10,624 research outputs found

    Geology orbiter comparison study

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    Instrument requirements of planetary geology orbiters were examined with the objective of determining the feasibility of applying standard instrument designs to a host of terrestrial targets. Within the basic discipline area of geochemistry, gamma-ray, X-ray fluorescence, and atomic spectroscopy remote sensing techniques were considered. Within the discipline area of geophysics, the complementary techniques of gravimetry and radar were studied. Experiments using these techniques were analyzed for comparison at the Moon, Mercury, Mars and the Galilean satellites. On the basis of these comparative assessments, the adaptability of each sensing technique was judged as a basic technique for many targets, as a single instrument applied to many targets, as a single instrument used in different mission modes, and as an instrument capability for nongeoscience objectives

    Experimental Polarization State Tomography using Optimal Polarimeters

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    We report on the experimental implementation of a polarimeter based on a scheme known to be optimal for obtaining the polarization vector of ensembles of spin-1/2 quantum systems, and the alignment procedure for this polarimeter is discussed. We also show how to use this polarimeter to estimate the polarization state for identically prepared ensembles of single photons and photon pairs and extend the method to obtain the density matrix for generic multi-photon states. State reconstruction and performance of the polarimeter is illustrated by actual measurements on identically prepared ensembles of single photons and polarization entangled photon pairs

    Tramp Ship Scheduling Problem with Berth Allocation Considerations and Time-dependent Constraints

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    This work presents a model for the Tramp Ship Scheduling problem including berth allocation considerations, motivated by a real case of a shipping company. The aim is to determine the travel schedule for each vessel considering multiple docking and multiple time windows at the berths. This work is innovative due to the consideration of both spatial and temporal attributes during the scheduling process. The resulting model is formulated as a mixed-integer linear programming problem, and a heuristic method to deal with multiple vessel schedules is also presented. Numerical experimentation is performed to highlight the benefits of the proposed approach and the applicability of the heuristic. Conclusions and recommendations for further research are provided.Comment: 16 pages, 3 figures, 5 tables, proceedings paper of Mexican International Conference on Artificial Intelligence (MICAI) 201

    Tailoring of motional states in double-well potentials by time-dependent processes

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    We show that the vibrational state tailoring method developed for molecular systems can be applied for cold atoms in optical lattices. The original method is based on a three-level model interacting with two strong laser pulses in a counterintuitive sequence [M. Rodriguez et al., Phys. Rev. A 62, 053413 (2000)]. Here we outline the conditions for achieving similar dynamics with single time-dependent potential surfaces. It is shown that guided switching between diabatic and adiabatic evolution has an essential role in this system. We also show that efficient and precise tailoring of motional states in optical lattices can be achieved, for instance, simply by superimposing two lattices and moving them with respect to each other.Comment: 9 pages, 11 figures, 25 references; accepted to PRA; v2: minor explanatory remarks added & typos correcte

    Evolving high-speed, easy-to-understand network intrusion detection rules with genetic programming

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    Proceeding of: EvoWorkshops 2009: EvoCOMNET, EvoENVIRONMENT, EvoFIN, EvoGAMES, EvoHOT, EvoIASP, EvoINTERACTION, EvoMUSART, EvoNUM, EvoSTOC, EvoTRANSLOG, Tübingen, Germany, April 15-17, 2009An ever-present problem in intrusion detection technology is how to construct the patterns of (good, bad or anomalous) behaviour upon which an engine have to make decisions regarding the nature of the activity observed in a system. This has traditionally been one of the central areas of research in the field, and most of the solutions proposed so far have relied in one way or another upon some form of data mining–with the exception, of course, of human-constructed patterns. In this paper, we explore the use of Genetic Programming (GP) for such a purpose. Our approach is not new in some aspects, as GP has already been partially explored in the past. Here we show that GP can offer at least two advantages over other classical mechanisms: it can produce very lightweight detection rules (something of extreme importance for high-speed networks or resource-constrained applications) and the simplicity of the patterns generated allows to easily understand the semantics of the underlying attack.Publicad

    Pharmacokinetic modeling of tranexamic acid for patients undergoing cardiac surgery with normal renal function and model simulations for patients with renal impairment

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    Tranexamic acid (TXA), an effective anti-fibrinolytic agent that is cleared by glomerular filtration, is used widely for cardiopulmonary bypass (CPB) surgery. However, an effective dosing regimen has not been fully developed in patients with renal impairment. The aims of this study were to characterize the inter-patient variability associated with pharmacokinetic parameters and to recommend a new dosing adjustment based on the BART dosing regimen for CPB patients with chronic renal dysfunction (CRD). Recently published data on CPB patients with normal renal function (n = 15) were re-examined with a two-compartment model using the ADAPT5® and NONMEMVII® to identify covariates that explain inter-patient variability and to ascertain whether sampling strategies might affect parameter estimation. A series of simulations was performed to adjust the BART dosing regimen for CPB patients with renal impairment. Based on the two-compartmental model, the number of samples obtained after discontinuation of TXA infusion was found not to be critical in parameter estimation (p > 0.05). Both body weight and creatinine clearance were identified as significant covariates (p < 0.005). Simulations showed significantly higher than normal TXA concentrations in CRD patients who received the standard dosing regimen in the BART trial. Adjustment of the maintenance infusion rate based on the percent reduction in renal clearance resulted in predicted plasma TXA concentrations that were safe and therapeutic (~100 mg·L(-1) ). Our proposed dosing regimen, with consideration of renal function, is predicted to maintain effective target plasma concentrations below those associated with toxicity for patients with renal failure for CPB

    Modelling growth of swietenia macrophylla (mahogany) plantation in Gum-Gum Forest Reserve, Sabah.

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    Growth models can contribute to the forest management decision making process by providing stand development forecasts. Mahogany plantation in Gum-Gum Forest Reserve Sabah was planted in 1968 with spacing 2.74×2.74 m within an area of 0.52 hectare. Diameter at breast height (dbh) and tree height data were collected from year 1969 to 2006. This study aimed to determine the efficient regression equations for growth prediction of the mahogany plantation. Regression models were developed by search from literature as a basis references. Four diameter prediction models and six height prediction models were developed. Proc Reg in SAS was used to evaluate the regression equations. Performance of the model was measured by using root mean square error (RMSE), bias and coefficient of determination (R2). The chosen diameter prediction model is lnH=3.07-10.42D-1+0.1lnA with RMSE (0.31), bias (1.76) and R2 (0.68). The recommended prediction model slightly underestimated the actual diameter. The chosen height prediction model is lnD=354-3.98A-1 with RMSE (0.11), bias (0.01) and R2 (0.91). This recommended height prediction model gives very close height estimate to the actual height

    Superconducting and normal-state interlayer-exchange-coupling in La0.67_{0.67}Sr0.33_{0.33}MnO3{3}-YBa2_{2}Cu3_{3}O7La_{7}-La_{0.67}SrSr_{0.33}MnO MnO{3}$ epitaxial trilayers

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    The issue of interlayer exchange coupling in magnetic multilayers with superconducting (SC) spacer is addressed in La0.67_{0.67}Sr0.33_{0.33}MnO3_{3} (LSMO) - YBa2_{2}Cu3_{3}O7_{7} (YBCO) - La0.67_{0.67}Sr0.33_{0.33}MnO3_{3} (LSMO) epitaxial trilayers through resistivity, ac-susceptibility and magnetization measurements. The ferromagnetic (FM) LSMO layers possessing in-plane magnetization suppress the critical temperature (Tc)_{c}) of the c-axis oriented YBCO thin film spacer. The superconducting order, however, survives even in very thin layers (thickness dY_{Y} \sim 50 {\AA}, \sim 4 unit cells) at T << 25 K. A predominantly antiferromagnetic (AF) exchange coupling between the moments of the LSMO layers at fields << 200 Oe is seen in the normal as well as the superconducting states of the YBCO spacer. The exchange energy J1_{1} (\sim 0.08 erg/cm2^{2} at 150 K for dY_{Y} = 75 {\AA}) grows on cooling down to Tc_{c}, followed by truncation of this growth on entering the superconducting state. The coupling energy J1_{1} at a fixed temperature drops exponentially with the thickness of the YBCO layer. The temperature and dY_{Y} dependencies of this primarily non-oscillatory J1_{1} are consistent with the coupling theories for systems in which transport is controlled by tunneling. The truncation of the monotonic T dependence of J1_{1} below Tc_{c} suggests inhibition of single electron tunneling across the CuO2_{2} planes as the in-plane gap parameter acquires a non-zero value.Comment: Accepted for publication in Phys. Rev.

    Magnetically Robust Non-Fermi Liquid Behavior in Heavy Fermion Systems with f^2-Configuration: Competition between Crystalline-Electric-Field and Kondo-Yosida Singlets

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    We study a magnetic field effect on the Non-Fermi Liquid (NFL) which arises around the quantum critical point (QCP) due to the competition between the f^2-crystalline-electric-field singlet and the Kondo-Yosida singlet states by using the numerical renormalization ground method. We show the characteristic temperature T_F^*, corresponding to a peak of a specific heat, is not affected by the magnetic field up to H_z^* which is determined by the distance from the QCP or characteristic energy scales of each singlet states. As a result, in the vicinity of QCP, there are parameter regions where the NFL is robust against the magnetic field, at an observable temperature range T > T_F^*, up to H_z^* which is far larger than T_F^* and less than min(T_{K2}, $Delta).Comment: 8 pages, 9 figur
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