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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5

Automatic Digitization and Orientation of Scanned Mesh Data for Floor Plan and 3D Model Generation

This paper describes a novel approach for generating accurate floor plans and 3D models of building interiors using scanned mesh data. Unlike previous methods, which begin with a high resolution point cloud from a laser range-finder, our approach begins with triangle mesh data, as from a Microsoft HoloLens. It generates two types of floor plans, a “pen-and-ink” style that preserves details and a drafting-style that reduces clutter. It processes the 3D model for use in applications by aligning it with coordinate axes, annotating important objects, dividing it into stories, and removing the ceiling. Its performance is evaluated on commercial and residential buildings, with experiments to assess quality and dimensional accuracy. Our approach demonstrates promising potential for automatic digitization and orientation of scanned mesh data, enabling floor plan and 3D model generation in various applications such as navigation, interior design, furniture placement, facilities management, building construction, and HVAC design.

Sharma, Ritesh↗

EOS: A project to investigate the design and construction of real-time distributed embedded operating systems

The EOS project is investigating the design and construction of a family of real-time distributed embedded operating systems for reliable, distributed aerospace applications. Using the real-time programming techniques developed in co-operation with NASA in earlier research, the project staff is building a kernel for a multiple processor networked system. The first six months of the grant included a study of scheduling in an object-oriented system, the design philosophy of the kernel, and the architectural overview of the operating system. In this report, the operating system and kernel concepts are described. An environment for the experiments has been built and several of the key concepts of the system have been prototyped. The kernel and operating system is intended to support future experimental studies in multiprocessing, load-balancing, routing, software fault-tolerance, distributed data base design, and real-time processing.

Campbell, R. H.↗

X-Windows Socket Widget Class

The X-Windows Socket Widget Class ("Class" is used here in the object-oriented-programming sense of the word) was devised to simplify the task of implementing network connections for graphical-user-interface (GUI) computer programs. UNIX Transmission Control Protocol/Internet Protocol (TCP/IP) socket programming libraries require many method calls to configure, operate, and destroy sockets. Most X Windows GUI programs use widget sets or toolkits to facilitate management of complex objects. The widget standards facilitate construction of toolkits and application programs. The X-Windows Socket Widget Class encapsulates UNIX TCP/IP socket-management tasks within the framework of an X Windows widget. Using the widget framework, X Windows GUI programs can treat one or more network socket instances in the same manner as that of other graphical widgets, making it easier to program sockets. Wrapping ISP socket programming libraries inside a widget framework enables a programmer to treat a network interface as though it were a GUI.

Barry, Matthew R.↗

Parameterization of Features on Spherical Surfaces

NASA’s Planetary Systems Laboratory (PSL) at the Goddard Spaceflight Center in Greenbelt, Maryland is tasked with the study of solar system objects. This work is frequently based on analysis of imagery from visiting spacecraft, orbiting telescopes, and ground-based sensors. A consequence of this mission is the need to characterize features on the spherical surface of planets and moons, such characterization including the overall area of the feature, its center, its moments of inertia, its perimeter, its compactness, its major axis, its bounding box, its aspect ratio and its North-South orientation. Accurate assessment of these measures from a “flat” two-dimensional image is a challenge, since the scale of distance observed at the center of a spherical object distorts in any direction towards the horizon. PSL has developed a technique to guarantee accurate and automated measurement at any point on the visible surface, by overlaying an imaginary grid of equal-area cells onto the two-dimensional image of the sphere. The technique is named Grid-Oriented Normalization for Analysis of Spherical Areas (GONASA). This paper discusses the construction of the normalization grid and describes specific algorithms for feature parameterization. The algorithms are implemented in an accompanying Excel spreadsheet, both for clarity and ease of adoption, and to emphasize their aptness for automation. Finally, a concrete use case is offered where the GONASA grid and algorithms are used to characterize methane clouds on the Saturnian moon Titan.

Planetary science↗

TraceContract: A Scala DSL for Trace Analysis

In this paper we describe TRACECONTRACT, an API for trace analysis, implemented in the SCALA programming language. We argue that for certain forms of trace analysis the best weapon is a high level programming language augmented with constructs for temporal reasoning. A trace is a sequence of events, which may for example be generated by a running program, instrumented appropriately to generate events. The API supports writing properties in a notation that combines an advanced form of data parameterized state machines with temporal logic. The implementation utilizes SCALA's support for defining internal Domain Specific Languages (DSLs). Furthermore SCALA's combination of object oriented and functional programming features, including partial functions and pattern matching, makes it an ideal host language for such an API.

log file analysis↗

X-Windows Information Sharing Protocol Widget Class

The X-Windows Information Sharing Protocol (ISP) Widget Class ("Class") is used here in the object-oriented-programming sense of the word) was devised to simplify the task of implementing ISP graphical-user-interface (GUI) computer programs. ISP programming tasks require many method calls to identify, query, and interpret the connections and messages exchanged between a client and an ISP server. Most X-Windows GUI programs use widget sets or toolkits to facilitate management of complex objects. The widget standards facilitate construction of toolkits and application programs. The X-Windows Information Sharing Protocol (ISP) Widget Class encapsulates the client side of the ISP programming libraries within the framework of an X-Windows widget. Using the widget framework, X-Windows GUI programs can interact with ISP services in an abstract way and in the same manner as that of other graphical widgets, making it easier to write ISP GUI client programs. Wrapping ISP client services inside a widget framework enables a programmer to treat an ISP server interface as though it were a GUI. Moreover, an alternate subclass could implement another communication protocol in the same sort of widget.

Barry, Matthew R.↗

Real-Time Payload Control and Monitoring on the World Wide Web

World Wide Web (W3) technologies such as the Hypertext Transfer Protocol (HTTP) and the Java object-oriented programming environment offer a powerful, yet relatively inexpensive, framework for distributed application software development. This paper describes the design of a real-time payload control and monitoring system that was developed with W3 technologies at NASA Ames Research Center. Based on Java Development Toolkit (JDK) 1.1, the system uses an event-driven "publish and subscribe" approach to inter-process communication and graphical user-interface construction. A C Language Integrated Production System (CLIPS) compatible inference engine provides the back-end intelligent data processing capability, while Oracle Relational Database Management System (RDBMS) provides the data management function. Preliminary evaluation shows acceptable performance for some classes of payloads, with Java's portability and multimedia support identified as the most significant benefit.

Sun, Charles↗

A Super-Resolution Algorithm for Enhancement of FLASH LIDAR Data: Flight Test Results

This paper describes the results of a 3D super-resolution algorithm applied to the range data obtained from a recent Flash Lidar helicopter flight test. The flight test was conducted by the NASA's Autonomous Landing and Hazard Avoidance Technology (ALHAT) project over a simulated lunar terrain facility at NASA Kennedy Space Center. ALHAT is developing the technology for safe autonomous landing on the surface of celestial bodies: Moon, Mars, asteroids. One of the test objectives was to verify the ability of 3D super-resolution technique to generate high resolution digital elevation models (DEMs) and to determine time resolved relative positions and orientations of the vehicle. 3D super-resolution algorithm was developed earlier and tested in computational modeling, and laboratory experiments, and in a few dynamic experiments using a moving truck. Prior to the helicopter flight test campaign, a 100mX100m hazard field was constructed having most of the relevant extraterrestrial hazard: slopes, rocks, and craters with different sizes. Data were collected during the flight and then processed by the super-resolution code. The detailed DEM of the hazard field was constructed using independent measurement to be used for comparison. ALHAT navigation system data were used to verify abilities of super-resolution method to provide accurate relative navigation information. Namely, the 6 degree of freedom state vector of the instrument as a function of time was restored from super-resolution data. The results of comparisons show that the super-resolution method can construct high quality DEMs and allows for identifying hazards like rocks and craters within the accordance of ALHAT requirements.

Bulyshev, Alexander↗

The oblique-wing research aircraft: A test bed for unsteady aerodynamic and aeroelastic research

The advantages of oblique wings have been the subject of numerous theoretical studies, wind tunnel tests, low speed flight models, and finally a low speed manned demonstrator, the AD-1. The specific objectives of the OWRA program are: (1) to establish the necessary technology base required to translate theoretical and experimental results into practical mission oriented designs; (2) to design, fabricate and flight test an oblique wing aircraft throughout a realistic flight envelope, and (3) to develop and validate design and analysis tools for asymmetric aircraft configurations. The preliminary design phase of the project is complete and has resulted in a wing configuration for which construction is ready to be initiated.

Gilyard, Glenn B.↗

Multimission high speed spacecraft simulation for the Galileo and Cassini missions

A simulation system has been developed which is capable of bit level simulation of spacecraft data systems. Object oriented techniques and an embedded interpreted language have been employed to produce a highly configurable tool for control and viewing of spacecraft states. Parallel processing computers have been used for running simulations to achieve execution performance of up to ten times real time, which allows for effective utilization of the simulator in testing spacecraft command sequences before they are committed to operation. Elements of simulations can be reused as-is in the construction of new simulators.

Morrissett, Alan↗

Rocket instrument for far-UV spectrophotometry of faint astronomical objects

A sensitive sounding rocket instrument for moderate (about 10-A) resolution far-UV (1160-1750-A) spectrophotometry of faint astronomical objects has been developed. The instrument employes a photon-counting microchannel plate imaging detector and a concave grating spectrograph behind a 40-cm Dall-Kirkham telescope. A unique remote-control pointing system, incorporating an SIT vidicon aspect camera, two star trackers, and a tone-encoded command telemetry link, permits the telescope to be oriented to within 5 arc sec of any target for which suitable guide stars can be found. The design, construction, calibration, and flight performance of the instrument are discussed.

Hartig, G. F.↗

Three-dimensional perspective software for representation of digital imagery data

A generalized three dimensional perspective software capability was developed within the framework of a low cost computer oriented geographically based information system using the Earth Resources Laboratory Applications Software (ELAS) operating subsystem. This perspective software capability, developed primarily to support data display requirements at the NASA/NSTL Earth Resources Laboratory, provides a means of displaying three dimensional feature space object data in two dimensional picture plane coordinates and makes it possible to overlay different types of information on perspective drawings to better understand the relationship of physical features. An example topographic data base is constructed and is used as the basic input to the plotting module. Examples are shown which illustrate oblique viewing angles that convey spatial concepts and relationships represented by the topographic data planes.

Junkin, B. G.↗

An automated quality assessor for Ada object-oriented designs

A tool for evaluating object-oriented designs (OODs) for Ada software is described. The tool assumes a design expressed as a hierarchy of object diagrams. A design of this type identifies the objects of a system, an interface to each object, and the usage relationships between objects. When such a design is implemented in Ada, objects become packages, interfaces become package specifications, and usage relationships become Ada `with' clauses and package references. An automated quality assessor has been developed that is based on flagging undesirable design constructs. For convenience, distinctions are made among three levels of severity: questionable, undesirable, and hazardous. A questionable construct is one that may well be appropriate. An undesirable construct is one that should be changed because it is potentially harmful to the reliability, maintainability, or reusability of the software. A hazardous construct is one that is undesirable and that introduces a high level of risk.

Bailin, Sidney C.↗

Technology Utilization House Study Report

The objectives of Project TECH are: (1) to construct a single family detached dwelling for demonstrating the application of advanced technology and minimizing the requirement for energy and utility services, and (2) to help influence future development in home construction by defining the interaction of integrated energy and water management systems with building configuration and construction materials. Components and methods expected to be cost effective over a 20 year span were studied. Emphasis was placed on the utilization of natural heating and cooling characteristics. Orientation and location of windows, landscaping, natural ventilation, and characteristics of the local climate and microclimate were intended to be used to best advantage. Energy conserving homes are most efficient when design for specific sites, therefore project TECH should not be considered a prototype design suitable for all locations. However, it does provide ideas and analytical methods which can be applied to some degree in all housing.

Source record↗

Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation: Second Year Progress Report

Mesh generation has long been recognized as a bottleneck in the CFD process. While much research on automating the volume mesh generation process have been relatively successful,these methods rely on appropriate initial surface triangulation to work properly. Surface discretization has been one of the least automated steps in computational simulation due to its dependence on implicitly defined CAD surfaces and curves. Differences in CAD peometry engines manifest themselves in discrepancies in their interpretation of the same entities. This lack of "good" geometry causes significant problems for mesh generators, requiring users to "repair" the CAD geometry before mesh generation. The problem is exacerbated when CAD geometry is translated to other forms (e.g., IGES )which do not include important topological and construction information in addition to entity geometry. One technique to avoid these problems is to access the CAD geometry directly from the mesh generating software, rather than through files. By accessing the geometry model (not a discretized version) in its native environment, t h s a proach avoids translation to a format which can deplete the model of topological information. Our approach to enable models developed in the Denali software environment to directly access CAD geometry and functions is through an Application Programming Interface (API) known as CAPRI. CAPRI provides a layer of indirection through which CAD-specific data may be accessed by an application program using CAD-system neutral C and FORTRAN language function calls. CAPRI supports a general set of CAD operations such as truth testing, geometry construction and entity queries.

Afjeh, Abdollah A.↗

Crack Offset Measurement With the Projected Laser Target Device

The device and associated analysis methodology summarized in this report were developed for the purpose of estimating the size of discontinuities in the surface of the foam that covers the Space Shuttle External Tank. These surface offsets are thought to be due to subsurface cracks in the foam insulation. The mathematical analysis and procedure described here provide a method to quantity the dimensions of the crack offset in a direction perpendicular to the surface, making use of the projected laser target device (PLTD) tool and a laser line projector. The keys to the construction and use of the PLTD are the following geometrical design requirements: Laser dots are on a square grid: length on a side. Laser beams are perpendicular to projected surface. Beams are parallel out to the distance being projected. The PLTD can be used to (1) calibrate fixed cameras of unknown magnification and orientation (far-field solution); (2) provide equivalent calibration to multiple cameras, previously achieved only by the use of known target points, for example, in 3.D foreign-object debris tracking on a fixed launch platform; (3) compute scaling for conventional 2.D images, and depth of field for 3.D images (near-field solution); and (4) in conjunction with a laser line projector, achieve accurate measurements of surface discontinuity (cracks) in a direction perpendicular to the surface.

Source record↗

A Mobile Robot for Locomotion Through a 3D Periodic Lattice Environment

This paper describes a novel class of robots specifically adapted to climb periodic lattices, which we call 'Relative Robots'. These robots use the regularity of the structure to simplify the path planning, align with minimal feedback, and reduce the number of degrees of freedom (DOF) required to locomote. They can perform vital inspection and repair tasks within the structure that larger truss construction robots could not perform without modifying the structure. We detail a specific type of relative robot designed to traverse a cuboctahedral (CubOct) cellular solids lattice, show how the symmetries of the lattice simplify the design, and test these design methodologies with a CubOct relative robot that traverses a 76.2 mm (3 in.) pitch lattice, MOJO (Multi-Objective JOurneying robot). We perform three locomotion tasks with MOJO: vertical climbing, horizontal climbing, and turning, and find that, due to changes in the orientation of the robot relative to the gravity vector, the success rate of vertical and horizontal climbing is significantly different.

Aeronautics↗

Formulation and calibration of two-dimensional constitutive models for composite structures based on panel tests

Steel Plate Concrete (SC) composite members have been widely adopted because of its cost-efficiency and enhanced structural behavior. While researchers have attempted to study its in-plane shear behavior in the past twenty years, very limited number of large-scale pure shear tests were performed due to the challenge of experimental set-up and the availability of facilities. In this paper, a series of uniaxial loading tests and two full-scale pure shear panel tests of SC members were reported, on which the “mechanics-based Membrane Model of SC elements (MM-SC)” is developed. The MM-SC model is based on the fixed-angle crack formulation and the smeared-crack formulation, in which the experimental-based uniaxial constitutive models are implemented, considering the local buckling of faceplate, the tension stiffening of steel plate, the strength degradation of cracked concrete and the confinement effect of concrete. The proposed MM-SC model is subsequently incorporated into the object-oriented software OpenSEES. Finally, the simulation results of proposed model well predict the SC test observations in terms of critical branch points and structural behaviors, including initial stiffness, cracking strength, post-crack stiffness, yield strength, maximum strength, and failure modes.

42 ENGINEERING↗