大型望遠鏡の主鏡鏡材最適配置問題へのシミュレーテッドアニーリングの応用

ACMAS program, in partnership with CNES and DGA, intends to develop an innovative concept of deformable mirror (DM) for next generation space telescopes, to manufacture an engineering model and to test it on optical and mechanical points of view. <br/> The design of this space compatible DM is based on ISP System’s technology, and is adapted to space constraints (ECSS) particularly in terms of vibrations and reliability. These electro-mechanical DMs offer some innovative characteristics for space telescopes with low speed wavefront variations. <br/> A specific version of the patented AME actuator is developed for space applications, and tested to TRL6. The deformable mirror’s actuators pattern is optimized in terms of quantity and position with respect to the wavefront corrections expected to apply during mission. The DM design is optimized thanks to finite element modeling in order to withstand the vibrations and shocks due to launching, and improve thermo-mechanical stability, and an innovative redundancy method is developed. <br/> The performance of an engineering model is measured using an optical test bench with high resolution wavefront sensor. The correction thermal stability is also measured and the performance with one and two disabled actuators is evaluated. Vibrations are then injected into the DM. All these measures are compared to simulation values and show an impressive correlation..

With the aperture of telescope becoming larger, the mass of primary mirror and other relevant structures will become heavier as well. Therefore, lighting weight for large space-based telescope is necessary. This paper purposed a method based on Neural Network aims to build a math model for primary mirror of large space-based telescope, which can reduce weight of the telescope and smaller mirror deformation caused by gravity release effectively. In the meantime, it can also improve stiffness of structure and reduce thermal strain caused by on orbit temperature variation effectively. The model describes the relationship between the structure of primary mirror of large space-based telescope and corresponding deformation, and describes the optical performance of mirror by using Zernike Polynomial. To optimize the structure of primary mirror lightweight, we take the deformation of mirror and its optical performance into consideration. To apply the structures parameters and its corresponding deformations to Neural Network training, we use the combination samples of different mirror lightweight structure parameters and corresponding deformation which caused by gravity release and thermal condition. Finally, by taking advantage of the Neural Network model to optimize the primary mirror lightweight of 1-meter rectangle space-based telescope, which can make the RMS 0.024λ (λ=632.8nm)and areal density under 15kg/m². This method combines existing results and numerical simulation to establish numerical model based on Neural Network method. Research results can be applied to same processes of designing, analyzing, and processing of large space-based telescope directly.

This thesis presents a concept for ultra-lightweight deformable mirrors based on a thin substrate of optical surface quality coated with continuous active piezopolymer layers that provide modes of actuation and shape correction. This concept eliminates any kind of stiff backing structure for the mirror surface and exploits micro-fabrication technologies to provide a tight integration of the active materials into the mirror structure, to avoid actuator print-through effects. Proof-of-concept, 10-cm-diameter mirrors with a low areal density of about 0.5 kg/m² have been designed, built and tested to measure their shape-correction performance and verify the models used for design. The low cost manufacturing scheme uses replication techniques, and strives for minimizing residual stresses that deviate the optical figure from the master mandrel. It does not require precision tolerancing, is lightweight, and is therefore potentially scalable to larger diameters for use in large, modular space telescopes. Other potential applications for such a laminate could include ground-based mirrors for solar energy collection, adaptive optics for atmospheric turbulence, laser communications, and other shape control applications. The immediate application for these mirrors is for the Autonomous Assembly and Reconfiguration of a Space Telescope (AAReST) mission, which is a university mission under development by Caltech, the University of Surrey, and JPL. The design concept, fabrication methodology, material behaviors and measurements, mirror modeling, mounting and control electronics design, shape control experiments, predictive performance analysis, and remaining challenges are presented herein. The experiments have validated numerical models of the mirror, and the mirror models have been used within a model of the telescope in order to predict the optical performance. A demonstration of this mirror concept, along with other new telescope technologies, is planned to take place during the AAReST mission.

For machining various parts, it is important to generate efficient tool paths for productivity. At the stage of roughing, the workspace is sliced and the paths are generated outside the part in each sliced plane. One of important decision variables in planar tool path generation is the direction in which paths are aligned. This paper is about decomposing the machining region and deciding the path direction in each subregion so that machining time can be reduced. The machining region is decomposed into discretized meshes and the path planning problem is formulated as a combinatorial optimization problem. The formulated problem is solved by the simulated annealing technique. To speed up the overall optimization procedure, the annealing procedure is rather prematurely terminated and a clearing algorithm is applied to remove small subregions. This is needed since the cost function of this problem has many ‘flat’ areas and provides ‘narrow’ passages to its optimum.

Future large aperture space telescopes may use lightweight correctable active mirrors. The Naval Postgraduate School's Segmented Mirror Telescope (SMT) test bed uses 1-meter silicon carbide (SiC) active mirror segments to form a sixsegment deployable 3-meter telescope. The active segments suffer from residual surface errors after a correction is applied. A deformable mirror is added at the SMT pupil plane to improve this residual error. The large active SMT segment represents the woofer, and a small continuous micro-electro-mechanical system (MEMS) deformable mirror represents the tweeter. A global influence matrix and closed loop constrained least squares controller command the active segment and additional deformable mirror as a single device. An interferometer measures the surface error and provides feedback to the controller. Simulation and experimental results demonstrate a significant improvement in wavefront error compared to a 2-step sequential woofer-tweeter constrained least squares control approach.

A novel scheme for remote alignment of adaptive optical systems is presented. In comparison to conventional methods where near-field measurements (in the form of near-field phase across the adaptive component or gaps between neighboring segments) are used for feedback control, Far-Field Optimization utilizes only the far-field intensity. A figure of merit based solely on the point spread function is used to iteratively configure the adaptive elements to optical alignment. In this review paper, we first describe the far-field optimization method and then discuss its application to three different adaptive optical systems - a deformable mirror, a segmented mirror and a multiple mirror telescope. The convergence, efficiency and robustness of the iterative far-field optimization are illustrated with computer simulations. Experimental validation of the novel technique for adaptive optics alignment is demonstrated with results from a laboratory test with a segmented mirror. Potential utility of far-field optimization for dynamic wavefront control (e.g. atmospheric turbulence compensation) is briefly discussed.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Earth observation satellite with a large mirror telescope has been studied in Japan Aerospace Exploration Agency to offer a fine ground sampling distance from geostationary orbit. Our latest optical design has a 3.6-m primary mirror and thus aims to obtain a ground sampling distance of sub-10 m from an altitude of 36,000 km at visible wavelengths. To achieve diffraction-limited performance in such optics on orbit, the telescope equips with not only actuators to control primary and secondary mirrors but also a deformable mirror (DM) at the exit pupil plane for the fine phasing. For on-orbit wavefront correction with a deformable mirror, a wavefront sensorless image-based aberration correction scheme is advantageous from the viewpoint of severely limited hardware resources in satellites. Phase diversity (PD) and stochastic parallel gradient descent (SPGD) optimization are known for promising image-based approaches. The former is model-based and thus the estimation accuracy of wavefront aberration significantly depends on the model accuracy, while the other requires many measurements to compensate for large aberration. To alleviate these issues, we propose sequential use of PD and SPGD optimization to efficiently reduce wavefront correction. We first developed an optical testbed with an incoherent light source, a MEMS DM, and extended image targets, and then a wavefront correction experiment was carried out. As a result, the proposed method successfully achieved diffraction-limited imaging performance with a small number of measurements. We will also discuss the image dependence of the wavefront correction performance.

For direct imaging of faint exoplanets, coronagraphs are widely used to suppress light and achieve a high contrast. Wavefront correction algorithms based on adaptive optics are introduced simultaneously to mitigate aberrations in the optical system. Stroke minimization is one of the primary control algorithms used for high-contrast wavefront control. This technique calculates the minimum deformation across the deformable mirrors' surface under the constraint that a targeted average contrast level in the search areas, namely the dark holes, is achieved. In this paper we present a modified linear constraint stroke minimization algorithm. Instead of using a single constraint on intensity averaged over all pixels, we constrain the electric field's real and imaginary part of each pixel in the dark holes. The new control algorithm can be written into a linear programming problem. Model reduction methods, including pixel binning and singular value decomposition (SVD), are further employed to avoid over-constraining the problem and to speed up computation. In numerical simulation, we find that the revised algorithm leads to more uniform dark holes and faster convergence.

Long-term stability of deformable mirrors (DM) is a critical performance requirement for instruments requiring open-loop corrections. The effects of temperature changes in the DM performance are equally critical for such instruments. This paper investigates the long-term stability of three different Iris AO PTT111 DMs that were calibrated at different times ranging from 13 months to nearly 29 months prior to subsequent testing. Performance testing showed that only a small increase in positioning errors occurred from the initial calibration date to the test dates. The increases in errors ranged from as little as 1.38 nm rms after 18 months to 5.68 nm rms after 29 months. The paper also studies the effects of small temperature changes, up to 6.2{\deg}C around room temperature. For three different arrays, the errors ranged from 0.62-1.42 nm rms/{\deg}C. Removing the effects of packaging shows that errors are $\le$0.50 nm rms/{\deg}C. Finally, measured data showed that individual segments deformed $\le$0.11 nm rms/{\deg}C when heated.

Main transformer ULTC and capacitors scheduling by simulated annealing approach

The paper concerns a measurement problem of identifying inadequacy in a mathematical model of an adaptive control system driving segments of a deformable mirror in a large telescope. This is necessary to assess the validity of this model. A dual-axis servo drive unit utilising permanent magnet synchronous machines controls the mirror segments. The servo unit rotates each segment of the deformable mirror with respect to its axis of symmetry and tilts each segment relative to the fixed central reference segment. The paper provides general descriptions of the model structure and the feedback in the current control loop employing phase current measurement and coordinate transformations. We present initial data sets for metrological certification of the model. We used the MMK-stat M software to perform the metrological certification so that we could check empirical equations, determine the scope of application for the model and validate it. The metrological certification allowed us to confirm that the model of an adaptive control system for a segmented deformable telescope mirror is valid, and to find the model structure that ensures a more accurate description of the measurement problem that concerns controlling the spatial position of the object simulated

This paper proposes a hybrid algorithm based on the variable neighborhood search (VNS) and the simulated annealing approach (SA) for minimizing the makespan in a blocking flowshop scheduling problem. The proposed hybrid algorithm (VNSSA) adopts simulated annealing approach (SA) as the local search method in the third stage of variable neighborhood search (VNS), and uses a perturbation mechanism consisting of various neighborhood operators to diversify the search. The destruction and construction phases of iterated greedy algorithm are used to generate a trial solution during the perturbation process of SA to further promote the search capability. To validate the performance of the proposed VNSSA algorithm, computational experiments and comparisons were conducted on the well-known benchmark problems of Taillard. The computational results of the proposed algorithm when evaluated against the state-of-art algorithms from the literature show good performance, some new best solutions for Taillard's instances are reported for this problem.

Rainfall-induced slope failures disrupt the traffic and warrant urgent slope repair works. The impact of roadside slope failures can be minimized if slopes are proactively rehabilitated. Nonetheless, transportation agencies are constrained in their budget to rehabilitate a limited number of slope segments due to competing maintenance needs among different transportation assets. Therefore, the transportation agencies should identify the critical slope combination that should be proactively rehabilitated under constraint budgets to lessen the impact on the transportation network during extreme rainfall events. The decision-making approach for slope rehabilitation should also ensure low risk associated with the selected rehabilitation strategy. Current slope-rehabilitation decision models do not consider the risk associated with the rehabilitation strategies in the decision-making process. The objective of this study is to develop a risk-averse stochastic combinatorial optimization to facilitate the selection of slope rehabilitation strategies, which leads to the least expected cost and conditional value at risk (CVaR) for extreme rainfall events. The simulated annealing approach is used to solve the risk-averse combinatorial optimization rehabilitation problem with the objective function that measures the total cost of traffic disruption and slope restoration post-failures. The approach is demonstrated using a transportation network in Lamar County, Texas. Unlike a genetic algorithm-based approach in the literature that yields a single slope rehabilitation strategy, the proposed risk-averse simulated annealing approach identifies rehabilitation strategies along the Pareto efficient frontier facilitating the rehabilitation decisions based on the tradeoff between expected cost and CVaR. For the network in Lamar County, the proposed risk-averse simulated annealing provided a solution in the Pareto front that reduced CVaR by 2.0% compared to the solution obtained from the genetic algorithm-based approach while only increasing the expected cost by 0.8%. The risk-averse optimization approach will aid transportation agencies in determining slope rehabilitation strategies for minimizing the impact of rainfall-induced failures at appropriate risk aversion levels.

1. Introduction 3721.1 Residual dipolar couplings as a route to structure and dynamics 3721.2 A brief history of oriented phase high resolution NMR 3742. Theoretical treatment of dipolar interactions 3762.1 Anisotropic interactions as probes of macromolecular structure and dynamics 3762.1.1 The dipolar interaction 3762.1.2 Averaging in the solution state 3772.2 Ordering of a rigid body 3772.2.1 The Saupe order tensor 3782.2.2 Orientational probability distribution function 3802.2.3 The generalized degree of order 3802.3 Molecular structure and internal dynamics 3813. Inducing molecular order in high resolution NMR 3833.1 Tensorial interactions between the magnetic field and anisotropic magnetic susceptibilities 3833.2 Dilute liquid crystal media: a tunable source of order 3843.2.1 Bicelles : from membrane mimics to aligning media 3853.2.2 Filamentous phage 3873.2.3 Transfer of alignment from ordered media to macromolecules 3883.3 Magnetic field alignment 3893.3.1 Paramagnetic assisted alignment 3893.3.2 Advantages of using magnetic alignment 3894. The measurement of residual dipolar couplings 3914.1 Introduction 3914.2 Frequency based methods 3924.2.1 Coupling enhanced pulse schemes 3924.2.2 In phase anti-phase methods (IPAP): 1DNH couplings in proteins 3934.2.3 Exclusive correlated spectroscopy (E-COSY): 1DNH, 1DNC′ and 2DHNC′ 3954.2.4 Extraction of splitting values from the frequency domain 3964.3 Intensity based experiments 3974.3.1 J-Modulated experiments: the measurement of 1DCαHα in proteins 3974.3.2 Phase modulated methods 3994.3.3 Constant time COSY – the measurement of DHH couplings 3994.3.4 Systematic errors in intensity based experiments 4005. Interpretation of residual dipolar coupling data 4015.1 Structure determination protocols utilizing orientational constraints 4015.1.1 The simulated annealing approach 4015.1.2 Order matrix analysis of dipolar couplings 4025.1.3 A discussion of the two approaches 4025.2 Reducing orientational degeneracy 4035.2.1 Multiple alignment media in the simulated annealing approach 4045.2.2 Multiple alignment media in the order matrix approach 4055.3 Simplifying effects arising due to molecular symmetry 4065.4 Database approaches for determining protein structure 4076. Applications to the characterization of macromolecular systems 4086.1 Protein structure refinement 4086.2 Protein domain orientation 4096.3 Oligosaccharides 4136.4 Biomolecular complexes 4156.5 Exchanging systems 4167. Acknowledgements 4188. References 419Within its relatively short history, nuclear magnetic resonance (NMR) spectroscopy has managed to play an important role in the characterization of biomolecular structure. However, the methods on which most of this characterization has been based, Nuclear Overhauser Effect (NOE) measurements for short-range distance constraints and scalar couplings measurements for torsional constraints, have limitations (Wüthrich, 1986). For extended structures, such as DNA helices, for example, propagation of errors in the short distance constraints derived from NOEs leaves the relative orientation of remote parts of the structures poorly defined. Also, the low density of observable protons in contact regions of molecules held together by factors other than hydrophobic packing, leads to poorly defined structures. This is especially true in carbohydrate containing complexes where hydrogen bonds often mediate contacts, and in multi-domain proteins where the area involved in domain–domain contact can also be small. Moreover, most NMR based structural applications are concerned with the characterization of a single, rigid conformer for the final structure. This can leave out important mechanistic information that depends on dynamic aspects and, when motion is present, this can lead to incorrect structural representations. This review focuses on one approach to alleviating some of the existing limitations in NMR based structure determination: the use of constraints derived from the measurement of residual dipolar couplings (D).

The necessity and possible ways of monitoring the deformations of the primary mirror directly at the BTA telescope during its operation are discussed. The most acceptable methods and control schemes are analyzed. A scheme is suggested on the basis of the pseudoreversal method, which simply and originally solves the control problem based on the experience of AST-1200 telescope with a composite primary mirror. Possible measurement errors of the system suggested for controlling primary mirror deformations are estimated.