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A data collection process is described for the purpose of discerning causation factors of accidents, and the establishment of boundaries or controls aimed at mitigating and eliminating accidents. A procedure is proposed that suggests a discipline approach to hazard identification based on energy interrelationships together with an integrated control technique which takes the form of checklists.
A catalog of crater dimensions that were compiled mostly from the Apollo-based Lunar Topographic Orthophotomaps is presented in its entirety. Values of crater diameter, depth, rim height, flank width, circularity, and floor diameter (where applicable) are tabulated for a sample of 484 craters on the moon and 22 craters on earth. Systematic techniques of mensuration are detailed. The lunar craters range in size from 400 m to 300 km across and include primary impact craters of the main sequence, secondary impact craters, craterlets atop domes and cones, and dark-halo craters. The terrestrial craters are between 10 m and 22.5 km in diameter and were formed by meteorite impact.
We describe Bayesian methods for analyzing the distribution of gamma-ray burst peak photon fluxes and directions. These methods fit the differential distribution, and have the following advantages over rival methods: (1) they do not destroy information by binning or averaging the data (as do, say, chi squared, the averaged value of V/V(sub max), and angular moment analyses); (2) they straightforwardly handle uncertainties in the measured quantities; (3) they analyze the strength and direction information jointly; (4) they use information available about nondetections; and (5) they automatically identify and account for biases and selection effects given a precise description of the experiment. In these methods, the most important information needed about the instrument threshold is not its value at the times of burst triggers, as is used in the average value of V/V(sub max) analyses, but rather the value of the threshold at times when no trigger occurred. We show that this information can be summarized as an average detection efficiency that is similar to the product of the exposure and efficiency reported in the First Burst and Transient Source Experiment (BATSE) Burst (1B) Catalog, but significantly different from it at low fluxes. We also quantify an important bias that results from estimating the peak flux by scanning the burst to find the peak number of counts in a window of specified duration, as was done for the 1B Catalog. When the duration of the peak of the light curve is longer than the window duration, a simple flux estimate based on the peak counts significantly overestimates the peak flux in a nonlinear fashion that distorts the shape of the log(N)-log(P) distribution. This distortion also corrupts analyses of the V/V(sub max) distribution that use ratios of counts above background to estimate V/V(sub max). The Bayesian calculation specifies how to account for this bias. Implementation of the Bayesian approach requires some changes in the way burst data are reported that we describe in detail. Subsequent papers will report analyses of the 1B Catalog data using the methods described here.
This document catalogs Space Shuttle hand-held Earth observations photography which was collected on the Space Transportation System (STS) 41-G mission of October 1984. The catalog includes the following data for each of 2480 frames: geographical name, feature description, latitude and longitude, percentage of cloud cover, look direction and tilt, lens focal length, exposure evaluation, stereopairs, and orbit number. The catalog is a product of the Space Shuttle Earth Observations Project, Solar System Exploration Division, Space and Life Sciences Directorate, of the National Aeronautics and Space Administration, Lyndon B. Johnson Space Center.
The autonomous optical navigation system technology for the Deep Space 1 (DS1) mission is reported on. The DS1 navigation system will be the first to use autonomous navigation in deep space. The systems tasks are to: perform interplanetary cruise orbit determination using images of distant asteroids; control and maintain the orbit of the spacecraft with an ion propulsion system and conventional thrusters, and perform late knowledge updates of target position during close flybys in order to facilitate high quality data return from asteroid MaAuliffe and comet West-Kohoutek-Ikemura. To accomplish these tasks, the following functions are required: picture planning; image processing; dynamical modeling and integration; planetary ephemeris and star catalog handling; orbit determination; data filtering and estimation; maneuver estimation, and spacecraft ephemeris updating. These systems and functions are described and preliminary performance data are presented.
This catalog contains a summary of many individual papers published in the Lowell Observatory Bulletins in the years 1958 to 1970. The data in the machine-readable version include observed positions, proper motions, estimated photographic magnitudes and colors, and references to identifications in other catalogs. Photoelectric data on the UBV system are included for many stars, but no attempt was made to find all existing photometry. The machine version contains all data of the published catalog, except the Lowell Bulletin numbers where finding charts can be found. A separate file contains the notes published in the original catalog.
The machine readable version of the compilation, as it is currently being distributed from the Astronomical Data Center, is described. The catalog contains redshifts and velocity dispersions for all Abell clusters for which these data had been published up to 1986 July. Also included are 1950 equatorial coordinates for the centers of the listed clusters, numbers of observations used to determine the redshifts, and bibliographical references citing the data sources.
In the 1990's space plasma physics studies will increasingly involve correlative analysis of observations from multiple instruments and multiple spacecraft. The solar terrestrial physics missions in the 1990's will be designed around simultaneous observations from spacecraft monitoring the solar wind, the polar magnetosphere and the near and distant magnetotail. Within these regions, clusters of spacecraft flying in formation will increasingly involve comparative magnetospheric studies. No single lab will have the expertise to process and analyze all of the different types of data so the data repositories will be distributed. Catalog and browse systems will be required to help select events for study. Data compression techniques may be useful in designing the data bases used for selecting events for study. Data compression onboard the spacecraft will be necessary, since instrument data rates will be much larger than available telemetry rates. However, considerable care will be necessary to avoid losing valuable data when applying data compression algorithms.
A computer program denoted OODT CAS has been transformed to enable performance of larger tasks that involve greatly increased data volumes and increasingly intensive processing of data on heterogeneous, geographically dispersed computers. Prior to the transformation, OODT CAS (also alternatively denoted, simply, 'CAS') [wherein 'OODT' signifies 'Object-Oriented Data Technology' and 'CAS' signifies 'Catalog and Archive Service'] was a proven software component used to manage scientific data from spaceflight missions. In the transformation, CAS was split into two separate components representing its canonical capabilities: file management and workflow management. In addition, CAS was augmented by addition of a resource-management component. This third component enables CAS to manage heterogeneous computing by use of diverse resources, including high-performance clusters of computers, commodity computing hardware, and grid computing infrastructures. CAS is now more easily maintainable, evolvable, and reusable. These components can be used separately or, taking advantage of synergies, can be used together. Other elements of the transformation included addition of a separate Web presentation layer that supports distribution of data products via Really Simple Syndication (RSS) feeds, and provision for full Resource Description Framework (RDF) exports of metadata.
A catalog of galactic O-type stars, a machine-readable version of the bright star catalog, a two-micron sky survey, sky survey sources with problematical Durchmusterung identifications, data retrieval for visual binary stars, faint blue objects, the sixth catalog of galactic Wolf-Rayet stars, declination versus magnitude distribution, the SAO-HD-GC-DM cross index catalog, star cross-identification tables, astronomical sources, bibliographical star index search updates, DO-HD and HD-DO cross indices, and catalogs, are reviewed.
Clustering algorithms can identify groups in large data sets, such as star catalogs and hyperspectral images. In general, clustering methods cannot analyze items that have missing data values. Common solutions either fill in the missing values (imputation) or ignore the missing data (marginalization). Imputed values are treated as just as reliable as the truly observed data, but they are only as good as the assumptions used to create them. In contrast, we present a method for encoding partially observed features as a set of supplemental soft constraints and introduce the KSC algorithm, which incorporates constraints into the clustering process. In experiments on artificial data and data from the Sloan Digital Sky Survey, we show that soft constraints are an effective way to enable clustering with missing values.
Catalogs are developed to survey the mission possibilities for the short period comets. In the first the physical and pertinent orbital characteristics are given for 65 short period comets. The second catalog is one containing the predicted perihelia for each of the 65 comets between 1974 and 2010. Geometry is included to indicate feasibility of Earth-based observation and sighting within 100 days of perihelion. The comets are divided on the basis of size and activity into three groups from the data in the first catalog: primary, secondary and low interest. The perihelia are separated into two groups: satisfactory and not satisfactory on the basis of earth-comet distance.
The End-to-End System (EES) is a unique collection of software modules created for use at the Center for EUV Astrophysics. The 'pipeline' is a shell script which executes selected EES modules and creates initial data products: skymaps, data sets for individual sources (called 'pigeonholes') and catalogs of sources. This article emphasizes the data from the all-sky survey, conducted between July 22, 1992 and January 21, 1993. A description of each of the major data products will be given and, as an example of how the pipeline works, the reader will follow a photon's path through the software pipeline into a pigeonhole. These data products are the primary goal of the EUVE all-sky survey mission, and so their relative importance for the follow-up science will also be discussed.
Application of data from the Celescope Catalog of Ultraviolet Observations to various problems of stellar and interstellar astrophysics. These include refinements in the incorporation of line blanketing in theoretical stellar-atmosphere models, variations in the law of interstellar extinction from one region of the sky to another, and selection and identification of various types of peculiar stars for further investigation. In addition, the data were analyzed to determine the photometric and astrometric accuracy of the Celescope equipment.
Data obtained from 30 earth resources aircraft missions, flown between September 1, 1973 and September 1, 1974, were screened, cataloged, and indexed using microfilm copy. The manhours required for completing the task are presented, and problems encountered during the project are reported. It is concluded that a cataloging and indexing report of remote sensor data can be prepared on a timely basis for a relatively low cost from microfilm. Recommendations are given in order to further facilitate the task.
From an analysis of the first catalog of the Burst and Transient Source Experiment (BATSE) experiment (Fishman et al. 1993, 1994a) on the Compton Gamma Ray Observatory (CGRO), we find an excessive number of pairs of gamma-ray bursts which are clustered in both a space and time . The angular separation between the two bursts in each pair is less than their positional uncertainties, and the interval between their occurrence times is within several days. Optimizing the signal, we find that the probability of observing such a clustered excess froma Poisson ensemble is approximately 2 x 10(exp -5). We suggest that these bursts arise from repeating sources. A detailed study of the most prolific source, GBS 0855-00, is presented in a separate paper (Wang & Lingenfelter 1993a, b). Unlike most of the 'soft' gamma-ray repeaters, these repeating bursts have relatively hard spectra, complex light curves, and widely varying durations, that are indistinguishable from classical gamma-ray bursts. Although the significance of the clustered excess was optimized a posteriori, because it depends on temporal and spatial bin sized that could not be defined a priori, we can use the optimizations from the first catalog to test subsequent BATSE data sets. Unfortunately, the failure of the on-board tape recorders during the second catalog period seriously reduced the number of accurately positioned bursts (Fishman et al. 1994b), so that we can neither confirm, nor refute, the predicted repitition in that sample, and we must await the results of the third catalog.
About 4000 X-ray images obtained with the Einstein Observatory are used to measure the 0.16-4.0 keV emission from 1545 B-type SAO stars falling in the about 10 percent of the sky surveyed with the IPC. Seventy-four detected X-ray sources with B-type stars are identified, and it is estimated that no more than 15 can be misidentified. Upper limits to the X-ray emission of the remaining stars are presented. In addition to summarizing the X-ray measurements and giving other relevant optical data, the present extensive catalog discusses the reduction process and analyzes selection effects associated with both SAO catalog completeness and IPC target selection procedures. It is concluded that X-ray emission, at the level of Lx not less than 10 exp 30 ergs/s, is quite common in B stars of early spectral types (B0-B3), regardless of luminosity class, but that emission, at the same level, becomes less common, or nonexistent, in later B-type stars.
Leaf angle distribution (LAD) in forest canopies affects estimates of leaf area, light interception, and global-scale photosynthesis, but is often simplified to a single theoretical value. Here, we present TLSLeAF (Terrestrial Laser Scanning Leaf Angle Function), an automated open-source method of deriving LADs from terrestrial laser scanning. TLSLeAF produces canopy-scale leaf angle and LADs by relying on gridded laser scanning data. The approach increases processing speed, improves angle estimates, and requires minimal user input. Key features are automation, leaf–wood classification, beta parameter output, and implementation in R to increase accessibility for the ecology community. TLSLeAF precisely estimates leaf angle with minimal distance effects on angular estimates while rapidly producing LADs on a consumer-grade machine. We challenge the popular spherical LAD assumption, showing sensitivity to ecosystem type in plant area index and foliage profile estimates that translate to c. 25% and c. 11% increases in canopy net photosynthesis (c. 25%) and solar-induced chlorophyll fluorescence (c. 11%). TLSLeAF can now be applied to the vast catalog of laser scanning data already available from ecosystems around the globe. The ease of use will enable widespread adoption of the method outside of remote-sensing experts, allowing greater accessibility for addressing ecological hypotheses and large-scale ecosystem modeling efforts.