The spacecraft control laboratory experiment optical attitude measurement system

A stereo camera tracking system was developed to provide a near real-time measure of the position and attitude of the Spacecraft COntrol Laboratory Experiment (SCOLE). The SCOLE is a mockup of the shuttle-like vehicle with an attached flexible mast and (simulated) antenna, and was designed to provide a laboratory environment for the verification and testing of control laws for large flexible spacecraft. Actuators and sensors located on the shuttle and antenna sense the states of the spacecraft and allow the position and attitude to be controlled. The stereo camera tracking system which was developed consists of two position sensitive detector cameras which sense the locations of small infrared LEDs attached to the surface of the shuttle. Information on shuttle position and attitude is provided in six degrees-of-freedom. The design of this optical system, calibration, and tracking algorithm are described. The performance of the system is evaluated for yaw only

Optical processing for distributed sensors in control of flexible spacecraft

A recent potential of distributed image processing is discussed. Applications in the control of flexible spacecraft are emphasized. Devices are currently being developed at NASA and in universities and industries that allow the real-time processing of holographic images. Within 5 years, it is expected that, in real-time, one may add or subtract holographic images at optical accuracy. Images are stored and processed in crystal mediums. The accuracy of their storage and processing is dictated by the grating level of laser holograms. It is far greater than that achievable using current analog-to-digital, pixel oriented, image digitizing and computing techniques. Processors using image processing algebra can conceptually be designed to mechanize Fourier transforms, least square lattice filters, and other complex control system operations. Thus, actuator command inputs derived from complex control laws involving distributed holographic images can be generated by such an image processor. Plans are revealed for the development of a Conjugate Optics Processor for control of a flexible object

Bulk and Interfacial Shear Thinning of Immiscible Polymers

Nonequilibrium molecular dynamics simulations are used to study the shear thinning behavior of immiscible symmetric polymer blends. The phase separated polymers are subjected to a simple shear flow imposed by moving a wall parallel to the fluid-fluid interface. The viscosity begins to shear thin at much lower rates in the bulk than at the interface. The entire shear rate dependence of the interfacial viscosity is consistent with a shorter effective chain length $s^*$ that also describes the width of the interface. This $s^*$ is independent of chain length $N$ and is a function only of the degree of immiscibility of the two polymers. Changes in polymer conformation are studied as a function of position and shear rate.Shear thinning correlates more closely with a decrease in the component of the radius of gyration along the velocity gradient than with elongation along the flow. At the interface, this contraction of chains is independent of $N$ and consistent with the bulk behavior for chains of length $s^*$. The distribution of conformational changes along chains is also studied. Central regions begin to stretch at a shear rate that decreases with increasing $N$, while shear induced changes at the ends of chains are independent of $N$.Comment: 8 pages, 8 figure

Multiyear defoliations in southern New England increases oak mortality

After decades of multiyear defoliation episodes in southern New England, Lymantria dispar dispar (LDD; previously gypsy moth) populations collapsed with the appearance of the LDD fungus in 1989. Multiyear defoliations did not occur again until 2015-2018. To assess the impact of the return of multiyear defoliations, we examined 3095 oaks on 29 permanent study areas in Connecticut and Rhode Island that were established at least eleven years before the latest outbreaks. Pre-defoliation stand level oak mortality averaged 2% (three-year basis). Post-defoliation mortality did not differ between managed and unmanaged stands, but was much higher in severely defoliated stands (36%) than in stands with moderate (7%) or low-no defoliation (1%). Pre-defoliation mortality of individual trees differed among species, was lower for larger diameter trees and on unmanaged than managed stands. Post-defoliation mortality on plots with no to moderate defoliation was similar to pre-defoliation mortality levels. Following multiyear defoliations, white oak mortality was higher than for northern red and black oak. There was weak evidence that mortality was elevated on stands with higher basal area following severe defoliation. Natural resource managers should not assume that oaks that survived earlier multiyear defoliations episodes will survive future multiyear outbreaks, possibly because trees are older

Mapping the Road from Childhood Trauma to Adult Somatization: The Role of Attachment

Objective: This study tested whether insecure attachment mediates the link between childhood trauma and adult somatization. Methods: A community sample of 101 couples completed self-report measures including the Relationship Scales Questionnaire, the Childhood Trauma Questionnaire, the Somatic Symptom Inventory, the Beck Depression Inventory, and the Conflict Tactics Scale. Results: Childhood trauma was associated with higher levels of somatization and insecure attachment. Insecure attachment style was also associated with higher levels of somatization. Controlling for age, income, and recent intimate partner violence, analyses showed that fearful attachment fully mediated the link between childhood trauma and somatization for women. For men there was no such mediation, but both childhood trauma and insecure attachment styles made independent contributions to predicting levels of somatization. Conclusions: Findings are consistent with the hypothesis that, for women, childhood trauma influences adult levels of somatization by fostering insecure adult attachment. For men, findings suggest that trauma and attachment are both important independent predictors of adult somatization. Study results support the idea that childhood trauma shapes patients’ styles of relating to others in times of need and these styles in turn influence the somatization process and how patients respond to providers. Screening for attachment style may provide information that could allow health care providers to tailor treatment more effectively. Key words: Attachment style, somatization, childhood trauma, interpersonal models. Abbreviations: CTQ = Childhood Trauma Questionnaire; CTS2 = Conflict Tactics Scale version 2; SSI = Somatic Symptom Inventory; RSQ = Relationship Scales Questionnaire; BDI = Beck Depression Inventory

Mapping the Road from Childhood Trauma to Adult Somatization: The Role of Attachment

Objective: This study tested whether insecure attachment mediates the link between childhood trauma and adult somatization. Methods: A community sample of 101 couples completed self-report measures including the Relationship Scales Questionnaire, the Childhood Trauma Questionnaire, the Somatic Symptom Inventory, the Beck Depression Inventory, and the Conflict Tactics Scale. Results: Childhood trauma was associated with higher levels of somatization and insecure attachment. Insecure attachment style was also associated with higher levels of somatization. Controlling for age, income, and recent intimate partner violence, analyses showed that fearful attachment fully mediated the link between childhood trauma and somatization for women. For men there was no such mediation, but both childhood trauma and insecure attachment styles made independent contributions to predicting levels of somatization. Conclusions: Findings are consistent with the hypothesis that, for women, childhood trauma influences adult levels of somatization by fostering insecure adult attachment. For men, findings suggest that trauma and attachment are both important independent predictors of adult somatization. Study results support the idea that childhood trauma shapes patients’ styles of relating to others in times of need and these styles in turn influence the somatization process and how patients respond to providers. Screening for attachment style may provide information that could allow health care providers to tailor treatment more effectively. Key words: Attachment style, somatization, childhood trauma, interpersonal models. Abbreviations: CTQ = Childhood Trauma Questionnaire; CTS2 = Conflict Tactics Scale version 2; SSI = Somatic Symptom Inventory; RSQ = Relationship Scales Questionnaire; BDI = Beck Depression Inventory

Random solids and random solidification: What can be learned by exploring systems obeying permanent random constraints?

In many interesting physical settings, such as the vulcanization of rubber, the introduction of permanent random constraints between the constituents of a homogeneous fluid can cause a phase transition to a random solid state. In this random solid state, particles are permanently but randomly localized in space, and a rigidity to shear deformations emerges. Owing to the permanence of the random constraints, this phase transition is an equilibrium transition, which confers on it a simplicity (at least relative to the conventional glass transition) in the sense that it is amenable to established techniques of equilibrium statistical mechanics. In this Paper I shall review recent developments in the theory of random solidification for systems obeying permanent random constraints, with the aim of bringing to the fore the similarities and differences between such systems and those exhibiting the conventional glass transition. I shall also report new results, obtained in collaboration with Weiqun Peng, on equilibrium correlations and susceptibilities that signal the approach of the random solidification transition, discussing the physical interpretation and values of these quantities both at the Gaussian level of approximation and, via a renormalization-group approach, beyond.Comment: Paper presented at the "Unifying Concepts in Glass Physics" workshop, International Centre for Theoretical Physics, Trieste, Italy (September 15-18, 1999

MMIC low-noise amplifiers and applications above 100 GHz

In this paper we will present recent work on low noise amplifiers developed for very high frequencies above 100 GHz. These amplifiers were developed with a unique InP-based HEMT MMIC process. The amplifiers have been developed for both cryogenic and room temperature amplifier applications with state-of-art performance demonstrated from 100 GHz to 215 GHz

ВЫБОР СМЕЩЕНИЯ ПРИ ПОШАГОВОЙ МАРШРУТИЗАЦИИ В БЕСПРОВОДНОЙ СЕТИ

In order to send the frame to the address the authors suggest selecting an adjacent node, taking into account the preferred predetermined weights of those nodes and their current load rates. The adaptive algorithm of alternate path choice is based on logical neural network. Simulation, made by the authors, has shown better values of mean time to execute applications and higher probability of their execution as compared to algorithm of non-alternative choice of neighboring routers. Thus a mean time of execution of application with alternative path choice algorithm DТalt exceeds minimum possible time for the range of change 12 ≤ s ≤ 16 (applications per step) in a changing range 0,3 ≤ DТальт ≤ 1 (steps). The mean time of execution of application with the method of alternative path choice has been reduced as compared to non-alternative path choice by 8% for s = 12, and by 23% – for s = 16.Для передачи кадра по адресу выбор смежного узла предлагается производить с учётом предпочтительных весов этих узлов, определённых заранее, и текущих значений коэффициентов их загрузки. В основе адаптивного  алгоритма альтернативного  смещения лежит логическая нейронная сеть. Моделирование, проведенное авторами, показало лучшие значения среднего времени и вероятности выполнения заявок  в данном варианте по сравнению с алгоритмом безальтернативного выбора искомого узла

The scaling limit of the incipient infinite cluster in high-dimensional percolation. II. Integrated super-Brownian excursion

For independent nearest-neighbour bond percolation on Z^d with d >> 6, we prove that the incipient infinite cluster's two-point function and three-point function converge to those of integrated super-Brownian excursion (ISE) in the scaling limit. The proof is based on an extension of the new expansion for percolation derived in a previous paper, and involves treating the magnetic field as a complex variable. A special case of our result for the two-point function implies that the probability that the cluster of the origin consists of n sites, at the critical point, is given by a multiple of n^{-3/2}, plus an error term of order n^{-3/2-\epsilon} with \epsilon >0. This is a strong statement that the critical exponent delta is given by delta =2.Comment: 56 pages, 3 Postscript figures, in AMS-LaTeX, with graphicx, epic, and xr package