Fuzzy logic applications to expert systems and control

A considerable amount of work on the development of fuzzy logic algorithms and application to space related control problems has been done at the Johnson Space Center (JSC) over the past few years. Particularly, guidance control systems for space vehicles during proximity operations, learning systems utilizing neural networks, control of data processing during rendezvous navigation, collision avoidance algorithms, camera tracking controllers, and tether controllers have been developed utilizing fuzzy logic technology. Several other areas in which fuzzy sets and related concepts are being considered at JSC are diagnostic systems, control of robot arms, pattern recognition, and image processing. It has become evident, based on the commercial applications of fuzzy technology in Japan and China during the last few years, that this technology should be exploited by the government as well as private industry for energy savings

Applications of fuzzy logic to control and decision making

Long range space missions will require high operational efficiency as well as autonomy to enhance the effectivity of performance. Fuzzy logic technology has been shown to be powerful and robust in interpreting imprecise measurements and generating appropriate control decisions for many space operations. Several applications are underway, studying the fuzzy logic approach to solving control and decision making problems. Fuzzy logic algorithms for relative motion and attitude control have been developed and demonstrated for proximity operations. Based on this experience, motion control algorithms that include obstacle avoidance were developed for a Mars Rover prototype for maneuvering during the sample collection process. A concept of an intelligent sensor system that can identify objects and track them continuously and learn from its environment is under development to support traffic management and proximity operations around the Space Station Freedom. For safe and reliable operation of Lunar/Mars based crew quarters, high speed controllers with ability to combine imprecise measurements from several sensors is required. A fuzzy logic approach that uses high speed fuzzy hardware chips is being studied

Study of winds, tides and waves in the middle atmosphere

The present thesis deals with the dynamics of the troposphere and lower stratosphere which form part of the middle atmosphere. Thesis presents the results of the studies of various mechanism like, tidal oscillations and equatorial waves (contributing to

Loading of bosons in optical lattices into the p band

We present a method for transferring bosonic atoms residing on the lowest s-band of an optical lattice to the first excited p-bands. Our idea hinges on resonant tunneling between adjacent sites of accelerated lattices. The acceleration effectively shifts the quasi-bound energies on each site such that the system can be cast into a Wannier-Stark ladder problem. By adjusting the acceleration constant, a situation of resonant tunneling between the s- and p-bands is achievable. Within a mean-field model, considering 87Rb atoms, we demonstrate population transfer from the s- to the p-bands with around 95 % efficiency. Nonlinear effects deriving from atom-atom interactions, as well as coupling of the quasi bound Wannier-Stark states to the continuum, are considered.Comment: 8 pages, 7 figure

Kepribadian Dan Efikasi Diri Dengan Motivasi Belajar Siswa Kelas V Sekolah Dasar

Abstrack: This research is one korelasional's research that aims to find personality relationship and efikasi self with learned motivation. Childrens living situation at evacuation impactedding to them psychological aspect, notably deep aspect motivates to study. Base hypothesis already being formulated, personality and efikasi self assumed in reference to student studying motivation. This research utilize survey's method, 95 student braze v elementary schools at posko evacuation is chosen at random. Instrument as kuesioner is validated through expertise and count quiz Pearson Product Moment and reliabilitas's quiz is done by use of Alpha Cronbach . Hypothesis verification is done with analisis regression via tests f and find mass media model amaan is regression, and correlation coefficient among variable configurational, efikasi self with belajarHasil's motivation research points out that relationship among configurational with learned motivation is .816(α . 001). Partial correlation is .629(α, . 001) among personality by motivates studying if done by pengontrolan to efikasi's variable self. Relationship among efikasi self with learned motivation is .674(α, . 001). kprelasi's coefficient efikasi's partial self with learned motivation if variable configurational being controlled is .111(α, . 05). Found by configurational correlation coefficient and efikasi self with learned motivation is .819(α, . 001)

Space time neural networks for tether operations in space

A space shuttle flight scheduled for 1992 will attempt to prove the feasibility of operating tethered payloads in earth orbit. due to the interaction between the Earth's magnetic field and current pulsing through the tether, the tethered system may exhibit a circular transverse oscillation referred to as the 'skiprope' phenomenon. Effective damping of skiprope motion depends on rapid and accurate detection of skiprope magnitude and phase. Because of non-linear dynamic coupling, the satellite attitude behavior has characteristic oscillations during the skiprope motion. Since the satellite attitude motion has many other perturbations, the relationship between the skiprope parameters and attitude time history is very involved and non-linear. We propose a Space-Time Neural Network implementation for filtering satellite rate gyro data to rapidly detect and predict skiprope magnitude and phase. Training and testing of the skiprope detection system will be performed using a validated Orbital Operations Simulator and Space-Time Neural Network software developed in the Software Technology Branch at NASA's Lyndon B. Johnson Space Center

Learning characteristics of a space-time neural network as a tether skiprope observer

The Software Technology Laboratory at the Johnson Space Center is testing a Space Time Neural Network (STNN) for observing tether oscillations present during retrieval of a tethered satellite. Proper identification of tether oscillations, known as 'skiprope' motion, is vital to safe retrieval of the tethered satellite. Our studies indicate that STNN has certain learning characteristics that must be understood properly to utilize this type of neural network for the tethered satellite problem. We present our findings on the learning characteristics including a learning rate versus momentum performance table

Fuzzy logic control for camera tracking system

A concept utilizing fuzzy theory has been developed for a camera tracking system to provide support for proximity operations and traffic management around the Space Station Freedom. Fuzzy sets and fuzzy logic based reasoning are used in a control system which utilizes images from a camera and generates required pan and tilt commands to track and maintain a moving target in the camera's field of view. This control system can be implemented on a fuzzy chip to provide an intelligent sensor for autonomous operations. Capabilities of the control system can be expanded to include approach, handover to other sensors, caution and warning messages

The Place Of Earth And Space Science And Engineering Design In The Next Generation Science Standards

The Next Generation Science Standards (NGSS) were recently adopted by the state of Connecticut. This paper describes the status of Earth and Space Science (ESS) and Engineering Design (ED) within the NGSS in the state of Connecticut. In this research, Connecticut District Science Coordinators were targeted. They were given questionnaires through Survey Monkey to obtain their views and experiences on the issue of teacher preparedness. Results showed that the ESS and ED did not yet occupy a high position in the state curriculum. There are several challenges to be faced to have ESS and ED status improved in the state. The adoption in itself was seen to be a clear indication that ESS and ED will gradually assume a high recognition in the curriculum of Connecticut schools