An Analysis of Applications Development Systems for Remotely Sensed, Multispectral Data for the Earth Observations Division of the NASA Lyndon B. Johnson Space Center

An application development system (ADS) is examined for remotely sensed, multispectral data at the Earth Observations Division (EOD) at Johnson Space Center. Design goals are detailed, along with design objectives that an ideal system should contain. The design objectives were arranged according to the priorities of EOD's program objectives. Four systems available to EOD were then measured against the ideal ADS as defined by the design objectives and their associated priorities. This was accomplished by rating each of the systems on each of the design objectives. Utilizing the established priorities, it was determined how each system stood up as an ADS. Recommendations were made as to possible courses of action for EOD to pursue to obtain a more efficient ADS

The automated multi-stage substructuring system for NASTRAN

The substructuring capability developed for eventual installation in Level 16 is now operational in a test version of NASTRAN. Its features are summarized. These include the user-oriented, Case Control type control language, the automated multi-stage matrix processing, the independent direct access data storage facilities, and the static and normal modes solution capabilities. A complete problem analysis sequence is presented with card-by-card description of the user input

Instant restore after a media failure

Media failures usually leave database systems unavailable for several hours until recovery is complete, especially in applications with large devices and high transaction volume. Previous work introduced a technique called single-pass restore, which increases restore bandwidth and thus substantially decreases time to repair. Instant restore goes further as it permits read/write access to any data on a device undergoing restore--even data not yet restored--by restoring individual data segments on demand. Thus, the restore process is guided primarily by the needs of applications, and the observed mean time to repair is effectively reduced from several hours to a few seconds. This paper presents an implementation and evaluation of instant restore. The technique is incrementally implemented on a system starting with the traditional ARIES design for logging and recovery. Experiments show that the transaction latency perceived after a media failure can be cut down to less than a second and that the overhead imposed by the technique on normal processing is minimal. The net effect is that a few "nines" of availability are added to the system using simple and low-overhead software techniques

Generalized Advanced Propeller Analysis System (GAPAS). Volume 2: Computer program user manual

The Generalized Advanced Propeller Analysis System (GAPAS) computer code is described. GAPAS was developed to analyze advanced technology multi-bladed propellers which operate on aircraft with speeds up to Mach 0.8 and altitudes up to 40,000 feet. GAPAS includes technology for analyzing aerodynamic, structural, and acoustic performance of propellers. The computer code was developed for the CDC 7600 computer and is currently available for industrial use on the NASA Langley computer. A description of all the analytical models incorporated in GAPAS is included. Sample calculations are also described as well as users requirements for modifying the analysis system. Computer system core requirements and running times are also discussed

Specification for a Program for an Interative Aeroelastic Solution (PIAS)

An engineering and software specification which was written for a computer program to calculate aeroelastic structural loads including the effects of nonlinear aerodynamics is presented. The procedure used in the program for an iterative aeroelastic solution (PIAS) is to alternately execute two computer codes: one to calculate aerodynamic loads for a specific wing shape, and another to calculate the deflected shape caused by this loading. A significant advantage to the design of PIAS is that the initial aerodynamic module can be replaced with others. The leading edge vortex (LEV) program is used as the aerodynamic module in PIAS. This provides the capability to calculate aeroelastic loads, including the effects of a separation induced leading edge vortex. The finite element method available in ATLAS Integrated structural analysis and design system is used to determine the deflected wing shape for the applied aerodynamics and inertia loads. The data management capabilities in ATLAS are used by the execution control monitor (ECM) of PIAS to control the solution process

BUILDING A SECURE NETWORK TEST ENVIRONMENT USING VIRTUAL MACHINES

The objective of this project is to provide an overview of how to create a secure network test environment using virtual machines with Red Hat CentOS 7. Using virtual machines to create a secure network test environment simplify the workflow of testing several servers including network segmentation, network path redundancy, and traffic control using a firewall. This study suggests a set of guidelines for building a secure network test environment that includes a Domain Name Server (DNS), Web Server, File Transfer Protocol (FTP) Server, and a firewall. The documentation provided in this project is primarily useful for IT students looking to recreate a similar environment of their own and to practice special skills needed within their field of study

Remote File Access: A Data-Access Protocol for Computer Networks

This paper deals with defining and implementing high-level protocols for computer networks, a subject now being studied by private, national, and international organizations. While line-level protocols already exist in standard formats, and these organizations are defining end-to-end protocols, higher level protocols are still a matter for study. Since some services have to be provided by a computer network, such services must use standardized protocols if portability, compatibility, and internetworking are to be achieved. This paper considers a possible network service and its related protocol

Size, Structure, and Strategies: Insolvency and "The Nature of the Firm" in Italy, 1920S-1970S

During the Twentieth century, Italian joint-stock companies remained relatively small and tended to die young. This fact constrained the development of the full potential of the Italian industry, as small-dimensioned companies struggled to implement the most efficient technologies and managerial techniques. This paper analyses this problem by looking at the functioning of insolvency procedures. Using quantitative and qualitative evidence, we show how various devices that progressively appeared on the scene failed in providing efficient solutions to re-start worthy companies. Insolvency procedures thus remained liquidation-prone, a factor that contributes to explain the peculiarity and the limits of Italian industrial capitalism.