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At least 595 records · Page 33

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NASA NTRS1992

Colour thresholding and objective quantification in bioimaging

Computer imaging is rapidly becoming an indispensable tool for the quantification of variables in research and medicine. Whilst its use in medicine has largely been limited to qualitative observations, imaging in applied basic sciences, medical research and biotechnology demands objective quantification of the variables in question. In black and white densitometry (0-256 levels of intensity) the separation of subtle differences between closely related hues from stains is sometimes very difficult. True-colour and real-time video microscopy analysis offer choices not previously available with monochrome systems. In this paper we demonstrate the usefulness of colour thresholding, which has so far proven indispensable for proper objective quantification of the products of histochemical reactions and/or subtle differences in tissue and cells. In addition, we provide interested, but untrained readers with basic information that may assist decisions regarding the most suitable set-up for a project under consideration. Data from projects in progress at Tulane are shown to illustrate the advantage of colour thresholding over monochrome densitometry and for objective quantification of subtle colour differences between experimental and control samples.

NASA Discipline Neuroscience↗

NASA NTRS2005

Humanoid Robotics: Real-Time Object Oriented Programming

Programming of robots in today's world is often done in a procedural oriented fashion, where object oriented programming is not incorporated. In order to keep a robust architecture allowing for easy expansion of capabilities and a truly modular design, object oriented programming is required. However, concepts in object oriented programming are not typically applied to a real time environment. The Fujitsu HOAP-2 is the test bed for the development of a humanoid robot framework abstracting control of the robot into simple logical commands in a real time robotic system while allowing full access to all sensory data. In addition to interfacing between the motor and sensory systems, this paper discusses the software which operates multiple independently developed control systems simultaneously and the safety measures which keep the humanoid from damaging itself and its environment while running these systems. The use of this software decreases development time and costs and allows changes to be made while keeping results safe and predictable.

Newton, Jason E.↗

NASA NTRS2006

NASA's Program to Monitor Orbital Debris in the GEO Belt and the General Problem of Measuring Near-Earth Object Orbits: Similarities and Differences

One of the goals for NASA s Orbital Debris Program Office has been to accurately characterize the population of debris in the geosynchronous Earth orbit (GEO) environment. Most objects larger than about 1 meter in size are regularly tracked and catalogued by the US Space Surveillance System in the GEO regime. The consequence has been that most large intact GEO objects are tracked, but the vast majority of GEO debris fragments are not. Only in recent years have observations been dedicated to characterize the GEO debris population. NASA s efforts have concentrated on using wide field-of-view telescopes to make complete surveys of the GEO regime to better our statistical understanding of the GEO debris population. These telescopes operate in a staring mode, and only make limited short-arc measurements of the orbits. This information, while limited, allows the possibility of debiasing the observations and constructing statistical distributions of orbits in inclination and ascending node. Recent work suggests that we may be able to use statistical methods to estimate better orbit parameters despite the limited data. Both of these types of studies estimating statistical orbit distributions, and estimating accurate orbits using limited short-arc data have direct analogues in ongoing studies of near-Earth objects (NEO) such as asteroids and comets. This talk will describe the GEO study methods in use and being developed at NASA, and will discuss how such methods may or may not be applicable for NEO studies as well.

Matney, Mark↗

NASA NTRS1997

High Performance Object-Oriented Scientific Programming in Fortran 90

We illustrate how Fortran 90 supports object-oriented concepts by example of plasma particle computations on the IBM SP. Our experience shows that Fortran 90 and object-oriented methodology give high performance while providing a bridge from Fortran 77 legacy codes to modern programming principles. All of our object-oriented Fortran 90 codes execute more quickly thatn the equeivalent C++ versions, yet the abstraction modelling capabilities used for scentific programming are comparably powereful.

Scientific Programming↗

NASA NTRS1995

A Systems Engineering Approach to the Analysis of a Planetary Mission Ground System in Terms of Science Objectives

The most fundamental objective of all planetary missions is to return data. To accomplish this, a spacecraft is fabricated and built, software is planned and coded, and a ground system is designed and implemented. However, a systems engineering approach to determine how the collection of data drives ground system capabilities has received little attention.This paper defines a technique by which science objectives can be quantitatively evaluated. For illustrative purposes, it will be applied to NASA's Cassini Mission. This mission, to be launched in 1997, is an international endeavor designed to orbit Saturn for four years.The results of this systems engineering approach will show which science objectives drive specific ground system capabilities. In addition, this technique can assist system engineers in the selection of the science payload during pre-project mission planning; ground system designers during ground system development and implementation; and operations personnel during the mission.

systems engineering, ground systems↗

NASA NTRS2006

Generalized Separation of an Object Jettisoned from the ISS

The International Space Station (ISS) Program faces unprecedented logistics challenges in both upmass and downmass. Some items employed on the ISS exterior present significant technical issues for a controlled de-orbit on either the shuttle or an expendable supply vehicle. Such manifest problems arise due to structural degradation, insufficient containment of hazardous pressures or contents, excessive size, or some combination of all of these factors. In addition, the mounting hardware and other flight service equipment to manifest the returned equipment must itself be launched, competing with other upmass. EVA techniques and equipment to successfully contain and secure such problematic equipment result in numerous significant risks to the spacewalking crews and cost and schedule risks to the program. The ISS Program office has therefore developed a policy that advises the jettison of the most problematic objects. Such jettisoned items join a small family of nearly co-planar orbital debris objects that threaten the ISS on several timescales, besides threatening all satellites with perigee below the ISS orbit and the general human population on Earth. This analysis addresses the governing physics and the ensuing risks when an object is jettisoned. It is shown that there are four time domains which must be considered, each with its own inherent problems, and that a ballistic solution is usually possible that satsfies all constraints in all domains.

Bacon, Jack↗

NASA NTRS2007

Orbit Processing and Analysis of a GEO Class of High Area-to-Mass Debris Objects

A population of recently discovered deep space objects is thought to be debris having origins from sources in the geosynchronous orbit (GEO) belt. Observations have been presented indicating that these objects have area-to-mass ratios (AMR's) of anywhere from 1's to 10's of m(exp 2)/kg, and thus would explain the observed migration of eccentricity (0.1-0.6) and inclination that distinguishes their orbital characteristics. The solar radiation perturbations on orbital period, inclination and eccentricity over a 20 year period for AMR's of 0.01, 1, 10 and 20 m(exp 2)/kg, are shown in the figures. There is a heightened interest in the international community due to the large number and small size of these objects, as they pose a hazard to active satellites operating in the vicinity of the GEO belt.

Kelecy, Tom↗

NASA NTRS2002

Method for distributed object communications based on dynamically acquired and assembled software components

A method for acquiring and assembling software components at execution time into a client program, where the components may be acquired from remote networked servers is disclosed. The acquired components are assembled according to knowledge represented within one or more acquired mediating components. A mediating component implements knowledge of an object model. A mediating component uses its implemented object model knowledge, acquired component class information and polymorphism to assemble components into an interacting program at execution time. The interactions or abstract relationships between components in the object model may be implemented by the mediating component as direct invocations or indirect events or software bus exchanges. The acquired components may establish communications with remote servers. The acquired components may also present a user interface representing data to be exchanged with the remote servers. The mediating components may be assembled into layers, allowing arbitrarily complex programs to be constructed at execution time.

Sundermier, Amy↗

NASA NTRS1997

Method and apparatus for evaluating multilayer objects for imperfections

A multilayer object having multiple layers arranged in a stacking direction is evaluated for imperfections such as voids, delaminations and microcracks. First, an acoustic wave is transmitted into the object in the stacking direction via an appropriate transducer/waveguide combination. The wave propagates through the multilayer object and is received by another transducer/waveguide combination preferably located on the same surface as the transmitting combination. The received acoustic wave is correlated with the presence or absence of imperfections by, e.g., generating pulse echo signals indicative of the received acoustic wave, wherein the successive signals form distinct groups over time. The respective peak amplitudes of each group are sampled and curve fit to an exponential curve, wherein a substantial fit of approximately 80-90% indicates an absence of imperfections and a significant deviation indicates the presence of imperfections. Alternatively, the time interval between distinct groups can be measured, wherein equal intervals indicate the absence of imperfections and unequal intervals indicate the presence of imperfections.

Heyman, Joseph S.↗

NASA NTRS2001

Optical device for measuring a surface characteristic of an object by multi-color interferometry

An interferometer having a light beam source that produces a plurality of separate and distinct wavelengths of light. Optic fibers are used to transport the wavelengths of light toward an object surface and to allow light reflected from the object to pass through a polarizer to improve the polarization ratio of the reflected light to determine a characteristic of the object surface.

Meyer, William V.↗

NASA NTRS2008

Desert Research and Technology Studies (RATS) 2007 Field Campaign Objectives and Results

Desert "RATS" (Research and Technology Studies) is a combined, multi-discipline group of inter-NASA center scientists and engineers, net-working and collaborating with representatives of industry and academia, for the purpose of conducting planetary surface exploration-focused remote field exercises. These integrated testing exercises conducted under representative analog Lunar and Mars surface terrain conditions, provide NASA the capability to validate experimental prototype hardware and software systems as well as to evaluate and develop mission operational techniques in order to identify and establish technical requirements and identify potential technology "gaps" applicable for future planetary human exploration. The 2007 D-RATS field campaign test activities were initiated based on the major themes and objectives of a notional 5-year plan developed for conducting relative analog test activities in support of the engineering evaluation and assessment of various system architectural requirements, conceptual prototype support equipment and selected technologies necessary for the establishment of a lunar outpost. Specifically, the major objectives included measuring task efficiency during robot, human, and human-robot interactive tasks associated with lunar outpost site surveying and reconnaissance activities and deployment of a representative solar panel power and distribution system. In addition, technology demonstrations were conducted with a new Lithium-ion battery and autonomous software to coordinate multiple robot activities. Secondary objectives were evaluating airlock concept mockups and prototype removable space suit over-garment elements for dust mitigation, and upgrades to the prototype extravehicular activities (EVA) communication and information system. Dry run test activities, prior to testing at a designated remote field site location, were initially conducted at the Johnson Space Center (JSC) Remote Field Demonstration Test Site. This is a multi-acre external test site located at JSC and has detailed representative terrain features simulating both Lunar and Mars surface characteristics. Both the local JSC and remote field test sites have terrain conditions that are representative and characteristic of both the Moon and Mars, such as strewn rock and volcanic ash fields, craters, rolling plains, hills, gullies, slopes, and outcrops. The D-RATS 2007 field campaign, representing the completion of its tenth year of analog testing, was conducted at the large Cinder Lake volcanic ash bed area adjacent to Flagstaff, Arizona.

Kosmo, Joseph↗

NASA NTRS2008

Design of a Model Execution Framework: Repetitive Object-Oriented Simulation Environment (ROSE)

The ROSE framework was designed to facilitate complex system analyses. It completely divorces the model execution process from the model itself. By doing so ROSE frees the modeler to develop a library of standard modeling processes such as Design of Experiments, optimizers, parameter studies, and sensitivity studies which can then be applied to any of their available models. The ROSE framework accomplishes this by means of a well defined API and object structure. Both the API and object structure are presented here with enough detail to implement ROSE in any object-oriented language or modeling tool.

Gray, Justin S.↗

NASA NTRS2008

Observing Solar System Objects with the James Webb Space Telescope

The James Webb Space Telescope (JWST) will have the capability to observe Solar System objects having apparent rates of motion up to 30 milliarcseconds/sec. The key science drivers are the study of Kuiper Belt Objects, asteroids, comets, and the outer planets and their moons at near and mid-infrared wavelengths. This poster presents the results from a recent study that defined the conceptual design for a capability for JWST to track and observe moving targets. We illustrate about how guide star acquisition and tracking wi11 be handled while retaining the efficient and flexible execution characteristics of JWST event-driven operations. We also show how the JWST pointing control system can readily support moving target observations. The characteristics of Solar System objects that can be observed by JWST are summarized along with descriptions of the major aspects of moving target science observation planning and on-board event-driven execution.

Sonneborn, George↗

NASA NTRS2009

Port-O-Sim Object Simulation Application

Port-O-Sim is a software application that supports engineering modeling and simulation of launch-range systems and subsystems, as well as the vehicles that operate on them. It is flexible, distributed, object-oriented, and realtime. A scripting language is used to configure an array of simulation objects and link them together. The script is contained in a text file, but executed and controlled using a graphical user interface. A set of modules is defined, each with input variables, output variables, and settings. These engineering models can be either linked to each other or run as standalone. The settings can be modified during execution. Since 2001, this application has been used for pre-mission failure mode training for many Range Safety Scenarios. It contains range asset link analysis, develops look-angle data, supports sky-screen site selection, drives GPS (Global Positioning System) and IMU (Inertial Measurement Unit) simulators, and can support conceptual design efforts for multiple flight programs with its capacity for rapid six-degrees-of-freedom model development. Due to the assembly of various object types into one application, the application is applicable across a wide variety of launch range problem domains.

Lanzi, Raymond J.↗

NASA NTRS2009

Objective Lens Optimized for Wavefront Delivery, Pupil Imaging, and Pupil Ghosting

An interferometer objective lens (or diverger) may be used to transform a collimated beam into a diverging or converging beam. This innovation provides an objective lens that has diffraction-limited optical performance that is optimized at two sets of conjugates: imaging to the objective focus and imaging to the pupil. The lens thus provides for simultaneous delivery of a high-quality beam and excellent pupil resolution properties.

Olzcak, Gene↗

NASA NTRS2009

Suzaku Observation of Strong Fluorescent Iron Line Emission from the Young Stellar Object V1647 Ori during Its New X-ray Outburst

The Suzaku X-ray satellite observed the young stellar object V1647 Ori on 2008 October 8 during the new mass accretion outburst reported in August 2008. During the 87 ksec observation with a net exposure of 40 ks, V1647 Ori showed a. high level of X-ray emission with a gradual decrease in flux by a factor of 5 and then displayed an abrupt flux increase by an order of magnitude. Such enhanced X-ray variability was also seen in XMM-Newton observations in 2004 and 2005 during the 2003-2005 outburst, but has rarely been observed for other young stellar objects. The spectrum clearly displays emission from Helium-like iron, which is a signature of hot plasma (kT approx.5 keV). It also shows a fluorescent iron Ka line with a remarkably large equivalent width of approx. 600 eV. Such a, large equivalent width indicates that a part of the incident X-ray emission that irradiates the circumstellar material and/or the stellar surface is hidden from our line of sight. XMM-Newton spectra during the 2003-2005 outburst did not show a strong fluorescent iron Ka line ; so that the structure of the circumstellar gas very close to the stellar core that absorbs and re-emits X-ray emission from the central object may have changed in between 2005 and 2008. This phenomenon may be related to changes in the infrared morphology of McNeil's nebula between 2004 and 2008.

Hamaguchi, Kenji↗

NASA NTRS2009

An Object-Oriented Computer Code for Aircraft Engine Weight Estimation

Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. At NASA Glenn Research Center (GRC), the Weight Analysis of Turbine Engines (WATE) computer code, originally developed by Boeing Aircraft, has been used to estimate the engine weight of various conceptual engine designs. The code, written in FORTRAN, was originally developed for NASA in 1979. Since then, substantial improvements have been made to the code to improve the weight calculations for most of the engine components. Most recently, to improve the maintainability and extensibility of WATE, the FORTRAN code has been converted into an object-oriented version. The conversion was done within the NASA's NPSS (Numerical Propulsion System Simulation) framework. This enables WATE to interact seamlessly with the thermodynamic cycle model which provides component flow data such as airflows, temperatures, and pressures, etc., that are required for sizing the components and weight calculations. The tighter integration between the NPSS and WATE would greatly enhance system-level analysis and optimization capabilities. It also would facilitate the enhancement of the WATE code for next-generation aircraft and space propulsion systems. In this paper, the architecture of the object-oriented WATE code (or WATE++) is described. Both the FORTRAN and object-oriented versions of the code are employed to compute the dimensions and weight of a 300-passenger aircraft engine (GE90 class). Both versions of the code produce essentially identical results as should be the case.

Tong, Michael T.↗

NASA NTRS2007

Fusing Image Data for Calculating Position of an Object

A computer program has been written for use in maintaining the calibration, with respect to the positions of imaged objects, of a stereoscopic pair of cameras on each of the Mars Explorer Rovers Spirit and Opportunity. The program identifies and locates a known object in the images. The object in question is part of a Moessbauer spectrometer located at the tip of a robot arm, the kinematics of which are known. In the program, the images are processed through a module that extracts edges, combines the edges into line segments, and then derives ellipse centroids from the line segments. The images are also processed by a feature-extraction algorithm that performs a wavelet analysis, then performs a pattern-recognition operation in the wavelet-coefficient space to determine matches to a texture feature measure derived from the horizontal, vertical, and diagonal coefficients. The centroids from the ellipse finder and the wavelet feature matcher are then fused to determine co-location. In the event that a match is found, the centroid (or centroids if multiple matches are present) is reported. If no match is found, the process reports the results of the analyses for further examination by human experts.

Huntsberger, Terrance↗