The success of a genetic optimization algorithm in continuous parameter space depends on the recombination (crossover) operators that it uses. In this paper we consider a wide spectrum of such operators within a unified framework and study their relative importance in the search process. We consider four basic types recombination operators which cover the relevant exploration potential of a continuous space: Interpolation, Extrapolation, Exchange and Mutation. Each of these basic types may have several variants. We characterize the various operators and their variants by their spatial sampling properties and examine their contributions to the search by applying different mixtures of the operators in several benchmark problems. The results suggest that the optimal mixture of operators may depend on the problem. But, in general, all basic types are needed for efficient optimization.

This article discusses improving the search on the internet by using WordNet and lexical operators.

In this paper we evaluate the design of the hybrid evolutionary algorithms (EAs) that are currently used to perform flexible ligand binding in the Autodock docking software. Hybrid EAs incorporate specialized operators that exploit domain-specific features to accelerate an EA's search. We consider hybrid EAs that use an integrated local search operator to reline individuals within each iteration of the search. We evaluate several factors that impact the efficacy of a hybrid EA, and we propose new hybrid EAs that provide more robust convergence to low-energy docking configurations than the methods currently available in Autodock.

Optimization is of central concern to a number of disciplines. Interval Arithmetic methods for global optimization provide us with (guaranteed) verified results. These methods are mainly restricted to the classes of objective functions that are twice differentiable and use a simple strategy of eliminating a splitting larger regions of search space in the global optimization process. An efficient approach that combines the efficient strategy from Interval Global Optimization Methods and robustness of the Evolutionary Algorithms is proposed. In the proposed approach, search begins with randomly created interval vectors with interval widths equal to the whole domain. Before the beginning of the evolutionary process, fitness of these interval parameter vectors is defined by evaluating the objective function at the center of the initial interval vectors. In the subsequent evolutionary process the local optimization process returns an estimate of the bounds of the objective function over the interval vectors. Though these bounds may not be correct at the beginning due to large interval widths and complicated function properties, the process of reducing interval widths over time and a selection approach similar to simulated annealing helps in estimating reasonably correct bounds as the population evolves. The interval parameter vectors at these estimated bounds …

This paper presents a convergence theory for evolutionary pattern search algorithms (EPSAs). EPSAs are self-adapting evolutionary algorithms that modify the step size of the mutation operator in response to the success of previous optimization steps. Previously, the authors have proven a stationary point convergence theory for EPSAs for which the step size is not allowed to increase. The present analysis generalizes this analysis to prove a convergence theory for EPSAs that are allowed to both increase and decrease the step size. This convergence theory is based on an extension of the convergence theory for generalized pattern search methods.

The authors describe a new technique for obtaining the phase and electric field from FROG measurements using genetic algorithms. Frequency-Resolved Optical Gating (FROG) has gained prominence as a technique for characterizing ultrashort pulses. FROG consists of a spectrally resolved autocorrelation of the pulse to be measured. Typically a combination of iterative algorithms is used, applying constraints from experimental data, and alternating between the time and frequency domain, in order to retrieve an optical pulse. The authors have developed a new approach to retrieving the intensity and phase from FROG data using a genetic algorithm (GA). A GA is a general parallel search technique that operates on a population of potential solutions simultaneously. Operators in a genetic algorithm, such as crossover, selection, and mutation are based on ideas taken from evolution.

I want to discuss the role of neutrino-electron scattering in the search for physics beyond the standard model. The standard model makes specific predictions about the nature of the neutrinos which participate in such processes and about the interactions responsible for them. The process upon which I shall concentrate is elastic scattering, but I shall pay some attention to inelastic processes in which the target electron is itself transformed into a heavier charged lepton, in other words the inverse of the decay of the heavier lepton. In the case of elastic scattering we are mainly looking at neutral-currents and we can ask a series of simple questions: Does the interaction conserve lepton flavor. Does it fit the prescriptions of the standard model. Are the neutrinos Majorana or Dirac particles. In the case of inverse muon and tau decays we are looking at charge-currents, and we want to pin down the identity of the neutrinos emitted in the decay of these charged leptons as well as to set bounds on non-(V-A) components of the interaction. In order to discuss these topics, it is useful to review the general properties of the scattering process, especially the kinematics and the general form of …

Using Lanczos exact diagonalization, we investigate the effects of the competition between the electro-electron and electron-phonon interactions in the context of the 1-D tight-binding Peierls-Hubbard Hamiltonian, studying various structural, optical, and vibrational properties of strongly correlated systems. We use polyacetylene as our experimental guide, and perform a parameter space search to determine the level at which a unique set of parameters can model this prototypical conducting polymer and, more generally, the applicability of the simple'' 1-D Peierls-Hubbard Hamiltonian to these highly interesting materials. 9 refs., 3 tabs.

We provide a comprehensive, up-to-date analysis of possible New Physics contributions to the mass difference {Delta}M{sub D} in D{sup 0}-{bar D}{sup 0} mixing. We consider the most general low energy effective Hamiltonian and include leading order QCD running of effective operators. We then explore an extensive list of possible New Physics models that can generate these operators, which we organize as including Extra Fermions, Extra Gauge Bosons, Extra Scalars, Extra Space Dimensions and Extra Symmetries. For each model we place restrictions on the allowed parameter space using the recent evidence for observation of D meson mixing. In many scenarios, we find strong constraints that surpass those from other search techniques and provide an important test of flavor changing neutral currents in the up-quark sector. We also review the recent BaBar and Belle findings, and describe the current status of the Standard Model predictions of D{sup 0}-{bar D}{sup 0} mixing.

Charged lepton flavor violating processes are unobservable in the standard model, but they are predicted to be enhanced in several extensions to the standard model, including supersymmetry and models with leptoquarks or compositeness. We present a search for such processes in a sample of 99 x 10{sup 6} {Upsilon}(2S) decays and 117 x 10{sup 6} {Upsilon}(3S) decays collected with the BABAR detector. We place upper limits on the branching fractions {Beta}({Upsilon}(nS) {yields} e{sup {+-}}{tau}{sup {-+}}) and {Beta}({Upsilon}(nS) {yields} {mu}{sup {+-}}{tau}{sup {-+}}) (n = 2, 3) at the 10{sup -6} level and use these results to place lower limits of order 1 TeV on the mass scale of charged lepton flavor violating effective operators.

A cluster expansion is used to predict the fcc ground states, i.e., the stable phases at zero Kelvin as a function of composition, for alloy systems. The intermetallic structures are not assumed, but derived regorously by minimizing the configurational energy subject to linear constraints. This ground state search includes pair and multiplet interactions which spatially extend to fourth nearest neighbor. A large number of these concentration-independent interactions are computed by the method of direct configurational averaging using a linearized-muffin-tin orbital Hamiltonian cast into tight binding form (TB-LMTO). The interactions, derived without the use of any adjustable or experimentally obtained parameters, are compared to those calculated via the generalized perturbation method extention of the coherent potential approximation within the context of a KKR Hamiltonian (KKR-CPA-GPM). Agreement with the KKR-CPA-GPM results is quite excellent, as is the comparison of the ground state results with the fcc-based portions of the experimentally-determined phase diagrams under consideration.

Studies show that vigilance decreases rapidly after several minutes when human operators are required to search live video for infrequent intrusion detections. Therefore, there is a need for systems which can automatically detect targets in live video and reserve the operator`s attention for assessment only. Thus far, automated systems have not simultaneously provided adequate detection sensitivity, false alarm suppression, and ease of setup when used in external, unconstrained environments. This unsatisfactory performance can be exacerbated by poor video imagery with low contrast, high noise, dynamic clutter, image misregistration, and/or the presence of small, slow, or erratically moving targets. This paper describes a highly adaptive video motion detection and tracking algorithm which has been developed as part of Sandia`s Advanced Exterior Sensor (AES) program. The AES is a wide-area detection and assessment system for use in unconstrained exterior security applications. The AES detection and tracking algorithm provides good performance under stressing data and environmental conditions. Features of the algorithm include: reliable detection with negligible false alarm rate of variable velocity targets having low signal-to-clutter ratios; reliable tracking of targets that exhibit motion that is non-inertial, i.e., varies in direction and velocity; automatic adaptation to both infrared and visible imagery with variable …

As part of the US-Russian Lab-to-Lab program for strengthening nuclear material protection, control, and accounting (MPC&A), a testbed facility has been established in a laboratory of the VNIIEF to demonstrate safeguards technology to nuclear facility operators. The design of the testbed MPC&A system provides the functions of nondestructive measurements for plutonium and highly enriched uranium, item control, personnel access control, radiation portal monitoring, search equipment, and computerized on-line accounting. The system controls, monitors, and accounts for nuclear material and people as the material moves through three MBAs. It also assists with physical inventory taking. A total of 39 instruments and control systems are being demonstrated in the present version of the testbed. Of these, about half are of Russian design and fabrication, including the software for the item monitoring and the accounting systems. These two computer systems are on an ethernet network and connected in a client-server local area architecture. The item monitoring system is integrated with the accounting system, providing alarm and status information to a central dispatcher terminal. The operation of the MPC&A testbed has been demonstrated under routine and alarm conditions in collaboration with safeguards staff from the six participating US national labs. Workshops and training for …

We present results of theoretical nuclear structure model calculations for the gamma-ray laser candidate nucleus /sup 186/Re proposed by Collins. Our calculations of this odd-odd transitional nucleus are based on an axially-asymmetric (particle plus triaxial rotor) model for constructing the orbitals of the odd nucleons that couple under the influence of the residual neutron-proton interaction. We include pairing correlations in the determination of these orbitals by using the BCS approximation with newly determined pairing strengths. The matrix elements of the residual neutron-proton interaction are obtained using phenomenological spin-dependent delta function potentials of both surface and volume forms. We examine the sensitivity of the calculated low-excitation level structure of /sup 186/Re to the strength of these potentials. Calculated energy levels of /sup 186/Re will be presented and compared with experiment. The impact of our results on the proposed use of /sup 186/Re as a gamma-ray laser will be discussed. In addition, based upon these and other model calculations to be described, we assess the level of effort necessary in a full-scale theoretical search for a viable candidate nucleus for a gamma-ray laser. 17 refs., 1 fig., 3 tabs.

A sensitive search for the rare decays {Omega}{sup -} {yields} {Lambda}{pi}{sup -} and {Xi}{sup 0} {yields} p{pi}{sup -} has been performed using data from the 1997 run of the HyperCP (Fermilab E871) experiment. Limits on other such processes do not exclude the possibility of observable rates for |{Delta}S| = 2 nonleptonic hyperon decays, provided the decays occur through parity-odd operators. They obtain the branching-fraction limits {Beta}({Omega}{sup -} {yields} {Lambda}{pi}{sup -}) < 2.9 x 10{sup -6} and {Beta}({Xi}{sup 0} {yields} p{pi}{sup -}) < 8.2 x 10{sup -6}, both at 90% confidence level.

There is a general consensus that robots could be beneficial in performing tasks within hazardous radiological environments. Most control of robots in hazardous environments involves master-slave or teleoperation relationships between the human and the robot. While teleoperation-based solutions keep humans out of harms way, they also change the training requirements to accomplish a task. In this paper we present a research methodology that allowed scientists at Idaho National Laboratory to identify, develop, and prove a semi-autonomous robot solution for search and characterization tasks within a hazardous environment. Two experiments are summarized that validated the use of semi-autonomy and show that robot autonomy can help mitigate some of the performance differences between operators who have different levels of robot experience, and can improve performance over teleoperated systems.

We address deceptiveness, one of at least four reasons genetic algorithms can fail to converge to function optima. We construct fully deceptive functions and other functions of intermediate deceptiveness. For the fully deceptive functions of our construction, we generate linear transformations that induce changes of representation to render the functions fully easy. We further model genetic algorithm selection recombination as the interleaving of linear and quadratic operators. Spectral analysis of the underlying matrices allows us to draw preliminary conclusions about fixed points and their stability. We also obtain an explicit formula relating the nonuniform Walsh transform to the dynamics of genetic search. 21 refs.

ATHEANA, a second-generation Human Reliability Analysis (HRA) method integrates advances in psychology with engineering, human factors, and Probabilistic Risk Analysis (PRA) disciplines to provide an HRA quantification process and PRA modeling interface that can accommodate and represent human performance in real nuclear power plant events. The method uses the characteristics of serious accidents identified through retrospective analysis of serious operational events to set priorities in a search process for significant human failure events, unsafe acts, and error-forcing context (unfavorable plant conditions combined with negative performance-shaping factors). ATHEANA has been tested in a demonstration project at an operating pressurized water reactor.

Motivated by the needs of large multi-physics simulation codes, we are interested in algebraic solvers for the linear systems arising in time-domain electromagnetic simulations. Our focus is on finite element discretization, and we are developing scalable parallel preconditioners which employ only fine-grid information, similar to algebraic multigrid (AMG) for diffusion problems. In the last few years, the search for efficient algebraic preconditioners for H(curl) bilinear forms has intensified. The attempts to directly construct AMG methods had some success, see [12, 1, 7]. Exploiting available multilevel methods on auxiliary mesh for the same bilinear form led to efficient auxiliary mesh preconditioners to unstructured problems as shown in [4, 8]. A computationally more attractive approach was recently proposed by Hiptmair and Xu [5]. In contrast to the auxiliary mesh idea, the method in [5] uses a nodal H{sup 1}-conforming auxiliary space on the same mesh. This significantly simplifies the computation of the corresponding interpolation operator. In the present talk, we consider several options for constructing unstructured mesh AMG preconditioners for H(curl) problems and report a summary of computational results from [10, 9]. Our approach is slightly different than the one from [5], since we apply AMG directly to variationally constructed coarse-grid operators, …

Effective operation of the multi-state Port ofNew York/New Jersey (Port), which contributes $20 billion to the regional economy and generates nearly 250,000 jobs, is dependent on yearly navigational dredging of several million m{sup 3} of sediment for channel maintenance and deepening. Further dredging is required for remediation of environmentally sensitive areas. However, more stringent ocean placement testing regulations in the Port region have necessitated a search for other means of handling the most contaminated dredged materials. Here, we describe a dredged material decontamination program for the Port aimed at the creation of sediment decontamination facilities that produce a beneficial use product to obviate the need for ocean placement. These facilities, to be a viable component of an overall dredged material management plan, must be environmentally balanced and economically feasible with the predictable ability to process large volumes of dredged materials with rapid turn-around. Our program recognizes that the responsible management of contaminated dredged materials is a complex problem that requires the effective application and coordination of a variety of cross-cutting skills to make decontamination facilities a reality. Participants do not come from a single agency, but are ad hoc teams of scientists, engineers, regulators, port authorities and operators, technology development …

Status of lattice calculations of hadron matrix elements along with CP violation in B and in K systems is reviewed. Lattice has provided useful input which, in conjunction with experimental data, leads to the conclusion that CP-odd phase in the CKM matrix plays the dominant role in the observed asymmetry in B {yields} {psi}K{sub s}. It is now quite likely that any beyond the SM, CP-odd, phase will cause only small deviations in B-physics. Search for the effects of the new phase(s) will consequently require very large data samples as well as very precise theoretical predictions. Clean determination of all the angles of the unitarity triangle therefore becomes essential. In this regard B {yields} KD{sup 0} processes play a unique role. Regarding K-decays, remarkable progress made by theory with regard to maintenance of chiral symmetry on the lattice is briefly discussed. First application already provide quantitative information on B{sub K} and the {Delta}I = 1/2 rule. The enhancement in ReA{sub 0} appears to arise solely from tree operators, esp. Q{sub 2}; penguin contribution to ReA{sub 0} appears to be very small. However, improved calculations are necessary for {epsilon}{prime}/{epsilon} as there the contributions of QCD penguins and electroweak penguins largely seem …

The use of sprayed flammable fluids as solvents in dissolution and cleaning processes demand detailed understanding of ignition and fire hazards associated with these applications. When it is not feasible to inert the atmosphere in which the spraying process takes place, then elimination of all possible ignition sources must be done. If operators are involved in the process, the potential for human static build-up and ultimate discharge is finite, and it is nearly impossible to eliminate. The specific application discussed in this paper involved the use of heated Dimethyl Sulfoxide (DMSO) to dissolve high explosives (HE). Search for properties of DMSO yielded data on flammability limits and flash point, but there was no published information pertaining to the minimum energy for electrical arc ignition. Due to the sensitivity of this procedure, The Hazards Control Department of Lawrence Livermore National Laboratory (LLNL) was tasked to determine the minimum ignition energy of DMSO aerosol and vapor an experimental investigation was thus initiated. Because there were no electrical sources in spray chamber, Human Electro-Static Discharge (HESD) was the only potential ignition source. Consequently, the electrostatic generators required for this investigation were designed to produce electrostatic arcs with the defined voltage and current pulse …

Nondestructive assay systems have been developed to allow data acquisition equipment to operate unattended in an automated mixed oxide facility, reducing inspector time in a facility and giving them time for other activities. Fewer inspector visits mean less impact on plant operators. Neutron detectors are located at key measurement points in the facility. Near each detector is located an electronics cabinet, which contains two JSR-11 shift registers, two COMPAQ Portable III computers, and a printer. The signal from the detector is split and sent to each shift register for redundancy and reliability. The software for unattended operation consists primarily of two programs, COLLECT and REVIEW. The COLLECT program runs on the computers in unattended operation; shift-register data are acquired each 60 s. The COLLECT program distinguishes between a normal background and a disconnected signal, between material moving near the detector and material in the detector, and whether the material in the detector is a sample or a californium normalization source. Depending on the type of assay, different data are stored on the hard disk. During an inspection, the inspector stops the current measurement campaign, examines the data from both computers briefly at the electronics cabinet, copies the campaign data to …

A short review of current efforts to determine the highly excited state spectrum of QCD, and in particular baryons, using lattice QCD techniques is presented. The determination of the highly excited spectrum of QCD is a major theoretical and experimental challenge. The experimental investigation of the excited baryon spectrum has been a long-standing element of the hadronic-physics program, an important component of which is the search for so-called 'missing resonances', baryonic states predicted by the quark model based on three constituent quarks but which have not yet been observed experimentally. Should such states not be found, it may indicate that the baryon spectrum can be modeled with fewer effective degrees of freedom, such as in quark-diquark models. In the past decade, there has been an extensive program to collect data on electromagnetic production of one and two mesons at Jefferson Lab, MIT-Bates, LEGS, MAMI, ELSA, and GRAAL. To analyze these data, and thereby refine our knowledge of the baryon spectrum, a variety of physics analysis models have been developed at Bonn, George Washington University, Jefferson Laboratory and Mainz. To provide a theoretical determination and interpretation of the spectrum, ab initio computations within lattice QCD have been used. Historically, the calculation …