditions compared to the time-invariant parameter model, persistent biases for low flows were apparent in the HyMOD case. It was found that HyMOD was not suited to representing the modified baseflow conditions, resulting in extreme and unrealistic time-varying parameter estimates. This work shows that the chosen model can be critical for ensuring the time-varying parameter framework successfully models streamflow under changing land cover conditions. It can also be used to determine whether land cover changes (and not just meteorological factors contribute to the observed hydrologic changes in retrospective studies where the lack of a paired control catchment precludes such an assessment.

  10. Response-only modal identification using random decrement algorithm with time-varying threshold level

    International Nuclear Information System (INIS)

    Lin, Chang Sheng; Tseng, Tse Chuan

    2014-01-01

    Modal Identification from response data only is studied for structural systems under nonstationary ambient vibration. The topic of this paper is the estimation of modal parameters from nonstationary ambient vibration data by applying the random decrement algorithm with time-varying threshold level. In the conventional random decrement algorithm, the threshold level for evaluating random dec signatures is defined as the standard deviation value of response data of the reference channel. The distortion of random dec signatures may be, however, induced by the error involved in noise from the original response data in practice. To improve the accuracy of identification, a modification of the sampling procedure in random decrement algorithm is proposed for modal-parameter identification from the nonstationary ambient response data. The time-varying threshold level is presented for the acquisition of available sample time history to perform averaging analysis, and defined as the temporal root-mean-square function of structural response, which can appropriately describe a wide variety of nonstationary behaviors in reality, such as the time-varying amplitude (variance) of a nonstationary process in a seismic record. Numerical simulations confirm the validity and robustness of the proposed modal-identification method from nonstationary ambient response data under noisy conditions.

  11. Robust pre-specified time synchronization of chaotic systems by employing time-varying switching surfaces in the sliding mode control scheme

    Science.gov (United States)

    Khanzadeh, Alireza; Pourgholi, Mahdi

    2016-08-01

    In the conventional chaos synchronization methods, the time at which two chaotic systems are synchronized, is usually unknown and depends on initial conditions. In this work based on Lyapunov stability theory a sliding mode controller with time-varying switching surfaces is proposed to achieve chaos synchronization at a pre-specified time for the first time. The proposed controller is able to synchronize chaotic systems precisely at any time when we want. Moreover, by choosing the time-varying switching surfaces in a way that the reaching phase is eliminated, the synchronization becomes robust to uncertainties and exogenous disturbances. Simulation results are presented to show the effectiveness of the proposed method of stabilizing and synchronizing chaotic systems with complete robustness to uncertainty and disturbances exactly at a pre-specified time.

  12. Robust pre-specified time synchronization of chaotic systems by employing time-varying switching surfaces in the sliding mode control scheme

    International Nuclear Information System (INIS)

    Khanzadeh, Alireza; Pourgholi, Mahdi

    2016-01-01

    In the conventional chaos synchronization methods, the time at which two chaotic systems are synchronized, is usually unknown and depends on initial conditions. In this work based on Lyapunov stability theory a sliding mode controller with time-varying switching surfaces is proposed to achieve chaos synchronization at a pre-specified time for the first time. The proposed controller is able to synchronize chaotic systems precisely at any time when we want. Moreover, by choosing the time-varying switching surfaces in a way that the reaching phase is eliminated, the synchronization becomes robust to uncertainties and exogenous disturbances. Simulation results are presented to show the effectiveness of the proposed method of stabilizing and synchronizing chaotic systems with complete robustness to uncertainty and disturbances exactly at a pre-specified time. (paper)

  13. Forecast Accuracy and Economic Gains from Bayesian Model Averaging using Time Varying Weights

    NARCIS (Netherlands)

    L.F. Hoogerheide (Lennart); R.H. Kleijn (Richard); H.K. van Dijk (Herman); M.J.C.M. Verbeek (Marno)

    2009-01-01

    textabstractSeveral Bayesian model combination schemes, including some novel approaches that simultaneously allow for parameter uncertainty, model uncertainty and robust time varying model weights, are compared in terms of forecast accuracy and economic gains using financial and macroeconomic time

  14. The time-varying role of the family in student time use and achievement

    Directory of Open Access Journals (Sweden)

    Marie C. Hull

    2017-10-01

    Full Text Available Abstract In this paper, I use a unique dataset linking administrative school data with birth records to quantify the importance of time-varying family factors for child achievement and time use. Specifically, I take a model of academic achievement commonly used in the test score literature, and I augment it to include a family-year effect. Identification comes from the large number of sibling pairs observed in the same year. While prior literature has focused on specific shocks, such as job loss, I capture the full set of innovations that are shared across siblings in a given year. The distributions of fixed effects reveal that annual family innovations, relative to what was expected based on the previous year, are more important than teacher assignment for student achievement and also play a substantial role in the time students spend on homework, free reading, and television. JEL Classification I21, J13, J24

  15. Time-lapse electrical geophysical monitoring of amendment-based biostimulation

    Science.gov (United States)

    Johnson, Timothy C.; Versteeg, Roelof J.; Day-Lewis, Frederick D.; Major, William; Lane, John W.

    2015-01-01

    Biostimulation is increasingly used to accelerate microbial remediation of recalcitrant groundwater contaminants. Effective application of biostimulation requires successful emplacement of amendment in the contaminant target zone. Verification of remediation performance requires postemplacement assessment and contaminant monitoring. Sampling-based approaches are expensive and provide low-density spatial and temporal information. Time-lapse electrical resistivity tomography (ERT) is an effective geophysical method for determining temporal changes in subsurface electrical conductivity. Because remedial amendments and biostimulation-related biogeochemical processes often change subsurface electrical conductivity, ERT can complement and enhance sampling-based approaches for assessing emplacement and monitoring biostimulation-based remediation.Field studies demonstrating the ability of time-lapse ERT to monitor amendment emplacement and behavior were performed during a biostimulation remediation effort conducted at the Department of Defense Reutilization and Marketing Office (DRMO) Yard, in Brandywine, Maryland, United States. Geochemical fluid sampling was used to calibrate a petrophysical relation in order to predict groundwater indicators of amendment distribution. The petrophysical relations were field validated by comparing predictions to sequestered fluid sample results, thus demonstrating the potential of electrical geophysics for quantitative assessment of amendment-related geochemical properties. Crosshole radar zero-offset profile and borehole geophysical logging were also performed to augment the data set and validate interpretation.In addition to delineating amendment transport in the first 10 months after emplacement, the time-lapse ERT results show later changes in bulk electrical properties interpreted as mineral precipitation. Results support the use of more cost-effective surface-based ERT in conjunction with limited field sampling to improve spatial

  16. Assessment and Comparison of TMPA Satellite Precipitation Products in Varying Climatic and Topographic Regimes in Morocco

    Directory of Open Access Journals (Sweden)

    Adam Milewski

    2015-05-01

    Full Text Available TRMM Multi-satellite Precipitation Analysis (TMPA satellite precipitation products have been utilized to quantify, forecast, or understand precipitation patterns, climate change, hydrologic models, and drought in numerous scientific investigations. The TMPA products recently went through a series of algorithm developments to enhance the accuracy and reliability of high-quality precipitation measurements, particularly in low rainfall environments and complex terrain. In this study, we evaluated four TMPA products (3B42: V6, V7temp, V7, RTV7 against 125 rain gauges in Northern Morocco to assess the accuracy of TMPA products in various regimes, examine the performance metrics of new algorithm developments, and assess the impact of the processing error in 2012. Results show that the research products outperform the real-time products in all environments within Morocco, and the newest algorithm development (3B42 V7 outperforms the previous version (V6, particularly in low rainfall and high-elevation environments. TMPA products continue to overestimate precipitation in arid environments and underestimate it in high-elevation areas. Lastly, the temporary processing error resulted in little bias except in arid environments. These results corroborate findings from previous studies, provide scientific data for the Middle East, highlight the difficulty of using TMPA products in varying conditions, and present preliminary research for future algorithm development for the GPM mission.

  17. Development of V2G and G2V Power Profiles and Their Implications on Grid Under Varying Equilibrium of Aggregated Electric Vehicles

    Science.gov (United States)

    Jain, Prateek; Jain, Trapti

    2016-04-01

    The objective of this paper is to examine the vehicle-to-grid (V2G) power capability of aggregated electric vehicles (EV) in the manner that they are being adopted by the consumers with their growing infiltration in the vehicles market. The proposed modeling of V2G and grid-to-vehicle (G2V) energy profiles blends the heterogeneous attributes namely, driven mileages, arrival and departure times, travel and parking durations, and speed dependent energy consumption of mobility trends. Three penetration percentages of 25 %, 50 % and 100 % resulting in varied compositions of battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) in the system, as determined by the consumers' acceptance, have been considered to evaluate the grid capacity for V2G. Distinct charge-discharge powers have been selected as per charging standards to match contemporary vehicles and infrastructure requirements. Charging and discharging approaches have been devised to replicate non-linear characteristics of Li-ion battery. Effects of simultaneous conjunction of V2G and G2V power curves with daily conventional load profile are quantified drawn upon workplace-discharging home-charging scheme. Results demonstrated a marked drop in load and hence in market price during morning hours which is hurriedly overcompensated by the hike during evening hours with rising penetration level and charge-discharge power.

  18. Parametric output-only identification of time-varying structures using a kernel recursive extended least squares TARMA approach

    Science.gov (United States)

    Ma, Zhi-Sai; Liu, Li; Zhou, Si-Da; Yu, Lei; Naets, Frank; Heylen, Ward; Desmet, Wim

    2018-01-01

    The problem of parametric output-only identification of time-varying structures in a recursive manner is considered. A kernelized time-dependent autoregressive moving average (TARMA) model is proposed by expanding the time-varying model parameters onto the basis set of kernel functions in a reproducing kernel Hilbert space. An exponentially weighted kernel recursive extended least squares TARMA identification scheme is proposed, and a sliding-window technique is subsequently applied to fix the computational complexity for each consecutive update, allowing the method to operate online in time-varying environments. The proposed sliding-window exponentially weighted kernel recursive extended least squares TARMA method is employed for the identification of a laboratory time-varying structure consisting of a simply supported beam and a moving mass sliding on it. The proposed method is comparatively assessed against an existing recursive pseudo-linear regression TARMA method via Monte Carlo experiments and shown to be capable of accurately tracking the time-varying dynamics. Furthermore, the comparisons demonstrate the superior achievable accuracy, lower computational complexity and enhanced online identification capability of the proposed kernel recursive extended least squares TARMA approach.

  19. Time-varying exchange rate pass-through: experiences of some industrial countries

    OpenAIRE

    Toshitaka Sekine

    2006-01-01

    This paper estimates exchange rate pass-through of six major industrial countries using a time-varying parameter with stochastic volatility model. Exchange rate pass-through is divided into impacts of exchange rate fluctuations to import prices (first-stage pass-through) and those of import price movements to consumer prices (second-stage pass-through). The paper finds that both stages of pass-through have declined over time for all the sample countries. The decline in second-stage pass-throu...

  20. Electric field measurement in the ionosphere using the time-of-flight technique

    International Nuclear Information System (INIS)

    Nakamura, Masato; Hayakawa, Hajime; Tsuruda, Koichiro

    1989-01-01

    The first successful electric field measurement in the ionosphere using the time-of-flight technique with a lithium ion beam was carried out on a S-520 sounding rocket launched from Kagoshima Space Center, Japan on January 15, 1987. The purpose of this experiment was to prove the validity of the time-of-flight technique when it is applied to the measurement of the dc electric field in the ionosphere. A time-coded ion beam was ejected from the rocket in the direction perpendicular to the Earth's magnetic field. The beam returned to the rocket twice per rocket spin when the initial beam direction was nearly perpendicular to the electric field. The electric field and the magnetic field were derived from the travel time of these return lithium ions. The accuracy of the electric field determination was ± 0.3 mV/m. The direction of the electric field was obtained from the direction of the returning ion beam after about one ion gyration. The main constituent of the measured electric field was a V x B field due to the rocket motion across the geomagnetic field. The ambient field was less than 1 mV/m. The magnetic field was measured with an accuracy of ± 2.7 nT in this experiment

  1. Semiclassical pair production rate for time-dependent electrical fields with more than one component: WKB-approach and world-line instantons

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Eckhard, E-mail: eckhard.strobel@irap-phd.eu [ICRANet, Piazzale della Repubblica 10, 65122 Pescara (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome (Italy); Université de Nice Sophia Antipolis, 28 Avenue de Valrose, 06103 Nice Cedex 2 (France); Xue, She-Sheng, E-mail: xue@icra.it [ICRANet, Piazzale della Repubblica 10, 65122 Pescara (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome (Italy)

    2014-09-15

    We present an analytic calculation of the semiclassical electron–positron pair creation rate by time-dependent electrical fields. We use two methods, first the imaginary time method in the WKB-approximation and second the world-line instanton approach. The analytic tools for both methods are generalized to time-dependent electric fields with more than one component. For the WKB method an expansion of the momentum spectrum of produced pairs around the canonical momentum P{sup →}=0 is presented which simplifies the computation of the pair creation rate. We argue that the world-line instanton method of [1] implicitly performs this expansion of the momentum spectrum around P{sup →}=0. Accordingly, the generalization to more than one component is shown to agree with the WKB result obtained via this expansion. However the expansion is only a good approximation for the cases where the momentum spectrum is peaked around P{sup →}=0. Thus the expanded WKB result and the world-line instanton method of [1] as well as the generalized method presented here are only applicable in these cases. We study the two-component case of a rotating electric field and find a new analytic closed form for the momentum spectrum using the generalized WKB method. The momentum spectrum for this field is not peaked around P{sup →}=0.

  2. A delay-dependent LMI approach to dynamics analysis of discrete-time recurrent neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Song, Qiankun; Wang, Zidong

    2007-01-01

    In this Letter, the analysis problem for the existence and stability of periodic solutions is investigated for a class of general discrete-time recurrent neural networks with time-varying delays. For the neural networks under study, a generalized activation function is considered, and the traditional assumptions on the boundedness, monotony and differentiability of the activation functions are removed. By employing the latest free-weighting matrix method, an appropriate Lyapunov-Krasovskii functional is constructed and several sufficient conditions are established to ensure the existence, uniqueness, and globally exponential stability of the periodic solution for the addressed neural network. The conditions are dependent on both the lower bound and upper bound of the time-varying time delays. Furthermore, the conditions are expressed in terms of the linear matrix inequalities (LMIs), which can be checked numerically using the effective LMI toolbox in MATLAB. Two simulation examples are given to show the effectiveness and less conservatism of the proposed criteria

  3. Determinants of Electricity Demand in Nonmetallic Mineral Products Industry: Evidence from a Comparative Study of Japan and China

    Directory of Open Access Journals (Sweden)

    Gang Du

    2015-06-01

    Full Text Available Electricity intensity is an important indicator for measuring production efficiency. A comparative study could offer a new perspective on investigating determinants of electricity demand. The Japanese non-metallic mineral products industry is chosen as the object for comparison considering its representative position in production efficiency. By adopting the cointegration model, this paper examines influencing factors of electricity demand in Japanese and Chinese non-metallic mineral products industries under the same framework. Results indicate that although economic growth and industrial development stages are different between the two countries, major factors that affect the sectoral energy consumption are the same. Specifically, economic growth and industrial activity contribute to the growth of sectoral electricity consumption, while R&D intensity, per capita productivity and electricity price are contributors to the decline of sectoral electricity consumption. Finally, in order to further investigate the development trend of sectoral electricity demand, future electricity consumption and conservation potential are predicted under different scenarios. Electricity demand of the Chinese non-metallic mineral products industry is predicted to be 680.53 TWh (terawatt-hours in 2020 and the sectoral electricity conservation potentials are estimated to be 118.26 TWh and 216.25 TWh under the moderate and advanced electricity-saving scenarios, respectively.

  4. Achieving Synchronization in Arrays of Coupled Differential Systems with Time-Varying Couplings

    Directory of Open Access Journals (Sweden)

    Xinlei Yi

    2013-01-01

    Full Text Available We study complete synchronization of the complex dynamical networks described by linearly coupled ordinary differential equation systems (LCODEs. Here, the coupling is timevarying in both network structure and reaction dynamics. Inspired by our previous paper (Lu et al. (2007-2008, the extended Hajnal diameter is introduced and used to measure the synchronization in a general differential system. Then we find that the Hajnal diameter of the linear system induced by the time-varying coupling matrix and the largest Lyapunov exponent of the synchronized system play the key roles in synchronization analysis of LCODEs with identity inner coupling matrix. As an application, we obtain a general sufficient condition guaranteeing directed time-varying graph to reach consensus. Example with numerical simulation is provided to show the effectiveness of the theoretical results.

  5. Nonlinear systems time-varying parameter estimation: Application to induction motors

    Energy Technology Data Exchange (ETDEWEB)

    Kenne, Godpromesse [Laboratoire d' Automatique et d' Informatique Appliquee (LAIA), Departement de Genie Electrique, IUT FOTSO Victor, Universite de Dschang, B.P. 134 Bandjoun (Cameroon); Ahmed-Ali, Tarek [Ecole Nationale Superieure des Ingenieurs des Etudes et Techniques d' Armement (ENSIETA), 2 Rue Francois Verny, 29806 Brest Cedex 9 (France); Lamnabhi-Lagarrigue, F. [Laboratoire des Signaux et Systemes (L2S), C.N.R.S-SUPELEC, Universite Paris XI, 3 Rue Joliot Curie, 91192 Gif-sur-Yvette (France); Arzande, Amir [Departement Energie, Ecole Superieure d' Electricite-SUPELEC, 3 Rue Joliot Curie, 91192 Gif-sur-Yvette (France)

    2008-11-15

    In this paper, an algorithm for time-varying parameter estimation for a large class of nonlinear systems is presented. The proof of the convergence of the estimates to their true values is achieved using Lyapunov theories and does not require that the classical persistent excitation condition be satisfied by the input signal. Since the induction motor (IM) is widely used in several industrial sectors, the algorithm developed is potentially useful for adjusting the controller parameters of variable speed drives. The method proposed is simple and easily implementable in real-time. The application of this approach to on-line estimation of the rotor resistance of IM shows a rapidly converging estimate in spite of measurement noise, discretization effects, parameter uncertainties (e.g. inaccuracies on motor inductance values) and modeling inaccuracies. The robustness analysis for this IM application also revealed that the proposed scheme is insensitive to the stator resistance variations within a wide range. The merits of the proposed algorithm in the case of on-line time-varying rotor resistance estimation are demonstrated via experimental results in various operating conditions of the induction motor. The experimental results obtained demonstrate that the application of the proposed algorithm to update on-line the parameters of an adaptive controller (e.g. IM and synchronous machines adaptive control) can improve the efficiency of the industrial process. The other interesting features of the proposed method include fault detection/estimation and adaptive control of IM and synchronous machines. (author)

  6. Prospective time-resolved LCA of fully electric supercap vehicles in Germany.

    Science.gov (United States)

    Zimmermann, Benedikt M; Dura, Hanna; Baumann, Manuel J; Weil, Marcel R

    2015-07-01

    The ongoing transition of the German electricity supply toward a higher share of renewable and sustainable energy sources, called Energiewende in German, has led to dynamic changes in the environmental impact of electricity over the last few years. Prominent scenario studies predict that comparable dynamics will continue in the coming decades, which will further improve the environmental performance of Germany's electricity supply. Life cycle assessment (LCA) is the methodology commonly used to evaluate environmental performance. Previous LCA studies on electric vehicles have shown that the electricity supply for the vehicles' operation is responsible for the major part of their environmental impact. The core question of this study is how the prospective dynamic development of the German electricity mix will affect the impact of electric vehicles operated in Germany and how LCA can be adapted to analyze this impact in a more robust manner. The previously suggested approach of time-resolved LCA, which is located between static and dynamic LCA, is used in this study and compared with several static approaches. Furthermore, the uncertainty issue associated with scenario studies is addressed in general and in relation to time-resolved LCA. Two scenario studies relevant to policy making have been selected, but a moderate number of modifications have been necessary to adapt the data to the requirements of a life cycle inventory. A potential, fully electric vehicle powered by a supercapacitor energy storage system is used as a generic example. The results show that substantial improvements in the environmental repercussions of the electricity supply and, consequentially, of electric vehicles will be achieved between 2020 and 2031 on the basis of the energy mixes predicted in both studies. This study concludes that although scenarios might not be able to predict the future, they should nonetheless be used as data sources in prospective LCA studies, because in many cases

  7. How the effects of winds and electric fields in F2-layer storms vary with latitude and longitude - A theoretical study

    Science.gov (United States)

    Mendillo, M.; He, X.-Q.; Rishbeth, H.

    1992-01-01

    The effects of thermospheric winds and electric fields on the ionospheric F2-layer are controlled by the geometry of the magnetic field, and so vary with latitude and longitude. A simple model of the daytime F2-layer is adopted and the effects at midlatitudes (25-65 deg geographic) of three processes that accompany geomagnetic storms: (1) thermospheric changes due to auroral heating; (2) equatorward winds that tend to cancel the quiet-day poleward winds; and (3) the penetration of magnetospheric electric fields are studied. At +/- 65 deg, the effects of heating and electric fields are strongest in the longitudes toward which the geomagnetic dipole is tilted, i.e., the North American and the South Indian Ocean sectors. Because of the proximity of the geomagnetic equator to the East Asian and South American sectors, the reverse is true at +/- 25 deg.

  8. Time varying behaviour of the loudspeaker suspension

    DEFF Research Database (Denmark)

    Agerkvist, Finn; Pedersen, Bo Rohde

    2009-01-01

    The compliance of the loudspeaker suspension is known to depend on the recent excitation level history. Previous investigations have shown that the electrical power as well as displacement and velocity plays a role. In this paper the hypothesis that the changes in compliance are caused mainly...... by how much the suspension has been stretched, i.e., the maximum displacement, is investigated. For this purpose the changes in compliance are measured when exposing the loudspeaker to different levels and types of electrical excitation signals, as well as mechanical excitation only. For sinusoidal...... excitation the change in compliance is shown to depend primarily on maximum displacement. But for square pulse excitation the duration of the excitation also plays an important role....

  9. Robust synchronization analysis in nonlinear stochastic cellular networks with time-varying delays, intracellular perturbations and intercellular noise.

    Science.gov (United States)

    Chen, Po-Wei; Chen, Bor-Sen

    2011-08-01

    Naturally, a cellular network consisted of a large amount of interacting cells is complex. These cells have to be synchronized in order to emerge their phenomena for some biological purposes. However, the inherently stochastic intra and intercellular interactions are noisy and delayed from biochemical processes. In this study, a robust synchronization scheme is proposed for a nonlinear stochastic time-delay coupled cellular network (TdCCN) in spite of the time-varying process delay and intracellular parameter perturbations. Furthermore, a nonlinear stochastic noise filtering ability is also investigated for this synchronized TdCCN against stochastic intercellular and environmental disturbances. Since it is very difficult to solve a robust synchronization problem with the Hamilton-Jacobi inequality (HJI) matrix, a linear matrix inequality (LMI) is employed to solve this problem via the help of a global linearization method. Through this robust synchronization analysis, we can gain a more systemic insight into not only the robust synchronizability but also the noise filtering ability of TdCCN under time-varying process delays, intracellular perturbations and intercellular disturbances. The measures of robustness and noise filtering ability of a synchronized TdCCN have potential application to the designs of neuron transmitters, on-time mass production of biochemical molecules, and synthetic biology. Finally, a benchmark of robust synchronization design in Escherichia coli repressilators is given to confirm the effectiveness of the proposed methods. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Rate Control for Network-Coded Multipath Relaying with Time-Varying Connectivity

    Science.gov (United States)

    2010-12-10

    Armen Babikyan, Nathaniel M. Jones, Thomas H. Shake, and Andrew P. Worthen MIT Lincoln Laboratory 244 Wood Street Lexington, MA 02420 DDRE, 1777...delay U U U U SAR 11 Zach Sweet 781-981-5997 1 Rate Control for Network-Coded Multipath Relaying with Time-Varying Connectivity Brooke Shrader, Armen

  11. The Scalp Time-Varying Networks of N170: Reference, Latency, and Information Flow

    Directory of Open Access Journals (Sweden)

    Yin Tian

    2018-04-01

    Full Text Available Using the scalp time-varying network method, the present study is the first to investigate the temporal influence of the reference on N170, a negative event-related potential component (ERP appeared about 170 ms that is elicited by facial recognition, in the network levels. Two kinds of scalp electroencephalogram (EEG references, namely, AR (average of all recording channels and reference electrode standardization technique (REST, were comparatively investigated via the time-varying processing of N170. Results showed that the latency and amplitude of N170 were significantly different between REST and AR, with the former being earlier and smaller. In particular, the information flow from right temporal-parietal P8 to left P7 in the time-varying network was earlier in REST than that in AR, and this phenomenon was reproduced by simulation, in which the performance of REST was closer to the true case at source level. These findings indicate that reference plays a crucial role in ERP data interpretation, and importantly, the newly developed approximate zero-reference REST would be a superior choice for precise evaluation of the scalp spatio-temporal changes relating to various cognitive events.

  12. Tesla the life and times of an electric messiah

    CERN Document Server

    Cawthorne, Nigel

    2014-01-01

    Despite being incredibly popular during his time, Nikola Tesla today remains largely overlooked among lists of the greatest inventors and scientists of the modern era.  Thomas Edison gets all the glory for discovering the light bulb, but it was his one time assistant and life long arch nemesis, Tesla, who made the breakthrough in alternating current technology.  Edison and Tesla carried on a bitter feud for years, but it was Tesla's AC generators that illuminated the 1893 World's Fair in Chicago; the first time that an event of such magnitude had ever taken place under artificial light.  Today, all homes and electrical appliances run on Tesla's AC current.Born in Croatia in 1856, Tesla spoke eight languages and as well as almost single handedly developing household electricity.  During his life, he patented more than 700 inventions.  He invented electrical generators, FM radio, remote control robots, spark plugs and fluorescent lights.  He had a photographic memory and did advanced calculus and physic...

  13. Research on Adaptive Neural Network Control System Based on Nonlinear U-Model with Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Fengxia Xu

    2014-01-01

    Full Text Available U-model can approximate a large class of smooth nonlinear time-varying delay system to any accuracy by using time-varying delay parameters polynomial. This paper proposes a new approach, namely, U-model approach, to solving the problems of analysis and synthesis for nonlinear systems. Based on the idea of discrete-time U-model with time-varying delay, the identification algorithm of adaptive neural network is given for the nonlinear model. Then, the controller is designed by using the Newton-Raphson formula and the stability analysis is given for the closed-loop nonlinear systems. Finally, illustrative examples are given to show the validity and applicability of the obtained results.

  14. Robust stability for uncertain stochastic fuzzy BAM neural networks with time-varying delays

    Science.gov (United States)

    Syed Ali, M.; Balasubramaniam, P.

    2008-07-01

    In this Letter, by utilizing the Lyapunov functional and combining with the linear matrix inequality (LMI) approach, we analyze the global asymptotic stability of uncertain stochastic fuzzy Bidirectional Associative Memory (BAM) neural networks with time-varying delays which are represented by the Takagi-Sugeno (TS) fuzzy models. A new class of uncertain stochastic fuzzy BAM neural networks with time varying delays has been studied and sufficient conditions have been derived to obtain conservative result in stochastic settings. The developed results are more general than those reported in the earlier literatures. In addition, the numerical examples are provided to illustrate the applicability of the result using LMI toolbox in MATLAB.

  15. Robust stability for uncertain stochastic fuzzy BAM neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Syed Ali, M.; Balasubramaniam, P.

    2008-01-01

    In this Letter, by utilizing the Lyapunov functional and combining with the linear matrix inequality (LMI) approach, we analyze the global asymptotic stability of uncertain stochastic fuzzy Bidirectional Associative Memory (BAM) neural networks with time-varying delays which are represented by the Takagi-Sugeno (TS) fuzzy models. A new class of uncertain stochastic fuzzy BAM neural networks with time varying delays has been studied and sufficient conditions have been derived to obtain conservative result in stochastic settings. The developed results are more general than those reported in the earlier literatures. In addition, the numerical examples are provided to illustrate the applicability of the result using LMI toolbox in MATLAB

  16. Acoustic Source Analysis of Magnetoacoustic Tomography With Magnetic Induction for Conductivity Gradual-Varying Tissues.

    Science.gov (United States)

    Wang, Jiawei; Zhou, Yuqi; Sun, Xiaodong; Ma, Qingyu; Zhang, Dong

    2016-04-01

    As a multiphysics imaging approach, magnetoacoustic tomography with magnetic induction (MAT-MI) works on the physical mechanism of magnetic excitation, acoustic vibration, and transmission. Based on the theoretical analysis of the source vibration, numerical studies are conducted to simulate the pathological changes of tissues for a single-layer cylindrical conductivity gradual-varying model and estimate the strengths of sources inside the model. The results suggest that the inner source is generated by the product of the conductivity and the curl of the induced electric intensity inside conductivity homogeneous medium, while the boundary source is produced by the cross product of the gradient of conductivity and the induced electric intensity at conductivity boundary. For a biological tissue with low conductivity, the strength of boundary source is much higher than that of the inner source only when the size of conductivity transition zone is small. In this case, the tissue can be treated as a conductivity abrupt-varying model, ignoring the influence of inner source. Otherwise, the contributions of inner and boundary sources should be evaluated together quantitatively. This study provide basis for further study of precise image reconstruction of MAT-MI for pathological tissues.

  17. Modeling the time--varying subjective quality of HTTP video streams with rate adaptations.

    Science.gov (United States)

    Chen, Chao; Choi, Lark Kwon; de Veciana, Gustavo; Caramanis, Constantine; Heath, Robert W; Bovik, Alan C

    2014-05-01

    Newly developed hypertext transfer protocol (HTTP)-based video streaming technologies enable flexible rate-adaptation under varying channel conditions. Accurately predicting the users' quality of experience (QoE) for rate-adaptive HTTP video streams is thus critical to achieve efficiency. An important aspect of understanding and modeling QoE is predicting the up-to-the-moment subjective quality of a video as it is played, which is difficult due to hysteresis effects and nonlinearities in human behavioral responses. This paper presents a Hammerstein-Wiener model for predicting the time-varying subjective quality (TVSQ) of rate-adaptive videos. To collect data for model parameterization and validation, a database of longer duration videos with time-varying distortions was built and the TVSQs of the videos were measured in a large-scale subjective study. The proposed method is able to reliably predict the TVSQ of rate adaptive videos. Since the Hammerstein-Wiener model has a very simple structure, the proposed method is suitable for online TVSQ prediction in HTTP-based streaming.

  18. Studi Perbedaan Niat Beli Green Electricity Product Berdasarkan Gender

    Directory of Open Access Journals (Sweden)

    Tias Andarini Indarwati

    2017-04-01

    Full Text Available Consumers adapt to this situation by considering environmental issue when shopping and  by their purchase behavior. The aims of this paper are examines of differences of environment awareness and purchase intentions between male and female of students of Surabaya State University. Secondly, examines also role linearly of environment awareness on purchase intentions. Examines role linearly of environment awareness on purchase intentions of green electricity product using simple linier regression analysis. The results indicate that there are no differences of environment awareness and purchase intentions at the students of Surabaya State University by gender. And finally, environmental awareness has also positive effect on purchase intentions. The results of this study have implications for marketers in identifying, designing, and managing marketing mix with consider discrepancy of purchase intentions in the green electricity product by gender.

  19. Robust stability of uncertain Markovian jumping Cohen-Grossberg neural networks with mixed time-varying delays

    International Nuclear Information System (INIS)

    Sheng Li; Yang Huizhong

    2009-01-01

    This paper considers the robust stability of a class of uncertain Markovian jumping Cohen-Grossberg neural networks (UMJCGNNs) with mixed time-varying delays. The parameter uncertainties are norm-bounded and the mixed time-varying delays comprise discrete and distributed time delays. Based on the Lyapunov stability theory and linear matrix inequality (LMI) technique, some robust stability conditions guaranteeing the global robust convergence of the equilibrium point are derived. An example is given to show the effectiveness of the proposed results.

  20. The time-varying shortest path problem with fuzzy transit costs and speedup

    Directory of Open Access Journals (Sweden)

    Rezapour Hassan

    2016-08-01

    Full Text Available In this paper, we focus on the time-varying shortest path problem, where the transit costs are fuzzy numbers. Moreover, we consider this problem in which the transit time can be shortened at a fuzzy speedup cost. Speedup may also be a better decision to find the shortest path from a source vertex to a specified vertex.

  1. Development of a “Current Energy Mix Scenario” and a “Electricity as Main Energy Source Scenario” for electricity demand up to 2100

    Directory of Open Access Journals (Sweden)

    Mário J. S. Brito

    2014-06-01

    Full Text Available In this work, we develop a model to forecast world electricity production up to 2100. We analyze historical data for electricity production, population and GDP per Capita for the period 1900–2008. We show that electricity production follows general trends. First, there is an electricity intensity target of 0.20-0.25 kWh per unit of GDP (US$2012 as economies mature, except in countries traditionally relying heavily on renewable electricity (hydroelectricity, for whom this target ranges between 0.50 to 0.80 kWh per unit GDP. Also, countries that belong to the same region tend to follow the evolution of electricity production and GDP/Capita of a regional “modelcountry”. Equations that describe the behavior of these model countries are used to forecast electricity production per capita up to 2100 under a low and a high scenario for the evolution of GDP per Capita. For electricity production two main scenarios were set: “Current Energy MixScenario” and “Electricity as Main Energy Source Scenario”, with two additional sub scenarios considering slightly different electric intensities. Forecasts up to 2100 yield a demand forelectricity production 3.5 to 5 times higher than the current production for the “Current EnergyMix Scenario” and about 9 to 14 times for the “Electricity as Main Energy Source Scenario”. Forecasts for the “Current Energy Mix Scenario” matched well with forecasts from IEA/EIA (International Energy Agency/ Energy Information Administration while the forecasts for the“Electricity as the Main Energy Source Scenario” are much higher than current predictions.

  2. Detection of random alterations to time-varying musical instrument spectra.

    Science.gov (United States)

    Horner, Andrew; Beauchamp, James; So, Richard

    2004-09-01

    The time-varying spectra of eight musical instrument sounds were randomly altered by a time-invariant process to determine how detection of spectral alteration varies with degree of alteration, instrument, musical experience, and spectral variation. Sounds were resynthesized with centroids equalized to the original sounds, with frequencies harmonically flattened, and with average spectral error levels of 8%, 16%, 24%, 32%, and 48%. Listeners were asked to discriminate the randomly altered sounds from reference sounds resynthesized from the original data. For all eight instruments, discrimination was very good for the 32% and 48% error levels, moderate for the 16% and 24% error levels, and poor for the 8% error levels. When the error levels were 16%, 24%, and 32%, the scores of musically experienced listeners were found to be significantly better than the scores of listeners with no musical experience. Also, in this same error level range, discrimination was significantly affected by the instrument tested. For error levels of 16% and 24%, discrimination scores were significantly, but negatively correlated with measures of spectral incoherence and normalized centroid deviation on unaltered instrument spectra, suggesting that the presence of dynamic spectral variations tends to increase the difficulty of detecting spectral alterations. Correlation between discrimination and a measure of spectral irregularity was comparatively low.

  3. Positive Almost Periodic Solutions for a Time-Varying Fishing Model with Delay

    Directory of Open Access Journals (Sweden)

    Xia Li

    2011-01-01

    Full Text Available This paper is concerned with a time-varying fishing model with delay. By means of the continuation theorem of coincidence degree theory, we prove that it has at least one positive almost periodic solution.

  4. Trade in electricity certificates: a new means for stimulating electricity from renewable energy sources: final report from the electricity certificate inquiry

    International Nuclear Information System (INIS)

    2001-01-01

    We recommend the introduction of a quota-based Swedish certificate system to promote production of electricity from renewable energy sources commencing on 1 January 2003. We recommend that the certificate system should be based on the following principles: The quota obligation should be set for the years 2003 to 2010 and for all intervening years. The quota is expressed as a share of the total amount of electricity used. It is proposed that as a guideline, a target of an increase in electricity production from renewable energy sources of 10 TWh, in a period from 2003 to 2010 inclusive, is adopted. It is estimated that approximately half of this increase can come from expansion of existing production and half from new plants. The following electricity production plants are to be entitled to certificates provided they comply with the requirement that electricity is to be produced from renewable energy sources and that they meet the environmental criteria set, including fuel requirements, where electricity is produced with the aid of: 1. wind power, 2. solar energy, 3. geothermal energy, 4. certain types of biofuel, 5. wave energy, 6. hydroelectric power at existing plants which, at the time of the Electricity Certificate law coming into effect, have a capacity not exceeding 1 500 kilowatt, 7. hydroelectric power at plants which have not been in operation after 1 July 2001 but which were commissioned after the coming into effect of the Electricity Certificate law, 8. increased installed capacity at existing hydroelectric power plants to the extent that capacity is increased by measures undertaken after 1 July 2002, and 9. hydroelectric power produced at plants, which started operation for the first time after 1 July 2002. The quota period is defined as one calendar year. Certificates may be 'banked' by those subject to quota should they have more certificates at the end of the quota period than need to be submitted. A certificate is valid for an unlimited period of

  5. Visualizing time: how linguistic metaphors are incorporated into displaying instruments in the process of interpreting time-varying signals

    Science.gov (United States)

    Garcia-Belmonte, Germà

    2017-06-01

    Spatial visualization is a well-established topic of education research that has allowed improving science and engineering students' skills on spatial relations. Connections have been established between visualization as a comprehension tool and instruction in several scientific fields. Learning about dynamic processes mainly relies upon static spatial representations or images. Visualization of time is inherently problematic because time can be conceptualized in terms of two opposite conceptual metaphors based on spatial relations as inferred from conventional linguistic patterns. The situation is particularly demanding when time-varying signals are recorded using displaying electronic instruments, and the image should be properly interpreted. This work deals with the interplay between linguistic metaphors, visual thinking and scientific instrument mediation in the process of interpreting time-varying signals displayed by electronic instruments. The analysis draws on a simplified version of a communication system as example of practical signal recording and image visualization in a physics and engineering laboratory experience. Instrumentation delivers meaningful signal representations because it is designed to incorporate a specific and culturally favored time view. It is suggested that difficulties in interpreting time-varying signals are linked with the existing dual perception of conflicting time metaphors. The activation of specific space-time conceptual mapping might allow for a proper signal interpretation. Instruments play then a central role as visualization mediators by yielding an image that matches specific perception abilities and practical purposes. Here I have identified two ways of understanding time as used in different trajectories through which students are located. Interestingly specific displaying instruments belonging to different cultural traditions incorporate contrasting time views. One of them sees time in terms of a dynamic metaphor

  6. Photodetachment of the H− ion in a linear time-dependent electric field

    International Nuclear Information System (INIS)

    Wang, De-Hua; Chen, Zhaohang; Cheng, Shaohao

    2016-01-01

    Using the time-dependent closed orbit theory, we study the photodetachment of the H − ion in a linear time-dependent electric field for the first time. An analytical formula for calculating the time-dependent photodetachment cross section of this system has been put forward. It is found when the external electric field changes very slowly with time, there is only one closed orbit of the detached electron and the photodetachment cross section is quite stable. However, when the electric field changes quickly with time, three different types of closed orbits are found and the photodetachment cross section oscillates in a much more complex way. The connection of each type of closed orbit with the oscillatory structure in the photodetachment cross section is analyzed quantitatively. In addition, the photon energy and the laser field parameters can also have great influence on the time-dependent photodetachment cross section of this system. This study provides a clear and intuitive picture for the photodetachment dynamics of a negative ion in the presence of a time-dependent electric field and may guide future experimental studies exploring the quantum effect in the photodetachment dynamics of negative ions from a time-dependent viewpoint. (paper)

  7. Utilization of hydrogen gas production for electricity generation in ...

    African Journals Online (AJOL)

    Utilization of hydrogen gas production for electricity generation in fuel cell by Enterobacter aerogenes ADH 43 with many kinds of carbon sources in batch stirred tank reactor. MA Rachman, LD Eniya, Y Liasari, MM Nasef, A Ahmad, H Saidi ...

  8. Intellectual Production Supervision Perform based on RFID Smart Electricity Meter

    Science.gov (United States)

    Chen, Xiangqun; Huang, Rui; Shen, Liman; chen, Hao; Xiong, Dezhi; Xiao, Xiangqi; Liu, Mouhai; Xu, Renheng

    2018-03-01

    This topic develops the RFID intelligent electricity meter production supervision project management system. The system is designed for energy meter production supervision in the management of the project schedule, quality and cost information management requirements in RFID intelligent power, and provide quantitative information more comprehensive, timely and accurate for supervision engineer and project manager management decisions, and to provide technical information for the product manufacturing stage file. From the angle of scheme analysis, design, implementation and test, the system development of production supervision project management system for RFID smart meter project is discussed. Focus on the development of the system, combined with the main business application and management mode at this stage, focuses on the energy meter to monitor progress information, quality information and cost based information on RFID intelligent power management function. The paper introduces the design scheme of the system, the overall client / server architecture, client oriented graphical user interface universal, complete the supervision of project management and interactive transaction information display, the server system of realizing the main program. The system is programmed with C# language and.NET operating environment, and the client and server platforms use Windows operating system, and the database server software uses Oracle. The overall platform supports mainstream information and standards and has good scalability.

  9. The development of the time dependence of the nuclear EMP electric field

    International Nuclear Information System (INIS)

    Eng, C.

    2009-01-01

    The nuclear electromagnetic pulse (EMP) electric field calculated with the legacy code CHAP is compared with the field given by an integral solution of Maxwell's equations, also known as the Jefimenko equation, to aid our current understanding on the factors that affect the time dependence of the EMP. For a fair comparison the CHAP current density is used as a source in the Jefimenko equation. At first, the comparison is simplified by neglecting the conduction current and replacing the standard atmosphere with a constant density air slab. The simplicity of the resultant current density aids in determining the factors that affect the rise, peak and tail of the EMP electric field versus time. The three dimensional nature of the radiating source, i.e. sources off the line-of-sight, and the time dependence of the derivative of the current density with respect to time are found to play significant roles in shaping the EMP electric field time dependence. These results are found to hold even when the conduction current and the standard atmosphere are properly accounted for. Comparison of the CHAP electric field with the Jefimenko electric field offers a direct validation of the high-frequency/outgoing wave approximation.

  10. Economic growth and electricity consumption in Cote d'Ivoire: Evidence from time series analysis

    International Nuclear Information System (INIS)

    Kouakou, Auguste K.

    2011-01-01

    This paper examines the causal relationship between the electric power industry and the economic growth of Cote d'Ivoire. Using the data from 1971 to 2008, a test was conducted for the cointegration and Granger causality within an error correction model. Results from these tests reveal a bidirectional causality between per capita electricity consumption and per capita GDP. A unidirectional causality running from electricity consumption to industry value added appears in the short run. Economic growth is found to have great effects on electricity consumption and a reverse causality from electricity to economic growth may also appear. In the long run, there is a unidirectional causality between electricity and both GDP and industry value added. From these findings, we conclude that the country will be energy dependent in the long run and must therefore secure the production network from shortfalls to ensure a sustainable development path. Accordingly, government should adopt policies aimed at increasing the investment in the sector by stepping up electricity production from existing and new energy sources. - Highlights: → We analyze the electricity-growth nexus for Cote d'Ivoire using causality tests. → Short run bi-directional causality appears between electricity and GDP. → We found a unidirectional causality running from electricity to industry and GDP. → Economic activities are electricity dependent and require appropriate policies.

  11. Perfect fluid Bianchi Type-I cosmological models with time varying G ...

    Indian Academy of Sciences (India)

    Abstract. Bianchi Type-I cosmological models containing perfect fluid with time vary- ing G and Λ have been presented. The solutions obtained represent an expansion scalar θ bearing a constant ratio to the anisotropy in the direction of space-like unit vector λi. Of the two models obtained, one has negative vacuum energy ...

  12. Inferring time-varying network topologies from gene expression data.

    Science.gov (United States)

    Rao, Arvind; Hero, Alfred O; States, David J; Engel, James Douglas

    2007-01-01

    Most current methods for gene regulatory network identification lead to the inference of steady-state networks, that is, networks prevalent over all times, a hypothesis which has been challenged. There has been a need to infer and represent networks in a dynamic, that is, time-varying fashion, in order to account for different cellular states affecting the interactions amongst genes. In this work, we present an approach, regime-SSM, to understand gene regulatory networks within such a dynamic setting. The approach uses a clustering method based on these underlying dynamics, followed by system identification using a state-space model for each learnt cluster--to infer a network adjacency matrix. We finally indicate our results on the mouse embryonic kidney dataset as well as the T-cell activation-based expression dataset and demonstrate conformity with reported experimental evidence.

  13. Time-of-Use Rates and Electricity Costs of Representative New York Dairy Farms

    OpenAIRE

    Boisvert, Richard N.; Bills, Nelson L.; Middagh, Mark C.; Schenkel, Mark

    1992-01-01

    Electric utilities throughout the Nation are experimenting with strategies to reduce total electricity consumption or to alter the timing of electrical power use by their customers. This report focuses on one such strategy, time-of-use (TaU) electric rates, and the likely effect of this pricing option on the New York dairy sector. The purpose of the study is to assess the change in farm electrical energy costs when power is sold to dairymen at higher rates for periods of peak power demand and...

  14. Public synthesis of the reference costs study of the electric power production

    International Nuclear Information System (INIS)

    2008-01-01

    Every 3 or 5 years, the DGEC published the reference costs study of the electric power production which evaluates, in a theoretical framework, the total cost of an electrical MWh, from different production ways. These studies bring information for the definition of the energy policy and the elaboration of the investments program. because of the great competition of the market, it was decided not to publish the absolute value of the hypothesis and the results but under indexed form. (A.L.B.)

  15. Electricity production from municipal solid waste in Brazil.

    Science.gov (United States)

    Nordi, Guilherme Henrique; Palacios-Bereche, Reynaldo; Gallego, Antonio Garrido; Nebra, Silvia Azucena

    2017-07-01

    Brazil has an increasing production of municipal solid waste that, allied to the current waste management system, makes the search for alternatives of energy recovery essential. Thus, this work aims to study the incineration of municipal solid waste and the electricity production through steam cycles evaluating the influence of municipal solid waste composition. Several scenarios were studied, in which it was assumed that some fractions of municipal solid waste were removed previously. The municipal solid waste generated in Santo André city, São Paulo State, Brazil, was adopted for this study. Simulation results showed that the removal of organic matter and inert components impacts advantageously on the cycle performance, improving their parameters in some cases; in addition, there is the possibility of reusing the separated fractions. The separation of some recyclables, as plastic material, showed disadvantages by the reduction in the electricity generation potential owing to the high calorific value of plastics. Despite the high energy content of them, there are other possible considerations on this subject, because some plastics have a better recovery potential by recycling.

  16. 3D modeling of electric fields in the LUX detector

    Science.gov (United States)

    Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Druszkiewicz, E.; Edwards, B. N.; Fallon, S. R.; Fan, A.; Fiorucci, S.; Gaitskell, R. J.; Genovesi, J.; Ghag, C.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Velan, V.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.

    2017-11-01

    This work details the development of a three-dimensional (3D) electric field model for the LUX detector. The detector took data to search for weakly interacting massive particles (WIMPs) during two periods. After the first period completed, a time-varying non-uniform negative charge developed in the polytetrafluoroethylene (PTFE) panels that define the radial boundary of the detector's active volume. This caused electric field variations in the detector in time, depth and azimuth, generating an electrostatic radially-inward force on electrons on their way upward to the liquid surface. To map this behavior, 3D electric field maps of the detector's active volume were generated on a monthly basis. This was done by fitting a model built in COMSOL Multiphysics to the uniformly distributed calibration data that were collected on a regular basis. The modeled average PTFE charge density increased over the course of the exposure from -3.6 to -5.5 μC/m2. From our studies, we deduce that the electric field magnitude varied locally while the mean value of the field of ~200 V/cm remained constant throughout the exposure. As a result of this work the varying electric fields and their impact on event reconstruction and discrimination were successfully modeled.

  17. Demand-driven biogas production in anaerobic filters

    International Nuclear Information System (INIS)

    Lemmer, Andreas; Krümpel, Johannes

    2017-01-01

    Highlights: • Feasibility of demand-driven biogas production in anaerobic filters demonstrated. • Predictable ramping up of gas production by 300–400% within one hour. • Degradation degree remained stable >92% for all substrates and operation modes. • Measure of responsiveness to sudden changes in organic loading rate introduced. • Carbon balance for demand-driven operation. - Abstract: The growth in electricity generated from renewable energy sources is posing challenges for grid stability and the need to counter balance the intermittent power supply by these sources. Biogas technology can offer such grid services by adapting biogas production to balance the demand and subsequent electricity production of the combined heat and power unit. Innovative plant designs, such as two-staged anaerobic digestion, could possibly adapt to imbalances in the electricity grid within shorter time frames than traditional continuously stirred tank reactors (CSTR). The scope of this research paper was to demonstrate the feasibility of operating an anaerobic filter for highly flexible gas production. The repeatability of this type of operation was examined to demonstrate its predictability. Based on gas production profiles, a measure of responsiveness was introduced to determine whether and how rapidly adaptations to the production process are possible. Furthermore, the influence of substrate composition was tested and finally a carbon balance was derived to evaluate operation performance. The results indicated that anaerobic filters are well suited for flexible gas production and the results were well reproduced under the conditions presented. Substrate composition was found to have no effect on increasing the rate of methane production. The pH value in the reactor did have an effect on the solubility of CO_2 and HCO_3"− and therefore marked an important parameter that determines biogas composition, especially under varying organic loading rates. The carbon balance had

  18. Time-Varying Dynamic Properties of Offshore Wind Turbines Evaluated by Modal Testing

    DEFF Research Database (Denmark)

    Damgaard, Mads; Andersen, J. K. F.; Ibsen, Lars Bo

    2014-01-01

    resonance of the wind turbine structure. In this paper, free vibration tests and a numerical Winkler type approach are used to evaluate the dynamic properties of a total of 30 offshore wind turbines located in the North Sea. Analyses indicate time-varying eigenfrequencies and damping ratios of the lowest...... structural eigenmode. Isolating the oscillation oil damper performance, moveable seabed conditions may lead to the observed time dependency....

  19. Complexity Variability Assessment of Nonlinear Time-Varying Cardiovascular Control

    Science.gov (United States)

    Valenza, Gaetano; Citi, Luca; Garcia, Ronald G.; Taylor, Jessica Noggle; Toschi, Nicola; Barbieri, Riccardo

    2017-02-01

    The application of complex systems theory to physiology and medicine has provided meaningful information about the nonlinear aspects underlying the dynamics of a wide range of biological processes and their disease-related aberrations. However, no studies have investigated whether meaningful information can be extracted by quantifying second-order moments of time-varying cardiovascular complexity. To this extent, we introduce a novel mathematical framework termed complexity variability, in which the variance of instantaneous Lyapunov spectra estimated over time serves as a reference quantifier. We apply the proposed methodology to four exemplary studies involving disorders which stem from cardiology, neurology and psychiatry: Congestive Heart Failure (CHF), Major Depression Disorder (MDD), Parkinson’s Disease (PD), and Post-Traumatic Stress Disorder (PTSD) patients with insomnia under a yoga training regime. We show that complexity assessments derived from simple time-averaging are not able to discern pathology-related changes in autonomic control, and we demonstrate that between-group differences in measures of complexity variability are consistent across pathologies. Pathological states such as CHF, MDD, and PD are associated with an increased complexity variability when compared to healthy controls, whereas wellbeing derived from yoga in PTSD is associated with lower time-variance of complexity.

  20. Novel criteria for exponential synchronization of inner time-varying complex networks with coupling delay

    International Nuclear Information System (INIS)

    Zhang Qun-Jiao; Zhao Jun-Chan

    2012-01-01

    This paper mainly investigates the exponential synchronization of an inner time-varying complex network with coupling delay. Firstly, the synchronization of complex networks is decoupled into the stability of the corresponding dynamical systems. Based on the Lyapunov function theory, some sufficient conditions to guarantee its stability with any given convergence rate are derived, thus the synchronization of the networks is achieved. Finally, the results are illustrated by a simple time-varying network model with a coupling delay. All involved numerical simulations verify the correctness of the theoretical analysis. (general)