Army-NASA aircrew/aircraft integration program (A3I) software detailed design document, phase 3

The capabilities and design approach of the MIDAS (Man-machine Integration Design and Analysis System) computer-aided engineering (CAE) workstation under development by the Army-NASA Aircrew/Aircraft Integration Program is detailed. This workstation uses graphic, symbolic, and numeric prototyping tools and human performance models as part of an integrated design/analysis environment for crewstation human engineering. Developed incrementally, the requirements and design for Phase 3 (Dec. 1987 to Jun. 1989) are described. Software tools/models developed or significantly modified during this phase included: an interactive 3-D graphic cockpit design editor; multiple-perspective graphic views to observe simulation scenarios; symbolic methods to model the mission decomposition, equipment functions, pilot tasking and loading, as well as control the simulation; a 3-D dynamic anthropometric model; an intermachine communications package; and a training assessment component. These components were successfully used during Phase 3 to demonstrate the complex interactions and human engineering findings involved with a proposed cockpit communications design change in a simulated AH-64A Apache helicopter/mission that maps to empirical data from a similar study and AH-1 Cobra flight test

Analysis and preliminary design of optical sensors for propulsion control

A fiber-optic sensor concept screening study was performed. Twenty sensor subsystems were identified and evaluated. Two concepts selected for further study were the Fabry-Perot fiber-optic temperature sensor and the pulse-width-modulated phosphorescent temperature sensor. Various designs suitable for a Fabry-Perot temperature sensor to be used as a remote fiber-optic transducer were investigated. As a result, a particular design was selected and constructed. Tests on this device show that spectral peaks are produced from visible white light, and the change in wavelength of the spectral peaks produced by a change in temperature is consistent with theory and is 36 nm/C for the first order peak. A literature search to determine a suitable phosphor for implementing the pulse-width-modulated fiber optic temperature sensor was conducted. This search indicated that such a device could be made to function for temperatures up to approximately 200 C. Materials like ZnCdS and ZnSe activated with copper will be particularly applicable to temperature sensing in the cryogenic to room temperature region. While this sensing concept is probably not applicable to jet engines, the simplicity and potential reliability make the concept highly desirable for other applications

Designing a training tool for imaging mental models

The training process can be conceptualized as the student acquiring an evolutionary sequence of classification-problem solving mental models. For example a physician learns (1) classification systems for patient symptoms, diagnostic procedures, diseases, and therapeutic interventions and (2) interrelationships among these classifications (e.g., how to use diagnostic procedures to collect data about a patient's symptoms in order to identify the disease so that therapeutic measures can be taken. This project developed functional specifications for a computer-based tool, Mental Link, that allows the evaluative imaging of such mental models. The fundamental design approach underlying this representational medium is traversal of virtual cognition space. Typically intangible cognitive entities and links among them are visible as a three-dimensional web that represents a knowledge structure. The tool has a high degree of flexibility and customizability to allow extension to other types of uses, such a front-end to an intelligent tutoring system, knowledge base, hypermedia system, or semantic network

High Redshift Supernovae in the Hubble Deep Field

Two supernovae detected in the Hubble Deep Field using the original December 1995 epoch and data from a shorter (63000 s in F814W) December 1997 visit with HST are discussed. The supernovae (SNe) are both associated with distinct galaxies at redshifts of 0.95 (spectroscopic) from Cohen etal. (1996) and 1.32 (photometric) from the work of Fernandez-Soto, Lanzetta, and Yahil (1998). These redshifts are near, in the case of 0.95, and well beyond for 1.32 the greatest distance reported previously for SNe. We show that our observations are sensitive to SNe to z < 1.8 in either epoch for an event near peak brightness. Detailed simulations are discussed that quantify the level at which false events from our search phase would start to to arise, and the completeness of our search as a function of both SN brightness and host galaxy redshift. The number of Type Ia and Type II SNe expected as a function of redshift in the two HDF epochs are discussed in relation to several published predictions and our own detailed calculations. A mean detection frequency of one SN per epoch for the small HDF area is consistent with expectations from current theory.Comment: 62 pages, 17 figures, ApJ 1999 in pres

Real -time Retinex image enhancement: Algorithm and architecture optimizations

The field of digital image processing encompasses the study of algorithms applied to two-dimensional digital images, such as photographs, or three-dimensional signals, such as digital video. Digital image processing algorithms are generally divided into several distinct branches including image analysis, synthesis, segmentation, compression, restoration, and enhancement. One particular image enhancement algorithm that is rapidly gaining widespread acceptance as a near optimal solution for providing good visual representations of scenes is the Retinex.;The Retinex algorithm performs a non-linear transform that improves the brightness, contrast and sharpness of an image. It simultaneously provides dynamic range compression, color constancy, and color rendition. It has been successfully applied to still imagery---captured from a wide variety of sources including medical radiometry, forensic investigations, and consumer photography. Many potential users require a real-time implementation of the algorithm. However, prior to this research effort, no real-time version of the algorithm had ever been achieved.;In this dissertation, we research and provide solutions to the issues associated with performing real-time Retinex image enhancement. We design, develop, test, and evaluate the algorithm and architecture optimizations that we developed to enable the implementation of the real-time Retinex specifically targeting specialized, embedded digital signal processors (DSPs). This includes optimization and mapping of the algorithm to different DSPs, and configuration of these architectures to support real-time processing.;First, we developed and implemented the single-scale monochrome Retinex on a Texas Instruments TMS320C6711 floating-point DSP and attained 21 frames per second (fps) performance. This design was then transferred to the faster TMS320C6713 floating-point DSP and ran at 28 fps. Then we modified our design for the fixed-point TMS320DM642 DSP and achieved an execution rate of 70 fps. Finally, we migrated this design to the fixed-point TMS320C6416 DSP. After making several additional optimizations and exploiting the enhanced architecture of the TMS320C6416, we achieved 108 fps and 20 fps performance for the single-scale, monochrome Retinex and three-scale, color Retinex, respectively. We also applied a version of our real-time Retinex in an Enhanced Vision System. This provides a general basis for using the algorithm in other applications

Detergency and its implications for oil emulsion sieving and separation

Separating petroleum hydrocarbons from water is an important problem to address in order to mitigate the disastrous effects of hydrocarbons on aquatic ecosystems. A rational approach to address the problem of marine oil water separation is to disperse the oil with the aid of surfactants in order to minimize the formation of large slicks at the water surface and to maximize the oil-water interfacial area. Here we investigate the fundamental wetting and transport behavior of such surfactant-stabilized droplets and the flow conditions necessary to perform sieving and separation of these stabilized emulsions. We show that, for water soluble surfactants, such droplets are completely repelled by a range of materials (intrinsically underwater superoleophobic) due to the detergency effect; therefore, there is no need for surface micro/nanotexturing or chemical treatment to repel the oil and prevent fouling of the filter. We then simulate and experimentally investigate the effect of emulsion flow rate on the transport and impact behavior of such droplets on rigid meshes to identify the minimum pore opening (w) necessary to filter a droplet with a given diameter (d) in order to minimize the pressure drop across the mesh and therefore maximize the filtering efficiency, which is strongly dependent on w. We define a range of flow conditions and droplet sizes where minimum droplet deformation is to be expected and therefore find that the condition of is sufficient for efficient separation. With this new understanding, we demonstrate the use of a commercially available filter--without any additional surface engineering or functionalization--to separate oil droplets from a surfactant stabilized emulsion with a flux of 11,000 L m$^{-2}$ hr$^{-1}$ bar$^{-1}$. We believe these findings can inform the design of future oil separation materials

New technologies for urban designers: the VENUE project

In this report, we first outline the basic idea of VENUE. This involves developing digital tools froma foundation of geographic information systems (GIS) software which we then apply to urbandesign, a subject area and profession which has little tradition in using such tools. Our project wasto develop two types of tool, namely functional analysis based on embedding models of movementin local environments into GIS based on ideas from the field of space syntax; and secondlyfashioning these ideas in a wider digital context in which the entire range of GIS technologies werebrought to bear at the local scale. By local scale, we mean the representation of urban environmentsfrom about 1: 500 to around 1: 2500