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41.
Daniela PatrascuAuthor VitaeIulia DavidAuthor Vitae Vasile DavidAuthor VitaeConstantin MihailciucAuthor Vitae Ioan StamatinAuthor VitaeJean CiureaAuthor Vitae Livia NagyAuthor VitaeGéza NagyAuthor Vitae Anton Alexandru CiucuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(2):731-736
Iron(II) phthalocyanine (FePc) modified multi-wall carbon nanotubes paste electrodes (MWCNTPEs) were used as voltammetric sensors to selectively detect dopamine (DA) in the presence of serotonin (5-HT). The electrochemical behavior of DA at the new modified electrode was investigated using CV. The enhanced current response of DA indicates that FePc modification of the MWCNTPE surface results in a high catalytic activity for the redox reaction of DA. Differential pulse voltammetry was applied in detection of DA and 5-HT at FePc-MWCNTPE. The method parameters were optimized. Detection limit of 2.05 × 10−7 M was obtained for DA by using the electrocatalytic oxidation signal corresponding to the FeII/FeIII redox process. The separation between the peak potentials of DA and 5-HT is 170 mV which is large enough for the simultaneously, selective determination of the two chemical species in their mixtures. There was no electrochemical response for ascorbic acid (AA) added in the sample. The monoamine neurotransmitter measuring method has been tested in analyzing deproteinized serum samples. 相似文献
42.
James Gray Yang-Hui He Anton Ilderton André Lukas 《Computer Physics Communications》2009,180(1):107-119
We give a simple tutorial introduction to the Mathematica package STRINGVACUA, which is designed to find vacua of string-derived or inspired four-dimensional N=1 supergravities. The package uses powerful algebro-geometric methods, as implemented in the free computer algebra system Singular, but requires no knowledge of the mathematics upon which it is based. A series of easy-to-use Mathematica modules are provided which can be used both in string theory and in more general applications requiring fast polynomial computations. The use of these modules is illustrated throughout with simple examples.
Program summary
Program title: STRINGVACUACatalogue identifier: AEBZ_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEBZ_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GNU GPLNo. of lines in distributed program, including test data, etc.: 31 050No. of bytes in distributed program, including test data, etc.: 163 832Distribution format: tar.gzProgramming language: “Mathematica” syntaxComputer: Home and office spec desktop and laptop machines, networked or stand aloneOperating system: Windows XP (with Cygwin), Linux, Mac OS, running Mathematica V5 or aboveRAM: Varies greatly depending on calculation to be performedClassification: 11.1External routines: Linux: The program “Singular” is called from Mathematica. Windows: “Singular” is called within the Cygwin environment from Mathematica.Nature of problem: A central problem of string-phenomenology is to find stable vacua in the four-dimensional effective theories which result from compactification.Solution method: We present an algorithmic method, which uses techniques of algebraic geometry, to find all of the vacua of any given string-phenomenological system in a huge class.Running time: Varies greatly depending on calculation requested. 相似文献43.
We propose a mathematical model for the Towers of Hanoi and London based on state graphs. The analysis of this model allows to address questions like equivalence of puzzles, difficulty of tasks and optimality of solutions using topological, metric and symmetry properties of the corresponding graphs.The mathematical model serves as a base for a computer program to administer tower puzzles in a variety of psychological test situations. It is suitable for bedside use and is equipped with numerous devices for post-processing of recorded data. Among these features is the graphical representation of the projection of the path taken by a test person onto the state graph. 相似文献
44.
Oriol Falivene Patricia Cabello Pau Arbués Josep Anton Muñoz Lluís Cabrera 《Computers & Geosciences》2009,35(8):1642-1651
Valid representations of geological heterogeneity are fundamental inputs for quantitative models used in managing subsurface activities. Consequently, the simulation of realistic facies distributions is a significant aim. Realistic facies distributions are typically obtained by pixel-based, object-based or process-based methods. This work presents a pixel-based geostatistical algorithm suitable for reproducing lateral gradual facies transitions (LGFT) between two adjacent sedimentary bodies. Lateral contact (i.e. interfingering) between distinct depositional facies is a widespread geometric relationship that occurs at different scales in any depositional system. The algorithm is based on the truncation of the sum of a linear expectation trend and a random Gaussian field, and can be conditioned to well data. The implementation introduced herein also includes subroutines to clean and geometrically characterize the obtained LGFT. The cleaned sedimentary body transition provides a more appropriate and realistic facies distribution for some depositional settings. The geometric measures of the LGFT yield an intuitive measure of the morphology of the sedimentary body boundary, which can be compared to analogue data. An example of a LGFT obtained by the algorithm presented herein is also flow simulated, quantitatively demonstrating the importance of realistically reproducing them in subsurface models, if further flow-related accurate predictions are to be made. 相似文献
45.
Sergei V. Gusev Anton S. Shiriaev Leonid B. Freidovich 《International journal of control》2016,89(7):1396-1405
Numerically finding stabilising feedback control laws for linear systems of periodic differential equations is a nontrivial task with no known reliable solutions. The most successful method requires solving matrix differential Riccati equations with periodic coefficients. All previously proposed techniques for solving such equations involve numerical integration of unstable differential equations and consequently fail whenever the period is too large or the coefficients vary too much. Here, a new method for numerical computation of stabilising solutions for matrix differential Riccati equations with periodic coefficients is proposed. Our approach does not involve numerical solution of any differential equations. The approximation for a stabilising solution is found in the form of a trigonometric polynomial, matrix coefficients of which are found solving a specially constructed finite-dimensional semidefinite programming (SDP) problem. This problem is obtained using maximality property of the stabilising solution of the Riccati equation for the associated Riccati inequality and sampling technique. Our previously published numerical comparisons with other methods shows that for a class of problems only this technique provides a working solution. Asymptotic convergence of the computed approximations to the stabilising solution is proved below under the assumption that certain combinations of the key parameters are sufficiently large. Although the rate of convergence is not analysed, it appeared to be exponential in our numerical studies. 相似文献
46.
This paper studies state synchronization of homogeneous time‐varying networks with diffusive full‐state coupling or partial‐state coupling. In the case of full‐state coupling, linear agents as well as a class of nonlinear time‐varying agents are considered. In the case of partial‐state coupling, we only consider linear agents, but, in contrast with the literature, we do not require the agents in the network to be minimum phase or at most weakly unstable. In both cases, the network is time‐varying in the sense that the network graph switches within an infinite set of graphs with arbitrarily small dwell time. A purely decentralized linear static protocol is designed for agents in the network with full‐state coupling. For partial‐state coupling, a linear dynamic protocol is designed for agents in the network while using additional communication among controller variables using the same network. In both cases, the design is based on a high‐gain methodology. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
47.
This work introduces a new algorithm for surface reconstruction in ℝ3 from spatially arranged one-dimensional cross sections embedded in ℝ3. This is generally the case with acoustic signals that pierce an object non-destructively. Continuous deformations (homotopies)
that smoothly reconstruct information between any pair of successive cross sections are derived. The zero level set of the
resulting homotopy field generates the desired surface. Four types of homotopies are suggested that are well suited to generate
a smooth surface. We also provide derivation of necessary higher order homotopies that can generate a C
2 surface. An algorithm to generate surface from acoustic sonar signals is presented with results. Reconstruction accuracies
of the homotopies are compared by means of simulations performed on basic geometric primitives. 相似文献
48.
This paper studies the so‐called inverse filtering and deconvolution problem from different angles. To start with, both exact and almost deconvolution problems are formulated, and the necessary and sufficient conditions for their solvability are investigated. Exact and almost deconvolution problems seek filters that can estimate the unknown inputs of the given plant or system either exactly or almostly whatever may be the unintended or disturbance inputs such as measurement noise, external disturbances, and model uncertainties that act on the system. As such they require strong solvability conditions. To alleviate this, several optimal and suboptimal deconvolution problems are formulated and studied. These problems seek filters that can estimate the unknown inputs of the given system either exactly, almostly or optimally in the absence of unintended (disturbance) inputs, and on the other hand, in the presence of unintended (disturbance) inputs, they seek that the influence of such disturbances on the estimation error be as small as possible in a certain norm (H2 or H∞) sense. Both continuous‐ and discrete‐time systems are considered. For discrete‐time systems, the counter parts of all the above problems when an ??‐step delay in estimation is present are introduced and studied. Next, we focus on the exact and almost deconvolution but this time when the uncertainties in plant dynamics can be structurally modeled by a Δ‐block as a feedback element to the nominally known plant dynamics. This is done either in the presence or absence of external disturbances. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
49.
Eremeev AV 《Evolutionary computation》2008,16(1):127-147
We consider the optimization problem of finding the best possible offspring as a result of a recombination operator in an evolutionary algorithm, given two parent solutions. The optimal recombination is studied in the case where a vector of binary variables is used as a solution encoding. By means of efficient reductions of the optimal recombination problems (ORPs) we show the polynomial solvability of the ORPs for the maximum weight set packing problem, the minimum weight set partition problem, and for linear Boolean programming problems with at most two variables per inequality, and some other problems. We also identify several NP-hard cases of optimal recombination: the Boolean linear programming problems with three variables per inequality, the knapsack, the set covering, the p-median, and some other problems. 相似文献
50.
Using resource dependency theory (RDT), this research analyzes how organizations control their information technology resources
to improve organizational performance. According to RDT, organizations must manage their dependency on external organizations
and limit external dependencies when resources are considered critical. The current study proposes and tests a portion of
a Strategic Control Model positing that managers seek to control important, strategic resources in order to create value for
the firm and to avoid dependency on external entities. Utilizing a research design that captured extensive quantitative data
on the control of IT functions and services, the research team gathered 5 years of data on 54 business units (BUs) in 27 global
companies located in seven countries. Study examined the linkages of these 54 BUs to firm performance. Locating the Extent
of Control within the firm in cases where the firm depends on IT as a strategic resource proves to be a good explanation for
effective decisions leading to higher performance. Viewing IT as a strategic resource alone does not lead to positive business
unit outcomes, but the moderating influence of Extent of Control is found to establish the complex statistical relationship
with business unit performance. For these reasons, it is critical that a theoretically grounded firm-wide process for decisions
on locating IT control is in place to capture business value.
Detmar Straub The J. Mack Robinson Distinguished Professor of Information Systems at Georgia State University, Detmar has conducted research in the areas of IT outsourcing, computer security, Net-enhanced organizations (e-Commerce), technological innovation, international IT studies, and IS research methods. He holds a DBA (Doctor of Business Administration) in MIS from Indiana and a Ph.D. in English from Penn State. Detmar has published over 145 papers in journals such as MIS Quarterly, Management Science, Information Systems Research, Journal of MIS, Journal of AIS, Decision Sciences Journal, Organization Science, Communications of the ACM, Information & Management, Communications of the AIS, IEEE Transactions on Engineering Management, DATA BASE, OMEGA, Academy of Management Executive, and Sloan Management Review. Detmar is Editor-in-Chief of MIS Quarterly and former Senior Editor for Information Systems Research and Journal of the AIS and Co-Editor of DATA BASE for Advances in Information Systems. He is also an Associate Editor for the Journal of International Management. In the past he has served as Associate Editor for Management Science and Information Systems Research, and Associate Publisher/Senior Editor/Associate Editor for MIS Quarterly as well as editorial board member on a variety of other journals. Former VP of Publications for the Association of Information Systems (AIS), he has held roles as co-program chair for AMCIS and ICIS and was elected an AIS fellow in 2005. Peter Weill is an MIT Senior Research Scientist and joined MIT Sloan faculty in 2000 to become director of MIT Sloan’s Center for Information Systems Research (CISR). MIT CISR is funded by sixty corporate sponsors, and undertakes practical research on how firms generate business value from IT. Peter has written award-winning books, journal articles, and case studies on how firms govern, invest in and get value from IT. Peter’s co-authored books include: Enterprise Architecture as Strategy: Creating a Foundation for Business Execution (Harvard Business School Press, July 2006), IT Governance: How Top Performers Manage IT Decision Rights for Superior Results (2004), Leveraging the New Infrastructure: How market leaders capitalize on information technology (1998) and Place to Space: Migrating to eBusiness Models, (2001) which won one of the Library Journal of America’s best business book of the year awards and was reviewed by the New York Times. Before joining Sloan as Director of CISR, Peter was Foundation Professor and Chair of Management and a member of the Board of Directors of Melbourne Business School. Peter has been an Associate Editor for MISQ and ISR and was a program co-chair for ICIS2000 in Brisbane. Kathy S. Schwaig is an Associate Professor of Information Systems and Associate Dean for Administration in the Coles College of Business at Kennesaw State University. Her research interests include information privacy, outsourcing, project management, knowledge management and electronic commerce. She also serves as a business consultant in information systems strategy. Dr. Schwaig has published in the Communications of the ACM, The Journal of Management Information Systems, DATABASE, Information and Organization, and Information Systems Research among others. 相似文献
Kathy S. SchwaigEmail: |
Detmar Straub The J. Mack Robinson Distinguished Professor of Information Systems at Georgia State University, Detmar has conducted research in the areas of IT outsourcing, computer security, Net-enhanced organizations (e-Commerce), technological innovation, international IT studies, and IS research methods. He holds a DBA (Doctor of Business Administration) in MIS from Indiana and a Ph.D. in English from Penn State. Detmar has published over 145 papers in journals such as MIS Quarterly, Management Science, Information Systems Research, Journal of MIS, Journal of AIS, Decision Sciences Journal, Organization Science, Communications of the ACM, Information & Management, Communications of the AIS, IEEE Transactions on Engineering Management, DATA BASE, OMEGA, Academy of Management Executive, and Sloan Management Review. Detmar is Editor-in-Chief of MIS Quarterly and former Senior Editor for Information Systems Research and Journal of the AIS and Co-Editor of DATA BASE for Advances in Information Systems. He is also an Associate Editor for the Journal of International Management. In the past he has served as Associate Editor for Management Science and Information Systems Research, and Associate Publisher/Senior Editor/Associate Editor for MIS Quarterly as well as editorial board member on a variety of other journals. Former VP of Publications for the Association of Information Systems (AIS), he has held roles as co-program chair for AMCIS and ICIS and was elected an AIS fellow in 2005. Peter Weill is an MIT Senior Research Scientist and joined MIT Sloan faculty in 2000 to become director of MIT Sloan’s Center for Information Systems Research (CISR). MIT CISR is funded by sixty corporate sponsors, and undertakes practical research on how firms generate business value from IT. Peter has written award-winning books, journal articles, and case studies on how firms govern, invest in and get value from IT. Peter’s co-authored books include: Enterprise Architecture as Strategy: Creating a Foundation for Business Execution (Harvard Business School Press, July 2006), IT Governance: How Top Performers Manage IT Decision Rights for Superior Results (2004), Leveraging the New Infrastructure: How market leaders capitalize on information technology (1998) and Place to Space: Migrating to eBusiness Models, (2001) which won one of the Library Journal of America’s best business book of the year awards and was reviewed by the New York Times. Before joining Sloan as Director of CISR, Peter was Foundation Professor and Chair of Management and a member of the Board of Directors of Melbourne Business School. Peter has been an Associate Editor for MISQ and ISR and was a program co-chair for ICIS2000 in Brisbane. Kathy S. Schwaig is an Associate Professor of Information Systems and Associate Dean for Administration in the Coles College of Business at Kennesaw State University. Her research interests include information privacy, outsourcing, project management, knowledge management and electronic commerce. She also serves as a business consultant in information systems strategy. Dr. Schwaig has published in the Communications of the ACM, The Journal of Management Information Systems, DATABASE, Information and Organization, and Information Systems Research among others. 相似文献