A theory of human error

Human errors tend to be treated in terms of clinical and anecdotal descriptions, from which remedial measures are difficult to derive. Correction of the sources of human error requires an attempt to reconstruct underlying and contributing causes of error from the circumstantial causes cited in official investigative reports. A comprehensive analytical theory of the cause-effect relationships governing propagation of human error is indispensable to a reconstruction of the underlying and contributing causes. A validated analytical theory of the input-output behavior of human operators involving manual control, communication, supervisory, and monitoring tasks which are relevant to aviation, maritime, automotive, and process control operations is highlighted. This theory of behavior, both appropriate and inappropriate, provides an insightful basis for investigating, classifying, and quantifying the needed cause-effect relationships governing propagation of human error

Diagnostics of seeded RF plasmas: An experimental study related to the gaseous core reactor

Measurements of the temperature profiles in an RF argon plasma were made over magnetic field intensities ranging from 20 amp turns/cm to 80 amp turns/cm. The results were compared with a one-dimensional numerical treatment of the governing equations and with an approximate closed form analytical solution that neglected radiation losses. The average measured temperatures in the plasma compared well with the numerical treatment, though the experimental profile showed less of an off center temperature peak than predicted by theory. This may be a result of the complex turbulent flow pattern present in the experimental torch and not modeled in the numerical treatment. The radiation term cannot be neglected for argon at the power levels investigated. The closed form analytical approximation that neglected radiation led to temperature predictions on the order of 1000 K to 2000 K higher than measured or predicted by the numerical treatment which considered radiation losses

Measurements of the extinction parameters of hot seeded hydrogen at high pressures

Measurement of extinction parameter of tungsten-hydrogen aerosols as function of wavelength at high pressures and temperature

Theoretical calculations of radiant heat transfer properties of particle-seeded gases

Radiant heat transfer properties of particle seeded gases, including absorption and scattering characteristics of carbon, silicon, and tungste

Soft singularity and the fundamental length

It is shown that some regular solutions in 5D Kaluza-Klein gravity may have interesting properties if one from the parameters is in the Planck region. In this case the Kretschman metric invariant runs up to a maximal reachable value in nature, i.e. practically the metric becomes singular. This observation allows us to suppose that in this situation the problems with such soft singularity will be much easier resolved in the future quantum gravity then by the situation with the ordinary hard singularity (Reissner-Nordstr\"om singularity, for example). It is supposed that the analogous consideration can be applied for the avoiding the hard singularities connected with the gauge charges.Comment: 5 page

Technical approaches for measurement of human errors

Human error is a significant contributing factor in a very high proportion of civil transport, general aviation, and rotorcraft accidents. The technical details of a variety of proven approaches for the measurement of human errors in the context of the national airspace system are presented. Unobtrusive measurements suitable for cockpit operations and procedures in part of full mission simulation are emphasized. Procedure, system performance, and human operator centered measurements are discussed as they apply to the manual control, communication, supervisory, and monitoring tasks which are relevant to aviation operations

Analysis of pilot control strategy

Methods for nonintrusive identification of pilot control strategy and task execution dynamics are presented along with examples based on flight data. The specific analysis technique is Nonintrusive Parameter Identification Procedure (NIPIP), which is described in a companion user's guide (NASA CR-170398). Quantification of pilot control strategy and task execution dynamics is discussed in general terms followed by a more detailed description of how NIPIP can be applied. The examples are based on flight data obtained from the NASA F-8 digital fly by wire airplane. These examples involve various piloting tasks and control axes as well as a demonstration of how the dynamics of the aircraft itself are identified using NIPIP. Application of NIPIP to the AFTI/F-16 flight test program is discussed. Recommendations are made for flight test applications in general and refinement of NIPIP to include interactive computer graphics

Mission-oriented requirements for updating MIL-H-8501. Volume 2: STI background and rationale

A supplement to the structure of a new flying and ground handling qualities specification for military rotorcraft structure is presented in order to explain the background and rationale for the specification structure, the proposed forms of criteria, and the status of the existing data base. Critical gaps in the data base for the new structure are defined, and recommendations are provided for the research required to address the most important of these gaps

A CubeSat for Calibrating Ground-Based and Sub-Orbital Millimeter-Wave Polarimeters (CalSat)

We describe a low-cost, open-access, CubeSat-based calibration instrument that is designed to support ground-based and sub-orbital experiments searching for various polarization signals in the cosmic microwave background (CMB). All modern CMB polarization experiments require a robust calibration program that will allow the effects of instrument-induced signals to be mitigated during data analysis. A bright, compact, and linearly polarized astrophysical source with polarization properties known to adequate precision does not exist. Therefore, we designed a space-based millimeter-wave calibration instrument, called CalSat, to serve as an open-access calibrator, and this paper describes the results of our design study. The calibration source on board CalSat is composed of five "tones" with one each at 47.1, 80.0, 140, 249 and 309 GHz. The five tones we chose are well matched to (i) the observation windows in the atmospheric transmittance spectra, (ii) the spectral bands commonly used in polarimeters by the CMB community, and (iii) The Amateur Satellite Service bands in the Table of Frequency Allocations used by the Federal Communications Commission. CalSat would be placed in a polar orbit allowing visibility from observatories in the Northern Hemisphere, such as Mauna Kea in Hawaii and Summit Station in Greenland, and the Southern Hemisphere, such as the Atacama Desert in Chile and the South Pole. CalSat also would be observable by balloon-borne instruments launched from a range of locations around the world. This global visibility makes CalSat the only source that can be observed by all terrestrial and sub-orbital observatories, thereby providing a universal standard that permits comparison between experiments using appreciably different measurement approaches

Use of ocean colour remote sensing to monitor sea surface suspended sediments

Ocean colour remote sensing (OCRS) from satellite platforms has revolutionised our ability to monitor the interplay of physical and biogeochemical processes in surface waters of the ocean. Since the launch of SeaWiFS in 1996, a continuous time series of OCRS data has been accumulated from a series of satellite sensors giving near daily global coverage. These sensors measure top of atmosphere (TOA) spectral radiance which is corrected for atmospheric effects (~80% of the measured signal in the blue - Gordon 1978) to give water leaving radiances. From these putrely optical signals, it is possible to derive a wide range of higher level products such as chlorophyll concentration, diffuse attenuation coefficients, photosynthetically available radiation (PAR) and a wide range of inherent optical properties (IOPs) to name but a few. In terms of surface area and primary productivity, the global ocean is heavily dominated by deep, oceanic waters, where the optical properties are driven by phytoplankton, associated dissolved organics and water itself. It is little surprise then that early standard OCRS products were developed for optimal performance over these globally significant regions. Standard chlorophyll algorithms were developed using changes in blue-green reflectance ratios (e.g. O’Reilley et al., 1998) that can be related to the effect of changing concentrations of microscopic scale (1µm-200µm) phytoplankton (Kirk,1983) forming blooms that can stretch for thousands of km. More recently, attention has shifted to economically important coastal regions where, for example, harmful algal blooms have potential to cause significant societal and economic impact. OCRS algorithms have been developed to specifically aid in the monitoring of both toxic species e.g. Karenia brevis in the Gulf of Mexico (Stumpf et al., 2003), and also to monitor for extreme eutrophication events where excessive levels of phytoplankton cause the reduction of oxygen dissolved in the water column (hypoxia) leading to animal mortality (e.g. Mallin et al., 2006). The optically complex nature of coastal waters, more generally, presents a particular problem for OCRS applications in these regions. Shallow shelf seas and other inshore waters are subject to the influence of sediment resuspension and freshwater discharge bringing additional loads of coloured dissolved organic materials (CDOM). This results in multiple, independently varying, optically significant components, each of which influences the water leaving radiance spectrum making interpretation of spectral changes significantly more difficult. Many studies have demonstrated the breakdown in performance of standard algorithms (e.g. Chl, McKee et al. 2007) in optically complex coastal waters. In this paper we will focus on the effect of suspended sediment on optical properties of the water column. Suspended sediment has long been known to influence light penetration (Gordon and McCluney, 1975) which can limit primary production and also contribute to hypoxia (Greig et al., 2005). There is interest in monitoring sediment concentration for coastal erosion applications and various OCRS algorithms have been developed that exploit the relatively strong backscattering properties of sediment. For example, Doxaran et al. (2002) successfully presented a sediment algorithm for the highly turbid Gironde estuary. More recently a radiative transfer approach was used to refine this type of approach to incorporate the potential impact of other materials on the red reflectance values that support sediment algorithms (Neil et al., 2011). This algorithm provides estimates of maximum and minimum sediment load concentrations assuming reasonable potential ranges of Chl and CDOM for coastal waters. The aim of this paper is to determine the extent to which the Neil et al. algorithm, which was developed for Irish Sea waters, can be applied to data collected in the North Sea. The ultimate goal is to assess the potential for using OCRS data to monitor suspended sediment concentrations in coastal waters, with monitoring marine turbine arrays an obvious and potentially important application